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The effects of dietary and other lifestyle behaviors on the risk of colorectal cancer among the Mexican -origin Latino population
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The effects of dietary and other lifestyle behaviors on the risk of colorectal cancer among the Mexican -origin Latino population
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INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMj films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction js dependent upon the quality Pf the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough. substandard margins, and improper alignment can adversely affect reproduction. in the unlikely event that the author did not send UM I a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note w ifi indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Photographs included in the original manuscript have been reproduced xerographicaliy in this copy. Higher quality 6- x 9" black and white photographic prints are available for any photographs or illustrations appearing |n this copy for an additional charge. Contact UM I directly to order. ProQuest Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. THE EFFECTS OF DIETARY AND OTHER LIFESTYLE BEHAVIORS ON THE RISK OF COLORECTAL CANCER AMONG THE MEXICAN-ORIGIN LATINO POPULATION by Kristine Robinson Monroe A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (EPIDEMIOLOGY) August 2001 Copyright 2001 Kristine Robinson Monroe R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 3054784 Copyright 2001 by Monroe, Kristine Bobinson All rights reserved. _ ___ _( D UMI UMI Microform 3054784 Copyright 2002 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48108-1346 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. UNIVERSITY OF SOUTHERN CALIFORNIA THE GRADUATE SCHOOL UNIVERSITY PARK LOS ANGELES, CALIFORNIA 90007 This dissertation, written by K r is tin e R obinson Monroe under the direction of h&x.. Dissertation Committee, and approved by all its members* has been presented to and accepted by The Graduate School, in partial fulfillment of re quirements for die degree of DOCTOR OF PHILOSOPHY Date..... DISSERTATION COMMITTEE R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Kristine Robinson Monroe Brian E. Henderson, M.D. ABSTRACT THE EFFECTS OF DIETARY AND OTHER LIFESTYLE BEHAVIORS ON THE RISK OF COLORECTAL CANCER AMONG THE MEXICAN-ORIGIN LATINO POPULATION The focus of this research was to examine the changes in dietary and other lifestyle behaviors (alcohol consumption, obesity, and physical activity) that are consistent with the changing rate of colorectal cancer incidence in the Mexican origin Latino population following migration to the United States. First, migrant studies have shown that colorectal cancer incidence is particularly sensitive to changes in environmental factors following migration. Second, colorectal cancer incidence rates within our prospective cohort show that US-bom Mexican Americans have rates that are two or more times that of Mexico-born immigrants. As a necessary foundation for the nutritional analysis of the Hawaii and Los Angeles Multiethnic Cohort Study of Diet and Cancer, Part I of this dissertation reviews the literature in five areas: (A) previous studies of cancer in migrant populations; (B) historical migration patterns of the Mexican-origin population into the southwestern United States; (C) dietary patterns in Mexico by regions of major emigration; (D) dietary changes among Mexican Americans following migration; and (E) comparison of dietary behaviors of Mexican American subjects with reported dietary behaviors of non-Latino whites in relation to colorectal cancer risks. 1 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. A preliminary nested case-control study was conducted among US-born Mexican Americans and Mexico-born immigrants to California to examine the association of colorectal cancer with nutrient intake. We used incident colorectal cancer cases that have occurred from cohort inception in 1993 to June 30, 1998, a date which we are confident we have complete case ascertainment. We used conditional logistic regression to estimate odds ratios, adjusted for calorie intake and other covariates. We found a strong, dose-dependent, inverse association with all measures of fiber intake. An elevated risk of colorectal cancer was associated with sedentary inactivity and dietary cholesterol intake. Part III describes an approach to validate the measure of fiber intake from our food frequency questionnaire with a relevant biochemical marker, investigate the role of dietary fiber in estrogen metabolism, and provide the groundwork for the characterization of gene-environment interactions in future breast and colorectal cancer research. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGEMENTS There are times in life when we find ourselves in a situation for which we cannot believe our good fortune. My graduate education at USC was such a time. While die journey has been a long one, I have cherished the opportunity to work with and learn from some of the most knowledgeable and highly respected scientists in the country. I thank the members of my dissertation committee, Drs. Brian Henderson, Malcolm Pike, Jean Hankin, Daniel Stram, and Gerhard Coetzee, for their support, encouragement, and for die contribution that each has made to make this dissertation a better body of work. They shared with me their enthusiasm, scientific curiosity, and most importantly for a student, their valuable time. My education was viewed as a daily teaching/learning experience for which my mentor, Dr. Henderson, took personal responsibility. He encouraged me to seek a doctoral degree and later challenged me to do my best work. I learned from him that sharing ideas and working together with as many colleagues as possible produces profound results for which there is no equal for the advancement of scientific knowledge. Dr. Pike taught me the importance of haying a good question . .. and that answers are not always to be believed. He challenged me to think, to be disciplined, and to defend my ideas. I have great admiration for both of these men and feel privileged to have studied under their guidance. Their influence will undoubtedly stay with me forever. I wish to thank Dr. Stanley Azen for “recruiting” me into the Biometry program, providing the research assistantships that made graduate education at USC possible, and for many years of valuable counsel. Thank you to Dr. Leslie Bernstein for her early guidance and encouragement, and for just being a valued friend. Thank you to my parents, Ted and Bobbi Robinson, for instilling in me that there is no limit to what I could accomplish with desire and perseverance. Finally, to my husband David and ray sons Tyler, Patrick, and Luke, thank you for caring, for encouraging, for “pressuring” [in a good sense}, and for enduring. I am proud and grateful that we made this journey together and, therefore, I dedicate this dissertation to you. ii R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ACKNOWLEDGEMENTS...................................................................................................................ii LIST OF TABLES............................................................................................................................... vi LIST OF FIGURES...............................................................................................................................ix INTRODUCTION................................................................................................................................. 1 PARTI. LITERATURE REVIEW...................................................................................................... 8 A. PREVIOUS STUDIES OF GANGER 04 MIGRANT POPULATIONS........................ 12 B. HISTORICAL MIGRATION PATTERNS OF MEXICANS TO THE U.S...................16 C. DIET PATTERNS IN MEXICO BY REGION OF MAJOR EMIGRATION............... 20 D. DIETARY CHANGES AMONG MEXICANS FOLLOWING MIGRATION.............29 E. COMPARISON OF MEXICAN AND NON-LATINO WHITE BEHAVIORS............ 39 Dietary Fiber ...........................................................................................................48 Carotenes................ 54 Saturated Fat............................................... 56 Red Meat........................................................................................................... 62 Calcium....................................................................................................................64 Cholesterol/Eggs......................................................................................................68 Physical Activity...................................................................................................... 72 Body Mass...............................................................................................................73 Alcohol.................... 75 PART II. DATA ANALYSIS............................................................................................................79 A. MIGRANT STUDY.........................................................................................................81 METHODS............................... 81 Selection of Subjects................................................................................................ 81 Assessment of Diet Using a Food Frequency Questionnaire................................... 83 Development of the Food Composition Table......................................................... 86 Assessment of the Equivalency of the Spanish and English Questionnaires........... 88 Assessment of Core Diet ............. 91 Assessment of Other Lifestyle Factors..................................................................... 92 Assessment of Physical Energy Expenditure........................................................... 93 Data Analysis...........................................................................................................95 RESULTS................................................................................. ................................. 97 Descriptive Statistics................................................................................................97 Association of Calorie Intake, Weight, Vigorous Work, and RMR........................103 Core Diet.............................. 106 Nutrient Intake........................................................................................................116 DISCUSSION ................................................................................................... 126 Dietary Fiber.......................................................................................................... 127 Total Eat................................................................................................................. 127 Saturated Fat.......................................................................................................... 128 Calcium....................... 128 Cholesterol....................................................................... 129 Body Mass............................................................................................................. 130 Relationship of Calorie Intake, Weight, Physical Activity, and RMR.....................131 B. NESTED CASE-CONTROL ANALYSIS OF COLORECTAL CANCER.................... 132 METHODS........................................................................................................ 132 Selection of Subjects...............................................................................................132 Data Analysis .....................................................................................................133 iii R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. RESULTS...................................................................................................................134 DISCUSSION.............................................................................................................144 Dietary Fiber ....................................................................................144 Vegetables.................................................. 157 Beta-carotene..........................................................................................................158 Vitamin C................................................................................................................159 Dietary Fat..............................................................................................................159 Saturated or Animal Fat..........................................................................................160 Red Meat.................................................................................................................161 Protein................................................................................................................... 162 Legumes............................................................................................. 163 Dietary Cholesterol and Eggs.................................................................................163 Calcium........................... 7 .7 ....................................................................................164 Methods of Cooking Meat......................................................................................165 Diabetes..................................................................................................................165 Alcohol....................................................................................................................166 Physical Activity/Inactivity........ ..........................................................167 Methodology................... .......................................... ........................................... 168 CONCLUSION...........................................................................................................171 PART III. GRANT PROPOSAL.....................................................................................................175 OVERVIEW AND SPECIFIC AIMS .........................................................................175 BACKGROUND AND SIGNIFICANCE........................................................ ......177 A. Racial/Ethnic Variation, Endogenous Estrogen Levels, and Breast Cancer Etiology 177 B. Dietary Factors and Endogenous Estrogen Levels ......................................................... 179 G. Mexican-Origin Latinos: Dietary Fiber and Breast Cancer Risk 180 D. The Influence of Dietary Fiber on Estrogen Metabolism............................................... 181 E. Dietary Fiber and Breast Cancer Risk....7....................................................................... 183 PRELIMINARY STUDIES............................................ 185 A. Incident Breast Cancer Among Postmenopausal Women in the Multiethnic Cohort 185 B. Significant Differences in Intake Patterns Between Latino Subgroups..........................185 G. Range of Dietary Fiber Exposure in Mexican-Americans............................................. 187 RESEARCH DESIGN AND METHODS................................................... 188 A. Dietary and Hormonal Biomarkers of Interest............................................................... 188 B. Description of die Multiethnic Cohort........................................................................... 191 C. Selection of Subjects...................................................................................................... 192 D. Assessment ofDietary Fiber Intake Using a Food Frequency Questionnaire................194 E. Development of the Food Composition Table............................................................... 195 F. Collection, Processing and Storage of Blood Specimens from the Sub-cohort..............196 G. Determination of Biochemical Markers of Fiber Intake................................... 197 H. Assays of Serum Hormones........................................................................................... 197 I. Assays of Urinary Metabolites....................................................................................... 19? J. Sample Size and Data Analysis......................................................................................199 REFERENCES.................................................................................................................................. 204 APPENDICES A. Nutrition Monitoring in the United States..................................................................... 226 B. Immigration of Latinos Originating from Central and South America......................... 232 Food Consumption in Other Central and South American Countries....................234 Food Consumption in Cuba and Other Caribbean Island Countries......................238 C. Basal Metabolism, Calorie Intake, andPhysical Activity............................................ 240 iv R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. D. Components of Dietary Fiber.......................................................................................242 E. Comparison of Language Version of the Questionnaire ..........................................244 F. Calibration Equation Estimates............... 247 G. Core Diet of Mexico-born Subjects..............................................................................249 H. Core Diet of US-born Subjects......................................................................................251 I. Percentage of Subjects Reporting Intake of Core Foods.............................................. 253 J. Percent Contribution of Core Foods to Specific Nutrients...........................................255 v R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. LIST OF TABLES 1. Studies that examined dietary changes following migration to the US among Mexican Americans.....................................................................................................~ 30 2. Mean dietary intake of selected nutrients by generation status for Mexican American women compared to American non-Latino white women............................... 32 3. Percent of subjects reporting intake of traditional and non-traditional Mexican foods by generation status for low income Mexican American women.......................................... 34 4. Mean food frequency scores for Mexican women by length of United States residence 36 5. Means and 95% confidence intervals of dietary measures among Low-acculturated Latino, High-acculturated Latino, and Anglo respondents in San Diego, California, 1989.................................................... “...;................................................... . 3 8 6. Studies that used federal nutrition survey data to examine dietary factors among the U.S. Mexican population...................................................................................................... 43 7. Studies that examined dietary factors among Mexicans residing in different regions of the United States ~ ...................................................._ .........„ 7 . 77.7 7.7 7 7 . 7 7 45 8. Mean dietary intake of total fiber among males and females by ethnicity, 50 9. Mean dietary intake of carotene in retinal equivalents (RE) among males and females 55 10. Mean dietary intake and percentage of energy from total fat among males and females.......57 11. Mean dietary intake and percentage of energy derived from saturated fat among males and females................... ;............ ;.............. 59 12. Mean dietary intake of calcium among males and females.....................................................65 13. Mean dietary intake of cholesterol among males and females............................................... 69 14. Age-adjusted incidence rates of colorectal cancer in the Mexican origin Latino cohort by migration status............................................................................ 80 15. Characteristics of the Los Angeles Mexican Origin Population.............................................98 16. Correlation matrix for daily vigorous work, sedentary hours, weight, height and body mass................................. „ . . . . . 7. . 7 .7.777.7.7............... 107 17. Ratio of resting metabolic rate to FFQ total calories by level of daily vigorous work.........108 18. Age-standardized mean gram intake (absolute amount) of food groups of the Mexican origin cohort................ ....................................................................................................... 112 19. Age-standardized mean gram intake (calorie adjusted) of food groups of the Mexican origin cohort................ “................................. ......... ............. ................................ 114 vi R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. 20. Age-standardized mean absolute nutrient intake of the Los Angeles Mexican origin cohort .. . ....................................................................................................................117 21. Age-standardized mean nutrient density intake of the Los Angeles Mexican origin cohort....................................... 118 22. Corrected (with age & bmi) mean nutrient intake of the Los Angeles Mexican origin cohort.........................................................................................................................120 23. Mean nutrient intake calculated from two 24hour recalls (Mexican origin calibration study subjects).................................................................. 121 24. Age-standardized mean gram intake (calorie adjusted) ofNSP of the Mexican origin cohort..................................................................................................................... 123 25. Age-standardized mean ethanol intake of the Los Angeles Mexican origin cohort.............. 124 26. Age-standardized mean daily sedentary or vigorous work hours of die Los Angeles Mexican origin cohort ............. 7. .................................................. 125 27. Demographic characteristics by gender and case-control status............................................135 28. Odds ratios and p values for demographic risk factors..........................................................136 29. Odds ratios and 95% confidence intervals for colorectal cancer by quartile of nutrient intake............................................................................................ 138 30. Odds ratios and 95% confidence intervals for colorectal cancer by quartile of dietary fiber intake........................................................................................................................... 139 31. Odds ratios and 95% confidence intervals for colorectal cancer by quartile of dietary fat intake..................................................................... 140 32. Odds ratios and 95% confidence intervals for colorectal cancer by quartile of various food intake..................................................................................... 142 33. Odds ratios and p values for methods of cooking meat.........................................................143 34. Sedentary hours by gender.....................................................................................................145 35. Stepwise logistic regression analysis..................................................................................... 146 36. Results of multivariate analysis.............................................................................................147 37. Percentage of total dietary fiber intake attributed to a particular food source....................... 151 38. Colorectal cancer odds ratios by dietary fiber intake as reported on a questionnaire for seven studies........................... 15? 39. Colorectal cancer odds ratios by insoluble fiber intake..........................................................155 40. Incident breast cancer cases in the multiethnic cohort...........................................................185 vii R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. 41. Daily mean intake of traditional Mexican foods and selected nutrients by Latino subgroup,.......................... ............................................................................................186 42. Median intake of certain nutrients and foods by category ofNSP intake..............................187 43. Distribution of the Latina cohort by age and birthplace, Los Angeles...................................192 44. Sample selection....................................................................................................................193 viii R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURES Figure 1: Food, Nutrition and Colorectal Cancer..................................................................................9 Figure 2; Mexican Migration to the United States.............................................................................. 18 Figure 3: Mexican Migration to the United States.............................................................................. 19 Figure 4: Diet of Rural Mexico............................................................................................................24 Figure 5: Diet of Urban Mexico.......................................................................................................... 26 Figure 6: Age Standardized Mean Calorie Intake by Category of Work and Weight (Males).......... 104 Figure 7: Age Standardized Mean Calorie Intake by Category of Work and Weight (Females)...... 105 ix R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. INTRODUCTION The dissertation, in fulfillment of the requirements for die Ph.D. degree in the Department of Preventive Medicine at the University of Southern California, is comprised of three components: (1) a review paper on an area of epidemiological research; (2) an independent and complete data analysis on data arising from an on-going epidemiological study; (3) a grant application to carry out a new epidemiological study. Described below are the specific aims and the rationale for each component of this dissertation. The primary focus of this research will be to examine the changes in dietary and other lifestyle behaviors (alcohol consumption, obesity, and physical activity) that are consistent with the changing rate of colorectal cancer incidence in the Mexican origin Latino1 population following migration to the United States. This topic was selected for two important reasons. First, migrant studies, along with rapidly changing incidence data from Italy, Japan, and Polynesians in Hawaii, haye shown that colorectal cancer incidence is particularly sensitive to changes in environmental factors following migration (Kolonel et ah, 1986; World Cancer Research Fund, 1997; Le Marchand et al., 1997). Second, preliminary colorectal cancer incidence rates within our Multiethnic Cohort show a dramatically divergent pattern of disease between US-bom Mexican Americans and Mexico- born immigrants. US-bom Mexican Americans have colorectal cancer incidence rates that are two or more times that of Mexico-born immigrants. 'The generic term ‘Latino’ derived from ‘Latin American’ is the term that best preserves both the national origin and political US-Latin American relationship established in 1823 when President James Monroe declared that the entire Western Hemisphere was in the US sphere of influence and the principle of non-intervention by European powers applied to all independent nations in the Americas (Monroe Doctrine) (Hayes-Bautista and Chapa, 1987). It is a term that is racially neutral and, importantly, it is a term that most people of Latin American origin find least objectionable. When the Los Angeles Times began investigative reporting among this population in Southern California, the staff learned that most individuals vigorously rejected the term ‘Hispanic’ and believed ‘Latino’ to be a more appropriate and acceptable self-description that expressed their desire to maintain a sense of national origin while expressing a link between them. The term ‘Latino’ in this paper thus refers to persons whose nationality or heritage is a Latin American country in the Western Hemisphere. 1 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. As a necessary foundation for the nutritional analysis of the Hawaii and Los Angeles Multiethnic Cohort Study o f Diet and Cancer, hereinafter, ‘Multiethnic Cohort Study’ (MEG), Part I of this dissertation reviews the literature in five areas: (A) previous studies of cancer in migrant populations; (B) historical migration patterns of the Mexican-origin population into die southwestern United States; (C) dietary patterns in Mexico by regions of major emigration; (D) dietary changes among Mexican Americans following migration; and (E) comparison of dietary behaviors of Mexican American2 subjects with reported dietary behaviors of non-Latino white Americans in relation to known colorectal cancer risks. Changes in the patterns of cancer incidence as people migrate from one part of the world to another provide some indication of the extent to which causes of disease are due to changes in environmental factors, including, most importantly, diet. The experience of other migrant populations will provide a meaningful and important comparison to the experience of the Mexican migrants to Los Angeles, and so will be briefly reviewed. An understanding of both the historical migration patterns of the Mexican population and their food consumption practices in Mexico is central to assessing the impact of contemporary American culture on dietary behaviors of Mexican immigrants. We can assume that at the time of entry into this country, an individual’s behavior primarily reflected the culture of origin (Bumam et al, 1987). However, Mexicans living in Los Angeles, like other migrant populations, are neither a homogeneous group (Food Marketing Institute, 1984) nor a random sample of the population of Mexico (Parkin, 1993). Therefore, the dietary and other lifestyle behaviors of recent immigrants are characterized by the demographic characteristics of the people who are migrating, the regions of Mexico from which individuals migrate, and the reasons for migration. Although the Multiethnic Cohort Study did not collect information on the region of Mexico from which Mexican immigrants 2 We use the term ‘Mexican American’ to describe a study population of Mexican national origin or descent now residing in the United States, regardless of US citizenship status. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. originated, a brief examination of regional food practices is included to provide an understanding of the possible differences in dietary practices among Mexican immigrants to die United States and to emphasize that they are not a homogeneous group. The results of the comparison of Mexican American dietary behaviors wife reported dietary behaviors of non-Latino whites will isolate fee more important factors feat may explain fee difference in rates of colorectal cancer between Mexican Americans and non-Latino whites and between US- bom Mexican Americans and first-generation Mexico-bom immigrants (Thomas and Karagas, 1987). However, this comparison assumes feat Mexican immigrants follow the traditional model of assimilation by adopting, over time, fee behaviors of fee non-Latino white American culture. The degree to which immigrants adopt fee behaviors of their host culture or retain fee behaviors of their culture of origin depends on each individual’s exposure to fee new environment and their ability or willingness to adapt (Thomas and Karagas, 1996). The fact feat individuals with similar backgrounds and amount of time in fee United States seem to acculturate at different speeds suggests there are elements of personal choice involved in fee process (Negy and Woods, 1992). Time since migration, age at migration, gender, level of education attained, and employment opportunities all play important roles in fee process of acculturation. Many of these factors have been considered by various investigators in their analyses of fee dietary behaviors of fee Mexican American population in comparison wife fee dietary practices of non-Latino whites. This body of literature is reviewed to provide direction for fee future analysis of the Multiethnic Cohort Study nutritional data particularly, wife regard to which components of the Mexican diet may confer fee greatest impact on fee changing rate of colorectal cancer incidence3. 3T w o studies observed feat US-born Mexican Americans had incidence rates of colon cancer that were intermediary between immigrant Mexicans and non-Latino whites residing in Los Angeles (Menck et al., 1975; Mack et al, 1985). Another study found fee risk among Spanish sumamed immigrants to be intermediary between fee risk for homeland residents and fee risk for native Latino residents (Shimizu et al., 1987). Preliminary data from fee Multiethnic Cohort Study shows feat US- bom Mexican Americans have incidence rates feat approximate fee rates of non-Latino whites residing in Los Angeles. First-generation migrants have incidence rates feat are one-half fee rates of US-bom Mexican Americans. 3 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The research goals of Part II of the dissertation will be to first determine what changes, if any, in dietary or other lifestyle practices are consistent with the changing rate of colorectal cancer incidence in the Los Angeles Mexican American population following migration to the United States. Specifically, as the length of US residence increases, are changes occurring in dietary and other lifestyle behaviors (alcohol consumption, obesity, and physical exercise) that are consistent with known risk factors for colorectal cancer? A migrant study is particularly suited for this type of analysis as dietary exposures may vary widely among migrants who are recent arrivals and those who have been in the United States for a generation or more. This broader range of exposure provides greater power to detect associations between cancer and specific dietary risk factors than a study with a more homogeneous population (Thomas and Karagas, 1996). The Multiethnic Cohort Study, given the large sample of Mexican Americans (particularly first-generation immigrants), provides a unique opportunity to study meaningfully the dietary and other lifestyle behaviors that may contribute to the observed increase in colorectal cancer rates in a migrant population not previously studied. The second goal will be to conduct a statistical analysis using nested case-control methods to examine the association of colorectal cancer with nutrient intake. This latter analysis provides the opportunity to test hypotheses that may emerge from the first investigation. This is an important step as a migrant study, while important, serves only to generate hypotheses about what factors may influence disease risk. This case-control analysis will be conducted with the incident colorectal cancer cases that have occurred from cohort inception in 1993 to June 30,1998, a date for which we are confident that we have complete case ascertainment in die Mexican American population. Part III of the dissertation describes an approach to (1) validate the measure of dietary fiber intake from our food frequency questionnaire with a relevant biochemical marker, (2) investigate the role of dietary fiber in estrogen metabolism, and (3) provide the necessary groundwork for the detection and characterization of gene-environment interactions in future breast and colorectal cancer research. A large and compelling body of epidemiological and experimental data implicates estrogen R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. in the etiology of human breast cancer-. Case/control and prospective studies, primarily among white populations, have both supported a strong positive association between levels of steroid hormones and breast cancer risk. In order to understand this association, scientists have provided evidence that dietary nutrients play an important role in estrogen metabolism, e.g., dietary fiber and/or fat may play a role in die regulation of the enterohepatic metabolism of estrogen thus influencing the estrogen levels in the body (Adlercreutz et al., 1987). Dietary fiber intake may alter cholesterol metabolism that also has a role as a biological precursor for estrogen synthesis. In fact, the etiology of breast cancer is most likely due to a complex interplay between many components and current trends in breast cancer research demonstrate the new focus on gene-environment interactions on disease risk. All three components of the dissertation, review paper, analysis of the cohort data, and grant proposal, will focus on exam ining only those Latinos of Mexican national origin for two reasons: (1) it is generally recognized that there are vast differences between national origin Latino groups; and (2) the interpretation and comparison of dietary analyses from studies where Latino subgroups have been combined becomes very difficult at best. First, studies that have examined the social and economic characteristics of ‘Hispanic’ subgroups have found that the differences are often greater than the similarities (Jaffe and Cullen, 198Q; Borjas and Tienda, 1985). Researchers have also observed that while dietary patterns of Cuban Americans and mainland Puerto Ricans share some similarities with the dietary patterns of Mexican Americans, the data from the Hispanic Health and Nutrition 4 I have elected to study breast cancer in addition to colorectal cancer for two reasons. First, the proposed study population, two generations of Mexican-origin Latino females now residing in tire US, provides a unique and important ethnic group for this research effort because of its broad range of dietary fiber exposure and a significant number of potential participants from an ongoing cohort. Also, preliminary incidence rates within the Multiethnic cohort show Mexican immigrants have a significantly lower rate of breast cancer than US bom Mexican Americans, the same pattern observed for colorectal cancer rates. Second, although the validation of dietary fiber intake from a food frequency questionnaire with a relevant biochemical marker will be of interest for our future colorectal cancer analyses, I am interested in taking the dietary fiber hypothesis one step further to examine its role in estrogen metabolism. I will be able to not only examine the effects of dietary fiber intake as measured by a food frequency questionnaire but also by a relevant and reliable, independent, biochemical measure of intake. 5 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Examination Survey (HHANES)5 show significant differences in consumption patterns of traditional and contemporary foods among the three Latino subgroups- (Aguirre-Molina and Molina, 1994; Romero-Gwynn and Gwynn, 1994). Other studies based on HHANES data have found significant differences in macronutrient and micronutrient intakes, including alcohol, as well (Loria et al, 1995; Looker et al, 1993; Black and Markides, 1994; Gaetano, 1988). Therefore, grouping may mask important differences not only between Latino subgroups but also between Latinos and other ethnic groups. Second, before populations can be compared, they must share a uniform definition (Hayes- Bautista, 1980; Hayes-Bautista and Chapa, 1987; Lowenstein, 1981). Unfortunately, various researchers use the term ‘Hispanic' to defme different study populations, and thus create an unnecessary opportunity for misinterpretation. Clearly, the ethnic distribution of the Latino sample included in a particular study would impact the findings of that study. The National Health Interview Surveys (NHIS), conducted by NCHS, treated Latinos as a single group and provide a good example of how the ethnic distribution may affect the findings of a study (Norris et al, 1997; Block and Subar, 1992; Patterson et al, 1995). The 1987 and 1992 samples included in the survey differed m terms of Latino ethnic distribution and language of interview. In 1992, the proportion of Mexican Americans increased from 43.5% to 53.9% with proportionately fewer Puerto Ricans, Cuban Americans and other Latin Americans. The proportion completing the survey in English also declined in 1992 to 38% from 47% in 1987. The study by Norris et al, in comparing the findings of the 1987 and 1992 5 A special survey of Mexican Americans, Puerto Ricans, and Cubans, aged 12-73 years, residing in the continental US was conducted in 1982-1984 by the National Center for Health Statistics (NCHS) of the CDC. HHANES was designed to provide baseline nutritional information for Latino subgroups that was comparable to other surveys conducted by NCHS, particularly NHANES If. By design, the survey included a single 24-hour dietary recall from weekdays only. A more complete discussion of the nutrition monitoring activities in the United States is included as Appendix A. 6 A discussion of the historical migration patterns and the dietary practices of Latinos originating from other Latin American countries is included as Appendix B. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. surveys, found that the percentage of energy from fat decreased from 35.1% to 32.3% among Latino males. This was the largest change in the percentage of fat for any race/ethnic group, whose levels were already the lowest of the three subgroups. The percentage of energy from saturated fat declined more dramatically, 12.9% in Latino females and 12.6% in Latino males relative to 198? estimates. Dietary cholesterol intake in 1992 declined by 21% in Latino females and 16% in Latino males relative to 1987 estimates. In Latino males, the percentage of energy from alcohol declined significantly in 1992. That decline represented a 23% decrease in percentage of calories from alcohol intake. Considering previous evidence of significant differences in dietary behavior between Latino subgroups, it is impossible to interpret the changes in dietary behaviors as reported by Norris et al. given that the ethnic distribution differed significantly between the 1987 and 1992 surveys (Norris et al., 1997). For these reasons, I will only focus on Mexican Americans in my background research and in the selection of the Multiethnic Cohort study population for data analysis. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. PARTI. LITERATURE REVIEW Changes in the patterns of cancer as people move from one part of the world to another provide evidence on the extent to which the causes of cancer are due to changes in environmental factors, including most importantly, diet. Doll and Peto estimate that as much as 90% of the variation in colorectal cancer rates between countries could be accounted for by dietary factors (Doll and Peto, 1981). Migrant studies along with rapidly changing incidence data from Italy, Japan, and Polynesians in Hawaii have shown that colorectal cancer incidence is especially sensitive to changes in environmental factors (Kolonel et al., 1986; World Cancer Research Fund, 1997; Le Marchand et al., 1997). A recent review of risk factors for colorectal cancer was published in the World Cancer Research Fund/American Institute for Cancer Research publication {Food, Nutrition and Prevention o f Cancers a global perspective) and is briefly summarized below (Figure 1). Among dietary factors, the most consistent and convincing observation has been the inverse association between vegetable consumption and risk. Dietary fiber, a measure of vegetable as well as grain, fruit, and legume intake, has also been found to be inversely associated with risk, although overall the findings have been inconsistent. Researchers have proposed that perhaps this inconsistency is because of the heterogeneous nature of fiber products and differences in the ways in which fiber is measured (World Cancer Research Fund, 1997). The particular component(s) of dietary fiber that could be responsible for the decreased risk include not only the type of fiber (soluble versus insoluble) but also the subcategories of fiber (e.g, cellulose, lignin, and pectin) and individual food sources such as vegetables, fruits, cereals, legumes, and seeds. There are also several reports of a low risk of colorectal cancer associated with a high intake of carotenoids, micronutrients found primarily in fruits and vegetables (van Poppel, 1993). The difficulty with examining the role of carotenoids in relation to colorectal cancer risk is the probability that the protective factor in foods containing P-carotene could be non-starch polysaccharides or starch rather than a particular 8 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. E v i d e n c e Convincing Probable Possible Insufficient p to X p lD ), f f t i f j i j j °iiTr! I o'lT i M M 1 i c 0 i r( g j | i g c Decreases risk I ncreases risk Physical activity vegetables Red meat Alcohol NSF/dietary fiber Starch Carotenoids High body mass Greater addilt height Frequeht eating Sugar Total fat Saturated/animal fat Processed meat Eggs Heavily cooked meat Resistant starch Vitamin C Vitamin D Vitamin E Folate Methionine Cereals Coffee From Food, Nutrition and the Prevention Of Cancer a global perspective, World Cancer Research Fund (1997) micronutrient (Key, 1994). It is also unclear whether the association could be due to other phytochemicals that are present in fruits and vegetables high in carotenoids (World Cancer Research Fund, 1997). The published data on red meat consumption show that this factor more than likely increases the risk of disease (World Cancer Research Fund, 1997). Methods of cooking meat and colorectal cancer risk have also been investigated and a statistically significant increased risk for hied meat with a heavily browned surface has been reported (Schiffinan 1990; Gerhardsson de Verdier et al., 1991). The epidemiological evidence of an association between total fat or saturated fat intake and colorectal cancer is mixed and, therefore, no current judgment is possible. The published data relating colorectal cancer and the consumption of legumes is very limited and the results have been inconsistent. High calcium intake has been hypothesized to provide a protective effect for colorectal cancer although the evidence suggests only a weak overall decrease in risk. Other dietary hypotheses include eggs and cholesterol as being associated with higher risk of colon cancer although no conclusive judgment is currently possible. The role of other lifestyle behaviors (physical activity, obesity, and alcohol) believed to be associated with colon cancer risk has been investigated extensively. In particular, reduced physical activity has emerged as die one behavior that is associated most consistently with an increased risk of colon cancer. The association has been shown in both genders. The published data on alcohol intake show that this factor more than likely increases the risk of disease (World Cancer Research Fund, 1997). Ecologic studies have generally shown a positive association between alcohol intake and colon cancer risk as have four of the five population cohort studies (Klatsky et al., 1988; Hirayama, 1989; Stemmermann et al., 1990; Giovannucci et al., 1995). Similarly, three cohort studies examining rectal cancer found significant associations with alcohol intake (Klatsky et al., 1988; Hirayama, 1989; Stemmermann et al., 1990) as did two other studies that did not distinguish between colon and rectum cancer (Garland et al., 1985; Kono et al., 1986). Among case-control studies, 50% 10 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. (9 of 18) found a significant positive association between alcohol and colon cancer and nine of seventeen case-control studies that examined rectal cancer risk factors found a significant association with alcohol intake. Published reports on the association between body size and colorectal cancer risk have been inconsistent. Three cohort studies (Garland et al, 1985; Phillips and Snowdon, 1985; Nomura et al, 1985) and nine case-control studies (Graham et al., 1978; Wu et al, 1987; Peters et al., 1989; West et al., 1989; Benito et al, 1990; Gerhardsson de Verdier et al., 1990; Whittemore et al, 1990; Le Marchand et al., 1994; Le Marchand et al., 1997) have found an increased risk for male subjects in the highest quintile of body weight. However, other studies in men have found no association (Thun et al, 1992; Dales et al, 1979; Berry et al, 1986; Kune et al, 1990). In women, two cohort studies (Wu et al, 1987; Chute et al., 1991) have reported no association of BMI and colorectal cancer risk while one cohort study (Bostick et al, 1994) of Iowa women found a statistically significant increased risk in the highest quintile of body weight. Two case-control studies (Gerhardsson de Verdier et al., 1990; Whittemore et al., 199Q) have also suggested an increased risk of colorectal cancer with increased body size. Several cohort studies (Albanes et al, 1988; Chute et al., 1991; Bostick etal., 1994; Giovannucci et al., 1995) have observed an increased risk of colon cancer in association with greater adult height. Strong associations between height and colon cancer were reported from the NHANES data in which men in the highest quintile for height had a relative risk of 2.1 compared to men in the lowest quintile (Albanes et al, 1988). On the other hand, four case-control studies have not found an association (Dales et al, 1979; Jain et al, 1980; Young and Wolf, 1988; Peters et al, 1989). It is these competing risk factor hypotheses that will be the focus of discussion in the latter part of this literature review when we compare dietary behaviors of Mexican Americans with dietary behaviors of non-Latino whites. They are also examined in detail in the data analysis of the Multiethnic Cohort Mexican American population. 11 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. A. PREVIOUS STUDIES OF CANCER IN MIGRANT POPULATIONS Previous studies of cancer in several migrant populations have shown that the risk of colorectal cancer increased to the rates of the host countries within one or two generations, or even as early as within die migrating generation as has been shown in Japanese and Chinese migrants to the United States (Buell and Dunn, 1965; Dunn, 1975; Menck et al, 1975; Kolonel et al, 1980; Mack et al, 1985; King etal, 1985; Tominaga, 1985; Shimizu et al, 1987; McMichael and Giles, 1988; Whittemore et al, 1990). The most prominent studies are those of Japanese migrants to Hawaii and California and of Chinese migrants to die United States (Parkin, 1993). Reports established that Hawaii Japanese experience rates of colorectal cancer that are in excess of three times those of indigenous Japanese and are the same or in excess of those of Caucasians residing in Hawaii within the migrating generation (Stemmermann et al, 1979; Kolonel et al, 1980; Tominaga, 1985; Shimizu et al, 1987; Stemmermann et al, 1991). Buell and Dunn compared cancer mortality between first-generation Japanese migrants (Issei) and their US-bom offspring (Nisei) and found that the shift in the risk of colon cancer was rapid. The study provided early evidence that colon cancer mortality among first- generation Japanese migrants approached the rates of California whites even within the migrating generation. Among those ages 65 and over, foreign-bom migrants had a ratio of .8 when standardized to California white rates. Among those ages 45-64, Califomia-bom Chinese had a mortality ratio of .9 when standardized to California white rates. The rates in Japan are one-fifth the rate of whites in California (Buell and Dunn, 1965). Tominaga reviewed cancer incidence rates of Japanese in Japan, Japanese migrants to Hawaii, San Francisco, and Los Angeles and Caucasians in the United States. The author found that migrant Japanese males had rates of colon cancer that were three and one-half times higher than rates of Japanese in Japan and even slightly higher than rates of US whites. Among females, rates of colon cancer in US Japanese migrants were three times as high as Japanese in Japan but slightly less than 12 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. rates in US whites. Rectum cancer showed a similar pattern of incidence (Tominaga, 1985). Finally, Kolonel et al. observed that rates of colon and rectum cancers increased four or more times in die first-generation Japanese immigrants compared with the rates in Japan. Incidence rates did not increase further among the US-bom Japanese (Kolonel et al, 1980). Among Chinese migrants to die US, King et al. observed that the colorectal cancer mortality rate among male, foreign-bom (Idai) migrants was twice the rate of rates for representative homeland populations. Among US-bom (Erdai) Chinese, the rates approximated those of Hong Kong rates. Among females, a higher risk was observed for US-bom than for foreign-bom representing a transposition of earlier findings of King and Haenszel (King et al., 1985). Other studies that examined colorectal cancer incidence among Chinese in North America and the People’s Republic of China found rates among male Chinese migrants that were higher than rates in China and approximated rates of whites. Incidence in migrant females was intermediate (Whittemore, 1989; Yu et al, 1991). Results from a case-control study of colorectal cancer among Chinese in North America and the People’s Republic of China found statistically significant trends of increased risk of cancer of the colon and rectum with increasing years lived in North America. Risk increased approximately twofold from the lowest (<10 years) category of residence in North America to the highest (>20 years) category (Whittemore et al, 1990). The two major groups of migrants from Latin America that have been investigated are the Mexicans and Puerto Ricans. Among Puerto Ricans, Warshauer et al observed that rates of colon cancer among first-generation immigrants nearly doubled from the rates in Puerto Rico but still remained considerably less than rates for US whites. Rates for second-generation immigrants were not available (Warshauer et al, 1986). Rosenwaike and Shai examined trends in cancer mortality among Puerto Rican-born migrants to New York City, comparing 1979-81 rates with the 1969-71 standardized rates. They observed that death rates from colon cancer for Puerto Ricans were somewhat lower than those of other residents ofNew York in 1979-81, but that the rates had 13 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. increased dramatically from 1969-71 levels. Among Puerto Rican males and females, the death rate increased 103% and 61% respectively from the previous decade (Rosenwaike and Shai, 1986). Among Mexicans, Menck et al. calculated age-standardized incidence ratios separately for immigrant Mexicans, Mexicans bom in the United States and non-Latino whites residing in Los Angeles. No reliable incidence rates are available for Mexicans in Mexico. Lower incidence rates of cancer of the colon were found in male and female Spanish sumamed residents when compared to other whites. These investigators observed that immigrant Mexicans had incidence rates most divergent from other whites and that US-bom Mexican Americans had rates between the other two groups. Mack et al. in comparing risk ratios and proportional incidence ratios observed that US-bom Latinos, regardless of socioeconomic status, lost the low risk characteristic of colon cancer in Mexico- born immigrants. The risk ratio for colon cancer among immigrants was intermediary between the risk for US non-Latino whites and the risk for a representative homeland population. Also, it is interesting to note that the colon cancer ratio was slightly greater in those who migrated as children, meaning they have been in the US for a longer duration, than those migrants who came to the US from Mexico as adults (Mack et at., 1985). Shimizu et al. calculated age-adjusted incidence rates for cancer of the three subdivisions of the large bowel among three race/ethnic populations in Los Angeles; Spanish sumamed whites, other whites, and Japanese. Within each race/ethnic group they compared native residents, immigrants, and representative “homeland” populations. For each colon site, the investigators found the risk among Spanish sumamed immigrants to be intermediary between the risk for homeland residents and the risk for native Latino residents. In contrast, among Japanese, the risk of colon cancer is considerably higher for both US-bom and non-US-bom immigrants compared to the risk of colon cancer in Japan (Shimizu et al., 1987). These data, along with the Mack study, suggest that the colorectal cancer experience among Latino migrants is different than the experience of Japanese and Chinese migrants. Whereas Japanese and Chinese migrants experience a 14 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. rapid shift in colorectal cancer risk within the migrating generation, the Mexican migrants appear to experience a much slower increase in rates of colorectal cancer incidence. Three groups of studies, notably the Japanese migrants to Hawaii, the European migrants to Australia, and the Chinese migrants to North America, have collected information on changes in food/nutrient and alcohol intakes following migration. For the Japanese in Hawaii, there is dietary information for a range of foods and nutrients (Kolonel et al, 1981; Kolonel et al, 1980; Hankin et al., 1983) and foe study populations can be separated into foreign-bom (Japan) versus those bom in Hawaii. Comparisons of foe diets in Japan versus Hawaii have also been reported from foe Japan- Hawaii Heart Study (Kagan et at., 1974; Stemmermann et al., 1979). For example, Hankin et al., (1983) found a significant increase in foe intake of total fat and animal fat between first-generation migrants (Issei) and their off-spring (Nisei). For European migrants to Australia, in which there are clear increases in colon cancer rates, migrants had largely adjusted to Australian dietary patterns consuming more meat and dairy products and (ess unrefined carbohydrates, vegetables, and fruits than their counterparts in Southern Europe from where they originated (Armstrong et al, 1983; McMichael and Giles, 1988). In a study of colorectal cancer among Chinese migrants in North America and Chinese in China, Whittemore and colleagues found that in a multivariate analysis of all the nutrients, only saturated fat increased risk (Whittemore et al, 1999). Further, foe association between colorectal cancer risk and saturated fat was stronger among foe sedentary than among foe active. Studies of cancer in migrant populations provide powerful indirect evidence of foe relative importance and nature (timing) of foe changes in dietary patterns and their contribution to risk (Parkin, 1993). Thus, they are of great interest and have provided observational “experiments of nature” that have furthered our understanding of cancer etiology by stimulating important research paths (Schottenfeld, 1981). 15 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. B. HISTORICAL MIGRATION PATTERNS OF MEXICANS TO THE U.S. During the early exploration of the New World, the Spanish were a dominant force seeking riches and territorial claims of new land for the Spanish crown. Throughout the 16th century, the Spanish explorers and missionaries gained control over native populations of what are now the southwestern United States, Mexico, Central and South America, and the Caribbean Islands (Ramirez et al. 1995). Diseases introduced by the early explorers decimated large numbers of the indigenous Indian populations. As a result of this population decrease, the migration of the Spanish and other white Europeans to the region, the encouragement of mixed marriages (Indian women and Spanish men) to ensure domination of the people inhabiting these territories, and the later introduction of African slaves, today’s Latino Americans are a racially diverse population (Ramirez et al., 1995). Whites, blacks, Asians, and Native Americans are represented.1 By the 1780s more than half of the present United States was under Spanish control. However, the purchase of the Louisiana Territory from France (1803) and the Treaty of Guadalupe- Hidalgo (1848), in which the United States acquired the northern regions of Mexico consisting of California, New Mexico, Arizona, and parts of Nevada, Colorado, Utah, and Wyoming, changed the political map of the region forever. As a result of these two acquisitions, thousands of the Southwest’s Mexican inhabitants were granted US citizenship. Although the Treaty of Guadalupe- Hidalgo guaranteed die rights of die native Mexicans inhabiting the southwest region of the United States, most of their property interests were soon lost to white settlers from the east. As a result, native Mexicans, once the majority, became a small portion of an increasingly white region (Rodriguez, 1999) and their economic condition deteriorated (Aguirre-Molina and Molina, 1994). 'While most of the population in Mexico today is made up of descendants of the mixture of Spaniards and Indians (Mestizos), descendants of Spaniards and other white European immigrants are also included. Approximately 20% of the population belongs to pure Indian groups that have survived in poverty and isolation (Rosovsky and Romero, 1996). Indian groups are concentrated in the country’s poorest states such as Chiapas, Oaxaca and Yucatan. 16 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. At the end of the Mexican Revolution in 1910, Mexicans again began moving north to the United States in search of political freedom and jobs. This migration continued through 1930. However, during the economic crisis of the Great Depression, President Hoover initiated the deportation of Mexicans and Mexican Americans to Mexico. Mexican immigration began again with the Bracero program in the 1940s in which die United States admitted guest male agricultural laborers. The labor force was needed when World War n created a shortage of railroad, factory, and agricultural workers (Chavira-Prado, 1994). However, these workers were expected to return to Mexico when the labor was no longer needed (McCarthy, 1986). Although large-scale immigration began in the Bracero period, a large portion of California’s permanent Mexican immigrants began entering the state in the 1960s2 (McCarthy, 1986). The passage of the US Immigration Act in 1965 changed the mles for legal immigration by allowing only those with close relatives in the US or those with job skills to immigrate. However, California’s need for low-wage labor did not end. Unemployment and poverty in Mexico, along with the demand for wage labor in the United States, continued to influence the massive and continuous immigration of Mexicans (Alvarez, 1994). Four of five Latino immigrants in California today arrived after 1970 (Rodriguez, 1999). The regions in Mexico from which people migrate are individually larger in area than many Latin American countries. The core area from which the majority of Mexican immigrants originate consists of the centra} states of Durango, Zacatecas, San Luis Potosi, Guanajuato, Jalisco, and Michoacan (Cross and Sandos, 1981; Bruhn and Pangbom, 1971) (see Figure 2). The majority of immigrants from these states have come to die southwestern United States, primarily to California and Texas. Mexicans have also migrated from the northern Mexican border states of Sonora, Chihuahua, Coahuila, Nuevo Leon, and the states of the Pacific coast, Sinoloa and Nayarit (see Figure 3). 2 This means that a large proportion of the state’s Mexican American population are either foreign-bom (48.4%) or second-generation US-bom, i.e., their parents were bom in Mexico (Bureau of Census). 17 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Mexican colonies in the United States are often settlements of people originating from specific Mexican regions and states. However, some Latino neighborhoods in Los Angeles are heterogeneous mixtures of individuals representing all principal migration areas in Mexico. Each of these regional groups expresses specific cultural practices (Alvarez, 1994). This variety is a result of recent immigration and is complicated further by the fact that Latinos were also the original populations in much of the Southwest (Alvarez, 1994). Figures from the 1990 Census, the most recent available, estimate the Mexican population in the United States to be 14.8 million or 68.8% of the total Latino population. The number of Mexican immigrants living in California rose from 150,000 in 1950 to over 1.3 million in 1980 (McCarthy, 1986). In the 1980s, hundreds of thousands of Central and South American immigrants seeking political refuge and escape from economic hardship diversified the five-county Southern California area- In 1990, the Mexican American population in Los Angeles County alone numbered 2.5 million or 76.2% of the total Latino population in Los Angeles (Bureau of Census). Mass immigration in the last three decades of the twentieth century has fundamentally altered the internal dynamics of Latin American culture here in Southern California. Recent Latino immigrants have been acculturating differently than have previous waves of immigrants including earlier migrations of Mexicans (Rodriguez, 1999). Large numbers of immigrants have made Mexican culture and associated behaviors more sustainable here in Southern California than ever before and acculturation to the contemporary American lifestyle is a more complex process of adaptation and integration (Rodriguez, 1999). C. DIET PATTERNS IN MEXICO BY REGION OF MAJOR EMIGRATION Upon arrival in Latin America, the Spanish explorers found a large diversity of foods. The diet of the indigenous population in Mexico included com, different varieties of beans and squash, tomatoes, chocolate, chilies, sweet potatoes, and several types of wild greens. A large variety of fruits 20 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. were consumed along with various large and small animals including deer, turkeys, birds, monkeys, tortoises, frogs, fish, and insects (Romero-Gwynn and Gwynn, 1994). The native Mexican cuisine began changing due to foods introduced by the Spaniards, including wheat, pastas, rice, barley, olives, citrus fruits, almonds, beef, mutton, goat, chickens, and dairy products. The Spanish also introduced onions, garlic, cinnamon, sugar cane, and hogs, the latter of which added a reliable source of protein and fat to the native diet. Although alcohol use3 was prevalent in Mexico prior to the conquest, the Spanish also introduced distilled beverages and grape growing for wine production (Rosovsky and Romero, 1996). In the 1860s, during Maximilian’s reign, there was a strong French influence on Mexican bread and pastries. Today, Mexican cuisine represents a blending of native cuisine with influences from Spain, France and recently, the United States. Indeed, there are many cuisines that have developed since Spanish colonization among the different regions of Mexico. In 1997, Romieu et al. developed and validated a food frequency questionnaire to study the dietary determinants of chronic diseases in Mexico. Perhaps most importantly, the authors found that significant differences existed in the amounts and types of food consumed by children in different regions of Mexico, specifically, the northern region and Mexico Gity compared with southern and central areas. They found important differences between various socioeconomic groups as well (Romieu et al., 1997). The reasons for die differences in food consumption can be explained in part by the topography of die country (Kennedy, 1972). Two ranges of volcanic mountains with peaks up to 17.000 feet run from north to south, between which are mountainous areas and plateaus ranging from 5.000 to 8,000 feet. Not only are regions isolated from one another, but also the agricultural conditions are varied and distinct. Writers on the Mexican cuisine often divide the country based on 3 Probably the substance in widest use in pre-Hispanic Mexico was pulque, a fermented beverage made from a type of cactus growing in the central region. Pulque was considered a divine substance that should only be consumed at ceremonial occasions such as those associated with agriculture, religion, birth, marriage, and death (Rosovsky and Romero, 1996). 21 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. the differences in traditional dishes or specialties of particular regions or localities (Romero-Gwynn and Gwynn, 1994). In the northern states, steaks, beef jerky, and chorizo (spiced pork sausage used in scrambled eggs and filling for tacos) are more common. In central Mexico, camitas (deep fried/slow rotated pork), fried tacos (tortillas, or thin unleavened pancakes of dried and ground com, wrapped around a filing), and red chile enchiladas (tortillas dipped in a chile or tomato sauce, deep fried and filled with cheese or meat) are popular. There is a strong native Indian influence in southern Mexico. Pork, goat, and poultry are popular meats and a large variety of hot peppers are extensively used. The Yucatan peninsula is influenced by Mayan culture. Pumpkin seeds used in the preparation of sauces, or moles, are popular, as is achiote (seeds of the annatto tree) used to color food. Banana leaves are used to wrap tamales (com dough seasoned and steamed) and meats. The cuisine of the Gulf of Mexico has a Caribbean and European influence. Seafood dishes are very popular as is the use of tomatoes and herbs as seasonings (Romero-Gwynn and Gwynn, 1994). Most of the knowledge about the nutritional status of Mexicans during the past forty years comes from the Institute Nacional de la Nutrician Mexico (INN or National Institute of Nutrition) founded in 1957. Their first task was the identification of dietary and nutritional characteristics of the population on a regional basis. After twelve years, approximately fifty surveys had been completed and specific problems such as nutritional anemia, pellagra, goiter, and malnutrition were identified for additional research and attention. The analysis of the data obtained from these surveys leads to the following conclusions: • There is a great variety of dietary patterns in Mexico. The patterns can be classified into three broad groups: (1) the marginal; (2) the proletarian; and (c) the middle and high socioeconomic urban class. A description of the dietary patterns is provided below. • Energy, protein, iron, retinol, riboflavin, and sometimes vitamin C are common deficiencies found in the marginal group. Deficiencies are also found in the proletarian group but to a lesser extent. • Nutritional deficiencies are more frequent and severe in rural regions of Mexico than in urban regions. • Malnutrition characteristics differ from region to region (Bourges, 1981). 22 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. These conclusions are important in understanding the dietary habits of the groups of people who came to the United States from Mexico during die period of large-scale migration. The marginal dietary pattern is based on com tortillas, common beans, and some local vegetables and fruits. Animal products are consumed infrequently. The effect of this diet is a low energy density (due to the low fat content) and high protein quality because die beans and corn compliment one another. This diet is prevalent in most rural areas and is eaten by about 30% of the country’s population. The proletarian pattern is also based on com tortillas and beans but wheat products such as pasta, bread, and cookies substitute for part of the com. Hie variety of fruits and vegetables is greater and animal products are consumed in a higher frequency. This dietary pattern is common to about 50-55% of the Mexicans residing in primarily urban areas and the more developed rural areas. The middle and high socioeconomic urban class dietary pattern is again centered on com tortillas and beans. However, all food groups are included regularly. The traditional culture has been enriched by the elaborate Mexican cuisine that has been strongly influenced by the Spanish, French, Italian, and American cuisines. Only this latter group, approximately 10-15% of the population, enjoys this cuisine (Bourges, 1981). In 1979, a national dietary survey was conducted in which over twenty-one thousand families from more than two hundred mostly rural communities participated. The composition of the rural family diet in 1979 is presented in Figure 4 in comparison to the composition of the rural family diet in 1963 (Bourges, 1981). Although rural diets in 1979 were less dependent on com tortillas, that one food staple still supplied more than 50% of total energy. Consumption of wheat products increased while the consumption of beans decreased. There was a slight increase in the consumption of milk and milk products, and a disproportionate increase in soft drink consumption in comparison to 1963. 23 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Figure 4. Diet of Rural Mexico Average Rural Family Diet in 1963 Soft drinks Sugar (46 gm) (18rtl1) Eggs (11 gm) Meats (57 gm) Milk (76 ml) Fruits & vegetables (117 gm) atm Beans (56 gm) Rice Wheat* (10 gm) (38 gm) Com* (407 gm) Average Rural Family Diet in 1979 Sdft drinks (101 ml) Oil & fats (27 gm) Sugar (40 gm Eggs (27 gm) Meats (57 gm) Milk (110 n r(l) Com (325 grri) Fruits & vegetables (108 gm) Wheat (45 grri) Rice (12 gm) Beans (35 gm) *com consumed as tortillas; Wheat consumed ad bread and pasta Bourges HI "Nutritional Status of the Mexican Population" Nutrition in the 1980s: Constraints on our Knowledge (1981) The composition of the urban family diet is presented in Figure 5, comparing 1963 to 1979. Again, the urban diet in 1979 was less dependent on com tortillas. Rice consumption increased four fold in the urban diet and egg consumption more than doubled between 1963 and 1979. The consumption of milk, beans, and wheat products did not change significantly during the fifteen-year period. However, like die average rural diet, the soft drink consumption in the urban setting almost doubled between 1963 and 1979. Figures 4 and 5 point out interesting differences in dietary habits between families living in the rural areas of Mexico compared to families living in urban cities. The consumption of com tortillas in the rural setting is more than double the consumption in the urban setting whereas the consumption of soft drinks in the urban setting is more than double the consumption in the rural regions. The consumption of wheat products in die urban setting is almost three times as great as the rural setting. Consumption of rice is four times as great in the urban as in the rural setting and the consumption of milk in the urban setting is three times as great as in the rural regions. The intake of meat in die urban diet is slightly greater than in die rural. The intake of beans, fruits and vegetables, oil and fats, and sugar are similar in die two settings. These figures also point out the changes that were occurring in dietary patterns within the population of Mexico itself between 1963 and 1979. Therefore, differences that we may observe in the dietary patterns of short-term migrants compared with long-term migrants in the Multiethnic Cohort Study may be partially due to acculturation but also importantly, to changes in dietary habits that were occurring in their own country before their migration to the United States. The results of a sub-study of a rural-to-urban migrant population, also conducted by the INN in 1978-1980, support the findings of the 1979 national survey (Cerqueira, 1984). The dietary habits of seventy families originally from a rural region of Mexico who had migrated to Mexico City within the previous ten years were compared to the dietary habits of seventy-five families still living in the small villages from which die migrant families had originated. In the rural communities where the 25 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Figure 5. Diet of Urban Mexico Average Ufban Family Diet in 1963 Sugar (33 gm) Eggs (21 gm) Meats (70 gm)! Milk (311 mi) Soft drinks (115 ml) Com* (202 gm) Wheat* (138 gm) Rice (11 gm ) Beans (41 gm) Fruits & vegetables (110 gm) Average Urban Family Diet in 1979 SOft drinks (219 ml) Sugar (37 gn(i) Eggs (53 gm) Meats (71 gm ) Oil & fats (31 gm) ‘com consumed as tortillas; wheat consumed as bread and pasta Bourges H. 'Nutritional Status of the Mexican Population" Nutrition in the 1980s; Constraints on our Knowledge (1981) Milk (300 ml) Com (151 gm) Wheat (125 gm) Rice (44 gm) Beans (43 gm) Fruits & vegetables (98 gm) N> C \ main dietary staple is com tortillas, the mean daily consumption of this one food item was 580 gm per person per day. The mean daily consumption in the rural-to-urban migrant families was 254 gm, less than one-half the consumption in the rural family. The reported family size (rural families had an average of seven children compared to the urban family’s four children) makes the observed difference in tortilla consumption even more significant. All of the rural families reported eating tortillas two or three times daily compared to only 21% of the urban families reporting consumption more than once a day. Urban families ate more refined cereals, animal products including ham, sausage, bacon, and lard, ‘ junk foods’ (undefined) and more fat from fried foods. Results also showed that urban families satisfied their basic energy and protein needs while the rural family’s diet was deficient in these nutrients. The urban diet was deficient in calcium and both diets were low in iron content. Sodium intake was higher in the urban family’s diet. They not only used salt for cooking and at the table in greater frequency, but also ate more canned and processed foods and salty snacks. Powdered consomme or cubes were particularly popular in the urban setting (Cerqueira, 1984). Today, com remains the most important dietary staple in Mexico. Com is consumed in Mexico in many ways: as tortillas, masa (com dough) products including tamales, gordas (thick tortillas prepared with com dough mixed with lard and sometimes beans and/or meat), and sopes (small appetizers made of tortilla dough), and a popular hot beverage called atole bianco. Although com stands out as the primary staple, other grains and grain products are also consumed. Wheat breads common in Mexico consist of medium sized french rolls used to prepare a sandwich called torta. Sweet bread or pan dulce is popular with a chocolate or coffee beverage for breakfast or dinner. Small whole-wheat rolls and white sliced bread are also consumed in Mexico. Tortillas made with wheat flour are common all over the northern regions of Mexico, particularly in Sonora and northern Sinaloa, which comprise the most important wheat-growing region in Mexico. They are often used for burritos (flour tortillas rolled around a filling of meat). 27 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Beans were a main dietary staple of die indigenous populations of Mexico prior to Spanish colonization and continue to be part of die core diet of Mexicans from all socio-economic levels. Two main ways of consuming beans in Mexico are boiled (frijoles de la pita) and refried. Rice and pasta, introduced by the Spaniards, continue to be an important component of the Mexican diet. Cooked rice is consumed on a weekly basis for most families. It is usually fried before cooking, contributing to the increased fat content. Pastas such as fideo (vermicelli), estrellitas and conchitas (pasta shells) are widely used in soups in Mexico. Vermicelli is also used to prepare a spaghetti-like dish. Like rice, the pasta is usually fried before cooking. The introduction of goat and cattie in Latin America by the Spanish had a profound and lasting impact on the dietary habits of the indigenous people. Milk and milk products have become an important part of die Mexican diet. Milk is consumed in both hot and cold beverages and is often combined with chocolate and coffee or blended with fruit. Cheese is also an important dairy food in the diets of Mexicans. The most common meats currently consumed in Mexico include beef, chicken, pork, and goat. Beef is eaten as bistecs (thin steaks), in stews, and used as filling for masa and tortilla dishes. The consumption of fish and shrimp is also common in Mexico. As in most of the Central American countries, vegetables are eaten in Mexico mainly as ingredients of other mixed dishes. Chopped vegetables are used as toppings for many traditional dishes such as tostadas (a fried com tortilla topped with refried beans or mashed potatoes, shredded meat, lettuce, chopped tomatoes, and cheese), chalupas (a com tortilla topped with shredded meat, refried beans, and chopped vegetables), and sopes (small appetizers made of tortilla dough). A variety of fruits were consumed in Mexico prior to Spanish colonization and continue to be widely consumed. Native, as well as fruits introduced by the Spanish, include papaya, pineapple, zapotes, guava, citrus fruits, apples, pears, grapes, strawberries, apricots, mango, and banana. Fruits are consumed as snacks, as the first course at meals, and in juices. 28 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Beer and spirits are the main alcoholic beverages consumed in the urban population while in rural areas, locally produced beverages such as pulque, aguardiente, and mezcal, are still popular (Rosovsky and Romero, 1996). Alcohol consumption, among Mexicans, is a part of almost every life event such as weddings, funerals, baptisms, and religious holidays, as well as business transactions and market events. Religion is strongly related to alcohol use where rituals mix elements of the Catholic Church ceremonies with ancient beliefs and traditions. The market practices of the alcohol industry result in a high availability of alcoholic beverages in every part of the country (Rosovsky and Romero, 1996). D. DIETARY CHANGES AMONG MEXICANS FOLLOWING MIGRATION Many studies have examined dietary behaviors among die US Mexican American population. Only four, summarized in Table 1, have examined changes in dietary behavior among Mexicans living in the US by comparing the diets of first-generation immigrants to second-generation US-bom Mexicans or by comparing the diets of first-generation immigrants based on the number of years they have lived in the United States (Guendelman and Abrams, 1995; Romero-Gwynn et at., 1993; Chavez et al., 1994; Elder et al, 1991). All four studies provide evidence of significant changes in dietary behaviors following migration while some food consumption behaviors are also retained. Each study is summarized below. Guendelman and Abrams examined the nutrient intake of ‘second-generation’ compared to ‘first-generation’ Mexican American women aged 16 to 44 years. In this study, the original HHANES three generation coding was collapsed into two groups to allow for sufficient sample size: first-generation are subjects bom in Mexico with parents bom outside the US and second-generation are subjects bom in the US with one or both parents bom in Mexico. Dietary intakes of eight nutrients were calculated from the 24-hour dietary recalls o f475 first-generation and 898 second- generation women, as well as for 2,326 non-Latino white women horn the NHANESII survey. 29 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 1. Studies that examined dietary changes following migration to the U.S. among Mexican Americans LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE N ETHNICITY/RACE DATA SOURCE METHODOLOGY 1. Elder; et al. 1991 sat. fat/choleSterol avoidance, men& mean: 38.9 fiber, high and low^calorie women mean:33.5 food scale mean: 47.7 167 low-acculturated Latinos 191 high-acculturated Latinos 113 Anglos San Diego; CA 64 item telephone survey 2. Romero-Gwynn, etal. 1993 foods combined adults 6,947 Mexican Americans HHANES 24-hour recall 2,642 Puerto Ricans (1982-1984) 1,315 Cuban Americans 3. Chavez; et al. 1994 food groups: dairy, protein, women breeds, snacks, vitamin 0 fruit & vegetables, vitamin A fruit & vegetables; other fruit & vegetables fats & Oils 60 Mexican 36 Puerto Rican 16 U.S. bom Puerto Rican Chicago] Illinois 2 ethnic specific WIC Clinic FFQ 4. Guendelman, Abrams 1995 energy, protein, tat, carbohydrate: calcium] iron, folic add; cholesterol, zincj vitamins A, C, E women 16-44 475 1st gen. Mexican American HHANES 24-hour recall 898 2nd gen. Mexican American * 2,326 non-Latino white NHANESII & NCI (1976-1980) u > O Dietary intakes of each nutrient were measured both as mean absolute intake and as mean percentage of recommended daily allowance (RDA). Table 2 presents the mean dietary intake of selected nutrients by ethnicity and generational status. First-generation women consumed considerably more protein, carbohydrate, cholesterol, vitamin A, vitamin C, folic acid, and calcium than second- generation Mexican Americans or white non-Latino women. Calcium intake was 779 mg per day for first-generation Mexican women compared with 645 mg per day and 678 mg per day for second- generation Mexican and white women respectively. With the exception of cholesterol and calcium, the mean dietary intake of the other major nutrients was remarkably similar for second-generation Mexican American women and white non-Latino women. Second-generation women consumed the fewest total calories followed by white non-Latino women. No significant differences were found for total fat or vitamin E across the three subgroups. However, both generations of Mexican American women reported a higher consumption of cholesterol than non-Latino white women. First-generation Mexican women reported the highest intake at 353 mg per day compared to 3Q6 mg per day and 267 mg per day for second-generation Mexican and white women, respectively. The investigators concluded, “as Mexican American women move to second-generation, the quality of their diet deteriorates and approximates that of white women” (Guendelman and Abrams, 1995). Guendelman and Abrams found important differences in the sociodemographic characteristics between die subgroups. Specifically, height and education were important predictors of the quality of diet for non-Latino whites but not for Mexican Americans. While low income was positively associated with an inadequate diet in white women, it was negatively associated in first- generation Mexican American women. The authors hypothesized that as income increased, food choices deteriorated because they adhered less to a traditional Mexican diet. There was no association between income and quality of diet for second-generation Mexican Americans. However, of particular concern to Guendelman and Abrams was that 24% of the HHANES subjects in this study were excluded because of missing data. The authors also note that the 31 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Table 2. Mean dietary intake of selected nutrients by generation status for Mexican American women compared to American non-Latino white women First-Generation3 Mexican Americans (n=475) Second-Generation3 Mexican Americans (n=898) non-Latino whiteb (n=2326) Energy, kcal 1722 1637 1654 Protein (gm) 74.3 68.3 63.9 Carbohydrate (gm) 205 185 187 Total Fat (gm) 69 69 68 % of kcal as fat 35 37 36 Calcium (mg) 778.8 644.5 677.7 Cholesterol (mg) 353 306 267 Vitamin A (IU) 6347 4241 4597 Vitamin C (mg) 104 84 I 0 0 I 0 0 Vitamin E 7.9 7.3 7.5 Folic acid (ug) 267 206 200 iron (mg) 11.7 10.6 1Q.9 3 data from HHANES b data from NHANES I! Guendelman and Abrams, Am J Public Health (1995) R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. nutritional databases used for the two surveys (NHANESII and HHANES) were not identical because food composition changed over time. This could have contributed to the observed differences in intake. However, even considering these limitations, die findings of strong differences in dietary intake based on generation status among Mexican women cannot be ignored. Romero-Gwynn et al. present findings from a recent study in low-income adult women aged 19-44 of Mexican descent living in several urban areas of California. They examined the food patterns of 165 immigrant women from Mexico and 101 Mexican American women who were either bom in die US or migrated at an early age. The frequency of foods eaten in Mexico which were part of the core diet, defined as those foods eaten two to seven times per week by one-third or more of the immigrants, were compared to the frequency of consumption by the Mexican American group. The investigators found that the consumption of most traditional foods consistently decreased between first- and second-generation women and the consumption of many nontraditional foods increased significandy. Table 3 provides a comparison between the percent of first- and second-generation respondents consuming various traditional and nontraditional foods. Of particular interest is the observation that the consumption of butter, margarine, mayonnaise, and salad dressing increased significandy from first-generation to second. Lard, on the other hand, decreased significantly. The number of respondents reporting die consumption of com tortillas in the core diet declined by 13% but still remains high at 84.2% of second-generation women consuming them as part of the core diet The consumption of flour tortillas actually increases from first-generation to second representing a growing popularity in the United States among Mexican immigrants from regions other than the northern wheat producing regions of Mexico. The consumption of beans decreased significandy among second-generation women. The percentage of respondents among first- generation women was 70.9% for both refried and boiled beans compared to 57.4% and 41.6% respectively among second-generation. Peanut butter is particularly popular among first-generation 33 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 3. Percent of subjects reporting intake of traditional and non-traditional Mexican foods by generation status for low income Mexican American women Foods eaten two or more days per week 1st generation (n=165) 2nd generation (n-101) % increase or decrease corn tortillas 96.4 84.2 -12.7% meat (any kind) 94.5 92.1 -2.5% fruit juices 93.3 89.1 -4.5% vegetables 91.5 93.1 1.7% fresh fruits 91.5 93.1 1.7% milk 84.8 88.1 3.9% cheese 81.2 91.1 12.2% vegetable oil 8 0 0 82.2 2.8% ready to eat cereal 78.2 71.3 -8.8% white sliced bread 77.6 84.2 8.5% Mexican red salsa 72.1 66.3 -8.0% refried beans 70.9 57.4 -19.0% boi|ed beans 70.9 41.6 -41.3% eggs (any preparation) 67.9 64.4 -5.2% peanut butter 61.2 43.6 -28.8% American sodas 61.2 67.3 10.0% butter/margarine 80.0 78.2 30.3% rice cooked with tomatoes 59.4 38.6 -35.0% mayonnaise 46.7 64.4 37.9% coffee with milk 46.7 39.6 -15.2% Mexican green salsa 46.1 37.7 -18.2% aguas frescas de frutas 40.6 16.8 -58.6% sopa de fideo 35.8 16.8 -53.1% flour tortilla 35.8 52.5 46.6% white rice 32.1 32.0 -0.3% licuado 31.5 0 -100.0% pan dulce 29.1 14.9 -48.8% lard 28.5 11.9 -58.2% meat prepared with chile 27.9 6.9 -75.3% salad dressing 26.7 59.4 122.5% chips (potato, etc.) 20.0 33.7 68.5% Romero-Gwynn et al., Nutr Today (1993) R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. women with 61% reporting consumption as part of the core diet4 . Although meat consumption declined by 2.5% from first-generation to second-generation, 92.1% of second-generation still reported this food item as part of the core diet. Vegetable consumption increased slightly (1.7%) as women moved to second-generation with 93.1% reporting vegetables as part of the core diet. Milk and cheese consumption also increased among second-generation women. Cheese intake especially increased by 12.2% with 91.1% of women reporting it as part of the core diet. Romero-Gwynn et al. note that while both generation groups were similar on the amount of money spent on food and the number of children, there were statistically significant differences between groups based on age of the respondent, number of years of education, the days-per-week the respondent was employed, and the number of trips to Mexico. The authors concluded that significant dietary changes have occurred in the diets of first- and second-generation immigrants of Mexican descent and that die food consumption practices of second-generation women have begun to resemble a more typical American diet. Changes in dietary habits reflect foe decline in consumption of traditional foods and foe adoption of new foods. Chavez et al. compared foe dietary intake of Mexican American women by length of United States residence. A food frequency questionnaire was used to record the usual frequency of consumption of sixty-eight food groupings which were then scored and combined into one of nine major food groups: dairy foods, protein foods (meats, poultry, fish, and legumes), breads, three fruit and vegetable groups (vitamin C-rich, vitamin A-rich, and other), combination dishes (traditional Mexican entrees), fats and oils, and snack foods (Table 4). The mean food group scores were analyzed by comparing categories defined by foe length of US residence (<5 years; 5-15 years; >15 years). The sample consisted of only 60 Mexican immigrant women with a mean age of 28.4 and a mean length of US residence of 9.4 years. Their analysis showed that longer periods of US residence were associated with decreased intake of vitamin A-rich (p = .01) and vitamin C-rich (p = .03) fruits 4 The authors point out that food assistance programs frequently provide peanut butter at no cost to low-income families. 35 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 4. Mean food frequency scores for Mexican women by length of U.S. residence Length of U.S. Residence Food Groups < 5 years 5-15 years > 15 years p value (total for ail groups n=60) Dairy foods 12.7 11.8 6.4 0.26 Protein foods 19.4 14.7 11.1 0.1 Breads 22.5 19.0 15.5 0.06 Fruits/vegetables Vitamin C rich 16.7 10.3 6.0 0.03 Vitamin A rich 13.2 6.6 4.4 0.Q1 Other 18.3 15.2 7.5 0.28 Combination dishes 8.1 4.6 12.0 0.47 Snack foods 12.2 8.2 13.6 0.22 Fats/oils 6.9 6.1 7.4 0.38 Chavez et al., J Nutr Educ (1994) R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. and vegetables, protein foods (p = .10), and breads (p = .06). Unlike the previous study by Romero- Gwynn et at, the mean consumption of dairy foods also decreased with length of US residence. The mean consumption for the >15 years group was one-half die consumption of dairy foods of immigrants that have been in the US for less than 5 years. The investigators examined the relationship of education and age to dietary measures. They found that food group scores were related to education level but unrelated to age. Mexican women with more than a primary school education consumed more protein foods and vitamin A-rich foods than did women with only a primary school education. The relationship of obesity to dietary measures was also examined. Obesity was defined as a body mass index (BMI) greater than 27. Forty-five percent of the Mexican women were classified as obese using this criterion. The authors found that BMI was negatively associated with level of education, that is, women with only a primary education weighed more and thus had a higher BMI. Elder et al. surveyed Latino adults living in the San Diego area on nutrition, smoking and cancer screening behaviors (Table 5). The Latino (primarily of Mexican descent) respondents were dichotomized into a low-acculturated (L-Latino) or high-acculturated (H-Latino) group according to a median split of their own acculturation index. Data were collected using a 64-item telephone survey administered by trained bilingual interviewers. The nutrition section of the survey addressed saturated fat/cholesterol avoidance, dietary fiber consumption of whole grain products, vegetables, fruits, and legumes, and low and high calorie food consumption using scales developed by Castro (Elder et ah, 1991). Following adjustment for age, years of education, gender, marital status, and income, there were statistically significant group differences for saturated fat/cholesterol avoidance (p < .91), fiber consumption (p < .01) and for high calorie food consumption (p < .01). The L-Latino respondents reported the lowest degree of fat avoidance suggesting a healthier pattern of avoiding fat containing foods with a greater level of acculturation. The level of fiber consumption followed the opposite pattern with the L-Latino respondents reporting the highest level of fiber consumption due to 37 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 5. Means and 95% confidence intervals of dietary measures among Lowracculturated Latino, High-acculturated Latino, and Anglo respondents in San Diego; California, 1989 Observed Adjusted3 Differences" L-Latino H-Latino Anglo L-Latino H-Latino Anglo L-H L-A H-A Saturated fat/cholesterol avoidance scale 3.60 (3.40,3.79) 3.71 (3.54, 3.89) 4.32 (4.10,4.56) 3.58 (3.41, 3.74) 3:85 (3.71,3.99) 4J13 (3.91,4.36) rOJ27 (rO'54,40.00) 40.56 (-0.86,-0.25) -0.28 (■0.63, 0.Q6) Fiber consumption (servings/day) 3.95 (3.67,4.23) 3.69 (3.36,4.03) 2:65 (2.32, 2.98) 3.88 (3J60, 4.16) 3:78 (3.54,4.01) : 2J66 (2.30,3.03) 0.11 (-0.35, 0.56) 1:22 (0.65,1.79) 1.11 (0.60,1.62) Highrcalorie food scale 14.36 (13.30,15.42) 14.14 (12.99,15.29) 9.75 (8.31,11:20) 14.62 (13.60,15:64) 13.13 (12.27,13.98) 10.92 (9.59,12.26) 1.49 (-0L17; 3L15) 3.70 (1.63,5.77) 2.20 (0.35,4.06) Low-calorie food scale 13.39 (12.56,14.22) 13.86 (13.10,14.63) 14.54 (13:35,15.73) 13.88 (12.85,14J91) 14.36 (13.72,15.01) 13.39 (12:36, 14.41) - - - ‘Adjusted for age, gender, income, education, and marital status using linear regression. Elder et al., Prev Med (1991) "Differences computed for measures which varied significantly by ethnicity. u > 00 greater intakes of traditional foods such as com tortillas and refried beans. For high calorie foods, the L-Latinos reported the highest weekly consumption. This study revealed important differences in dietary behaviors based on level of acculturation among Latinos and reinforces the need to consider this factor in the analyses of dietary data. The findings of these dietary studies, although limited, corroborate previous evidence of rapid dietary adaptation to a new range of foods and consequently, changes in the mean intakes of certain nutrients among Latino migrants to the United States. They also reinforce that assessment of dietary intake among migrants must take into account the length of US residence and the effects of gender, age at migration, and factors related to the level of acculturation, such as language preference, education, and economic status. However, while acculturation has caused changes in the diet of Mexicans in the United States, many food traditions have also been retained. The preservation of traditional food consumption habits is facilitated by a geographic closeness to Mexico and the availability of Mexican foods and products in the United States (Romero-Gwynn, 1993). E. COMPARISON OF MEXICAN AND NON-LATINO WHITE BEHAVIORS The two agencies with the greatest responsibility for the conduct of nutrition monitoring3 activities in the US are the Human Nutrition Information Service of the US Department of Agriculture (USDA) and the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (GDC) of the US Department of Health and Human Services (DHHS). The Departments of Defense, Labor, Commerce and State also conduct nutrition surveys but they are usually limited to a specific population they serve. The activities of these six federal departments are collectively referred to as the National Nutrition Monitoring and Related Research Program (NNMRRP) which was enacted by the passage of the Nutrition Monitoring and Related Research Act of 1990 (Woteki, 1995). The goal of this Act is to improve dietary assessment methodology and population dietary 5 A more complete discussion of the nutrition monitoring activities in the United States is included as Appendix A. 39 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. estimates through better coordination and timing of national surveys, standardizing data-collection methods, conducting research to improve dietary assessment methods and standardizing food composition databases used for analyses (Briefel, 1994). The most frequently cited federal nutrition surveys are the Nationwide Food Consumption Survey (NFCS) conducted by the USDA and the National Health and Nutrition Examination Survey (NHANES) conducted by the National Center for Health Statistics (NCHS) of the CDC. NHANES III conducted by NCHS in 1988-1991, uses self reported race and ethnicity to classify persons as non-Latino white, non-Latino black, Mexican American, or ‘Other.’ NCHS also conducted the Hispanic Health and Nutrition Examination Survey (HHANES), a special survey of Mexican Americans, Puerto Ricans, and Cubans, aged 12-73 years, residing in the Continental US (1982-1984). A brief description of NHANES III and HHANES follows. It is important to understand the design differences in order to assess the comparability of these studies. NHANES III (1988-1994) used a single 24-hour dietary recall for persons two months and older and a food frequency questionnaire for persons twelve years and older. In order to improve the overall usual dietary intake estimates, 24-hour dietary recalls included weekend days for the first time. This survey was designed as a six-year survey and was conducted in two three-year phases. In 1988, NCHS contracted with the University of Minnesota’s Nutrition Coordinating Center to develop an automated dietary interview and coding system called the Dietary Data Collection (DDC) System (McDowell et al., 1994). This system provided a standardized interview format and automated probes for the interviewers. USDA food codes were used and nutrients were calculated using the USDA Survey Nutrient database. Many brand specific food codes were added to the USDA nutrient database and hundreds of new foods with reduced fat, sodium and sugar content were also added. A large number of ethnic foods, particularly Mexican American foods were added and significant changes were made to the nutrient composition table. For example, the revised cholesterol content of eggs was incorporated based on updated nutrient composition data- As under reporting has been 40 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. documented in previous studies, ratios of energy intake to basal metabolic rate were calculated for adults based on published formulas. These results suggested a more complete reporting of intake in the NHANES HI survey compared to earlier surveys (McDowell et al., 1994). The HHANES survey consisted of 9455 Mexican Americans from the southwestern states of Texas, New Mexico, Colorado, Arizona, and California (representing 84% of the total Mexican American population in the United States in 1980), 2125 Cubans from Dade County, Florida (representing 57% of die total Cuban population in 1980), and 3525 Puerto Ricans from the New York City metropolitan area including New Jersey and Connecticut (representing 59% of the total Puerto Rican population in 1980) (Delgado et al., 1990). A single 24-hour dietary recall was administered in mobile examination centers by trained bilingual interviewers. Response rates were 7Q% and 75% for Mexican Americans and Puerto Ricans respectively and 60% for Cubans. HHANES was designed to provide baseline nutritional information for Latino subgroups comparable to other surveys conducted by NCHS, particularly NHANES n (Delgado et al., 1990). By design, both surveys included recalls from weekdays only. However, in order to increase response rates in HHANES, some recalls were from weekend days. Few or no recalls were completed for weekend days for Puerto Ricans and Mexican Americans whereas 14% of recalls for Cuban Americans were from weekend days. The Human Nutrition Information Service of the US Department of Agriculture developed the HHANES nutrient database. It is also important to note that unlike the previous NHANES surveys, HHANES was not designed as a national Latino survey. HHANES was restricted to three regions of the country in order to facilitate a cost efficient and logistically feasible operation of the survey (Delgado et al., 1990). Therefore, national estimates for Latino subgroups cannot be drawn based on the survey’s findings. Although HHANES was not designed as a national survey, NCHS estimates that it represented approximately 76% of the total 1980 US Latino population aged six months through seventy-four years (Delgado et at., 1990) and it does allow inferences to the majority 41 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. of Latinos of these three ethnic subgroups (Block et al., 1995). However, limitations of this survey include die lack of important traditional foods and food preparations as well as the fact that food items were frequently collapsed into categories that do not apply to Latin American diets (Romero-Gwynn, 1993). As presented in Table 6, eight studies (Romero-Gwynn et al., 1993; Looker et al., 1993; McDowell et al., 1994; Alaimo et al., 1994; Guendelman and Abrams, 1995; Abrams and Guendelman, 1995; Ballew and Sugerman, 1995; Loria et al., 1995) using federal nutrition survey data, and, as presented in Table 7, approximately fifteen smaller, individually funded studies (Bruhn and Pangborn, 1970; Wallendorf and Reilly, 1983; Dewey et al., 1984; Haffner et al., 1985; Knapp et al, 1985; Knapp etal., 1988; Newell etal., 1988; Patterson etal., 1988; Borrud etal, 1989; Bartholomew et al., 1990; Elder et al, 1991; Romero-Gwynn et al, 1993; DiSogra et al, 1994; Chavez et al, 1994; Winkleby et al, 1994) conducted in various regions of the US have examined nutritional factors among the Mexican American population residing in the United States. Most of the studies were conducted in the 1980s and 1990s and provide important clues about the dietary patterns of Mexican Americans in relation to known risk factors for colorectal cancer. Other studies have examined cultural differences in consumption of vegetables between Mexicans and whites. Bartholomew et al. analyzed data obtained from a food frequency survey of one hundred and ninety Mexican Americans and sixty-two non-Latino whites residing in a San Antonio barrio (a chiefly Spanish-speaking community or neighborhood). Weekly intake of selected foods was determined using HHANES questionnaire data. No information was obtained on the quantity of food consumed and only foods that were consumed at least once per week were considered. The authors found that the weekly intake of orange/green vegetables was lower for Mexican Americans (2.02 servings per week) compared with non-Latino whites (3.34 servings per week). For all vegetables combined, die weekly intake among Mexicans was considerably lower 42 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 6. Studies that used federal nutrition survey data to examine dietary factors among the U.S. Mexican population LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE T n ETHNICITY/RACE SOURCE METHODOLOGY 1. Romero-Gwynn, et al. 1993 foods combined adults 6,947 Mexican Americans HHANES 2,642 Puerto Ricans (1982+1984) 1,315 Cuban Americans 24-hour recall 2. Looker, etal. 1993 calcium men & women 11-74 4739 1,835 1,076 11,773 1,728 Mexican American Puerto Rican Cuban non,Latino White non-Latino black HHANES (1982,1984) NHANES II (1976-1980) 24-hour recall 24-hour recall 3. McDowellj et al. 1994 energy, carbohydrate, total men& 2 mo. - 5,780 non-Latino white NHANES III, fat, protein, alcohol, sat fat, women 80+ years 3J883 non-Latino black Phase 1 mono fah poly fat, cholesterol 4,598 Mexican American (1988-1991) 24-hour recall 4. Alaimo, et al. 1994 vitamins/minerals, dietary men & 2 mo. - fiber women 80+ years 5,780 3,883 4.598 non,Latino white non-Latino black Mexican American NHANES III, Phase 1 (1988-1991) 24-hour recall 5. Guendelman, Abrams 1995 energy, protein, fat, carbohydrate, calcium, iron, folic acid; cholesterol, zinc, vitamins A, C, E women 16-44 475 1st geni Mexican American HHANES 898 2nd gen. Mexican American 2,326 non-Latino white NHANES II & NCI (1976-1980) 24-hour recall Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE N ETHNICITY/RAGE SOURCE METHODOLOGY 6. Abrams; Guendelman 1995 energy, protein, fat, carbohydrate, calcium; iron, folic acid; cholesterol, zinc, vitamins A, C women 16-44 I1J373 2,326 Mexican American non-Latino White HHANES NHANES II 24-hour recall 7. Ballew & Sugerman 1995 energy, protein, cholesterol, women mean 29.9 186 Mexican GENAS 1991 24-hour recall carbohydratej fiber, fat, vitamins A & C, iron, calcium, beta carotene 8. Loria,etal. 1995 energy & cholesterol intake; % of calories derived from carbohydrate, protein; total : fat, sat fat, mono fat; poly fat men & women 20-74 3,317 1,210 861 not specified not specified Mexican American Puerto Rican Cuban non-Latino white non-Latino black HHANES NHANES II 24-hour recall x * * > ■ Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 7. Studies that examined dietary factors among Mexicans residing in different regions of the United States LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE N ETHNICITY/RACE SOURCE OF DATA METHODOLOGY 1 1 . Bruhn & Rangbom 1970 foods combined 18-69 65 Mexican migrant families Northern California 100 item FFQ 26 Anglo'families agricultural labor camps 2. Wallendorf & Reilly 1983 foods combined 102 Mexican American homes Tucson, AZ 97 Anglo homes urban setting garbage analysis 3. Dewey,etal. 1984 foods 71 Mexican American migrants Sacramento Valley 54 item FFQ 69 Mexican Amer non-migrants northern California 4. Haffner, at al. 1985 energyj cholesterol; % of kcal from protein, fat, carbohydrate, sat. tit, mono, fat, poly, fat, cholesterol men& women 25-64 1,221 916 Mexican American Anglo American San Antonid Heart 24-hour recall Study 1979+1982 5. Knapp, et al. 1985 energyj calcium^ vitamin A & men & C, iron, thiamin, riboflavin, women niadn. phosphorus, potassium 2 5 6 4 1J221 913 Mexican American Anglo American San AntoniO Heart Study 1979+1982 24-hour recall 6. Knapp, et al. 1988 saturated fat/cholesterol men & 2564 1,210 Mexican American San Antonio Heart 24-hour recall & avoidance scale women 866 Anglo American Study FFQ 197941982 i / i Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE 7. Newell, etal. 1988 energy * carbohydrate; protein men& 20-60 total fat, sat. fat, cholesterol, women vitamins A & C, calcium, phosphorus, dietary fiber 8. Patterson, et al. 1988 energy; % kcal from total fat, families sat fat, sodium, potassium 9. Borrud, et al. 1989 % food group contribution to men & 20-60 energy; carbohydrate, protein, women total fat, sat. fat, chblesterol, dietary fiber, phosphorus, calcium, vitamins A & C, % food type contribution to total fat, vitamins A & C 10. Bartholomew,etal. 1990 foods men& mean: women mean: 11. Elder; etal. 1991 sat. fat/cholesterol avoidance, men & mean: fiber, high arid low-calorie women mean: food scale mean: ON N ETHNICITY/RACE SOURCE OF DATA METHODOLOGY 98 Mexican American Southeast Texas 24-hour recall 102 black (1984) 231 white 102 Mexican American San Diego Fairiily 24-hour recall, 95 Anglo American Health Project 3 day food diary, 36 item FFQ 98 Mexican American Southeast Texas 24-hour recall 102 black (1984) 231 White 190 Mexican American San Antonio, TX 57 item FFQ 62 white HHANES 167 low-acculturated Latinos San Diego, CA 64 item telephone 191 high-acculturated Latinos survey 113 Anglos Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. LEAD AUTHOR DATE FOOD/NUTRIENTS GENDER AGE 12. Romero-Gwynn Otai. 1993 128 traditional Mexican foods women 19-44 13. DiSogra, et al. 1994 7 foods: green salad, two men& adults servings of fruit, vegetable at women lunch or dinner, fried foods, reduced^fat milk, ground beef 14. Chavez, et al. 1994 food groups: dairy; protein, women breads, snacks, vitamin C fruit & vegetables, vitamin A fruit & i vegetables, Other fruit & veg, 15. Winkleby etal. 1994 high fat foods, eggs, alcohol, combined 20-64 carbohydrates, fiber, fruits, vegetables, % kcal from total fat, sat fat, cartoo, protein; alcohol N ETHNICITY/RACE SOURCE OF DATA I METHODOLOGY 165 101 128 381 60 36 16 426 460 Mexico bom Lafa'nas California U:S. bom Latinas Of Mexican descent Mexican American Fresno County; CA non-Hispanic white Mexican Chicago, IL Puerto Rican WIG Clinic U:Si bam Puerto Rican Hispanid (95.3% Mexican) Stanford Five-City non-Hispanic white California Project (1981-1990) food behatrior checklist 2 ethnic specific FFQ questionnaire & 244tour recall (2.60 per week) than intake for non-Latino whites (7.08 per week; p < .000). In the fruit/vegetable category, only the intake of tomatoes and peppers was slightly higher for Mexicans than non-Latino whites. DiSogra et al. used a simplified 24-hour recall to examine fruit, vegetable and fat intake behaviors among Mexican Americans (n=128) and non-Latino whites (n=381) of Fresno County, California. Dietary behavior was measured using the Food Behavior Checklist that consisted of yes/no questions ahout foods consumed the previous day. The authors found that Mexican American males consumed fewer servings of salad and vegetables than non-Latino white males. Mexican American females also reported fewer servings of salad and vegetables at dinner but slightly more servings of vegetables at lunch than non-Latino white females. Winkleby et al., using data from the Stanford Five-City Project, examined the Latino/white dietary differences among adult subjects aged 20-64 with less than a high school education. The investigators observed no difference in vegetable intake between Latinos and non-Latino whites. The findings of Bartholomew, DiSogra, and Winkleby are contrary to what one would expect given the protective effect observed for vegetable intake. However, the studies are based on servings per day instead of actual consumption and thus must be viewed with caution. The study by DiSogra et al. is especially limited in scope inquiring only about salad, vegetables at dinner, or vegetables at lunch. In the following section we present the findings from eight studies that used federal nutrition survey data and fifteen individually funded studies related to individual nutrients, foods, or other lifestyle behaviors of Mexican Americans. Dietary Fiber Foods high in fiber, a measure of vegetable, fruit, gram, and legume intake, have also been found to be inversely associated with risk of colorectal canter. Cultural differences between Mexican 48 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Americans and non-Latino whites in dietary fiber intake among males and females have been reported in four studies (Alaimo et al., 1994; Newell et al., 1988; Elder et al., 1991; Winkleby et al, 1994). The data from die last study combines males and females. One additional study (Ballew and Sugerman, 1995) reports dietary fiber intake for Mexican females only. Therefore, the data are limited regarding intake of this dietary component among Mexicans. The study by Alaimo et al. uses NHANES III survey data and provides estimates of dietary fiber by age group and gender for the total population and separately for three race/ethnic groups: non-Latino whites, non-Latino blacks and Mexican Americans. Dietary fiber estimates include both insoluble (cellulose, hemicellulose, and lignin) and soluble (gums in cereal grains and pectin in fruits and vegetables) components. The investigators found that dietary fiber intakes were higher for males compared with females for all race/ethnic groups, and generally higher in Mexican Americans compared to the non-Latino whites. Table 8 shows the mean daily dietary fiber intake by age, sex, and ethnicity for subjects aged 30-79 years. Since data are not age adjusted, race/ethnic comparisons are only possible using age-specific mean estimates. Dietary fiber estimates in the 40-49 age group are 24% higher in Mexican American males compared to non-Latino white males. In the 50-69 age range, dietary fiber estimates are 16-17% higher in Mexican American males compared to white males. In females, Mexican Americans consume more dietary fiber than non-Latino whites in the 30- 59 age groups. Estimates in Mexican American females are 25%-28% higher than non-Latino whites in the 30-39 and 40-59 age groups respectively. After age 59, non-Latino white females consume the higher amount of dietary fiber although the differences in intake by race/ethnic group are not as great as seen in die younger age categories. In the second study, Newell et al. reported dietary fiber intake by sex and ethnicity for ninety-eight Mexican Americans (twenty-one males and seventy-seven females) and two hundred and thirty-one non-Latino whites (sixty-five males and one hundred and sixty-six females) aged 20-60 49 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 8. Mean dietary intake of total fiber among males and females by ethnitiity LEADAUTHOR METHODOLOGY SOURCE OF DATA AGE n MEXICAN (g/day) per/1 OOOkcal NON-LATINO WHITE n (g/day) per/1 OOOkcal Males Alaimo, etal. 24-hour recall NHANES III 30439 (225) 23.7 9.0 (271) 20.3 6.9 40449 (181) 22.8 9.0 (243) 18.4 7.1 50,59 (96) 21.8 10.2 (251) 18.7 7.8 60-69 (152) 20.9 10.6 (247) 17.8 8.4 70-79 (60) 18.0 10.8 (285) 17.7 9.2 Newell; et al. 24-hour recall Southeast Texas 20460 (21) * 12:7 6.2 (65) * 18.6 6.6 Females Alaimo, et al. 24,hour recall NHANES III 20429 (317) 16:7 C O © (244) 12.3 6.3 3009 (247) 17L 1 a 2 (279) 13.7 7.2 40-49 (185) 16.4 9.3 (224) 12.8 7.2 50,59 (100) 17.6 10.8 (221) 13.7 8.4 60-69 (153) 13:7 10.5 (246) 15.2 9.5 70-79 (51) 13.0 10.2 (253) 14.7 10.3 Ballew & Sugerman 24-hour recall CENAS mean: 30 (186) 20:8 Newell, et al. 24-hour recall Southeast Texas 20-60 (77) * 15.3 8.2 (166) * 14.1 8.2 'crude measure - value in publication reported per 1000 kcal O residing in southeast Texas. Nutrient intakes were calculated from 24-hour reca}} data using the US Department of Agriculture nutrient data bank. Interestingly, unlike the previous study, die mean dietary fiber intakes were higher for females compared with males for both ethnic groups. The unadjusted mean dietary fiber estimate was slightly higher for Mexican American females (15.3) compared to white females (14.1). However, when adjusted per 1000 kcal, the estimates are the same for both groups (8.2 grams). The estimate of dietary fiber among Mexican males was 12.7 grams per day compared to 18.6 grams per day among whites. However, the sample size of only twenty-one Mexican males suggests this is an unreliable estimate of dietary fiber intake. Elder et al. found that the high acculturation group in their study consumed only slightly fewer servings of fiber per day (3.78 servings) compared with the low acculturated group (3.88 servings). ‘Anglos’ consumed a mean of 2.66 servings per day in comparison. All estimates were adjusted for age, gender, income, education, and marital status. Winkleby et al. found that Latinos consumed a statistically significant greater intake of dietary fiber (26.0 g) compared with non-Latino whites (17.1 g; p s .001) The study conducted by Ballew and Sugerman in Chicago, Illinois using the CENAS Survey, reports a mean intake of 20.8 grains of dietary fiber for 186 low-income Mexican women that is higher than the estimates from the NHANES in survey and the study conducted by Newell. The authors explain that the comparisons between these studies suggest that there may be substantial regional differences in the diets of Mexicans living in the United States. However, methodological differences must also be considered. Although both studies used 24-hour recall methodology, the nutrient databases differed. Further, the NHANES III survey was designed to represent a wider range of Mexican American women in the United States. Cultural differences in fiber rich foods have also been reported. Bartholomew et al. found that Mexican Americans reported significantly more frequent consumption of legumes (p < .000) and flour tortillas (p < .000) than non-Latino whites. Unfortunately, values for com tortilla consumption 51 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. are not reported. On the other hand, whites reported a significantly higher weekly consumption of bread (11.0) than Mexican Americans (4.25; p < .000). Borrud et al. calculated the percentage that specific food groups contribute to nutrient intake in whites (n=231) and Mexican Americans (n=98) residing in Texas. The investigators found that vegetables, other than potatoes, were the greatest contributor to dietary fiber for whites, whereas the legumes group was the main contributor to dietary fiber for Mexican Americans. Mexicans received approximately 29% of their total dietary fiber from legumes compared with about 12% for whites. In fact, legumes were the main contributor to dietary fiber for Mexican Americans followed by grain products primarily from the bread and tortilla food group. Whites received about 27% of their dietary fiber from vegetables followed closely by grains and grain products at 26%. In comparison, Mexican Americans received about 20% of their dietary fiber from vegetables and 21% from grain and grain products, primarily from the bread and tortilla food group as opposed to other grains, cereals, pasta, pancakes or crackers. Interestingly, tortillas made from all purpose white flour were reported three times more often than com tortillas. Finally, a study of ethnic migration, assimilation, and consumption of Mexican Americans residing in the Southwest compared the food consumption patterns of Mexican Americans with those of income matched ‘Anglos’ from the same residential neighborhoods (Wallendorf and Reilly, 1983). However, instead of relying on self- reported data of usual intake, the investigators used data gathered from the analysis of the garbage from the individual households. For this study, seven types of foods were selected for study. All had strong norms connected with them in the American culture and different norms connected with them in Mexico. They are food categories that show changes during the assimilation process and can be measured using the ‘garbology’ methodology. Meats, breads (white, dark, tortillas), cereals, caffeine products, soft drinks, alcohol, and convenience foods (including canned and frozen vegetables) were selected by the investigators. With respect to dietary fiber, the intake of breads, cereals, and vegetables provides a surrogate measure of a portion of total fiber. The study found that Mexican Americans have continued the Mexican pattern of serving 52 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. tortillas. However, instead of preparing tortillas at home from com and flour, Mexican Americans have chosen a pattern of using packaged prepared tortillas. The weighted mean quantity consumed by household was 18.9 per day for Mexican Americans compared to 7.6 per day for ‘Anglos.’ Mexican Americans also consume more white bread than die ‘Anglos’ whereas ‘Anglos’ consume proportionally more dark breads. Mexican Americans use more canned and frozen vegetables, the latter of which is virtually unavailable in Mexico. Mexican Americans have thus adopted the pattern of using many prepared foods that minimize the time and effort required to serve them. The authors conclude that Mexican American consumption patterns are not a simple blending of Mexican and ‘Anglo’ intake patterns as might be expected. Instead, Mexican American consumption patterns suggest the emergence of a unique cultural style. Other studies have provided insight into dietary habits of the Mexican American population concerning fiber rich foods. Bruhn and Pangbom found that refried beans, followed by com tortillas, were the most frequently served foods among Mexican families. Dewey et al. also found that the consumption of tortillas and beans stayed the same for migrant and non-migrant Mexicans after moving to the United States. Romero-Gwynn et al. found the number of respondents reporting the consumption of com tortillas in the core diet declined by 13% from first-generation to second. However, the intake of this food item remains high at 84.2% among second-generation respondents. The intake of beans decreased significantly among second-generation women. Among first- generation women, the percentage of respondents was 70.9% for both refried and boiled beans compared to 57.4% and 41.6% respectively among second-generation women. Based on the limited evidence, a decrease of dietary fiber intake among Mexicans remains a strong candidate for explaining the increase in colorectal cancer rates as the length of US residence increases for these immigrants. 53 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Carotenes Only one study, that by Alaimo et al, examined the cultural differences in carotene intake between Mexican Americans and whites and is shown in Table 9. The investigators present age stratified mean estimates of carotene intake in retinol equivalents (RE) using NHANES HI data. However, the authors caution that estimates of carotene intake are very skewed and therefore means and standard errors should be interpreted with caution. Among males, the mean intakes of carotene for Mexican Americans are 15-57% higher than the mean intakes for whites depending on the age of the respondents. Among subjects aged 30-39, the calorie adjusted crude estimate is 310 RE for Mexican Americans and 198 RE for whites. The difference in carotene intake is not as great for subjects aged 60-69. In that age category, the calorie adjusted crude estimate is 323 RE for Mexican Americans compared with 280 RE for whites. Among females, the cultural differences in carotene intake are more extreme. Among die younger age groups (30-39 and 40-49) Mexican American’s intake is approximately 65% higher than the intake reported for whites. However, among the older age groups the differences in intake are not as significant. In the 60-69 age group there is even a 20% decrease in carotene intake in Mexican American females compared with intake in white females. These finding are inconsistent with the findings reported for vegetable consumption among Mexican Americans and whites given that carotenes are found primarily in fruits and vegetables. The studies that examined cultural differences in vegetable intake found that Mexican Americans consumed fewer servings of vegetables than whites. However, these studies were small, based on servings of vegetables rather that actual consumption, and were limited in the number of questions about vegetable intake. Therefore, the inconsistent findings highlight that there is still a considerable amount of information to be learned about vegetable and carotene intake in the Mexican American population. 54 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 9. Mean dietary intake of carotene in retinol equivalents (RE) among males and females LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE n MEXICAN (RE/day) per/1 OOOkcal NON-LATINO WHITE n (RE/day) per/IOOOkcal Males 1. Alaimo eta l., (1994) 24-hour recall NHANES III 30-39 (225) 819 *310 (271) 582 *198 40-49 (181) 871 344 (243) 582 226 50r59 (96) 661 311 (251) 553 230 60-69 (152) 634 323 (247) 592 280 70-79 (60) 686 413 (285) 570 296 Females 30-39 (247) 769 *413 (279) 471 * 249 40449 (185) 698 396 (224) 431 241 50459 (100) 511 313 (221) 439 272 60-69 (153) 391 302 (246) 601 375 70-79 (51) "5 7 2 447 (253) 605 423 ‘crude estimate ‘^unstable estimate due to small sample size Saturated Fat Several studies have examined cultural differences between Mexican Americans and whites with regard to total fat and saturated fat intake. Mean absolute dietary intake and percentage of energy derived from total fat and from saturated fat are shown in Tables 10 and 11, respectively. Interestingly, comparisons of the percent of calories derived from saturated fat are remarkably similar between Mexican Americans and non-Latino whites. McDowell et al. found from their analysis of NHANES III data that although the actual intake of fat grams/day is higher for non-Latino whites, the percentage of calories derived from saturated fat, by gender, are virtually the same. There are a couple of exceptions. For example, among females aged 40-49, the percentage of calories derived from saturated fat is 11.2% for Mexicans compared to 12.6% for whites. Among males aged 50-59, the percentage of calories derived from saturated fat is 11.0% for Mexicans and 12.3% for whites. This represents a 12% difference in the percentage of calories from saturated fat among whites as compared to Mexican Americans in that one age category . The results presented by Haffher et al. from the San Antonio Heart Study are even more similar than the findings from NHANES HI. In this study, comparisons were made by social class for three different classifications of neighborhood; low income barrio, transitional neighborhood, and an upper income suburb. ‘Anglos’ were included in the latter two classifications. The percentage of calories from saturated fat was 13.2% for Mexican females and 13.4% for white females among respondents from the transitional neighborhood. Among respondents from the upper income suburb, the percentage of calories for females is exactly the same (13.8%) for both Mexicans and whites. Among males, the percentage of calories derived from saturated fat is 13.4% for Mexicans and 13.8% for whites from the transitional neighborhood. The pattern is the same in the upper income suburb with Mexican males consuming 14.5% and white males consuming 14.8% of their energy from saturated fat. 56 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 10. Mean dietary intake and percentage of energy from total fiat among males and females LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE MEXICAN n fat (g/day) % Calories NON-LATINO WHITE n fat (g/day) % Calories Mdles 1. McDowellj et al. 24-hour recall NHANES III 30^39 (225) 100 *34.0% (271) 116 35.5% 40-49 (181) 93 33.0% (243) 100 35.0P/o 501-59 (96) 78 33.0% (251) 99 37.0% 60-69 (152) 73 33.5% (247) 81 34.4% 70-79 (60) 59 32.0% (285) 74 34.6% 2. I Haffner, et al. 24-hour recall San Antonio Heart 25-64 All (536) 38.6% (391) 39.5% Study Barrio 36.6% Transitional 38.5% 3817% Suburb 40.3% 40.2% 3. Patterson, et al. 24-hour recall San Diego Family mean: 38 (42) 37.0% Health Project 4. Newell, et al. 24-hour recall Southeast Texas 20?60 (21) “ 77 33.9% (65) ** 117 3714% * crude measure - i derived by calculating fat g.*9/total kcal ** crude measure - value in publication reported per 1000 kcal Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 10. Mean dietary intake and percentage of energy derived from! total fat among males and females LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE MEXICAN n fat (g/day) % Calories NQN41A7INO WHITE n fat (g/day) % Calories Fem ales 1. Guendelman, Abrams 24-hour recall HHANES, 16-44 1st gen (475) 69 35.0% NHANES II & NCI 2nd gen (898) 69 37.0% (2326) 68 36.0% 2. McDowell, et al. 24-hour recall NHANES III 30^39 (247) 70 * 3319% (279) 76 36.1% 40-49 (185) 66 3317% (224) 72 36.3% 50r59 (100) 58 31.9% (221) 63 35.1% 60-69 (153) 46 31:9% (246) 60 33.7% 70-79 (51) 45 3116% (253) 53 33.3% 3. Ballew & Sugerman 24-hour recall CENAS 1991 mean: 30 (186) 71 3410% 4. Haffner, et al. 24-hour recall San Antonio Heart 25-64 All (718) 3912% (511) 39.4% Study Barrio 3913% Transitional 3819% 38.8% Suburb 3914% 39.9% 5. Patterson, et al. 24-hour recall San Diego Family mean: 35 (101) 3810% Health Project 6. Newell, et al. 24-hour recall Southeast Texas 20r60 (77) **73 3514% (166) **73 38.1% U i 00 Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 11. Mean dietary intake and percentage of energy derived from saturated fat among males and females MEXICAN NON-LATINO WHITE LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE n Fat (g/day) % Calories n Fat (g/day) % Calories Males 1. McDowell, et ai. 24-hour recall NHANES III 30-39 (225) 35 * 11:9% (271) 41 12.6% 40-49 (181) 31 11.0% (243) 33 11.5% 50-59 (96) 26 11.0% (251) 33 12.3% 60-69 (152) 25 11.5% (247) 28 11.9% 70-79 (60) 20 10:8% (285) 26 12.2% 2. Haffner, et al. 24-hour recall San Antonio Heart 25-64 All (536) 14:3% (391) 13.6% Study Barrio 1218% Transitional 1314% 13.8% Suburb 1415% 14.8% 3. Patterson, et al. 24-hour recall San Diego Farrtily mean: 38 (42) 13.0% not specified Health Prbject 4. Newell, et al. 24-hour recall Southeast Texas 20-60 (21) **21 9:4% (65) **32 10.4% * crude measure - derived by calculating sat. fat g.*9/total kcal ** crude measure - value ir r publication reported per 1000 kcal I C/1 SO Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 11. Mean dietary intake and percentage 6f energy derived from saturated fat among males and females LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE n MEXICAN Fat (g/day) % Calories i NON-LATINO WHITE n Fat (g/day) % Calories Fem ales 1 1 . McDowell, et al. 24-hour recall NHANES III 30-39 (247) 25 * 12:1% (279) 27 12.8% 40-49 (185) 22 11:2% (224) 25 12.6% 50-59 (100) 20 11.0% (221) 21 11.7% 60-69 (153) 16 11:1% (246) 20 11.2% 70-79 (51) 15 1016% (253) 18 11.3% 2. Ballew & Sugerman 24-hour recall CENAS 1991 mean: 30 (186) 22 11.0% not specified 3. Haffnerj et al. 24-hour recall San Antonio Heart 25-64 All (718) 13:7% (511) 13.6% Study Barrio 14.0% Transitional 13:2% 13.4% Suburb 13.8% 113.8% 4. Pattersonj et al. 24-hour recall San Diego Family mean: 35 (101) 14.0% notspedified Health Project 5. Newell, et al. 24-hour recall Southeast Texas 20-60 1(77) " 2 2 1016% (166) " 2 2 11.4% •crude measure - derived by calculating sat: fat g.*9/total kcal “ crude measure - value in publication reported per 1000 kcal A study by Loria et al. compared saturated fat intake between adult Mexican Americans and non-Latino whites. Age-specific mean intakes were estimated based on 24-hour recalls from die HHANES (1982-1984) and NHANESII (1976-1980) surveys. Differences between males and females in percent of calories from energy components were small, and therefore, the investigators combined the data for both genders. Therefore, these findings do not appear on Table 11 that is gender specific. Percentage of calories from saturated fat intake was higher in Mexican Americans (13%) than in whites (12.4%) in die 60-74 age group only. In contrast, the percentage of calories from saturated fat intake was higher in whites (13.1%) than in Mexican Americans (12.4%) in the 40- 59 age group. In the 20-39 age group, the percentages were almost identical, 12.8% for Mexican Americans and 12.9% in whites. Winkleby et al. also combined data for males and females in a study of cardiovascular disease and dietary risk factors among Latino (95.3% Mexican American) and non-Latino white adults aged 20-64. The findings of this study are also not included in Table 11 as this table is gender specific. However, in support of the above findings, Winkleby et al. found the percentage of calories from saturated fat intake was significantiy (p s .001) higher in non-Latino whites (13.7%) than in Mexican Americans (11.8%). One other study examined cultural differences in saturated fat intake and is shown on Table 11 (Newell et al, 1988). Among females, the unadjusted intake of saturated fat is the same (22 g/day) for both ethnic groups. However, the percentage of calories is about 8% higher for whites (11.4%) than for Mexicans (10.6%). The values for males appear unreliable due to the small sample size especially among Mexicans. There is little information on the impact of American culture on total or saturated fat intake in Mexican Americans. Elder et al. compared saturated fat/cholesterol avoidance among low- acculturated Latinos, high-acculturated Latinos, and “Anglos.” The L-Latino group reported the lowest degree of fat avoidance and “Anglos” reported the highest degree. This suggests a healthier 61 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. pattern of avoiding fat containing foods as die level of acculturation increases. Pairwise comparisons revealed that the L-Latino group score was significantly lower than both die H-Latino group score and the “Anglo” group score. However, to study genetic and environmental determinants of non-insulin dependent diabetes, Stem et al. compared a random sample of Mexican American men and women living in several low-income barrio neighborhoods of San Antonio to similarly aged Mexicans living in a low-income colonia in Mexico City. The investigators found that Mexico City residents ate less fat (18-19% of total calories) compared to their San Antonio counterparts (31-32% of total calories). A measure of saturated fat intake is not provided (Stem et al., 1992). The results of these studies point to the need for further research regarding the intake of saturated fat following migration to the United States and the effect of increasing acculturation to the contemporary American culture. However, most of the cross-cultural comparisons showed little if any difference in the saturated fat intake between Mexican Americans and whites. If Mexican Americans followed the traditional model of assimilation by adopting, over time, the behaviors of the contemporary American culture, then saturated fat intake would most likely not be responsible for the changing rate of colorectal cancer in the Mexican American population. Red Meat There is limited data on red meat consumption in the Mexican American population. Romero-Gwynn et al. found that the percentage of respondents who consumed meat of airy kind decreased slightly from first-generation to second-generation. Among first-generation, 94.5% of respondents reported intake compared to 92.1% of second-generation respondents. The consumption of traditional meat soup decreased from 25.5% of first-generation to 13.9% of second-generation respondents. Meat prepared with chile also showed a decline in consumption with 27.9% of first- generation respondents reporting intake compared to 6.9% of second-generation respondents. No measures of actual quantity were reported. 62 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Dewey et al. found that the intake of beef and pork stayed the same among Mexican migrants and increased among Mexican non-migrants. The intake of liver decreased in both groups since moving to the US and the intake of other organ meats stayed the same among migrants and increased among non-migrants. Chorizo, Mexican pork sausage, decreased or stayed the same in both immigrant groups. Cultural differences in red meat consumption have been examined in four studies. Bartholomew et al. found that Mexican Americans reported significantly more (p = .01) frequent consumption of organ meat and significantly less (p = .003) frequent consumption of beef than non- Latino whites. The investigators also found level of education to be a significant (p < .001) predictor of frequency of beef intake in a regression analysis whereas income and ethnicity were associated with frequency of organ meat consumption. Winkleby et al. found that Mexican American reported significantly more (p s .02) frequent consumption of red meat and significantly less (p s .001) frequent consumption of cured meats than non-Latino whites. On the other hand, Wallendorf and Reilly in comparing food consumption patterns of Mexican Americans and whites residing in the Southwest using ‘garbology’ methods found Mexican American households eat more red meat, both beef and other red meats, than “Anglo” households although the differences are not statistically significant. Borrud et al. calculated the percentage that specific foods contribute to total energy and nutrient intake. They reported that 48.8% of the meat, fish, and poultry contribution to protein came from beef and veal for Mexican Americans compared to 45.7% for whites. Further, 49.5% of saturated fat intake among Mexican Americans was attributable to the meat, fish, and poultry food group with beef and veal contributing the greatest. Beef and veal contributed 32% to total saturated fat intake among Mexican Americans. In comparison, 31.5% of saturated fat intake among whites was attributable to the meat, fish, and poultry food group with beef and veal making the greatest 63 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. contribution. However, only 18.4% of total saturated fat intake among whites is attributable to their beef and veal intake. The contrasting findings of these studies highlight the need for further study of the “red meat hypothesis,” i.e., high red meat intake increases risk of colorectal cancer, in the Mexican American population. Calcium Several studies have examined cultural differences in calcium intake among Mexican Americans and whites. The findings are shown in Table 12. Among males, the findings are consistent with Mexican Americans reporting a lower intake of calcium than non-Latino white males in four separate studies. Among females, the findings are more mixed. Abrams and Guendelman found a higher intake of calcium among Mexican American women aged 16-44 when the two- generation strata were collapsed and compared to non-Latino white women. Looker et al. using HHANES data for Mexican Americans in comparison to NHANESII data for non-Latino whites found that Mexican American women in age groups 18-39 and 55-74 consumed a higher intake of calcium than white women. The middle age group of40-54 years consumed less calcium than their non-Latino white counterparts. Among Mexican American women aged 18-74, the top, single-food contributor to total calcium intake was whole milk (24% of total calcium) followed by com tortillas (8%), cheese (9%), and low-fat milk (6%). Refried beans, wheat bread and flour tortillas also contributed smaller percentages to total calcium intake. Alaimo et al., using NHANES III data, found similar results as Looker et al. with unadjusted values. However, when adjusted per 1000/kcal, the estimates for calcium intake are very similar between Mexican Americans and non-Latino whites. Knapp et al. using data collected as part of the San Antonio Heart Study found that the intake of calcium was lower in Mexican American women as compared to non-Latino white women. Of interest however, is that in the latter study, as the socio-economic status of the women improved, the 64 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 12. Mean dietary intake of calcium among males and females LEAD AUTHOR METHODOLQG SOURCE OF DATA AGE n MEXICAN (mg/day) I ! NON-LATINO WHITE n (mg/day) per/1 OOOkcal Males 1 1 . Looker, etai. 24-hour recall HHANES, NHANES II 118439 (943) 985 (1957) 1092 40454 (359) 742 (870) 868 55-74 (273) 743 (2032) 785 2. Alaimo.et al. 24-hour recall NHANES III 30439 (225) 995 376 (271) 1122 382 40-49 (181) 890 351 (243) 851 331 50459 (96) 749 352 (251) 902 374 60469 (152) 837 426 (247) 895 423 70-79 (60) 673 405 (285) 832 432 3. Knapp, et al. 24-hour recall San Antonio Heart 25464 All Study Barrio (157) 506 Transitional (185) 578 (180) 732 Suburb (179) 622 (215) 742 4. Newell, et al. 24-hour recall Southeast Texas 20460 (21) 248.1 (65) 30918 Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. iTablei12. Mean dietary intake of calcium among males andi females LEAD AUTHOR METHODOLO SOURCE OF DATA AGE n MEXICAN (mg/day) per/1 OOOkcal NON-LATINO WHITE n (mg/day) per/1 OOOkcal Females 1. Guendelman, Abrams 24-hour recall HHANES, NHANES II 16-44 1st gen 2nd gen (475) (898) 779 645 (2326) 678 2. Abrams, Guendelman 24-hour recall HHANES, NHANES II 16-44 (1373) 691 (2326) 678 3. Lookerj et al. 24-hour recall HHANES, NHANES II 18-39 40-54 55-74 (1064) (496) (337) 650 561 582 (1991) (928) (2325) 642 617 564 4. Alalmoj etal. 24-hour recall NHANES III 30-39 40-49 50-59 60-69 70-79 (247) (185) (100) (153) (51) 847 701 701 606 593 455 397 429 467 483 (279) (224) (221) (246) (253) 788 416 717 401 660 408 743 464 651 455 5. Ballew & Sugerman 24-hour recall CENAS mean: 30 (1 8 6 ) 880 6. Knapp, etal. 24-hour recall San Antonio Heart Study 25-64 All Barrio Transitional Suburb (277) (231) (192) 408 439 471 (243) (275) 561 505 7. Newell, et al. 24-hour recall Southeast Texas 20-60 (77) 257 (166) 339 ^unstable estimate due to small samplesize ! ON I ON intake of calcium increased. Mexican American women residing in the suburb reported the highest intake of calcium (471 mg) whereas women residing in a low-income barrio reported the lowest intake (408 mg). Women from die transitional neighborhood reported a median value o f439 mg per day. This pattern of calcium intake by socio-economic stratum was found in Mexican American males in the same study as well. Only one study, that by Guendelman and Abrams, examined the impact of the American culture on dietary habits of Mexican American immigrant women aged 16-44. The authors found that first-generation Mexican American women had a higher intake of calcium than either second- generation Mexican American women or non-Latino white women. First-generation women consumed a significantly higher amount (779 mg) of calcium in comparison to second-generation (645 mg) and non-Latino white (678 mg) women. Second-generation Mexican American women resembled white non-Latino women with respect to their intake of calcium. Several studies have examined dietary sources of calcium among Mexican Americans and the US non-Latino white population. Chavez et al. found that the intake of dairy foods decreased as die length of US residence increased. The mean dairy food frequency score for women who have lived in die United States for more than fifteen years was one-half the mean dairy food frequency score for women in the US for less than five years. Romero-Gwynn et al. observed that certain milk- based sources of calcium such as atole (gmel thickened with masa, com starch, ground rice, or oats and sweetened with sugar), arroz con leche (rice pudding), and licuado (cold beverage prepared with fruit and milk, blended and sweetened with sugar) tended to disappear either after immigration or among second-generation Mexican Americans, but the consumption of cheese, milk, and ice cream increased over time in the United States. Dewey et al. also observed that the consumption of milk and ice cream stayed the same or increased since moving to the US among low-income first-generation Mexican American families in northern California. Bartholomew et at. found that US non-Latino whites reported significantly (p = .007) more frequent consumption of skim milk whereas Mexican 67 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Americans reported more frequent consumption of whole milk. Overall intake of milk, however, is similar between the two ethnic groups. Non-Latino whites reported more frequent consumption of cheese and ice cream than Mexican Americans. Borrud et al. observed that the milk and milk products group was the main contributor to calcium intake for both non-Latino whites and Mexican Americans. Non-Latino whites consumed 47% of total calcium from milk products whereas Mexican Americans consumed 40 percent. Grain and grain products accounted for 17% andl2% of total calcium intake for Mexicans and non-Latino whites respectively. Legumes accounted for 6% of total calcium intake among Mexican Americans compared with 2% among non-Latino whites. These three food groups account for most of the discrepancy between Mexican Americans and non-Latino whites regarding dietary sources of calcium. Other food group contributions to calcium intake are similar between the two ethnic groups. The findings, especially among females, regarding calcium intake highlight that additional research is needed to sort out actual cultural differences between Mexican Americans and whites as well as the effect of the contemporary American culture on the intake of this micronutrient among Mexican immigrants. However, the preliminary findings cited above do not suggest that the calcium hypothesis, i.e., higher calcium intake is protective, will explain the changing rate of colorectal cancer incidence in the Mexican American population following migration to the United States. Cholesterol/Eggs Several studies have reported cholesterol intake among Mexican Americans (see Table 13). In comparing first-generation Mexican American women to second-generation, Guendelman and Abrams found that first-generation women reported the highest intake of cholesterol at 3S3 mg per day compared to 306 mg per day for second-generation and 267 mg per day for non-Latino white women (Guendelman and Abrams, 1995). The findings of three other studies are supportive. All three reported a higher mean intake of cholesterol among Mexican Americans compared to non- 68 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 13. Mean dietary intake of cholesterol among males and females LEAD AUTHOR METHODOLOGY SOURCE OF DATA AGE n MEXICAN (mg/day) per/1 OOOkcal NON-LATINO W HITE n (mg/day) per/1000kcal Males 1 1 . Loria, et al. 24-hour recall HHANES. NHANES II 20^39 Total male 505 not specified 40-59 & females 459 60-74 (3317) 441 all 479 2. McDowell, et al. 24-hour recall NHANES III 30-39 (225) 434 164 (271) 372 126 4049 (181) 421 166 (243) 329 128 50r59 (96) 383 180 (251) 320 133 60-69 (152) 354 180 (247) 306 144 70-79 (60) 310 187 (285) 264 137 3. Haffner, et al. 24-hour recall San Antonio Heart 25-64 (536) 222 (391) 185 Study 4. Newell, et al. 24-hour recall Southeast Texas 20-60 (21) 187 (65) 136 Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 1:3. i Mean: dtetaryi intake of cholesterol among males andi females LEAD AUTHOR METHQDDLO SOURCE OF DAT AGE n MEXICAN (mg/day) per/1 OOOkcal NON-LATINO WHITE n (mg/day) per/1 OOOkcal Females 1. Guendelman, Abrams 24-hour recall HHANES, 16444 Istgen (475) 353 (2326) 267 NHANES II & NCI 2nd gen (898) 306 2. Loria, et al. 24-hour recall HHANES, 20439 total males 332 not specified NHANES II 40459 & females 300 60-74 (3317) 302 all 317 3. McDowell, et al. 24-hour recall NHANES III 30439 (247) 283 152 (279) 242 128 40-49 (185) 284 161 (224) 232 130 50-59 (100) 264 161 (221) 217 134 60-69 (153) 227 175 (246) 204 127 70-79 (51) 243 190 (253) 187 131 4. Bailew & Sugerman 24-hour recall CENAS 1991 mean: 30 (186) 366 not specified 5. Haffner, etal. 24-hour recall San Antonio Heart 25-64 (718) 225 (511) 209 Study 6. Newell, etal. 24-hour recall Southeast Texas 20-60 (77) 324 174 (166) 289 169 © Latino whites. The findings are consistent for males and females and across all age strata. McDowell et al. found that Mexican American women, aged 40-59, reported cholesterol intake that was 22% higher than that reported by non-Latino white women in the NHANES III study. In the 60-69 age category, Mexican American women reported an 11% higher intake and in the oldest age category, cholesterol intake among Mexican women was 29% higher compared with non-Latino white women (McDowell et al., 1994). The San Antonio Heart Study reported an 8% higher intake of cholesterol among Mexican American women compared with non-Latino white women (Haffner et al., 1985) and in a study in Southeast Texas, the investigators found that Mexican American women reported a 12% higher intake of cholesterol than their non-Latino white counterparts (Newell et al., 1988). Both studies adjusted for calorie intake. Among men, the differences in cholesterol intake between Mexicans and non-Latino whites are more significant. In the two studies where the sample size was sufficient, the investigators reported a 16%-28% higher intake among Mexican Americans depending on the age category examined (McDowell et al., 1994; Hafiher et al., 1985). Cholesterol is found only in foods derived from animals. Foods containing very high amounts of cholesterol are organ meats such as kidney, liver, brains, and beef heart. More commonly consumed foods that are leading contributors of cholesterol in the diet are eggs, beef, pork, whole milk, poultry, and hot dogs (Wardlaw and Insel, 1993). Cheese, ice cream, low fat milk, butter, mayonnaise, and shrimp also contribute to cholesterol intake in the diet. Several studies have examined die intake of these commonly consumed foods among Mexicans and non-Latino whites. Borrud et al. found that Mexican Americans consumed a greater percentage of their cholesterol intake from meats than non-Latino whites as a result of a substantially greater intake of organ meats. In the meat, fish, and poultry food group, organ meats accounted for 13.1% of the intake of cholesterol among Mexican Americans compared to 2.5% among non-Latino whites. The percentage of cholesterol from consumption of beef and poultry were similar between the two groups. Mexican 71 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Americans also consume a greater percentage of their cholesterol from eggs whereas non-Latino whites consumed a greater percentage from milk and milk products (Borrud et al, 1989). Bartholomew et al. found that Mexican Americans reported significantly more frequent consumption of poultry, organ meats, and eggs compared with non-Latino whites but statistically significant less frequent consumption of beef (Bartholomew et al., 1990). Romero-Gwynn et al. found that the consumption of eggs decreased after immigration to the US and among second-generation respondents (Romero-Gwynn et al., 1993). Wallendorf and Reilly found that egg consumption among Mexican Americans is between that of Mexicans and non-Latino whites confirming the traditional model of assimilation into die American culture (Wallendorf and Reilly, 1983). Knapp et al. report that Mexican Americans are less likely to drink low fat milk than non-Latino whites and that whites recognize milk, eggs, and visible fat on meat as food sources to avoid. Cholesterol avoidance increased significantly with increasing socio-economic status in both ethnic groups (Knapp et al., 1988). Winkleby et al. observed that Latino adults were significandy (p s .001) more likely to drink whole milk rather than low- or nonfat milk than non-Latino whites. Latinos also consumed more eggs per week (3.5) than their non-Latino white counterparts (3.3). These findings suggest that the intake of high cholesterol foods, including eggs, decreases among Mexican Americans following migration to the United States and as they become acculturated to the American diet. Therefore, this change in dietary habits would not explain the increasing rate of colorectal cancer incidence within this population. Physical Activity There are few published findings of physical activity levels in the Mexican American Latino population. Leisure-time physical activity was measured among US adults as part of the third National Health and Nutrition Examination Survey (NHANES in). Questions were asked about the type and frequency of physically active hobbies, sports, and exercise. The findings of the study 72 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. showed that the prevalence of no leisure-time physical activity (LTPA) was highest in Mexican American men (33%) and women (46%) of any of the race/ethnic groups studied (Crespo et al, 1996). Second, a study of the genetic and environmental determinants of non-insulin dependent diabetes compared Mexican American men and women Jiving in low-income barrio neighborhoods of San Antonio to similarly aged Mexicans living in a low-income colonia in Mexico City. The investigators found that Mexico City residents performed more physical activity than San Antonio Mexican Americans (Stem et al., 1992). The scarcity of information on physical activity levels among Mexican Americans particularly with regard to the effect of acculturation, confirms the need to examine this variable in future studies. Body Mass Several previous studies have shown that Latinos have a higher prevalence of overweight and obese individuals than non-Latino white populations in the United States (Hazuda et al., 1991; Balcazar and Cobas, 1993; Kumanyika, 1993; Samet et al, 1988; Winkleby et al, 1993; Winkleby et al., 1996). While this has been a consistent finding, there is little information on the effect of acculturation on the prevalence of obesity in the Mexican American population following migration to the US. Further, the results of two studies that did examine the relationship between socioeconomic status, acculturation and obesity among Mexican Americans were not consistent. Hazuda et al observed that the effect of socioeconomic status and acculturation on overall obesity and body fat distribution differed by sex group. In both men and women, increased acculturation to the contemporary American culture was accompanied by a statistically significant linear decline in obesity. Socioeconomic status had no effect on obesity in men. However, in women, socioeconomic status was associated with lower overall obesity (Hazuda et al, 1988). Khan et al. based on HHANES data observed that significant interactions existed between generation status and language 73 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. preference among Mexican Americans making it difficult to sort out die effect of each. Considered individually, generation status was significandy associated with body mass index in Mexican Americans with second and third-generation respondents reporting a greater BMI relative to first- generation men and women. However, the investigators also observed that increasing preference for English was associated with a decrease in the BMI for Mexican American women. Given die interactions, the investigators examined the independent relationship of language preference with BMI for each generation. In men, English language preference was significantly associated with lower body mass in third-generation only. Greater body mass was significantly associated with Spanish language preference in first and second-generation Mexican American men and women (Khan etal., 1997). The findings presented by Khan et al., were similar to the findings of the San Antonio Heart Study. Khan found that two indicators of socioeconomic status, namely education and income, are not strong predictors of body mass. Measures of acculturation were found to be more strongly associated with BMI and, therefore, exert a greater influence on obesity in Mexican Americans than socioeconomic factors. However, while both studies agree that acculturation has a greater effect on changes in body mass, the findings of the two studies are not consistent. In fact, the San Antonio Heart Study reports a statistically significant linear decline in obesity with increasing acculturation. The HHANES data, on the other hand, found that second- and third-generation respondents reported a greater BMI relative to first-generation Mexican American men and women. These conflicting findings may be partially explained by the difference in definition of acculturation used by the two studies. In the San Antonio Heart Study, acculturation was defined by three criteria which measure functional integration with mainstream society, value placed on preserving Mexican cultural origin, and attitude toward traditional family structure and sex-role organization (Hazuda et al., 19S8). In the Khan et al. study based on HHANES data, acculturation was defined using generation status in the United States and language preference of the respondent (Khan et al, 1997). These indicators, the 74 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. investigators point out, have been used by other studies using HHANES data to study the association between acculturation and other indices of health or behavioral practices. Alcohol There is a considerable body of published literature on alcohol use and misuse in the Mexican American population in the United States. There have been studies of the effects of aging (Black and Markides, 1994), acculturation (Maks et al., 1990; Caetano et al, 1988; Markides et al, 1990; Marin and Posner, 1995; Markides et al, 1988; Neff and Hoppe, 1992), gender (Corbett et al, 1991; Marin and Posner, 1995), income and education (Corbett et al, 1991; M aks et al, 1990), as well as studies on the influence of attitudes and expectancies on drinking behavior (Corbett et al, 1991; M ain, 1996). There is also extensive literature from studies conducted in Mexico because alcohol contributes to the highest rates of social problems among several countries due to its use and misuse (Rosovsky and Romero, 1996). Data from several recent studies conducted in different regions in Mexico show the proportion of drinkers and abstainers by gender (Rosovsky and Romero, 1996). Among males, the proportion of drinkers ranges from about 70% in Baja California to 85% in Nuevo Leon. A national study conducted in 1988 and reported by Medina-Mora etal found 73.4% and 26.6% of males in Mexico were drinkers and abstainers respectively. Among females, the proportion of drinkers’ ranges from 42% reported in Baja California to 51% in the Federal District. This study found 36.5% of females were drinkers and 63.5% were abstainers (Rosovsky and Romero, 1996). However, the study also found that reported per capita consumption is not an average intake because of the fact that not all the population has equal access to alcohol. In fact, it is estimated that the 25% of drinkers at the top of the consumption scale ingest 78% of the available alcohol (Caetano, 1996). 75 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Results from a household survey in the state ofMichoacan, a core region from which people immigrate to the United States6 , showed similar findings as die national study for both genders. However, in the rural area ofMichoacan, more abstainers (33%) as well as more excessive drinkers (12%) were found among males. It was estimated that the excessive drinkers consume approximately 65% of the available alcohol in the region (Rosovsky and Romero, 1996; Gaetano and Medina-Mora, 1988). The national household survey in 1988 found the proportion of frequent heavy drinkers7 was high among males (14.2%) but low among females (0.6%). However, the general pattern of alcohol consumption among males in the Mexican population is best characterized as high quantity per occasion but in moderate frequency. Among females, on the other hand, the pattern of drinking is characterized by infrequent or less frequent occurrence with low quantity of consumption. Pulque and pure sugarcane alcohol are consumed by individuals with lower education and income compared to wine and distilled spirits consumed by people with a higher income and education. Beer is consumed by people of every status in Mexico (Rosovsky and Romero, 1996). In general, cross cultural studies have found that Mexican males who migrate to the United States shift their pattern of alcohol use to the American pattern of frequent drinking but continue the pattern of consuming a large quantify of alcohol per occasion (Caetano and Medina Mora, 1988). Changes in drinking patterns seem to occur soon after coming to the United States, often within five years. Marital status was found to have an effect on frequent heavy drinking. The rate of frequent heavy drinking among immigrants who reported being single (34%) is almost twice as high as the rate among married immigrants (18%). In contrast, Mexican migrant women do not change their pattern of alcohol use characterized by abstinence or infrequent drinking. However, by second-generation, 6 More than half of the study sample reported a relative living permanently in the US. 7 Frequent heavy drinking is defined as five or more drinks per occasion at feast once per week. 76 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. there is an increase in the percentage of drinkers among Mexican American women (Rosovsky and Romero, 1996). Analysis of HHANES data found that 77.4% of Mexican American males and 34.7% of females are current alcohol users. As in other studies, increased acculturation, more education, and higher income were associated with increased alcohol consumption among women (Marks et al, 1990; Corbett et al., 1991). The relationship of acculturation with alcohol intake is not consistent among men (Markides et al., 1990; Caetano, 1987). Investigators also found that as age increased alcohol consumption decreased (Marks et al, 1990; Markides et al., 1990). Studies of Mexican Americans in Northern California and San Antonio, Texas observed significant gender differences in drinking patterns and the frequency of heavy drinking consistent with die findings of Caetano and Medina Mora reported above (Corbett et al., 1991; Marin and Posner, 1995; Markides et al., 1988; Neff and Hoppe, 1992). Corbett et al. found that in the heavier drinking category (frequent high maximum and frequent heavy) there were fewer that 3% of women in comparison to 25% of men. In the lower categories of drinking, 45.1% of women are abstainers and an additional 33.5% are infrequent drinkers. In contrast, 22% of men are abstainers and only 14.6% are infrequent drinkers. However, the findings related to the effect of acculturation on alcohol consumption were not consistent. Marin and Posner, as in other studies, observed that the level of acculturation significantly affected the proportion of abstainers in both men and women with the more acculturated reporting fewer abstainers (Marin and Posner, 1995). However, in a study conducted in San Antonio, quantity and frequency of consumption was slightly higher among the least acculturated males and moderately acculturated females (Neff and Hoppe, 1992). These findings are consistent with those of Markides et al. who observed that acculturation is related to lower alcohol consumption among men in the middle generation of a three generation family study. The authors failed to find any relationship between acculturation and alcohol intake in the older and younger generations of men (Markides et al, 1988). Among women, Markides etal. found less acculturated middle-generation 77 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. women to be more frequent drinkers and to consume higher quantities of alcohol. However, among younger women, acculturation is associated with greater frequency of consumption, greater volume, and a higher probability of being a drinker of alcohol (Markides et al., 1988). It is important to point out that the definition of ‘generation’ in this study is significantly different than the definition used in other migrant studies where generation usually represents the length of time ones family has been in the United States. These individuals are related to one another: older parents, their middle-aged children, and younger (adult) grandchildren. In fact, the investigators point out, most older generation members are Spanish speaking. Therefore, it is difficult to compare the findings of this study with other studies since we do not know the nativity of the respondents or the length of time in the US. This provides only a brief overview of the vast amount of literature on the use of alcohol in the Mexican American population. It is not intended to be a comprehensive review but rather a summary of the major findings. Nevertheless, the findings reported above reinforce the need for careful analysis of this dietary variable in relation to other risk factors for colorectal cancer. There is certainly evidence that alcohol consumption increases among Mexican Americans as they become acculturated to the American way of life, thus making alcohol consumption a candidate for explaining the increasing rate of colorectal cancer in this population. 78 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. PART II. DATA ANALYSIS There are two research goals of die data analysis component of this dissertation: (A) to determine what changes, if any, in dietary and other lifestyle behaviors (alcohol consumption, obesity, and physical exercise) are consistent with the changing rate of colorectal cancer incidence in the Los Angeles Mexican American population following migration to die United States; and (B) to conduct a nested (from within a prospective cohort study) case-control study to examine the association of colorectal cancer with nutrient intake and a limited number of demographic variables using the Mexican American cohort population. The colorectal cancer incidence rates presented in Table 14 provide a compelling reason to conduct this research. Among males, US-bom Mexican Americans have a colorectal cancer incidence rate that is more than three times that of Mexico-bom immigrants, specifically 237.3 and 66.1 respectively. Among females, preliminary incidence rates among US- bom Mexican Americans are about double the rates of Mexico-bom immigrants, specifically 113.6 and 59.3 respectively. Interestingly, rates of male and female Mexico-bom immigrants are essentially the same whereas rates of male and female US-bom Mexican Americans differ by a factor of two. By examining food and nutrient intake of the Mexico-bom immigrant population by the number of years of US residence and comparing those values with the food and nutrient intake of US- bom Mexican Americans, we can examine the speed at which dietary change occurs and determine whether this may explain the observed increase in colorectal cancer rates among US-bom Mexican Americans. However, a migrant analysis, while important, serves only to generate hypotheses about which factors might influence disease risk. The nested case-control analysis that will follow, not only provides the opportunity to test hypotheses that emerge from the first investigation but also allows us to further investigate risk factors of colorectal cancer that have emerged from previously published studies. The latter analysis will serve as a preliminary examination of risk factors for the reason that there are only a limited number of incident cases within the Mexican American cohort population to 79 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 14. Age-adjusted incidence rates of colorectal cancer in the Mexican origin Latino cohort by migration status Mexico-born US-born (bath parents bom in Mexico) Standard Population (1970 US Population) # person . 1 # person . 1 # events years rate events years rate events pop rate MALES 45149 0 2428.6 0.0 0 288.2 0.0 50-54 0 4209.5 0.0 2 658.7 303.6 4 54643 7j 3 55-59 3 5318.5 56.4 4 1614.5 247.7 8 49077 I16J3 60-64 4 5673:7 70.5 4 3443.4 116.2 19 42403 44J8 65-69 3 4375.6 68.6 19 5471.6 347.2 31 34406 90.1 70-74 7 3356.9 208.5 5 3758.0 133.0 23 26789 85.9 75-79 3 13249 226.4 5 1407.0 355.4 All Ages 20 26687.6 66.11 39 16641.4 | 237.3 85 207318 FEMALES 45-49 1 2749.7 36.4 0 372.6 0.0 50-54 1 4739;7 21.1 1 828.5 120.7 55-59 0 6152.5 0.0 1 1989.6 50.3 60-64 7 5751.3 121.7 4 3654:7 109.4 65-69 3 3601.9 83.3 6 5149.2 116.5 70-74 3 2577.8 116.4 8 3675:7 217.6 75-79 3 1181.7 253.9 1 1214.7 82.3 All Ages 18 26754.7 59.3| 21 16885.0 113.6 1 Age4standardized rate (standardized to 1970 U.S. population); incident cancer ca ses diagnosed 1993 through 1997 00 o date. It is, nevertheless, an important culmination to the migrant analysis. We use data from the Hawaii and Los Angeles Multiethnic Cohort Study o f Diet and Cancer, hereinafter, “Multiethnic Cohort Study,” for both analyses. A. MIGRANT STUDY METHODS Selection o f Subjects The design and implementation of a large multiethnic cohort study in the populations of Hawaii and Los Angeles to study diet in relation to cancer causation has been described elsewhere (Kolonel et al., 2000). Briefly, participants entered the cohort from 1993 to 1996 by completing a 26- page, self-administered mail questionnaire that asked about the normal intake of approximately 180 foods and beverages, as well as information on ethnicity, previous medical diagnoses, physical activity, and, for women, reproductive factors and use of estrogen. The dietary component comprises the major portion of the questionnaire and covers a } } the major sources of nutrients for each of the ethnic populations. The primary goal in establishing the Los Angeles component of the Multiethnic Cohort Study was to recruit African American and Latino males and females aged 45-75 from all socioeconomic strata that would be roughly representative of these groups in the population of Los Angeles County. Individuals from other ethnic/racial groups were included if they replied to the mailed questionnaire. We used the Department of Motor Vehicles (DMV) drivers’ license file for Los Angeles County as the primary source of potential subjects. As the drivers’ license database did not contain a race/ethnicity designation, we used two methods for identifying potential subjects. First, ethnic- specific surname files were created from several different sources, including the files of the 81 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. population-based tumor registry in Los Angeles, rosters of participants in our previous epidemiological studies, a listing of surnames compiled as a result of technicians going into Los Angeles communities for several months to obtain ethnic-specific surnames, commercial publications, and church membership directories. This effort resulted in a database of separate lists for Japanese, Latino, Filipino, Chinese, Korean, Samoan, and Hawaiian surnames. These files were not mutually exclusive since the same name may appear on more than one list. Names not appearing on any of the above surname lists were used to identify potential African American participants. However, because the number of names remaining was large and we could not distinguish African Americans from whites, we limited our mailings to specific census tracts with a high concentration of African Americans. Data files of the tumor registry in Los Angeles and census data identified these specific tracts or zip codes. The Latino (Spanish surname) list included all zip codes in Los Angeles County. For purposes of this analysis, we considered only those Latinos of Mexican national origin or descent who are currently residing in California. We focused on the comparison between first- generation (Mexico-bom) immigrants and second-generation (US-bom) Mexican Americans. While we suspect that most of our third-generation (or higher) Latino cohort members are most likely of Mexican-origin, we could not verify this from the questionnaire. Furthermore, our main interest was to isolate those factors that may contribute to the increase in colorectal cancer incidence that occurs between the migrating generation and second-generation Mexican Americans. Subjects of Mexican-origin were identified based on their responses to four questions on the questionnaire: race/ethnicity, place of birth, the number of years in die US for Mexico-bom subjects, and parents’ place of birth. Eligible subjects were of “Mexican or other Hispanic” ethnicity who were bom either in the United States or Mexico and whose parents were both bom in Mexico. Length of US residence was determined by the following response categories: 5 years or less; 6-10 years; 11-15 years; 16-25 years; 26 years or more. 82 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Subjects were excluded if their birthplace was South America or a Central American country other than Mexico (5,826), Cuba or other Caribbean country (1,657), or other (278). We excluded third-generation Latino cohort subjects (5,810), subjects whose parents were not both born in Mexico (6,637), and subjects whose mother or father was not of Mexican or other Hispanic ethnicity (392). Subjects were excluded if we could not determine the number of years of US residence (260) in order to compare incidence rates of colorectal cancer based on this factor. We also excluded subjects of mixed race, specifically, Latino Indian, Latino Asian, and Latino white (738) subjects in order to minimize any potential confounding genetic or environmental effects on colorectal cancer incidence. The Los Angeles component of the Multiethnic Cohort Study consists of 45,114 self-identified Latino subjects, aged 45-75 at entry into the cohort. A total of 23,516 Latinos of Mexican-origin met the above described inclusion criteria. Additionally, subjects were excluded from analyses if their calorie intake or its components (fat, protein, and carbohydrate) from the food frequency questionnaire fell outside a relevant range based on a log-normal model for nutrients (535). Further, subjects were excluded if weight variables were missing (222). A total of 22,759 (96.8%) subjects of the eligible Mexican-origin study population met all these additional inclusion criteria. Our final study population included 8,702 US-bom and 14,057 Mexico-bom subjects with an almost equal distribution of males (50.4%) and females (49.6%). Among Mexico-bom subjects, 2.3% have lived in the US for 5 years or less, 4.2% for 6-10 years, 6.6% for 11-15 years, 25.7% for 16-25 years, and 61.2% for 26 years or more. Mexico-bom subjects who have lived in the US for 15 years or less were collapsed into one group for preliminary analyses. Assessment o f Diet Using a Food Frequency Questionnaire The methods for diet assessment have been described in detail elsewhere (Kolonel et al., 2000). In brief, we decided to develop a single diet questionnaire that would be used for all ethnic/racial groups in our study. This decision was made for several reasons but, most importantly, 83 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. we did not know a priori die ethnic identification of each prospective participant at the time the questionnaire was mailed. The questionnaire was pilot tested extensively in each major ethnic population. Subjects were asked to record foods that were eaten regularly but had not yet been included in the questionnaire. Among Latinos, a bilingual interviewer helped Spanish-speaking individuals complete the pilot questionnaire. Following die pilot phase of questionnaire development, we commenced a year-long preliminary calibration sub-study in which 24-hour dietary recalls were collected once per month from a random sample of subjects representing both genders and ah racial/ethnic groups that had completed the pilot questionnaire. This enabled us to make further modifications to the questionnaire, including the addition of important foods that had not been previously identified. This was especially important in the Latino population where we were developing a dietary questionnaire appropriate for the ethnic group for the first time. This is a racially, socially, and culturally diverse population for which there was a paucity of dietary information available. Therefore, we were careful to ensure that all commonly eaten foods were identified and included. We developed the food frequency questionnaire (FFQ) based on the methods used for many years by the University of Hawaii for eliciting dietary information from personal interviews. This method asks the respondent to report how often they ate a particular food item during the past year and the usual portion size. Usual intake for food items was reported by marking one of the eight following frequencies: never or hardly ever; once a month; 2 to 3 times a month; once a week; 2 to 3 times a week; 4 to 6 times a week; once a day; 2 or more times a day. For beverage items, usual intake is reported by marking one of nine frequencies, the same eight as above plus 1 additional (4 or more times a day). Photographs showing three different portions are included to assist the respondent in estimating intake. The FFQ included 164 questions on foods, 13 questions on beverages, and 5 questions about condiments added to food such as salt, catsup, and sour cream. 84 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The performance of the FFQ, by correlation analysis, was assessed in a calibration sub-study. The methods and findings have been described in detail elsewhere (Stram et al, 2000). Briefly, we collected three 24-hour dietary recalls from a random sample of cohort subjects of each sex/ethnic group to calibrate die dietary information from the FFQ. The correlation between nutrient intake from the 24-hour recalls and nutrient intake as reported on the FFQ is used as a standard measure of validity of the study instrument. The calibration sub-study also aided in the development of the food composition table by providing intake measurements of ethnic specific foods and it provided data that will be used for correction of risk estimates in nutrient analyses. A ssuming that a 24-hour dietary recall provides an unbiased estimate of a single day’s diet, a regression equation calculated from the average of 3 dietary recalls can be used for imputing an estimate of true nutrient consumption from the FFQ nutrient value. Latino participants in the calibration sub-study included a total of 340 subjects representing a random sample of the Latino population of the Los Angeles component of the Multiethnic Cohort Study. Each subject had completed three reliable 24-hour dietary recalls and a follow-up food frequency questionnaire. To calculate parameter estimates for determining “corrected” nutrient intake in our study of Mexican-origin subjects we first only included subjects from the calibration sub-study who met our inclusion criteria, i.e., Mexico- or US-bom subjects with both parents bom in Mexico. We excluded third-generation cohort subjects and subjects of mixed race. A total of 167 (90 males and 77 females) subjects met our inclusion criteria and also participated in the calibration sub-study. The distribution of the Mexican-origin sample in the calibration sub-study mirrored the distribution of Mexican-origin subjects in die entire “Latino” cohort. Our final sample included an almost equal distribution of Mexico-bom and US-bom subjects, i.e., 44 and 46 males, respectively and 38 and 39 females, respectively. However, because of concerns about small sample size, we decided to recalculate parameter estimates using the total 340 Latino subjects if the estimates for die sub groups were not statistically different than the estimates from the total. In other words, we used the data from 85 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. the total 340 Latino subjects for creating intercept and slope parameters for calculating “corrected” nutrient intake from regression equations if the parameter estimates were not statistically different (0.05 significance level) from parameter estimates calculated from only the Mexican origin subjects. To further evaluate the performance of the FFQ in terms of its ability to measure energy intake and to address any apparent under- or over-reporting of food intake, we first calculated an estimate of resting metabolic expenditure (RMR) using a previously published formula, die Harris-Benedict equation. This formula is used widely by registered dietitians for hospital patients, and considers weight, height, and age when determining resting energy expenditure. (For a description of die relationship of basal metabolic rate (BMR) and RMR see Appendix G). This formula has been found to yield reasonable estimates of RMR (Wardlaw and Insel, 1993). Using our estimate of RMR we then calculated the ratio of RMR to energy intake measured by the FFQ. After stratifying by amount of daily vigorous physical activity, we could then examine whether the percent of calories accounted for by RMR in our data was comparable to published estimates for the general population. Development o f the Food Composition Table An extensive food composition database for use in nutritional epidemiology studies had been developed and maintained at the Cancer Research Center of Hawaii for several years. For the current project, additional data on foods consumed by Latinos and African Americans were added and food composition data were modified to account for the questions where similar foods were grouped. The methods have been described in detail elsewhere (Kolonel et al., 20Q Q; Stram et al., 2000). A few of the grouped food questions were assigned different nutrient values depending on the ethnicity of the subjects, i.e., the food composition table is ethnic-specific for a few FFQ food items. The grouping of “com tortillas, com muffins, and combread” is a good example of where we used the calibration sub study to determine the weight to give to each food in this group. As expected, com tortillas dominate 86 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. the diet of Latinos as opposed to com muffins or com bread. Therefore, the nutrient composition of this question is more heavily weighted from the nutrient composition of com tortillas for Latino subjects. The food composition values were based primarily on the US Department of Agriculture’s nutrient database, supplemented with data from special (unpublished) laboratory analyses and other research/commercial publications (Chavez et al., 1992;Kagawa, 1995; Pennington, 1998). To better understand the role of “dietary fiber,” we include several measurements of intake in our food composition table. Dietary fiber is the sum of lignin and “non-starch polysaccharides” (NSP) in foods (see Appendix D). The NSP values (total, insoluble, and soluble) reported in this analysis were obtained by the Englyst procedure which aims to measure plant cell-wall NSP as the sum of their chemically identified constituent sugars. This measurement reflects the plant cell-wall material that is characteristic of the high fiber diet embodied in the dietary fiber hypothesis. The Englyst procedure (Englyst et al, 1994) is an extension of the work of McCance and Widdowson and later, Southgate. It measures NSP using enzymic-chemical methods allowing fiber to be divided into soluble and insoluble fractions as well as into individual fiber components, cellulose and noncellulose polysaccharides, and into individual constituent sugars (arabinose, xylose, mannose, galactose, and glucose) and uronic acids. The “dietary fiber” measurements reported in this analysis are those published in the USDA tables and are primarily obtained with the Association of Official Analytical Chemists (AOAC) Prosky procedure. The aim of this procedure is to measure NSP and lignin. However, it has been demonstrated that this method gives dietary fiber values that represent NSP, lignin, some starch, Maillard reaction products, and degradation products formed as a result of heat processing (J Assoc Publ Analysts, 1996). Further, detailed analysis of the gravimetric residue showed that the AOAC Prosky procedure underestimates die NSP content of foods by 12% on average and that from 5 to 42% of the residue material remains unidentified and not accounted for as lignin. 87 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Assessment o f the Equivalency o f the Spanish and English Questionnaires During the pilot phase of our study, we discovered that a Spanish translation of the FFQ was required in order to enroll Spanish-speaking Latinos in our cohort. Therefore, when the final English version questionnaire was complete, we hired three translators to first work independently and then in collaboration with each other to develop the Spanish translation. Because of significant heterogeneity among Latinos in Los Angeles County, it was decided to put together a team of translators representing different national origins. One translator was a food consultant and registered dietitian with years of experience in the Latin food and health industry. She heads up Cocina Associates, a comprehensive food consulting service that specializes in the Latino market in Los Angeles. Her family was of Mexican-origin and although she spoke Spanish fluently, her first language was English, having been bom and educated in the United States. Our second translator was a student from the Graduate Program within the Department of Spanish and Portuguese at the University of Southern California. She had been working in the Department of Preventive Medicine, School of Medicine at USC for two years translating questionnaires for use in Latino epidemiological studies. Our third translator was a California State University (Los Angeles) Spanish teacher with a Masters degree in Spanish. She also headed up her own Spanish translating service in Los Angeles. She was a first-generation immigrant from South America and Spanish was her first language. As the Spanish version of the questionnaire was developed by well-educated individuals, all three with college degrees, we wanted to make sure that it was appropriate for a less educated Spanish-speaking population. Therefore, we asked two Mexican American women to review the draft translation to identify awkward wording or poorly understood questions. Both of these women were raised in Mexican American families where Spanish was the first language and they received a high school diploma as their highest level of education. This exercise proved beneficial as they pointed out several areas where the language was not easily understood. 88 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. During the final phase of the translation process, we hired three additional professional translators from different Latino national origins to identify misspellings, any incorrect usage of language that might be found offensive by a particular Latino subgroup, and any incorrect translations. The Spanish questionnaire, along with the English version, was included in every mailing packet to Spanish sumamed individuals. The cover letter and mailing envelope included a Spanish version of the text and both questionnaires were labeled with identical mailing/address labels. Subjects were instructed to choose whichever language version they preferred. After data collection, we conducted an extensive review and analysis of the subject responses based on language version of the questionnaire. This analysis was undertaken to assess the comparability of the two language versions and to assure us that each version was in fact asking the same questions and that they were equivalent instruments. As a majority of Mexico-born subjects filled out the Spanish version and about 94% of US-born subjects filled out the English version, we wanted to ensure that a cross-language analysis would reflect hue between group differences rather than an artifact of differences in the language versions. We selected a subset of the population covering a large sample of both Spanish and English language subjects where demographic traits were similar in the two groups. We chose as this subset Mexico-bom subjects, aged 50-69, who had been in die United States for more than 25 years and reported an education level between 6th grade and vocation school. We excluded Mexico-bom subjects who have been in the US for 25 years or less because we did not have a large enough number of English language individuals in this group. Likewise, we excluded US-bom subjects because not enough of them filled in the Spanish questionnaire. We excluded college educated individuals as well as subjects with less than a 6th grade education because there were not large numbers of both Spanish and English language respondents. We chose a narrow age range to ensure a more homogeneous population given that the age distribution of the Mexico-bom group is younger than the US-bom group. The final sample included 89 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1,435 English and 2,896 Spanish language respondents with an even distribution of males and females in each group. Even with this narrow subset of subjects, we recognized that some differences in food intake would exist between the two language version groups. It would be expected that persons completing the English version would have become more acculturated to the standard American diet than persons completing the Spanish version. We compared die mean daily intake in grams by language version. We identified 16 of the 182 food items in the questionnaire for further review based on large differences in reported intake between language versions. We then went back to the questionnaire, back translated the Spanish questionnaire into English (something that should have been done earlier in development), and compared the two questions. We also used information about foods reported in the calibration sub study as a comparison (see Appendix E). Of the 16 food items identified, it is clear that three of the differences in mean intake were due to an unsatisfactory Spanish translation of the English question. The English and Spanish wording of these three food items were (1) English: oriental salted or pickled vegetables; Spanish: salted, pickled or marinated vegetables such as kim chee, jalapenos, cauliflower; (2) English: chow mein, chow fun or yakisoba-, Spanish: pasta soup - Mexican or oriental style like sopa de fideo, chow mein, ox yakisoba-, (3) English: pork and greens or laulaus; Spanish: pork meat with vegetables like pork meat with verdolagas or cactus. After checking the responses from the calibration sub-study, we excluded these three food items from the nutrient calculations for all Latinos. Fortunately, intake of these three food items is low in both the Spanish and English language groups so excluding them did not significantly alter the total calorie/nutrient composition of the diets. Three other food items identified for review were related to the same language wording, namely (1) stir fried beef or pork and vegetables, or fajitas', (2) stir fried chicken and vegetables or fajitas-, and (3) stir fried vegetables. The food description in Spanish translated to (1) beef with vegetables, pan-fried (such as fajitas, steak picado, chop suey-Mexican style); (2) chicken with 90 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. vegetables, pan-fried (such as fajitas, chicken Mexican style, chow mein); and (3) vegetables, pan- fried (without meat). Unfortunately, there is not a word for “stir fry” in the Spanish language. For all three questions, Spanish language subjects reported a higher intake than English language subjects. As it would not be possible to question subjects about their interpretation of the question, we agreed that the most sensible way to deal with the possible unsatisfactory translation of these three food questions was to calculate the nutrient content of these foods separately so that we could see the impact of including or excluding them in the future analysis of the cohort data. Of the remaining ten food items identified for review, it was clear that differences in reported intake were not because of errors in translation but were real differences in food intake based on information from the calibration sub-study or what has been reported in the literature. Assessment o f Core Diet We defined a core diet for each of our study groups in order to better understand the changes that are occurring in the foods eaten most frequently between Mexico-bom and US-bom subjects and to compare our results with what is reported in the literature regarding the typical diets of Mexico- bom immigrants and US-bom Mexican Americans. Differences in food intake patterns of traditional and contemporary foods can therefore be more easily identified. A model of “food patterning” originally described by Bennet (1942) and later adopted by Jerome (1982) proposed a model to study patterns of food intake among groups or individuals. The model depicts a hierarchical frequency of food consumption over a year’s period and proposes the following five levels: core diet (foods eaten two or more days per week); secondary core (foods eaten once a week); peripheral foods (foods eaten two to three days per month); ceremonial foods (foods eaten several times per year in a constant recurrence); and marginal foods (foods eaten several times per year in an inconsistent recurrence) (Romero-Gwynn and Gwynn, 1994). Romero-Gwynn et al. used this model as a framework to study the degree of retention and/or abandonment of traditional foods among first-generation Mexican 91 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. immigrant women, aged 19-44, in comparison to US-bom women of Mexican descent (Romero- Gwynn et al., 1993). The primary core diet was defined as foods eaten 2 to 7 times per week by 15% or more of the study sample. We adopted Romero-Gwynn’s model, with modification, to define a core diet for each of our two nativity groups, Mexico-bom and US-bom. Our definition is not gender specific. It is defined as 10% or more of subjects consume the food item 2-7+ times per week (or) 65% or more of the group population consumes it at least once per month. The latter criteria were added to our definition because there are foods being consumed by a majority of the population that contribute significantly to overall calorie intake. Food items that fell into this latter category among Mexico-bom subjects included Mexican meat soup, spaghetti, beef tacos, tostadas, sopes, or taco salad, chicken tacos, tostadas, sopes, or taco salad, cheese enchiladas, Med chicken, french Mes, and baked potatoes. Among US-bom subjects, we included Mexican meat soup, spaghetti, hamburgers, canned tuna fish, bacon, beef tacos, tostadas, sopes, taco salad, cheese enchiladas, french Mes, and baked potatoes. We also added two beverages, regular and light beer, to both study groups. Assessment o f Other Lifestyle Factors Questionnaire subjects were asked to report their current weight and height as well as their weight and height at age 21. Subjects could answer in either pounds or kilograms for weight and feet/inches or centimeters for height. In addition, for all subjects for whom we had drivers’ license information, we had die height and weight as reported to the DMV. This information allowed us to estimate the weight and height of subjects for whom these variables had been left missing or had been, clearly, incorrectly marked on their questionnaire. Unfortunately, one problem with weight on the drivers’ license file is that we do not know at what age an individual's weight was reported by the subject as license renewals do not require updated information on this factor. Therefore, in order to impute weight, we first plotted questionnaire weight against DMV weight for all cohort subjects for 92 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. whom we had information for both variables and eliminated outliers. For Latinos, we established the normal weight range to be 75-400 pounds. We then calculated age-, gender-, and ethnic-specific regression equations. Using the intercept and slope estimates we calculated “corrected weight” for all persons with missing weight or weights out-of-range and for whom we had DMV weight. We did not impute height but rather substituted DMV height for missing height on the questionnaire. Of the approximately 22,759 Mexican-origin subjects identified for this study, we have weight as reported on the questionnaire for 95% of the males and 92% of foe females. We were able to impute weight for the remainder. A body mass index (BMI) was calculated for each subject with foe formula: (weight in kg)/(height in meters) 2. Assessment o f Physical Energy Expenditure The questionnaire assessed expenditure of physical energy by the following four questions: (1) “On foe average, during foe last year, how many hours in a day did you sleep?”; (2) “On foe average, during foe last year, how many hours in a day did you spend in foe following sitting activities: sitting in a car or bus, sitting at work, watching TV, sitting at meals, other sitting activities such as reading, playing cards, or sewing?”; (3) “On foe average, dining foe last year, how many hours in a week did you spend in foe following activities: strenuous sports, vigorous work, or moderate activity?”; and (4) “On foe average, during foe last year, how many times a week did you take part in vigorous physical activity (strenuous sports or work) long enough to work up a sweat?” With respect to foe sitting question, subjects were asked to report hours for each of foe five sitting activities. Response categories included never, less than 1 hour, 1-2 hours, 3-4 hours, 5-6 hours, 7-10 hours, and 11 hours or more. With respect to question (3) above, subjects were asked to report hours of strenuous sports, vigorous work, and moderate activity separately. Response categories for those questions included never, 14 -1 hour, 2-3 hours, 4-6 hours, 7-JG hours, 11-20 hours, 21-30 hours, and 31 hours or more. 93 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. In order to calculate the mean number of hours spent in various physical activities, we assigned the midpoint of a particular category for all but the highest category. For the highest category of sitting activities, we assigned 11 hours. When a respondent marked two bubbles for a particular question, the midpoints from each category were averaged. This occurred infrequently, in less than 0.5% of the subjects. If a particular sitting question was left blank and at least one other sitting question was filled in we assigned the value of “never” or zero hours to the missing question. However, if all sitting questions were left blank then they were coded as missing values and excluded from analysis. Total sedentary hours in a day were then the sum of the hours from the five sitting activities. However, if total sedentary hours exceeded 24 hours minus the number of hours spent sleeping, assuming hours of sleeping was not missing, we assigned total sedentary horns to be 24 hours minus hours sleeping. If the variable “hours sleeping” was missing, we capped total sedentary hours at nineteen, allowing for approximately 5 hours of sleep, which was the lowest category on our sleep question. Of the approximately 22,000 subjects in our analysis, we assigned 19 for total sedentary hours in the above-described manner for less than one percent (0.3%) of subjects. With respect to foe three physical activity questions, we decided to use only foe question about vigorous work in our assessment of energy expenditure. Upon careful examination of foe responses, we discovered that for foe question about hours per week of moderate activity, foe example of “housework” was inadvertently left off foe Spanish version of foe questionnaire. Further, foe examples of strenuous sports such as tennis, racquetball, and swimming laps do not pertain to foe Mexico-bom immigrant population. We observed differences in “moderate activity” level and “strenuous sports” between Mexico-bom and US-bom subjects that were better explained by foe inadequacy of foe question or foe Spanish translation rather than any real difference between study groups. Finally, reporting horns in a week spent in physical activity becomes very difficult at best especially when hours of strenuous sports are but a few. In fact, 88% of all subjects reported “never” or “1 hour or less” per week for foe strenuous sports question. 94 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. With respect to the question about hours per week of vigorous work we calculated the mean number of hours by assigning the midpoint of a particular category for all but the highest category: 0 hours, .75 hours, 2.5 hours, 5.0 hours, 8.5 hours, 15.5 hours, and 25.5 hours. For die highest category of vigorous work (i.e., 31 hrs or more), we assigned 35.5 hours. When a respondent marked two bubbles, the midpoints from each category were averaged. If the question was left blank it was coded as missing and excluded from analysis. Data Analysis Dietary intake of each nutrient was examined as mean absolute intake, as a percentage of calories for protein, carbohydrate, and fat, and as a nutrient density per 1000 calories (kcal) for all other nutrients. All means, their standard errors, and medians are age-standardized to the combined population for all groups and both genders by 5-year age group. To study the effects of acculturation on dietary and other lifestyle behaviors, die sample was stratified by the number of years of US residence for Mexico-bom subjects and compared to US-bom subjects. Three groups of Mexico-bom subjects were created: in the US <=15 years, 16-25 years, and 26+ years. All analyses were performed separately by gender. Dietary intake was also examined as “corrected” nutrient intake using regression coefficients of the intercept and slope calculated from the calibration sub-study. Calibration equation estimates are shown in Appendix F. We wanted to present “corrected” nutrients in the same manner as uncorrected nutrient intake, i.e., stratified by the number of years of US residence for Mexico-bom subjects compared to US-bom Mexican American subjects. However, our calibration study consisted of small numbers of each of these sub-groups as the original sample for the calibration study was drawn on die entire Latino cohort population. We decided to first combine the three Mexico-bom groups and keep die US-bom Mexican Americans separate for the computation of regression coefficients. We plotted the residuals from the 24-hour recall nutrient value against the nutrient value 95 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. from the FFQ to examine the validity of combining them However, based on small numbers of calibration subjects we decided to test for statistically significant differences in the intercept and sfope estimates for each nutrient between each nativity group (Mexico-bom or US-bom) and the total population of Latino calibration study participants and between Mexico-bom calibration subjects and US-bom calibration subjects to evaluate the differences between using a subset of calibration subjects versus the entire Latino calibration population for the computation of regression coefficients. We first tested for differences in the intercept and slope separately and then tested for differences with both intercept and slope parameters in the model simultaneously. We adopted a strict cutoff of 0.05 to determine statistical significance. Based on that analysis, we used all Latino calibration subjects for calculating parameter estimates for calories, protein, cholesterol, and beta-carotene for males. For all other nutrient densities, we calculated parameter estimates using the smaller Mexico-bom or US-bom calibration study group when the significance level for either parameter (intercept or slope) was less than or equal to 0.05. Among females, we used total Latino calibration subjects for calculating intercept and slope estimates for percent fat, percent saturated and monounsaturated fat, percent protein, percent carbohydrate, cholesterol, and calcium. For all other nutrients, we calculated parameter estimates using only the Mexico-bom or US-bom calibration study group. Parameter estimates were calculated with backward, stepwise regression methods using the average nutrient intake of three 24-hour dietary recalls as the dependent variable and the nutrient value from the FFQ as the independent variable. Calibration equations were adjusted for possible age and BMI effects. To judge the fit of the regression equation, i.e., to measure the strength of the straight line relationship, we calculated a coefficient of determination (r2 ) for every nutrient by sex/nativity group. “Corrected” nutrients are expressed as a percentage of calories for protein, carbohydrate, and fat, and as a nutrient density per 1000 calories (kcal) for all other nutrients. For analyses of calorie intake in relation to body mass, physical activity, and resting metabolic rate, quartile cut points are gender specific for the combined populations of Mexico-bom 96 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. and US-bom subjects. We used log-transformed total calories computed from the food frequency questionnaire for these comparisons. Statistics were computed by using SAS for Windows version 6.12 (SAS Institute, Cary, NC) and Epilog Plus: Statistical Package for Epidemiology and Clinical Trials, version 3 (Epicenter Software, Pasadena, CA). RESULTS Descriptive Statistics Table IS shows age-standardized demographic characteristics and smoking status at baseline of the Mexican American cohort by sex and the number of years in the US. The sample includes 11,463 males and 11,296 females aged 45-74 at time of entry into die cohort. Among males, 7% had been in the US for 15 years or less, 16% had been in die US for 16-25 years, 39% had been in the US for 26 years or more, and 38% are US-bom. Among females, die percentages are similar with 9% reporting being in the US for 15 years or less, 16% reporting being in the US for 16-25 years, 37% reporting being in the US for 26 years or more, and 38% reporting they are US-bom. Mexicorbom subjects in the US for 25 years or less are 3-5 years younger on average than Mexico-bom subjects who had been in the US for 26 years or more and 7-8 years younger, on average, than US-bom subjects. Among males, the mean age ranges from 55.7 in Mexico-bom subjects in die US for 16-25 years to 63.8 in US-bom subjects. Similarly, among females the mean age ranges from 55.7 among immigrants in the US for 16-25 years to 63.3 among US-bom subjects. Among Mexico-bom subjects who had been in die US for 25 years or less, approximately 88% filled out the Spanish version of the questionnaire compared with 62%-67% of Mexico-bom males and females respectively who have been in the US for 26 years or more. Among US-bom males and females, only 6% filled out the Spanish questionnaire. Short-term (in US<=15 years) immigrants had a lower level of education with 74% of males and 81% of females reporting an 8th grade education or less compared with 97 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. i Table! ■ 1 5 . Characteristics of the Los Angeles1 Mexican Origin! Population in the U.S. Males Females <=15 years Mexico bom 16425 years >=26 years U.S. bom1 Mexico bom <=15 years 16425 years >=26 years U.S. bom1 No: of respondents 856 1778 4464 4358 961 1826 4119 4334 Age at baseline (mean) 56.1 55:7 60.8 63.8 57j 2 55:7 59.0 63.3 Spanish version of questionnaire 4549 91% 80% 49% 3% 90% 81% 60% 3% 50-54 95% 83% 62% 3% 92% 87% 65% 2% 55-59 93% 84% 64% 4% 94% 88% 68% 2% 60-64 93% 87% 67% 8% 92% 90% 75% 9% 65-69 69% 91% 67% 9% 91% 88% 70% 11% 70-74 87% 91% 57% 8% 88% 86% 54% 8% All Ages2 92% 86% 62% 6% 92% 87% 67% 6% Highest education level2 a 8th grade 74% 75% 57% 14% 81% 80% 57% 16% high school 10% 13% 20% 42% 8% 9% 22% 54% some college or vocation school 8% 7% 16% 28% 3% 5% 13% 21% college graduate 6% 2% 6% 14% 3% 2% 5% 8% Marital Status2 married 80% 82% 84% 80% 45% 44% 57% 58% separated or divorced 10% 10% 9% 11% 17% 19% 18% 19% widowed 6% 4% 3% 4% 27% 24% 17% 16% never married 4% 4% 3% 5% 10% 12% 7% 7% 'both parents bom in Mexico 2 age-standardized rate (standardized ta combined population for dll groups and both genders) <o oo Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. in the U.S. Mdles Fem ales <415 years Mexico bom 16-25 years >=26 years U.S. bom <415 years Mexico bom 16425 years >426years U:S: bom Number Of children (mean) 45-49 4.0 3.6 3.2 2.2 4.0 3.6 3.4 2.4 50^54 4.8 4.2 3.5 2.9 4.9 4.2 3.6 3.2 55-59 5,2 4.9 4.0 3.0 5.0 4.4 4.0 3.6 60-64 5.7 5.2 4.6 3.6 5:3 4.9 4.0 3.9 65-69 6.3 5.6 4.5 3.6 I 5:7 5.2 4.0 3.7 70-74 5.5 5.8 4.4 3.5 5.8 5.6 3.8 3.6 All Ages2 ! 5.4 5.0 4:1 3.2 5,2 4.7 3,9 3.5 Ever Smoker 45-49 61% 61% 58% 58% 34% 27% 29% 39% 50-54 65% 63% 61% 68% 30% 21% 27% 41% 55r59 64% 64% 62% 67% 19% 28% 27% 36% 60-64 72% 64% 68% 69% 27% 29% 28% 40% 65r69 64% 66% 69% 70% 29% 33% 30% 33% 70-74 56% 66% 65% 66% 17% 28% 24% 28% All Ages2 65% 64% 65% 67% 25% 28% 28% 36% Current smoker 45-49 24% 24% 24% 14% 14% 11% 10% 16% 50-54 23% 20% 22% 25% 9% 6% 10% 15% 55r59 17% 21% 18% 17% 3% 8% 9% 9% 60-64 20% :20% 17% 16% 7% 10% 8% 10% 65r69 22% 15% 15% 13% 5% 11% 7% 8% 70f74 20% 9% 14% 12% 0% 4% 7% 5% All Ages2 21% 18% 18% 16% 6% 9% 8% 10% 2 age-standardized rate (standardized to combined population for all groups and both genders) Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Males Fem ales in the U.S. <=15 years Mexico bom 16425 years >x26 years U.S. bom <=15years Mexico bom 16425 years >=26 years U,S, bom Family history of colon cancer 45-49 0.5% 1.9% 0.0% 4:4% 5.0% 2.2% 2.8% 613% 50-54 1.6% 2.3% 1.9% 615% 2.2% 1.5% 3.4% 7:0% 55-59 2.7% 1.2% 2.9% 6:2% 0.4% 3.6% 2.8% 7:6% 60-64 0.0% 1.9% 2.1% 511% 1.4% 1.7% 3.8% 6.7% 65-69 0.0% 0.8% 2.1% 518% 0.9% 5.0% 3.0% 619% 70-74 1.8% 0.0% 3.2% i 518% 0.0% 1.0% 4.2% 7.9% All Ages2 1.1% 1.3% 2.2% 517% 1.4% 2.6% 3.3% 7.1% Polyps of the intestines 45-49 1.0% 0.2% 1.0% 0:9% 1:7% 0.7% 1.0% 1.4% 50-54 0.0% 0.8% 1.4% 218% 1:2% 1.8% 1.6% 3.2% 55-59 1,2% 2.4% 2.0% 3.0% 2.3% 2.0% 2.1% 3.2% 60-64 0.7% 2.7% 3.0% 417% 1.0% 2.1% 1.8% 3.5% 65-69 0.0% 2.4% 2.8% 512% 2.1% 11.8% 2.3% 3.5% 70-74 0.0% 1.1% 4.4% 616% 1.9% 2.2% 3.9% 4.9% All Ages2 0.0% 1.9% 2.5% 411% 1:7% 1.9% 2.1% 3.4% Diabetes 45-49 7i7% 7.6% 7.4% 6:2% 7.1% 7.3% 5.8% 7.8% 50-54 11.4% 12:0% 13:9% 17.1% 9:3% 1316% 1112% 9.5% 55-59 15.9% 1911% 15:4% 17.1% 20.4% 16:3% 1216% 14.9% 60-64 18.1 % 1 7 1 4% 17:9% 20.4% 22.9% 1 8 1 4% 1 1 6 :5% 19.4% 65-69 13.9% 19:9% 17:6% 20.8% 24.0% 24.0% 20.1% 19.0% 70-74 20.0% 2215% 22:5% 20.7% 19.0% 3116% 2018% 20.7% All Ages2 15.2% 1712% 16.4% 18.0% 18.8% 19.0% 1512% 16:1% 2 age-standardized rate (standardized to combined population for 4 1 1 groups and both genderis) o o Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. in the U.S. Males Fem ales <=15 years Mexico bom 16425 years >=26 years U.S. bom <=15 years Mexico bom 16-25 years >=26 years U.S. bom Height + cm (mean) 45-49 169.4 170.2 172.3 174.9 158.6 159:4 159.1 160.8 50-54 169.3 169.6 171.3 174.3 159.4 158.5 159.2 158.8 55-59 168.4 168.8 170.5 174.0 158.1 158:8 158.9 159.2 60-64 167.9 168.2 170.3 173:2 158.1 158.5 158.0 158.4 65-69 167.7 168.4 169.9 172:7 155.7 159.0 158.3 158.3 70-74 166.9 167.4 169.8 172:2 154.9 156:6 158.2 158:2 All Ages2 168.2 168.6 170.5 173.5 157.5 158.5 158.5 158.8 Weight - kg (mean) 45-49 78:6 79.5 82.0 88.4 70.7 70.8 6911 74.2 50-54 79J0 80:2 80.9 88.0 70.5 71:7 70.8 72.0 55-59 78.1 80.0 81.0 84.6 72.0 70.8 71.5 73.0 60-64 77.1 77.0 79.5 82.3 71.2 70:7 68.8 70.9 65-69 76.6 77.6 77.6 80.2 66.9 67:7 68:3 69.4 70-74 75.7 75.6 76.8 79.3 66.9 68.3 67.5 67.6 All Ages2 77.4 78:2 79.5 83.3 69.9 70.0 69 A 71.1 Body Mass - kg/m2 (mean) 4549 27.4 27.5 27:6 28.9 28.2 27.9 27.3 28:7 50-54 27.6 28.0 27:6 28.9 27.9 28.6 28.0 28.6 55-59 27.5 2811 27J8 27.9 28.8 28:2 28.4 28.8 60-64 27.4 27.3 27.4 27.4 28.7 28.3 27.7 28.3 65-69 27.3 27.3 26.9 26.9 27.7 27.0 27.4 27:7 70-74 27.2 27.0 26.7 26.8 28.0 27.9 27J O 27.0 All Ages2 27.4 27.5 27.3 27.7 28.3 28.0 27.7 28.2 2 age-standardized rate (standardized to combined population for ail groups ahd both genders) o approximately 14% and 16% of US-bom males and females respectively. Qn the contrary, 42% of US-bom males and 29% of US-bom females had some college, vocational school, or were a college graduate. All categories of education show a considerable discrepancy between Mexico- and US-bom subjects. There is a wide discrepancy in marital status between males and females but not by nativity status within each gender. Considerably more males reported being married than females. Among males, there is little difference in marital status between migration groups whereas we see a different pattern among females. More US-bom and long-term (in US>=26 years) immigrant females are married compared with immigrants who have been in the US for 25 years or less. With regard to anthropometric measures, US-bom males are taller and weigh more on average than their Mexico- bom counterparts although body mass index (BMI) is not significantly different between nativity groups. Among females, US-bom subjects are just slightly taller and heavier than Mexico-bom subjects. There is virtually no difference in BMI among the four gender/nativity groups. The number of children reported by subjects shows a large discrepancy between short-term immigrants and US- bom subjects and is consistent in both males and females. The subjects who have been in the US for the shortest time (<=15 years) report the highest mean number of children (5.4 and 5.2 for males and females, respectively) and US-bom subjects report the lowest (3.2 and 3.5 children for males and females, respectively). The percentage of ever smokers among males (64%-67%) is quite similar among all Mexico-bom and US-bom subjects although the highest percentage of current smokers (21%) is found among Mexico-bom immigrants in the US for <=15 years. US-bom males have the smallest percentage (16%) of current smokers. Among females, a higher percentage of ever smokers are found in the US-bom group (36%) compared with Mexico-bom subjects (25%-28%). This same pattern is evident with 10% of US-bom subjects reporting current smoking status compared to 6% of Mexico-bom subjects in the US for <=15 years. A higher percentage of US-bom subjects report a family history of colon cancer (5.7% and 7.1% among males and females, respectively) and a slightly hjgher percentage of US-bom subjects report a previous diagnosis of polyps of the intestines (4.1% 102 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. and 3.4% among males and females, respectively). With respect to diabetes among females, more (19%) short-term Mexico-bom subjects report the disease compared with 15%-16% for long-term Mexico-bom and US-bom subjects. Among males, diabetes is reported most frequently among US- bom (18%) followed by Mexico-bom subjects in the US for 16-25 years (17%). Mexico-bom males in the US for 15 years or less report the lowest frequency of diabetes (15%). Association of Calorie Intake, Weight, Vigorous Work, and Resting Metabolism Age-standardized mean calorie intakes by weight and daily vigorous work are presented in Figures 6 and 7 for males and females, respectively. Our data show a relationship between calorie intake and weight, with weight increasing as calorie intake increases for both genders. Without exception, the heaviest subjects report the highest mean calorie intake and the lightest subjects report the lowest mean calorie intake when stratified by category of vigorous work. Among males in the lowest weight group, we found an 18% increase in calorie intake between the lowest quartile of daily vigorous work compared with the highest quartile of daily vigorous work. Among males in both the middle and highest weight groups, we found a 17% increase in calorie intake between the lowest and highest quartiles of daily vigorous work. Among females in the lowest weight group, we found a 12% increase in calorie intake between the categories of no daily vigorous work compared with some daily vigorous work. Among females in the middle weight group, we found a 10% increase in calorie intake and in the highest weight group we found an 11% increase between no vigorous work and some daily vigorous work. Our data also show a relationship between calorie intake and vigorous work. As vigorous work hours increase so does calorie intake when stratified by weight. These observations are in agreement with what is generally believed about the relationship between calorie intake, weight, and physical activity in the general population, i.e., the tendency that larger, more active individuals eat more food in general than smaller, less active individuals (Willett, 1990). 103 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Figure 6. Age Standardized Mean Calorie Intake by Category of Work and Weight MALES 3000 2500 2000 Calorie Intake 1500 1000 500 >75% (n=2598) 1-75% (n=3244) 0 (n=5446) >=191 lbs. 161-190 lbs. ■ >= 191 lbs. ■ 1614190 lbs. □ <= 160 lbs. Weight <= 160 lbs. o Daily Vigorous Work (0 C ft . a < /) JQ £ Q h - w b - co T — T C O II C O n A V ■i □ -- -- -- m if 3) ■ 2 e i (A 3 e e D > > > * a 105 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Before we commenced the analysis of calorie intake with an estimate of resting metabolic rate (RMR), we created a correlation matrix for daily vigorous work, sedentary hours, weight, height and body mass index (see Table 16) to understand the relationships of vigorous work and sedentary hours with the anthropometric measures in these data. We found a statistically significant correlation of sedentary hours with weight among both males and females with weight increasing as sedentary hours increase (data not shown). We also found a significant correlation of sedentary hours wife hours of vigorous work. As expected, subjects reporting fee lowest number of sedentary hours report fee highest number of vigorous work hours and subjects reporting fee highest number of sedentary hours report fee lowest mean daily hours of vigorous work (data not shown). The ratios of RMR to energy intake (FFQC) are shown in Table 17. We stratified by category of daily vigorous work because of fee relationship between calorie intake and vigorous work in these data. The ratio of RMR/FFQC appears quite reasonable. We found feat among subjects in fee lowest category of vigorous work (i.e., no vigorous work), about 83% of FFQC are accounted for by RMR. As daily vigorous work increases, the percentage of FFQC accounted for by RMR decreases. Among males in the middle category of daily vigorous work, RMR accounts for about 78% of FFQC and among subjects in fee highest category of daily vigorous work, RMR accounts for about 69% of FFQC. The ratio of RMR/FFQC by strata of daily vigorous work shows the same pattern among females. Among females in fee lowest category of vigorous work (i.e., no vigorous work), about 84% of FFQC are accounted for by RMR. As daily vigorous work increases, fee percentage of FFQC accounted for by RMR decreases, i.e., RMR accounts for about 75% of FFQC. Core Diet Com tortillas are fee most commonly reported food among Mexico-bom subjects with 79% reporting intake 2-7+ tunes per week (see Appendix G). Among US-bom subjects, 39% continue the practice of intake 2-7+ times per week (see Appendix H). Beans were a main dietary staple of fee 106 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 16. Correlation Matrix for Daily Vigorous Work, Sedentary Hours, Weight, Height and Body Mass Daily vigorous work Sedentary hours Weight (kg) Height (cm) BMI Daily vigorous work 1,00 MALES Sedentary hours rO J05 1.00 (p=.00) Weight (kg) 0J01 0.12 1.00 (p- -28) (p=J00) Height (cm) 0J01 0.08 0141 1.00 (P= L 18) <P=J00) (p= .00) BMI 0.00 0.07 0:83 -0.15 1.00 (P= -70) (p=J00) (p^.00) (p=.00) Daily vigorous work 1.000 FEMALES Sedentary hours t 0.02 1.00 (p=03) Weight (kg) 0.01 0.10 1.00 (p = r 146) (p=.00) Height (cm) 0.00 0.03 0:24 1.00 (P= -81) (P=.00) (p= .00) BMI 0.01 0.08 0.89 -0.23 1.00 (P-31) (p=.00) (p= .00) (p= :00) O Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 17. Ratio of Resting Metabolic Rate to FFQ Total Calories by Level of Daily Vigorous Work Percentile of Vigorous Work N Weight (kg) Height (cm) Age at baseline Hrs/day sitting Hrs/day : activity Hrs/day vig work Estimate of RMR1 GeomMean FFQkcal Ratio RMR/FFQ2 MALES 0 3446 80.1 170.9 62.4 6.47 10.33 0.00 1604 2225 0.83 1-75"’% 3244 80.2 171.6 60*7 6.72 0.91 0.21 1620 2377 0:78 > 75th % 2598 80.3 171.0 58.3 6.19 8.68 1.94 1636 2698 0.69 FEMALES Never 8718 70.2 158.5 60.8 6.53 10.33 0.00 1418 1934 0.84 Ever 2323 70.2 158.6 57.6 6L75 9.65 0.55 1439 2204 0:75 1 Hanis-Benedict equation: 66.5 + 13.6*(weightin kg) + 5*(height in cm) - 6.76*(age in years) 2 Ratios are calculated per person before the mean is determined © 00 populations of Mexico and continue to be part of the core diet of Mexicans residing in the US. Two main ways of consuming beans in Mexico are boiled (Jrijoles de la olla) and refried. Among Mexico- bom immigrants, 39% report intake of boiled beans 2-7+ times per week and 33% report intake of refried beans 2-7+ times per week. Among US-bom subjects, 20% of subjects report intake of refried beans 2-7+ times per week and 18% report intake of boiled beans at this frequency. Rice, an important component of the Mexican diet in Mexico, continues to be an important component of the diet among Mexico-bom immigrants with 24% reporting intake of Mexican rice 2-7+ times per week and an additional 63% reporting intake 1-4 times per month. White rice is also consumed frequently. Among US-bom subjects, intake of rice decreases with about 12% of subjects reporting intake of either Mexican or white rice 2-7+ times per week. In describing other components of the core diet of Mexico-bom subjects from our study population, many different fruits and fruit juices contribute, as do lettuce, carrots, tomatoes, broccoli, com, and other vegetables. White and whole wheat breads are consumed frequently by a large percentage of the population. Flour tortillas are consumed 2-7+ times per week by a greater percentage of US-bom subjects (51%) than Mexico-bom subjects (28%). Milk is an important component of the Mexican diet. Low-fat milk is consumed by 35% of the Mexico- bom study population 2-7+ times per week and whole milk is consumed by 29% of this population at least 2-7+ tunes per week. An additional 12% and 17% consume low-fat and whole milk at least 1-4 times per month, respectively. Low fat milk continues to be consumed 2-7+ times per week by a large percentage of US-bom subjects (38%) and whole milk is consumed at the same frequency by 16% of the US-bom population. Beef and chicken (roasted, baked, grilled, or fried) including the traditional Mexican foods made with beef and chicken, e.g., tacos, enchiladas, and Mexican meat soup, are part of the core diets of both Mexico-bom and US-bom subjects, although the majority of subjects report intake 1-4 times per month. Soda, either regular or diet, and coffee are popular among both Mexico-bom and US-bom subjects alike. Milk or cream added to coffee is reported by 97% of both the Mexico- and US-bom study populations. Among US-bom subjects, we notice the addition of 109 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. margarine, mayonnaise, and salad dressing to the core diet. Forty-two percent of subjects report margarine intake 2-7+ times per week followed by 29% reporting intake of mayonnaise in sandwiches 2-7+ times per week. Regular salad dressing intake of 2-7+ times per week is reported by 25% of US- bom subjects whereas low-cal salad dressing is reported in the same frequency by 20% of US-bom subjects. Eggs are also consumed more frequently among US-bom with 26% of subjects reporting intake 2-7+ times per week compared to 14% among Mexico-bom subjects reporting the same frequency of intake. Potato chips and french fries become part of the core diet of US-bom subjects. We present the percent change (from Mexico-bom to US-bom) in the percentage of subjects reporting frequent intake (2-7+ times per week) of core foods and beverages by nativity in Appendix I. Fifty-one percent of US-bom subjects report red meat intake compared with 65% of Mexico-bom subjects who have been in the US for fifteen years or less. This represents a 22% decrease in the number of US-bom subjects reporting intake of red meat on a frequent basis. Poultry intake shows a larger linear decline of 32% from Mexico-bom subjects in the US for fifteen years or less to US-bom subjects. There is a dramatic linear decline in legume intake with only about 20% of the US-bom population continuing consumption of boiled dried beans or refried beans two or more times per week. In the vegetable category, subjects are substituting certain vegetables for others, e.g., intake of tomato soup and yellow-orange vegetables decreases whereas intake of light green lettuce and other vegetables increases. Among fruits that are part of the core diet, intake of several i.e., tangerines, peaches, avocados, and pears decline substantially among US-bom subjects. Intake of other fruit juices and cantaloupe increase among US-bom subjects. The percentage of US-bom subjects reporting frequent intake of com tortillas declines dramatically whereas the percentage of subjects reporting frequent intake of all other breads and cereals increases significantly. The core diet of Mexico-bom subjects consists of 65 food items and represents 63.7% of the mean calories from the total diet as measured by our FFQ. The core diet of US-bom subjects consists of 66 food items and also represents 63.7% of the mean calories from the total diet as measured by the 110 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. FFQ. Appendix J shows the percent contribution of core foods to specific nutrients by nativity status. The biggest contribution to overall calorie intake comes from grains and cereal followed by fruit and fruit jukes for both Mexico- and US-born subjects. The contribution of legumes as well as the contribution of rice and pasta to overall calorie intake is double for Mexico-bom subjects than that for US-bom subjects. The contribution of red meat and poultry to calorie intake is similar between the nativity groups. Mexico-bom subjects report a slightly larger contribution of vegetables to overall calorie intake whereas US-bom subjects report a slightly larger contribution of milk and cheese products. The contribution of snacks and dessert to calorie intake is almost three times greater in US- bom subjects than Mexico-bom subjects. The contribution of alcohol (beer) is similar between the two nativity groups. Age-standardized mean gram intakes of specific food groups, e.g., red meat, legumes, vegetables, fruit, bread, and milk are shown in Tables 18 and 19. Means are reported in absolute amount in Table 18 and calorie adjusted in Table 19 to account for differences in overall calorie intake between comparison groups. Calorie adjustment is just the daily grams of a particular food divided by calories (without alcohol) and multiplied by 1000 to get daily grams per kcaL US-bom subjects reported substantially lower mean absolute intakes of aU foods than Mexico-bom subjects reflecting the lower overall food/calorie intake among US-bom subjects. When examining foods that have been adjusted by calorie intake, we found essentially no difference in beef, pork, or red meat as a whole in terms of daily grams of average intake. We found a fairly large decrease in average legume intake as well as a noticeable decrease in vegetable intake. A lot of the difference in vegetable intake is coming from a decrease in yellow-orange and cruciferous vegetables among US-bom subjects. There is very little difference in overall fruit and fruit juice intake between the two groups. However, we found a substantial increase in breakfast cereal intake (+46% and + 21% among males and females respectively) and a large increase in egg consumption (+60% and + 66% for males and females, respectively) among US-bom subjects. Mexico-bom subjects report a higher average intake of milk 111 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 18. /^standardized mean gram intake (absolute amount) of food groups of the Mexican origin cohort in the U.S. Mexico-bom 15years 16425 years >=26 years US4born %change1 Mexico-bom <=15 years 16r25 years >=26 years US4>om */• change1 Males Females Beef 65.9 63.3 61.4 52.9 416.8% 48.3 46J3 40:7 37.8 -16:1% Pork 15.6 14.4 12.5 10.5 426.0% 10.5 9.9 7:7 7.6 -18:7% Red meat 85.7 81.5 76.9 65.2 419.8% 62.0 59.0 50.4 46.9 -18.0% Processed meat 25.0 22.3 21.7 22.8 -1.0% 17.5 16.7 14.5 14.5 -10:7% Poultry 75.8 77.0 73.7 52.0 431.1% 74.2 71.7 63.5 51.3 r26i6% Fish 16.6 14.4 14.2 11.1 426.1% 13.0 12.2 11.0 9.6 -20.7% Soy products 8.2 8.3 7.1 3.8 452.4% 7.7 7.8 6.3 3.5 r52!2% Legumes excluding soy 166.9 154.5 130.6 84.3 444.0% 122.5 114.8 94.7 66.4 -4010% Vegetables 576.2 553.8 519.8 382.6 430.4% 548.1 527.7 477.9 370.0 r28!5% Light green vegetables 79.5 79.0 78.1 60:6 423.2% 87.0 85.4 80.6 67.5 -20.0% Dark green vegetables 46.1 43.7 46.9 3711 -18.5% 51.0 49.1 50:3 43.1 41411% Yellownorange vegetables 42j 6 42.7 40.2 24.0 -42.7% 55.5 53.2 47.8 29.7 44311% Cruciferae 46.5 45.8 45.9 3 1 1 8 431.0% 55:2 54.9 5 0 1 4 38.3 -28.5% Tomato products 112.5 108.0 102.5 86.3 -19.8% 98:7 97.1 89.0 77.2 41817% Carrots i_______ * __.'i-...- 29.4 30.3 28.8 19.6 -33.4% 37.2 34.6 33:2 23.9 -31.6% Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 18. Age-standardized mean gram intake (absolute amount) of food groups of the Mexican origin cohort Mexico-born in the U.S. <=15 years 16-125 years : >=26 years US^born %change1 Mexico-bom <=15 years 16-25 years >=26 years U8-bom % change1 Males Females Vegetables excl legumes 4Q 1J1 391.0 382.1 294.5 -24.7% 417.8 405.1 376.9 300.2 -25.0% Rice 72.3 71.2 72.0 57 J -19.6% 7917 70.6 66.7 50.5 -30.2% Potatoes & tubers 45.5 45.6 42.0 37.4 -15.5% 43.4 41.0 35.8 30.6 -23.7% All frtiits&fnJit juice 434.1 441.6 452.1 357.9 419.1% 492.1 503.9 503.0 403.7 -19.2% Fruit juice only 76.7 85.3 90.0 81.0 ^3.6% 86.3 90.3 95.8 85.3 -6.0% Citrus fruit 175.2 173.8 176.3 143.6 418.0% 190.7 192.5 192.1 153:3 -20.1% Yellow-orange fruit 58.9 60.7 59.3 37.1 -37.7% 80.7 81.0 79.3 53.9 -32.9% Breakfast cereal 45.5 47.3 58.0 59.5 18.3% 58.3 60.6 69.6 62.4 -0.7% Bread I183J0 178.3 177.7 153:7 -14.5% 156.8 152.0 145.8 132.7 -12.4% Pasta 37J 3 34.4 31.8 27.4 420.6% 34.9 3411 27.7 26.7 -17.0% Eggs 18.8 16.3 17.2 22.6 29.7% 12.9 11.9 11.8 15.8 29.1% All dairy 386.0 317.4 321.3 260.8 423.7% 353.5 36511 319.3 260.9 -24.6% Milk 281.8 229.6 235.9 182.0 426.9% 250.4 262.3 231.0 183.2 -26.1% Beer 166.3 183.8 281.8 33211 57.7% 11.7 29.7 25.2 36.9 66.3% Wine 7.1 4.0 11.1 18 2 145.7% 1.4 1.6 4.5 9.1 264:8% Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 19. Age-standardized mean gram intake (calorie adjusted) of food groups of the Mexican origin cohort Mexico-born inthCU.S. <-15 years 16-25 years >=26 years US-born % change1 Mexico-bom <415 years 16-25 years >=26 years US-bom % Change1 Males Females Beef 22.6 22.2 21.8 21.3 -3.8% 18.1 17.7 17.0 17.7 0:5% Pork 5.2 4.9 4.5 4.3 -11.0% 4.0 3.7 3.2 3.6 -1:2% Red meat 29.1 28.3 27.3 26J4 -6.5% 23.5 22.5 21.1 22.0 -1:8% Processed meat 8.4 7.9 7.7 9.3 16.7% 6.6 6J4 6.0 6.8 7:4% Poultry 26.3 27.3 26.7 21.9 -18.3% 28.5 28.4 27.6 25.0 -11:2% Fish 5.7 4:9 5.0 4.7 -9.5% 4.8 4.5 4.6 4.6 -0.9% Soy products 2.9 3.0 2.5 1,5 -45.0% 3.1 3.1 2.6 1.7 -43:2% Legumes excluding soy 55.3 55.0 45.2 32.2 -37.9% 48.3 44.6 38.3 29.2 +33:3% Vegetables 197.0 200.4 187.5 157.4 -19.3% 216.8 212.3 206.0 180.5 -14:8% Light green vegetables 27.4 28.5 28.6 25.8 -8.6% 34.5 34.8 35.6 34.1 r2!4% Dark green vegetables 16.3 16.5 17.9 16.1 -4.4% 20.5 20.5 22:7 22.4 5.6% Yellow-orange vegetables 14.3 15.5 14.5 10.2 -31.2% 22.2 21.7 20.7 14.9 +30:7% Crudferae 16.1 17.0 17.0 13.8 -17.6% 22.0 22.7 22.2 19.5 -12.8% Tomato products 38.9 38.8 36.8 35.5 -7.1% 38.0 38.2 38.0 37.5 A M o Carrots i— -i « _ _ .. 10.1 11.2 10.6 8.5 -20.7% 15.3 14.3 14.7 12.2 +17:5% Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 19. Age-standardized mean gram intake (calorie adjusted) of food groups of the Mexican origin cohort in thS U.S. Mexico-bom <=15 years 16-25 years >=26 years US-born % change1 Mexico-bom <=15 years 16-25 years >=26 years US-bom % change1 Males Females Vegetables excl legumes 138.9 142.4 139.7 123.7 -11.8% 165.4 164.6 165.1 149.6 -9.3% Rice 24.4 26.0 26.1 23.3 -8.5% 30.8 28.9 28.9 24.7 -16.5% Potatoes & tubers 15:2 16.0 14.8 15.3 -0.2% 15.9 15.9 14.9 14.5 -6.6% All fruits & fruit juice 143.5 162.1 166.2 152.6 -3.0% 197.6 20511 220.9 199.8 -3.9% Fruit juice only 2418 30.8 33.0 34:7 17.3% 32.3 3611 41.6 43.1 17.6% Citrus fruit 57:6 65:7 65.6 62.5 -0.7% 78.3 79.1 85.9 77.2 -418% Yellow-orange frUit 18.7 20:7 21.0 15.2 -24.3% 31.2 32J4 34.3 25.9 r20.7% Breakfast cereal 14.7 17.9 22.9 27.0 46.1% 23.1 25.7 32.3 32.8 21.1% Bread 64.9 67.9 66.2 63.3 -4.6% 64.0 63:3 64:7 62.9 -1:7% Pasta 12.8 11.9 11.1 11.5 -3.8% 13.2 13.1 11:6 12.8 1:7% Qggs 6.3 5:9 6.4 919 59.6% 4.8 4.5 5:2 8.0 66.0% All dairy 135.3 119.9 120.8 112:2 -10.4% 146.9 I153J3 143.6 131.9 -1018% Milk 102.7 89.5 91.2 80:3 -14.9% 107.1 114:2 107.0 93.8 -14:3% Beer 52.8 593 88.9 I114J4 70.8% 5.0 10.4 10.6 18.1 10913% Wine 2.7 1.3 4.1 7:6 181.5% 0.6 0.6 2.2 5.5 38616% and all dairy products combined than US-born subjects. We found a large increase in average beer intake (+71% and +109% for males and females, respectively) among US-bom subjects as well as an increase in wine intake although fee overall absolute amount is still quite limited. Nutrient Intake Mean dietary intake of twejve nutrients by gender and generation status is shown in Tables 20 and 21. Table 20 lists age-standardized mean nutrient intake in terms of absolute nutrient intake. Table 21 lists age-standardized mean nutrient intake in terms of percentage of calories for protein, carbohydrate, and fat and in terms of nutrient densities for all other nutrients. Also shown in Tables 20 and 21 is fee percent increase or decrease between Mexico-bom and US-bom subjects. US-bom subjects reported substantially lower mean absolute intakes of all nutrients than Mexico-bom subjects. This is not surprising given feat intake of most nutrients tend to he positively correlated wife total energy intake and energy intake is approximately 14%-16% lower among US-bom subjects in comparison to Mexico-bom subjects. When calories are included in fee calculation of nutrient intake either in terms of percent or nutrient density as in Table 21, fee four measures of fat (total, saturated, polyunsaturated, and monounsaturated) and cholesterol show an increased intake among US-bom subjects. There is virtually no difference in starch intake. Intake of all other nutrient densities show decreased intake among US-bom subjects. Of note is fee 18% and 14% decrease for mean beta- carotene intake among males and females, respectively. For soluble NSP intake we found an 11% decrease among US-bom males and a 9% decrease among females. We found a decrease among US- bom subjects for all other measures of fiber intake as well. We found a 7% increase for total fat among US-bom males and 6% increase among US-bom females. While saturated fat intake increased 4.3% in US-bom males it only increased 1.8% among females. The largest percent increase in fat intake was found for monounsaturated fat wife US-bom subjects reporting a 9% higher intake than 116 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 20. Age-standardized mean absolute nutrient intake of the Los Angeles Mexican origin cohort in the U.S. Mexico-born 15 years 16-25 years >=26 years US-bom % change1 Mexico-bom <=15 years 16425 years >=26 years US-born % change1 Males Females Calories w/o Alcohol 2965.0 2781.1 2773:2 2431.9 -14.4% 2561.6 2519.0 2325.7 2083.5 -15.6% Protein; (gm) 126.0 119.0 1116.1 97.0 -19.4% 108.9 106.2 96.0 83.8 41912% Carbohydrate (gm) 384.2 363.4 363.8 309.9 -16.4% 343.4 340.1 320:0 277.1 417.2% Total fat (gm) 109.5 101.4 101J9 95.3 +816% 90.7 88.8 8110 76.6 41118% Saturated fat (gm) 35.4 32.0 31.8 29.2 -11.5% 29.2 28.7 2518 23:7 415.0% Monounsaturated fiat (gm) 39.7 36.7 37.5 35.4 -6.8% 32.3 31.3 28.9 28.0 -9.1% Polyunsaturated fat (gm) 2511 23.5 23.7 22:4 -7.4% 2114 20.8 19.1 18.4 -10.1% Starch (gm) 166.8 159.5 159.4 141.0 -12.9% 149.8 144.2 136.1 122.7 -14.4% Dietary Fiber (gm) I42J4 41.2 39.6 31.3 423.9% 39.9 38.8 36.7 29.5 423.3% Total NSP (gm) 29.2 27.9 26.9 22.3 420.5% 27:5 26.8 25.2 2111 420.3% Insoluble NSP (gm) 16.0 15.5 15.2 12.5 -19.7% 1513 14.5 14.2 11.8 -19.8% Soluble NSP (gm) 13.1 12.2 12.1 9.6 423.2% 1212 11.9 11.2 911 423.0% Cholesterol (mg) 368:5 337.2 326.8 30014 -12.7% 292.1 282.1 245.0 233.8 -14.4% Calcium (gig) 1342.8 1211.9 1208.0 1003.9 420.0% 1212.0 1216.6 1101.7 926.5 421.3% Vitamin C (mg) 219.7 213.4 220.0 17711 -18.6% 237.4 239:2 234.1 189.9 -19.8% Beta Carotene (meg) faveraoeor v a lu e s fro m M e x ic o -D o m r 6502.6 K o o n d e n ts c c 6659.6 m a a re d id U b -o c x 6447.5 nresDonaem s 4508.3 431.0% 7906.4 7740.2 7432.9 5463.6 -29.0% Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 21. Age-standardized mean nutrient density intake of the Los Angeles Mexican origin cohort Mexico-bom iritheU.S. 15 years 16-25 years >=26 years US-bom % change1 Mexico-born <=15 years 16-25 years >=26 years US-born %change1 Males Females Protein (% of calories) 16.8 16.6 16.4 15.7 -5.5% 16.5 16.4 16.1 15.8 -313% Carbohydrate (%) 51.0 52.0 51.7 50:2 -2.7% 53.0 53.3 53.9 52.2 -2.3% Total fat (%) 32.2 31.3 31.9 34.1 7.2% 30.4 30.3 30:0 32.0 610% Saturated fat (%) 10.6 10.2 10.2 10.8 4.3% 10.1 10.1 9.7 10:1 118% Monounsaturated fat (%) 13.2 12.8 13.2 I14J3 9.5% 12;2 12.2 12.2 13.2 816% Polyunsaturated fat (%) 8.4 8.3 8.5 9.1 8.1% 8.2 8.1 8:2 8:7 618% Starch (density per kcal) 57.0 58.7 58.1 58.1 0.3% 59.0 58.3 5912 59.0 0.2% i Dietary Fiber (density) 14.4 15i1 14.5 113.0 -111.0% 15 9 15.6 1518 14.2 410.2% Total NSP (density) 9.7 10.1 9.8 9.1 -7.8% 11.0 10.7 I11J0 10.1 -7.2% Insblbble NSP (density) 5.4 5.6 5.5 5.2 -5.1% 611 5.9 6.1 5:7 -5.7% Soluble NSP (density) 4.4 4i5 4.3 3.9 -11.0% 4.8 4.8 4.8 4.4 -9.4% Ghdlesterol (density) 123.9 118.5 117.3 124.9 4.2% 111.9 108.9 104.4 113.1 4.4% Calcium (density) 459.7 445.6 443.2 419.9 -6.6% 4862 495.0 483.1 453.8 -7.0% Vitamin C (density) 73.5 78.9 81.1 75.5 -3.0% 94.7 97.2 103.4 94.6 -3.9% Beta Carotene (density) 1 ________t_i___< ___ 2103.5 2384.5 2326.6 ----- - J 1 lo 1891.8 -17.8% 3145:3 3121.2 3218.4 270114 -14.6% 'average of values from Mexico-bom respondents compared to US-bom respondents Mexico-bom subjects among both genders. Interestingly, there is remarkable similarity in die percent change in all nutrient values between males and females in these data. “Corrected” nutrient densities are shown in Table 22. For every measure of nutrient intake, the differences between Mexico- and US-bom subjects become considerably less after “correction.” For example, with soluble NSP intake we found an 11% decrease among US-bom males and a 9% decrease among females without correction. After correction, we found a 5.2% decrease among US- bom males and a 6.0% decrease among US-bom females. We found a smaller decrease among US- bom subjects for all other measures of fiber intake, after correction, as well. With correction, we found a 4.2% increase for total fat among US-bom males and 2% increase among US-bom females. The largest percent increase in fat intake was still found for monounsaturated fat with US-bom males reporting a 5.5% higher intake than Mexico-bom males. Whereas the difference in intake of uncorrected |3-carotene values between Mexico- and US-bom subjects was similar for males and females, change in corrected p-carotene intake is not similar. US-bom males have an 11.5% decrease in “corrected” P-carotene intake whereas US-bom females have a 40.7% decrease in “corrected” P- carotene intake. We see the same discrepancy between males and females in corrected measures of fat although not to the same degree as seen in corrected p-carotene. Corrected values of various fiber measures show the same pattern of decreased intake among US-bom males and females. Age- standardized means calculated from two 24-hour dietary recalls for Mexican origin subjects participating in the calibration study are reported in Table 23. While the number of subjects for each group is relatively small, it nevertheless provides an interesting comparison. The pattern of intake is similar to what we have shown using data from the food frequency questionnaire, i.e., among males, fat intake increases in US-bom Mexicans whereas fiber intake decreases. Fat intake actually remains relatively the same between Mexico-bom and US-bom females according to 24-hour dietary recall data. In agreement with males, measures of dietary fiber intake decrease in US-bom females. We also found significant decreases in calcium, vitamin G and beta-carotene intakes among US-bom 119 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 22. Corrected (With age & bmi) mean nutrient intake of the Los Angeles Mexican origin cohort Mexicorbom US-born Mexico-bom US-bom ______________ in theU.S. <=15years 16-25 years >=26 years___________% change** <=15 years 1S-25 years >=26 years___________% change** Males Females Calories w/o alcohol 1813 1791 1790 1745 Protein (% of calories) 17.8 17.8 17.7 17.6 Carbohydrate (%) 50.7 51.2 51.1 50.4 Total fat (%) 33.0 32.4 32:7 34.1 Saturated fat (%) 11.6 11.3 11.4 11.7 Monounsaturated fat (%) 12.4 12.2 12.4 13.0 Polyunsaturated fat (%) 7.3 7.3 7.3 7.5 Dietary Fiber 11.1 11.3 11J1 10.4 Total NSP (density) 7.0 7.2 7.0 6.8 Soluble NSP (density) 3.1 3.2 3.2 3.0 Insoluble NSP (density) 3.9 3.9 3.9 3.8 Cholesterol (density) 153 152 151 155 Ceicium (density) 450 440 439 425 Vitamin C (density) 55 57 58 56 Beta Carotene (density) 1205 1269 1252 1099 -2.9% 1385 1379 1359 1318 -4.1% -1.0% 17.5 17.4 117J3 17.3 rOJ8% -1:2% 52:5 52.7 52.8 52.4 t OJ5% 4:2% 30.4 30.4 30J3 31.0 2j 0% 2.0% 10:7 10.7 10.5 10.8 1.1% 5:5% 11.9 11.9 11.0 12.2 2.3% 3:3% 7.2 7.1 7.2 7.3 2.4% r7!1% 12.2 12.1 12.1 11.2 -7.6% -4.3% 8.0 7.9 8.0 7.6 *4.3% 75:2% 3.6 3.6 3.6 3.4 -6.0% r3i0% 4:4 4.4 4.4 4.3 -2.3% 1.8% 145 144 142 144 0.2% -4.1% 447 452 444 424 -5.2% -1: 7% 78 79 82 78 -2.1% t11:5% 2023 2023 2055 1206 -40.7% ‘average of values from Mexico-bom respondents compared to US-bom respondents Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 23. Mean nutrient intake calculated from two 24hour recalls (Mexican origin calibration Study subjects) Mexico-born i M A LES US-bom % change Mexico-bom F E M A L E S US-bom % change n=44 n446 n-38 n4=39 Calories w/o alcohol 1780.9 1763.8 -1.0% 1351.4 1350.9 0.0% Protein (% of calories) 17.2 1711 - o : 7 % 17.5 16.8 r3:8% Carbohydrate (%) 54.4 51.1 • • 6:2% 54.1 54.4 015% Total fat (%) 28.4 31:7 11.6% 28.7 28.9 017% Saturated hit (%) 10.7 10.9 1:8% 1:0.1 10.0 4011% Monounsaturated fat (%) 11.1 13.4 20.5% 11.7 11.6 r015% Polyunsaturated fat (%) 6.5 7.6 17.1% 6.8 7.1 3:9% Dietary Fiber (density) 22.5 18.5 417j8% 18.1 15.9 -1215% Starch (density) 64.2 60.2 -6.3% 58.3 60.3 315% Insoluble NSP (density) 4.7 4.0 -13.9% 4.8 4.7 -110% Soluble NSP (density) 3.5 3.2 -8.9% 3.9 3.6 -7.9% Cholesterol (density) 136.7 166.3 21.6% 138.6 139.7 0J8% Calcium (density) 473.1 374.8 -20.8% 437.6 391.0 41017% Vitamin C (density) 74.0 49.9 -32.5% 90.2 74.9 416:9% Beta Garotene (density) 1549.2 1083:7 430.0% 2202.7 1875.9 41418% males and females. We found a discrepancy in cholesterol intake. US-bom males report considerably more dietary cholesterol intake whereas Mexico-bom and US-bom females report the same intake. Age-standardized mean gram intakes of NSP fractions from specific food sources, eg., total NSP from grains, insoluble NSP from vegetables, and soluble NSP from legumes, are shown in Table 24. Overall, we found a 35.5% decrease in NSP from legumes among US-bom male subjects. Conversely, we found a 35.6% increase in NSP from grains among die same population. Among US- bom females the pattern is similar. We also found small decreases in NSP from fruits and vegetables among US-bom males and females. Ethanol intake, both absolute amount and as a percent of total calories, is described in Table 25. We found a linear trend of increasing daily intake among both males and females as Mexico-bom immigrants reside in the US for a greater amount of time. Among males, Mexicans in the US for fifteen years or less report 8.4 gm (1.9% of calories) of daily intake compared to 14.0 gm (3.1% of calories) for Mexican in the US for 26 years or more. Intake of alcohol doubles among US-bom males from Mexico-bom recent migrants. While the pattern is similar among females, overall daily intake remains low. US-bom females report one-quarter the amount of daily alcohol intake as a percentage of calories (1%) than do US-bom males at 4%. Last, we looked at the difference in sedentary hours and vigorous work between our comparison groups (see Table 26). Among both males and females, US-bom subjects report a 20% increase in total sedentary hours over the average of the Mexico-bom groups. A majority of the increase can be attributed to sedentary hours at work and watching TV while sedentary hours from meals and other sitting activity contributes slightly. Sedentary horns attributable to riding in a car or bus decrease by about 30% among US-bom males and females from the average of the Mexico-bom groups. It is noteworthy to point out the similarity of reporting sedentary hours between males and females. 122 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 24. Age-standardized mean gram intake (calorie adjusted) of NSP of the Mexican origin cohort in the U.S. Mexico-born 15 years 16+25 years >=26 years US-born % change1 Mexico-bom <=15 years 16-25 years >=26 years US-bom % change1 Males Females NSP from fruits 2.06 2.24 2128 1.98 -9.7% 2.85 2:89 3.05 2.56 -12.6% NSP from grains 1.69 1.85 2.08 2.54 3516% 2.08 2J04 2.41 2.66 22.2% NSP from legumes 3135 3.32 2.77 2.03 -35.5% 2.91 2170 2.34 1.83 -30.9% NSP from vegetables2 2:37 2.42 2J36 2.05 -14.0% 2.88 2.85 2:86 2.57 -10.2% Insoluble NSP from fruits 0:91 0.99 I1J01 i 0.87 +10:3% 1.26 1.28 1.34 1.12 -13.4% Insoluble NSP from grains 1:13 1.25 1.39 1:67 32.9% 1.43 1.39 1:64 1.75 17:7% Insoluble NSP from legumes 1:85 1.83 1.53 1.11 -36.1% 1.61 1.49 1:29 1.00 -31l 7% Insoluble NSP from vegetables2 1:33 1.35 1.32 1:14 +14:5% 1.61 1.60 1.60 1.43 -10:8% Soluble NSP from fruits 1J14 1.25 1.27 1111 -9J0% 1:58 1.61 1171 1.43 -12:4% Soluble NSP from grains 0.55 0.59 0.68 0.86 41J8% 0.64 0.65 0:76 0.90 3117% Soluble NSP from legumes 1:52 1.51 1.26 0:93 -35.0% 1:32 1.22 1.06 0.83 +3018% Soluble NSP from vegetables2 1J04 1.06 1.04 0:91 +13.1% 1:26 1.24 1:26 1.14 ^9.0% * average of values from Mexico-bom respondents compared to US+bom respondents Excludes NSP from legumes. The sum of NSP from legumes and NSP from vegetable; provides total, overall Intake from "vegetables'. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 25. Age-Standardized mean ethanol intake Of the Los Angeles Mexican origin cOhort Mexico-bom US-bom Mexicb-bom US-born in the ULS. <415 years 16-25 years >=26 years___________ % change1 ________ <=15 years 16-25 years >=26 years___________ % Change1 Males Females Ethanol (gm) 8.4 9:2 14.0 16.3 55% 0.8 1i4 1.7 2.8 120% Ethanol Calories 58.6 64.0 97.9 114.2 55% 5.4 9.7 11.9 19.7 118% Ethanol - % of Calories 1.9 2.0 3.1 4.1 73% 0.2 0.3 0.5 1.0 199% 'average of values from MexicO-bom respondents compared to US-bom respondents to 4^ Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 26. AgerStandardized mean daily sedentary or vigorous work hours of the Los Angeles Mexican origin cohort Mexico-bom in th6 U.S. <-15 years 16-25 years >=26 years US-born % change1 Mexico-bom <=15 years 16-25 years >=26 years US-bom % change1 Males Females Sitting in car or bus 2.1 1.8 1.6 1.3 -28.8% 1.7 1.5 1.4 1:0 432.6% Sitting at work 1.1 0.9 1.1 1.6 52.9% 0.8 1.3 1.3 1.8 63.9% watching TV 1.7 1:8 2.0 2.7 48.4% 1.7 1:7 1.9 2.5 44.7% Sitting at meals 0.7 0.6 0.7 0.8 22.1% 0.7 0:7 0.6 0:8 23.7% Other sitting activity 0.9 1.0 0.9 1 1 1 15.8% 1.3 1.2 1.3 1:4 8.3% TOTAL sedentary hours 6.4 5.9 6.1 7.3 19.5% 6.0 6 11 6.4 7.4 19.9% Daily vigorous work 0.7 0.6 0.6 0.5 -17.1% 0.1 0:2 0.1 0.1 -22.8% ‘averageof values from Mexico-bom respondents compared to US-bom respondents N> t- * There appears to be a decrease among US-bom subjects for daily vigorous work compared with Mexico-bom subjects although the overall mean number of hours of daily vigorous work remains small for all of the study sub-populations. DISCUSSION Our most striking finding is the consistency of reported food intake in our study population with food intake reported from previous studies among Mexican American populations (Romero- Gwynn et al, 1993; Chavez et al, 1994; Elder et al., 1991; Bruhn and Eangbom, 1970; Dewey et al., 1984). It is important to note that all of these studies had limitations when we assess their comparability to the Multiethnic Cohort Study. The study by Romero-Gwynn et al. included only women and die age distribution was considerably younger than the age distribution of the Multiethnic Cohort Study. The sample size in that study is also quite small with only 165 and 101 subjects in the two comparison groups (Romero-Gwynn et al., 1993). The study by Chavez et al. not only had a very small sample of Mexicans but also combined foods into broad food groups (Chavez et al., 1994). Additionally, the study by Elder et at. used a different study design, comparing dietary patterns of low- and high-acculturation groups (Elder et at., 1991). The study by Bruhn and Pangbom consisted of only 65 Mexican migrant families living in agricultural labor camps and the study by Dewey et al. had 71 Mexican American migrant women and 69 Mexican American non-migrant women with diet assessed by a 54 item food frequency questionnaire. Nevertheless, the findings of these dietary studies corroborate many of our findings. While acculturation has caused dietary adaptation to a new range of foods and consequently, changes in die mean intakes of certain nutrients among Mexican Americans, many food traditions have also been retained. We also found support in the literature for our findings related to nutrient intake. Eight studies (Romero-Gwynn et al, 1993; Looker eta/., 1993; McDowell etal., 1994; Alaimo et al., 1994; Guendelman and Abrams, 1995; Abrams and Guendelman, 1995; Ballew and Sugerman, 1991; Loria 126 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. et al., 1995) examined certain nutritional factors among the Mexican American population residing in the US using federal nutrition survey data. A comparison of their findings with ours is discussed below. Dietary Fiber A study by Alaimo et al. uses NHANES III survey data and provides estimates of dietary fiber by age group and gender for Mexican Americans. Dietary fiber estimates include both insoluble and soluble components. Dietary fiber estimates are in the range of 9.0-10.8 gm day/1000 kcal for both males and females (Alaimo et al, 1994). This range is in agreement with our estimate of total NSP (range of 9.1-11.0 gm day/1000 kcal) intake shown in Table 21. A study conducted by Ballew and Sugerman in Chicago, Illinois using the CENAS Survey, reports an unadjusted mean intake of 20.8 grams of dietary fiber for 186 low-income Mexican women. We found mean absolute gram intake to range from 21.1 gm day/1000 kcal among US-bom Mexican women to 27.5 gm day/1000 kcal among Mexico-bom women in the US for fifteen years or less (Ballew and Sugerman, 1995). Total Fat We found that the percentage of calories from total fat ranged from 30% among Mexico-bom females to 32% among US-bom Mexican-origin females. Among males, the percentage of calories from total fat ranged from 31% among Mexico-bom to 34% among US-bom subjects. Our estimates corroborate findings from a study using NHANES III data. McDowell et al. presented mean absolute dietary intake and percentage of energy from total fat among Mexican-origin males and females. The percentage of calories from fat ranged from 32% among males and females aged 70-79 to 33% and 34% among males and females aged 40-49, respectively (McDowell et al., 1994). Two other studies reported slightly higher values for percentage of calories from fat. Among females, Guendelman and Abrams reported 35% and 37% of calories were attributed to fat intake among 1s t generation Mexican 127 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. immigrants and US-bom Mexican Americans, respectively, using data from HHANES (Guendelman and Abrams, 1995). Using data from the 1991 CENAS survey, Ballew and Sugerman reported 34% of calories from fat among Mexican women. Saturated Fat McDowell et al. found from their analysis of NHANES III data that calories derived from saturated fat was consistent across age strata, ranging from 11% among Mexican American males aged 70-79 to 11.5% among males aged 60-69. Among females, the percentage of calories derived from saturated fat ranges from 10.6% among subjects aged 70-79 to 11.2% among subjects aged 40- 49 (McDowell et al. 1994). These results represent just a slightly higher percentage of calories from saturated fat then we found in our data. The range among males in our Mexican-origin population was 10.2% among Mexico-bom to 10.8% among our US-bom population. Among females, the percentage of calories from saturated fat was 9.7% among Mexico-bom women in the US for 26 years or more and 10.1% for the other three comparison groups. A study by Loria et al. compared saturated fat intake between adult Mexican Americans and non-Latino whites. Age-specific mean intakes for Mexicans were estimated based on 24-hour recalls from the HHANES (1982-1984) survey. Differences between males and females in percent of calories from energy components were small, and therefore, the investigators combined the data for both genders. The percentage of calories from saturated fat intake ranged from 12.4% among Mexican Americans in the 40-59 age group to 13% among Mexican Americans aged 60-74 (Loria et al.. 1995). Calcium Several studies have examined calcium intake among Mexican Americans using federal nutrition survey data. Abrams and Guendelman found a higher absolute intake of calcium among 128 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Mexico-bom immigrant women (779 mg/day) compared to US-bom Mexican American women (645 mg/day) aged 16-44 using data from HHANES (Abrams and Guendelman, 1995). Looker et al. using HHANES data for Mexican Americans found that women aged 40-74 consumed a range of calcium from 561 mg/day to 582 mg/day (Looker et al., 1993). Among Mexican American women aged 18- 74, the top, single-food contributor to total calcium intake was whole milk (24% of total calcium) followed by com tortillas (8%), cheese (9%), and low-fat milk (6%). Refried beans, wheat bread and flour tortillas also contributed smaller percentages to total calcium intake. Alaimo et al., using NHANES III data, reported a range of absolute calcium intake from 593 mg/day among Mexican American women aged 70-79 to 701 mg/day among women aged 40-59 (Alaimo et al., 1994). While these absolute amounts are smaller than the absolute calcium intake in our study population, calorie adjusted calcium intake is similar between the two studies. We found calcium densities to range between 454 mg day/1000 kcal for US-bom women to about 490 mg day/1000 kcal among Mexico- bom women in the US for Jess than twenty-six years. Conversely, Alaimo et al. found calcium density to range between 397 mg day/}000 kcal among Mexican American women aged 40-49 and 467 mg day/lOOOkcal among women aged 60-69 (Alaimo et al., 1994). Among men, we found calcium densities to range between 420 mg day/1000 kcal for US-bom to about 460 mg day/1000 kcal among Mexico-bom men in the US for fifteen years or less. Conversely, Alaimo et al. found calcium densities to range between 351 mg day/1000 kcal among Mexican American men aged 40-49 and 426 mg day/1000 kcal among men aged 60-69 (Alaimo et al., 1994). Interestingly, both studies reported lower calcium intake among men compared to women. Cholesterol Several studies have reported cholesterol intake among Mexican Americans. In comparing first-generation Mexican American women to second-generation, Guendelman and Abrams found that first-generation women reported the higher absolute intake of cholesterol at 353 mg per day compared 129 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. to 306 mg per day for second-generation women (Guendelman and Abrams, 1995). Loria et al. using HHANES date found a similar range of absolute cholesterol intake i.e.. about 300 mg/day for Mexican American females aged 40-74. Among males, they found absolute cholesterol intake to be higher, i.e., 441-459 mg/day for subjects ages 40-74 (Loria et al., 1995). McDowell et al. found the range of absolute cholesterol intake among Mexican Americans to be 227-284 mg/day among females and 310-421 mg/day among males aged 40-79. Calorie adjusted cholesterol intake ranged from 161 to 190 mg day/1000 kcal forMexican American females and 166 to 187 mg day/1000 kcal for Mexican American males aged 40-79 (McDowell et al., 1994). Estimates of absolute cholesterol intake in our study population ranges from 234-292 mg/day for females and 300-369 mg/day among males depending on nativity and the number of years of US residence. Estimates of calorie adjusted cholesterol intake in our study population ranged from 104-113 mg day/1000 kcal among females and 117-125 mg day/1000 kcal among males. Generally, findings from other studies related to absolute intake are in agreement with results from our study. In terms of calorie adjusted cholesterol intake, estimates reported by McDowell et al. are higher than estimates from our study (McDowell et al., 1994). Body Mass In our study population we found no appreciable difference in BMI between Mexico-bom and US-bom Mexican American males and females. We did find a modest increase in height among US-bom Mexicans compared to Mexico-bom subjects for males and females as well as a modest increase in weight (kg) among US-bom Mexicans. The age-standardized mean BMI ranged from 27.3-27.7 among males and 27.7-28.3 among females. If we adopt a cut off of 27 to define obesity, then 50% of both males and females are considered obese in our study population. Several previous studies have shown that Latinos have a higher prevalence of overweight and obese individuals than non-Latino white populations in the United States (Hazuda et al., 1991; 130 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Balcazar and Cobas, 1993; Kumanyika, 1993; Samet et al., 1988; Winkleby et al, 1993; Winkleby et al., 1996). While this has been a consistent finding, there is little information on the effect of acculturation on the prevalence of obesity in the Mexican American population following migration to the US. Relationship o f Calorie Intake^ Weight, Physical Activity, andRMR The relationship between weight, calorie intake, physical activity, and an estimate of resting metabolic rate seen in these data is certainly noteworthy. We show a consistent pattern of increasing weight as calorie intake increases when stratified by level of daily vigorous physical activity among both genders. We also show an association between calorie intake and vigorous work in agreement to what is generally believed about this relationship in the general population, i.e., the tendency for larger more active individuals to eat more food in general than smaller less active individuals (Willett, 1990). In order to address possible under- or over-reporting of food intake in Mexican Americans we calculated a ratio of basal metabolism to energy intake. Within the general population, RMR usually represents approximately 70% of daily energy expenditure in sedentary individuals, 60-65% in moderately active individuals, and less in more physically active individuals. Without a measure of “moderate” physical activity or a precise measure of daily vigorous work, it is difficult to define just how physically active or conversely, how sedentary this population really is. However, even with these limitations, our data show an association between RMR and FFQC when stratified by quartile of vigorous activity that is at least consistent, i.e., a greater percentage of calories are accounted for by RMR in more sedentary individuals, with the above estimates. We found that among subjects in the lowest category of vigorous work (i.e., no vigorous work), about 83% of FFQC are accounted for by RMR. As would be expected, as daily vigorous work increases, the percentage of FFQC accounted for by RMR decreases. Our results suggest that Mexican American subjects either over-reported food 131 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. intake on the food frequency questionnaire or they are less physically active then the “general population” from which the above estimates were calculated. Nevertheless, reporting appears to be consistent across physical activity/inactivity groups and across genders. B. NESTED CASE-CONTROL ANALYSIS OF COLORECTAL CANCER METHODS Selection o f Subjects The cases were identified by die California Cancer Registry (CCR) and the Los Angeles Cancer Surveillance Program (CSP), a member of the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program. Both registries use a software program that conducts a probabilistic data linkage using the social security number, name, date of birth, and gender. Four blocking passes are done for each linkage where it is required that die blocking variables for each pass match exactly to be considered a possible linked pair of records. Results from the CCR linkage are then compared with results from the CSP linkage to ensure that all cancer cases residing in Los Angeles County had been found by both registries. This latter analysis provides assurance that all incident cancer cases occurring in the cohort are, in fact, ascertained. Eligible cases were members of the Mexican American Multiethnic Cohort population described in detail above and were newly diagnosed with histologically confirmed colorectal cancer during the time between their entry into the cohort and June 30, 1998, a date for which we are confident that we have complete case ascertainment in the Mexican American cohort population. Exclusion criteria included personal history of previous colorectal cancer as reported on the initial study questionnaire and diagnosis of in-situ colorectal cancer. 132 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The controls were randomly selected from the Mexican American Multiethnic Cohort population described in detail above. Four controls were matched to each case on sex, date of birth (± 2 yrs), date the original dietary questionnaire was returned (± 3 mos), case status (the control must not have been diagnosed with colorectal cancer at date of diagnosis of the case), and vital status (the control must be alive at the date of diagnosis of the case). Subjects were allowed to serve as controls for more than one case assuming they met all eligibility criteria for the control set. Data Analysis The hypothesis of interest that emerged from the migrant analysis included all standard measures of dietary fiber intake, including insoluble and soluble fractions from various food sources. The nutrient P-carotene also was of interest because of the dramatic decrease in intake among US- bom Mexican Americans. Intake of foods such as legumes, vegetables and eggs showed significant change following migration and were considered good candidates along with the two nutrients identified above for explaining the differences in colorectal cancer risk between Mexico-bom and US- bom Mexican Americans. We used conditional (stratum=case-control sets) logistic regression models to compute odds ratios and 95% confidence intervals for demographic characteristics, daily nutrient, and food intakes, with adjustment for relevant covariate(s). Since we have a limited number of cases, males and females were combined for most analyses. A separate analysis was performed for only one variable, sedentary hours, where we identified a possible interaction effect of gender. Quartile cut-points were not sex specific and based on data from the controls. We adjusted nutrient intakes for calories by the multivariate nutrient density model, and we adjusted the odds ratios by including generation status in the conditional logistic regression model. For sedentary hours, we report gender specific odds ratios and p values adjusted for generation status. P values for trend are based on continuous variables. 133 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. RESULTS Sixty-one male and 40 female cases of colorectal cancer have occurred in the Mexican American cohort population since the study’s inception (Table 27 shows demographic characteristics by gender and case-control status). The mean age for males was 65.3 and 65.2 for cases and controls respectively, and 64.7 and 64.4 for female cases and controls respectively. Sixty-seven percent of male cases and 58% of female cases are US-bom Mexican Americans. Among female subjects, the highest Jeyei of education attained is similar between cases and controls. Among males, more controls (61%) than cases (54%) report their highest level of education as less than 11th grade. Additionally, more male cases (31%) than male controls (22%) reported at least some college, vocation school, or that they were a college graduate. Among males, marital status is similar between cases and controls. Among females, more controls (49%) than cases (40%) reported current marital status as married and fewer controls (43%) than cases (53%) reported current status as separated, divorced or widowed. The mean number of children born to cases and controls is remarkably similar between die two groups, as is height and weight when stratified by gender. BMI (wtkg/htm2) is also remarkably similar, not only between cases and controls, but also between males and females. We found no association for weight or height and colorectal cancer risk in our data. Both anthropometric measures were homogeneous among cases and controls in this Mexican American population. More females than males report a family history of colon cancer, but the difference between cases and controls by gender is not large. Current smoking status and pack years of smoking does not differ between cases and controls when stratified by gender. Odds ratios and confidence intervals for certain demographic characteristics are shown in Table 28. The odds ratios for generation status (1.84 for US-bom) and language version of the questionnaire (1.83 for English language) were both statistically significant (p=0.01). Since both variables are highly correlated with one another and adjusting for one or the other produces nearly identical results, we adjusted for only generation status in the remaining analyses. There was no 134 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 27. Demographic Characteristics by Gender and Case-Control Status Males Females Cases Controls Cases Controls No. of subjects 61 244 40 160 Age at baseline (mean) 65.3 65.2 64.7 64.4 Generation status US bom 67% 51% 57.5% 50% Mexico bom: <=15 years in US 3% 5% 5% 5% 16-25 years 7% 8% 7.5% 10% 25+ years 23% 36% 30% 35% Highest education level <= 10th grade 54% 61% 60% 58% high school 15% 17% 23% 24% some college or vocation school 26% 15% 13% 12% cojlege graduate 5% 7% 5% 6% Marita! status married 82% 84% 40% 49% separated, divorced or widowed 18% 12% 53% 43% never married 0% 3% 5% 7% Number of children (mean) 4.3 4.1 3.8 3.9 Height-cm (mean) 171.8 171.4 157.7 159.0 Weight - kg (mean) 78.8 79.2 68.4 68.9 Body mass - wtkg/htm2 (mean) 26.7 27.0 27.7 27.4 Pack years of smoking (mean) 11.4 11.3 7.8 7.9 Smoking status Never 25% 29% 63% 66% Current 16% 15% 8% 4% Past 57% 54% 25% 25% Family history of colon cancer 4.9% 3.3% 7.5% 6.9% 135 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 28. Odds Ratios and P values for Demographic Risk Factors n Cases % n Controls % OR P value Generation status US born 64 63% 204 51% 1.84 0.01 Mexjco born 37 37% 200 49% Version of questionnaire English 71 70% 229 57% 1.83 0.01 Spanish 30 30% 175 43% Smoking status1 Ever 58 57% 214 53% 1.12 0.64 Never 43 43% 190 47% Family history of colon cancer1 Yes 6 6% 19 5% 1.14 0.79 No 95 94% 385 95% High blood pressure1 Yes 43 43% 152 38% 1.21 0.39 No 58 57% 252 62% Current untreated hypertension1 Yes 24 24% 57 14% 1.94 0.02 No 77 76% 347 86% Ever treated hypertension1 No 13 13% 35 9% 1.63 0.16 Yes 88 87% 369 91% Diabetes1 Yes 28 28% 70 17% 1.75 0.04 No 73 72% 334 83% Polyps1 Yes 6 6% 10 2.5% 2.55 0.10 No 95 94% 394 97.5% Current use aspirin1 Yes 18 18% 79 20% 0.86 0.60 No 83 82% 325 80% Adusted by conditional logistic regression forgeneration status R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. association for smoking status, family history of colon cancer, history of high blood pressure or current use of aspirin. More cases (6%) than controls (2.5%) reported history of polyps but the numbers were too small to reach statistical significance. We did find a significant association of diabetes with colorectal cancer (OR=1.75) and an association with current untreated high blood pressure (OR=l .94). Ever treatment of high blood pressure is suggestive of an increased risk (OR=1.63) but is not statistically significant. The covariate-adjusted odds ratios for increasing sedentary hours show an increased risk of colorectal cancer (OR=1.95) in the highest category (p for trend=0.02). The covariate-adjusted odds ratios for increasing intake of macronutrients, various types of fiber and fiber components, and selected micronutrients are shown in Table 29. We found a strong inverse association for dietary fiber, total NSP, insoluble NSP, and soluble NSP. Very similar effect estimates were found for the highest quartile of dietary fiber (OR, 0.37; 95% confidence interval, 0.18 to 0.75), total NSP (OR, 0.36; 95% confidence interval, 0.17 to 0.75), and insoluble NSP (OR, 0.39; 95% confidence interval, Q.19 to 0.78) intake, all of which provide substantial protection for colorectal cancer. The odds ratio for the highest quartile of soluble fiber is 0.52, 95% confidence interval, 0.26 to 1.03. There is a statistically significant, dose-response, inverse association for Vitamin C (OR for highest quartile, 0.55). We found a statistically significant increased risk for total fat (OR for highest quartile, 1.70; 95% confidence interval, 0.90 to 3.19) and polyunsaturated fat (OR for highest quartile, 1.74; 95% confidence interval, 0.92 to 3.27). We found a strong association for dietary cholesterol with the highest quartile of intake producing a two-fold (OR=2.02, 95% confidence interval, 1.036 - 3.96) risk of colorectal cancer compared to the baseline reference group. We found no association between colorectal cancer risk and alcohol intake, neither in absolute gram intake nor in percentage of calories from alcohol, among males and females. The colorectal cancer odds ratios for dietary fiber and dietary fat by food source are shown in Tables 30 and 31, respectively. We used dietary fiber to examine food source because the P value for 137 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 29. O dds Ratios arid 95% Confidence Intervals fori Colorectal C ancer by Quartile of Nutrient Intake Calorie-Adjusted Nutrieht Densities1 N Ca:Co Qi (Low) N CaiCo q 2 N CaiCo q 3 N Ca:Co cu (High) Confidence Interval Pfbr Trend Total calories 26:101 1.00 261101 1J00 271101 1.08 221101 0:88 (0147 -41166) 01817 Protein 271101 1100 171101 0.62 311101 1.20 261101 0191 (0149-1167) 01870 Carbohydrate 311101 1100 341101 1.14 181101 0162 181101 I0162 (0132-1120) 0.060 Fat 201101 1100 151101 0175 291101 1142 371101 1170 (0190-3.19) 01026 Saturated fat 181102 1100 28:100 1151 301101 1158 251101 1129 (0165 - 2156) 0.100 Monounsaturated fat 231101 1100 191101 0J81 241101 1104 351101 1134 (0173 - 2.48) 0J074 Polyunsaturated fat 181101 1J00 161101 0J91 331101 1172 341101 1174 (0.92 - 3127) 01015 Ethanol 311101 1100 161101 0157 271101 0186 271101 0187 (0146-1164) 01593 Dietary fiber 381101 I1J00 311101 0187 181101 0150 141101 0137 (0118-0.75) 01001 Total NSP 371101 1100 231101 0168 271101 0177 141101 0136 (0i17 - 0.75) 0J002 Insoluble NSP 361101 1100 271101 0.78 241101 0169 141101 0139 (0119-0.78) 0.002 Soluble NSP 331101 11100 321101 1101 1191101 0163 171101 0152 (0.26-11.03) 0J007 Starch 321101 1100 251101 0174 241101 0169 201101 0162 (0133-1.19) 0.138 Calcium 311101 1100 321101 1.11 131101 0147 251101 0185 (0147-1.53) 01279 Vitamin C 341101 1100 261101 0.78 231101 0172 181101 0155 (0128-1.06) 0.037 Beta carotene 341101 1100 24:101 0172 221101 0167 211101 0164 (0133-1.26) 01345 Cholesterol 161101 1J00 21:101 1132 291100 1178 351102 2102 (1.036 - 3.96) 0903 'Adjusted by conditional logistic regression for generation status (1st or 2nd) and total calories by the multivariate nutrient density model The interquartile ranges (25th-75th percentile) for daily nutrient intake among controls were a s follows: calories w/o alcohol: 141443036; protein(g): 54-126; % protein: 14.1-17.6; carbohydrate(g): 188-407; % carbohydrate: 46.7-58.2; fat(g): 46-110; % fat 27.1-36.3; saturated fat(g) 14.2-34.5; % saturated fat 8.3-11.9; monounsaturated fat(g): 1616-40:6; % monounsaturated fat 10.1-13.5; polyunsaturated fat(g): 10.7-26.5; % polyunsaturated fat 6.548.7; ethanol(g): 0-4.5; % ethanol: 0-1.5; dietary fiber(g): 19.8445.0; NSP(g): 13.1-31.2; insoluble NSP(g): 7.2-17.6; sblubld NSP(g): 5.6-13.8; starch(g): 78.5-183.1;: calciurh(mg): 60741374; vitamin C(mg): 95-279; beta carotene(mcg): 221747440; cholesteroi(mg): 1244345. w o o Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 30. Odds Ratios and 95% Confidence Intervals for Colorectal Cancer by Quartile of Dietary Fiber Intake Calorie-Adjusted Nutrient/Food Densities1 Qr (Low) Q2 Confidence Interval q 3 Confidence Interval Q4 (High) Confidence Interval P Value forTrerid Dietary fiber Median intake (g/day) 20.3 26.8 311 40:6 No. of cases 38 31 18 14 Multivariate OR (95% Cl) 1.00 0.87 (0.51-1.51) 0.50 (0.27 n 0:94) 0J37 (0.18-0.75) 0.00 Dietary fiber from fruit Median intake (d/day) 1.6 4:3 7.6 13.3 No. of cases 25 32 23 21 Multivariate OR (95% Cl) 1.00 128 (0.72-2.29) 0.99 0.52-1.90) 0J85 (0.43-1.66) 0.17 Dietary fiber from grain Median intake (g/day) 4.1 7.7 10:7 12.0 No. of cases 36 25 20 20 Multivariate OR (95% Cl) 1.00 0.67 (0.37-1.2) 0:57 (0.31 ^1J07) 0.59 (0:32-11.10) 0.02 Dietary fiber from legumes Median intake (g/day) 1.4 3.5 7.1 I14J0 No. of cases 33 31 17 20 Multivariate OR (95% Cl) 1.00 0.90 (0.51-159) 0.56 (0.29-1.08) 0.61 (0J32- 1.19) 0.44 Dietary fiber from vegetables (exCI legumes) Median intake (g/day) 2.9 4.6 6.6 9.6 No. of cases 33 34 16 18 Multivariate O R (95% Cl) 1.00 1.02 (0.59 - 1 7 8 ) 0J50 0 .2 6 - 0.98) 0.58 (0.30 -1 .1 2 ) 0.04 ? Adjusted by conditional logistic regression for generation status and total calories by the multivariate nutrient density model. In the calculation of the odds ratios, the grogp with the lowest intake of dietary fiber from a given source served aS the reference group. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 31. Odds Ratios and 95% Confidence Intervals for Colorectal Cancer by Quartile of Dietary Fat Intake Calorie-Adjusted Nutrient Densities1 Qi (Low) Q2 Confidence Interval Qs Confidence Interval Q4 (High) Confidence Interval P Value for Trend Dietary fat Median intake (g/day) 20.3 26.8 31.1 40.6 No. Of cases 20 15 29 37 Multivariate OR (95% Cl) 1.00 0175 (037-1156) 1.42 (0.74-2.75) 1.70 (0.90-3.19) 0.03 Dietary fat from dairy Median intake (g/day) 511 1011 15.0 19.7 No. Of cases 20 22 31 28 Multivariate OR (95% Cl) 1.00 1,12 (0156-2123) 1.51 (0.80-2.86) 1.43 (0.75 r 2.73) 0119 Dietary fat from fish Median intake (d/day) 0,0 0.3 0.5 0.9 No. of cases 19 23 27 32 Multivariate OR (95% Cl) 1.00 1.11 (0157 - 2.16) 1.35 (0171 - 2.57) 1.58 (0.85 - 2.93) 0112 Dietary fat from meat incl. processed Median intake (g/day) 3.1 8.5 13.3 23.2 No. of cases 19 31 25 26 Multivariate OR (99% Cl) 1.00 1156 (0.84-2.91) 1.22 (0.63-2.38) 1.27 (0.66 - 2.48) 0186 Dietary fat from poultry Median intake (g/day) 1.4 2.9 5.2 8.5 No. of cases 24 19 34 24 MultivariateOR (95% Cl) 1.00 0.73 (0138-1.42) 1.43 (0.78 - 2.62) 1.07 (0.5712.01) 0149 1 Adjusted by conditional logistic regression for generation status and total calories by the multivariate nutrient density model. In the calculation of the odds ratios, £ the group with the lowest intake of dietary fiber from a given source served as the reference group. trend was the most significant of the various measures of fiber. We found a statistically significant inverse association for dietary fiber from grain (OR for highest quartile, 0.59; 95% confidence interval, 0.32 to 1.10) and dietary fiber from vegetables, excluding legumes (OR for highest quartile, 0.58; 95% confidence interval, 0.30 to 1.12). We found an appreciable reduction in risk for the highest two quartiles of dietary fiber from legumes (OR for two highest quartiles, 0.56 and 0.61) but the overall trend was not statistically significant. In fact, the risk estimates are similar in the two highest quartiles for dietary fiber from grain, vegetables, and legumes. Dietary fiber from fruit shows no association. None of the measures of fat from individual food sources show a statistically significant association with colorectal cancer. While risk estimates are higher for fat from fish the median daily gram intake is quite small for all quartiles. The colorectal cancer odds ratios for various foods that have been investigated in previous studies are shown in Table 32. We found a strong inverse association for total vegetables and vegetables without legumes. We found no statistically significant association for legumes, although, like dietary fiber from legumes, there appears to be a protective effect in the highest two quartiles of intake. There is no association for cruciferous vegetables. In agreement with our finding for dietary cholesterol, we found a strong association for egg intake. The risk in the highest quartile is two-fold compared to a risk of essentially 1.0 in the other three quartiles. We found no statistically significant association between red meat and colorectal cancer in these data, although there appears to be an increased risk from higher intake. Odds ratios for colorectal cancer associated with different methods of cooking meat are shown in Table 33. Our data suggests there is an association between colorectal cancer and certain cooking methods, specifically fried and barbequed meat, although the numbers are too small to achieve statistical significance. For subjects who eat fried meat one or more times per week the risk of colorectal cancer is 1.75 (p=0.07) compared to subjects who never eat fried meat. Similarly, 141 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 32. Odds Ratios and 95% Confidence Intervals for Colorectal Cancer by Quartile of Various Food Intake Calorie-Adjusted Nutrieht Densities1 Qi (Low) 0 2 Confidence Interval Q s Confidence interval 0 4 (High) Confidence Interval P Value for Trend Red Meat Median intake (g/day) No. Of cases Multivariate OR (95% Gl) 12.7 19 1.00 34.2 31 I1J62 (0.86 - 3.08) 56.7 27 1.45 (0.74 - 2.82) 87.6 24 1.23 (0.63 t 2.41) 0.93 Eggs Median intake (g/day) No. Of cases Multivariate OR (95% Cl) 1 2:0 19 1.00 7.7 19 0J97 (0149-1.95) 11.6 19 0.87 (0143-1.77) 34.4 44 2.02 (-5eggs/week) (1.09-3.73) 0.00 Legumes i Median intake (g/day) No. Of cases Multivariate OR (95% Cl) 15.5 35 1.00 14114 30 0185 (0148-1.52) 82.0 15 0.46 (0123-0.89) 11868 21 0.61 (0.32-1.16) 0136 Total vegetables Median intake (g/day) No. of cases Multivariate OR (95% Cl) 202J4 41 1.00 331.0 19 0.49 (0127-0.91) 453.2 25 0.67 (0137-1.21) 61318 16 0.40 ' (0.20 4 0179) 0101 Vegetables (excluding legumes) Median intake (g/day) No. of cases Multivariate OR (95% Cl) 15314 40 1.00 241.2 26 0.67 (0J34-1.18) 316.0 18 0.47 (0.25-0.88) 502.5 17 0145 (0.24 4 0187) 0:02 Cruciferous vegetables Median intake (g/day) No. of cases MultivariateOR (95% Cl) 6.9 35 1.00 1719 23 0.65 (0135-1.21) 35.0 25 0.71 (0.39-1.29) 82.8 18 0156 (0.30-1.04) 0122 'Adjusted by conditional logistic regression for generation status and total calories by the multivariate nutrient density model. In the calculation of the odds ratios, the group With the lowest intake of dietary filler from a given source served as the reference group. Table 33. Odds Ratios and P values for Methods of Cooking Meat n C ases % n Controls % O R P value C harcoal-broiled Never 24 29% 114 35% 1.00 1-3 times/month 41 50% 165 51% 1.06 1+ times/week 17 21% 46 14% 1.44 0.36 O ven-broiled Never 16 19% 98 29% 1.00 1-3 times/month 55 §4% 140 42% 2.16 1+ times/week 15 17% 96 29% 0.74 0.55 Fried Never 22 25% 101 30% 1.00 1-3 times/month 31 36% 136 41% 1.17 1+ times/week 34 39% 96 29% 1.75 0.07 B arbequed Never 23 28% 130 40% 1.00 1-3 times/month 42 51% 144 44% 1.43 1+ times/week 18 22% 54 16% 1.69 0.14 1 Adusted by conditional logistic regression for generation status R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. subjects who eat barbequed meat one or more times per week have an increased risk of colorectal cancer of 1.69 (P=0.14). Odds ratios for sedentary hours are shown in Table 34. We also present this data separately by gender because we observed significant differences in risk. The interaction effect of sex (p=0.13), however, is non-significant. Increasing sedentary hours is highly significant (p for trend=0.01) among males. Colorectal cancer odds ratios among men reporting 6-8 hours and 8.5 or more hours sitting (>75* percentile) are 2.32 (p=0.04) and 2.59 (p=0.01) respectively. We found an increased risk of colorectal cancer among women reporting 8.5 or more hours sitting (OR=1.67) although the p value is not statistically significant. In a stepwise logistic regression analysis only three risk factors entered the model and remained statistically significant: dietary fiber and cholesterol adjusted for total energy intake, and sedentary hours (see Table 35). No other variables, including generation status, had p-values less than 0.05 for inclusion. The results of the stepwise analysis demonstrate dietary fiber and sedentary hours are independent risk factors for colorectal cancer whereas dietary fiber and cholesterol are correlated with one another. Table 36 shows the odds ratios and confidence intervals obtained from a multivariate model adjusted by conditional logistic regression for calorie intake. Whereas the estimates of risk for dietary fiber intake are slightly attenuated by inclusion of cholesterol, the effects of cholesterol are substantially diminished by adjustment for fiber. The estimates of risk for sedentary hours are unaffected in the multivariate model. DISCUSSION Dietary Fiber The finding most striking of our research was the strong, dose-dependent, inverse association between dietary fiber intake and colorectal cancer risk. In fact, we found a significant inverse association for various measures of fiber intake: total dietary fiber, total NSP, insoluble NSP, soluble 144 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 34. Sedentary hours by gender Sedentary hours1 Cases Controls OR2 Confidence interval P value COMBINED <=5.5 hrs 39 208 1.00 6.0 - 8.0 24 98 1.29 0.715-2.341 0.39 8.5+ hrs 34 86 2.03 1.195-3.451 0.01 p for linear trend 0.04 MALES <=5.5 hrs 17 119 1.00 6.0 - 8.0 19 62 2.32 1.046-5.140 0.04 8.5+ hrs 22 58 2.59 1.250-5.354 0.01 p for linear trend 0.01 FEMALES <=5.5 hrs 22 89 1.00 6.0 - 8.0 5 36 0.54 0.185-1.551 0.25 8.5+ hrs 12 28 1.67 0.740 - 3.743 0.22 p for linear trend 0.92 pfor interaction term 0.13 (sex*sed hrs) ’Categories were created from controls - combined for both males and females - the upper outpoints for the reference group and the 6-8 hour group are the 50th and 75th percentiles. Adjusted by conditional logistic regression for generation status R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 35. Stepwise logistic regression analysis Variable* Exp(b) Chi2 P value STEP NO. 1 generation status 1.98 7.27 0.01 % fat 1.04 6.14 0.01 dietary fiber density 0.91 11.63 0.00 vitamin C density 0.99 4.63 0.03 cholesterol density 1.01 11.12 0.00 sedentary hours 1.07 5.14 0.02 dietary fiber density chosen for inclusion in the model STEP NO. 2 generation status 1.71 4.22 0.04 % fat 1.01 0.39 0.53 vitamin C density 1.00 0.08 0.78 cholesterol density 1.01 5.40 0.02 sedentary hours 1.07 5.42 0.02 sedentary hours chosen for inclusion in the model STEP NO. 3 generation status 1.62 3.30 0.07 cholesterol density 1.01 5.71 0.02 cholesterol density chosen for inclusion in the model STEP NO. 4 generation status 1.54 2.63 0.10 no variables havep-values for inclusion < 0.05 *all variables are continuous R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table 36. Results of Multivariate Analysis Median Odds Confidence P value Variable* Daily Intake Ratios Intervals linear trend* Dietary fiber density q2 26.8 g 0.90 0.500-1.605 Q? 31.1 g 0.48 0.2339 - 0.959 cu 40.6 g 0.44 0.1197-0.960 0.016 Cholesterol density q2 195.9 mg 1.17 0.551 - 2.503 Q3 245.2 mg 1.31 0.613-2.784 Q4 346.3 mg 1.50 0.717-3.154 0.016 Sedentary hours 6.0 - 8.0 1.30 0.703 - 2.394 8.5+ hrs 2.17 1.262 - 3.745 Q.017 * p value based on continuous variable R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. NSP, dietary fiber from vegetables, and dietary fiber from grain. There is a greater protective effect from insoluble NSP than from soluble NSP, although both measures are highly significant. The beneficial effect of fiber in cancer etiology had its origins in the work of Burkitt and colleagues in the early 1970s by examining the association with colon cancer and disorders of the gastric-intestinal tract (Burkitt et al, 1974). Many studies have since examined the role of dietary fiber (a measure of vegetable as well as grain, fruit, and legume intake) and colorectal cancer risk. Since the early 1970s, most case-control studies have consistently found a reduced risk associated with higher consumption. An analysis of combined data from thirteen case-control studies found a statistically significant trend of a decreased risk as fiber intake increased (Howe et al, 1992). This inverse association was seen in twelve of the thirteen studies, and is similar in magnitude for both colon and rectal cancers (Howe et al., 1992). Similar findings have also been reported in a meta analysis of sixteen case-control studies (Trock et al, 1990). Negri et al found a significant inverse association of total fiber intake in a large case-control study in Italy (Negri et al, 1998) and Le Marchand et a l found a significant inverse association in a population-based case-control study among different ethnic groups in Hawaii (Le Marchand et al, 1997). Data from prospective studies, however, is either weakly supportive of the fiber association (Heilbrun et al, 1989; Steinmetz et al, 1994) or non-supportive (Willett et al., 1990; Giovannucci et al, 1994; Fuchs et al, 1999; Terry et al, 2001). Recently, Fuchs et al reported no association between dietary fiber intake and colorectal cancer among women who participated in the Nurses’ Health Study (Fuchs et al, 1999) and Terry et al found no association among women participating in a population-based prospective mammography screening study in Sweden (Terry et a l, 2001). As discussed, we found a particularly strong inverse association between colorectal cancer and intake of insoluble NSP, soluble NSP, dietary fiber from vegetables, and dietary fiber from grain. While support for these findings has been shown in several studies, other studies report no association. Recently, Terry et al examined the association of fruit, vegetables, and dietary fiber with 148 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. colorectal cancer risk in a population-based prospective mammography screening study in Sweden. They found total fruit and vegetable consumption was inversely associated with colorectal cancer risk but cereal fiber had no association with risk (Terry et al, 2001). Le Marchand et al found a strong, dose-dependent inverse association with fiber intake from vegetable sources, measured as crude fiber, dietary fiber, or non-starch polysaccharides. Inverse associations were also found for soluble and insoluble fiber fractions and for cellulose and noncellulosic polysaccharides. No clear association was found for fiber from fruits or cereals (Le Marchand et al, 1997). Benito reported that the protective effect of fiber was attributable to legumes in a population based case-control study in Majorca (Benito et al., 1990). Freudenheim et al reported that cereal intake for both genders and fruit/vegetable intake for men was responsible for the decreased risk of colon cancer in their study (Freudenheim et al, 1990). They also found a greater protective association for insoluble cereal fiber than for soluble cereal fiber. More recently, Negri et al found a significant inverse association for insoluble and soluble components as well as fiber from vegetables and fiber from fruit. Grain fiber was not associated with colorectal cancer risk (Negri et al, 1998). Conversely, data from the Nurses’ Health Study found only fruit fiber was associated with a modest, though not statistically significant, reduction in risk. In contrast, greater consumption of vegetable fiber was associated with a significant increase in the risk of colorectal cancer (Fuchs et al, 1999). This latter study prompted Potter to question in an editorial comment, “where to now?” (Potter, 1999) Investigators have proposed that perhaps these inconsistencies are because of the heterogeneous nature of fiber products and differences in the ways in which fiber is measured and quantified (World Cancer Research Fund, 1997; Potter, 1999). The “heterogeneous nature of dietary fiber” hypothesis is a plausible explanation when one considers the proportion of overall dietary fiber intake that is attributed to an individual food source (such as vegetables, fruits, cereals, or legumes). Studies conducted in different parts of the world have a measure of dietary fiber whose composition Would vary dramatically from study population to study population. We can demonstrate this point 149 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. with our own study data. Among Mexican-origin Latinos, grain accounts for approximately 32% of dietary fiber on average. Fruit accounts for about 23%, legumes for 23%, and vegetables for 22% of dietary fiber on average. These percentages are similar to the percentage Borrud et al. calculated in Mexican Americans (n=98) residing in Texas. The investigators found that the legumes group was the main contributor to dietary fiber. In their study population, Mexicans received approximately 29% of their total dietary fiber from legumes, about 20% of their dietary fiber from vegetables and 21% from grain and grain products, primarily from foe bread and tortilla food group as opposed to other grains, cereals, pasta, pancakes or crackers (Borrud et al, 1989). Table 37 shows foe percentage of total dietary fiber by food source (fruit, grain, legumes, or vegetables) within our control population. We have stratified by quartile of total dietary fiber intake adjusted by conditional logistic regression for generation status and total energy. Among controls in our highest quartile of dietary fiber intake (OR=0.37), grain accounts for 31% of foe total grams followed by fruit at 27%, legumes at 22%, and vegetables at 20%. We are not aware of any other studies where legumes contribute so significantly to foe overall composition of dietary fiber as it does in foe Mexican American population. Negative results from foe Nurses’ Health Study have led some researchers to propose that inconsistencies from various studies are because of foe magnitude of absolute gram intake of dietary fiber (Terry et al., 2001). When one considers the amount of dietary fiber that is being consumed in each category (quartile or quintile), defined by foe overall intake in a particular study’s population, in actuality, findings may not be as inconsistent as they currently appear. In fact, we argue that our findings are consistent with those of most other studies discussed above when gram intake of dietary fiber is taken into consideration and foe absolute amount is sufficiently high. We attempted to demonstrate this point in Table 38. We plotted foe colorectal cancer odds ratios associated with varying amounts of dietary fiber intake as calculated from questionnaires for seven recent studies: Terry et al, Fuchs et al, Negri et al., LeMarchand et al, Howe et al., Steinmetz et al, and ours. Four 150 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Table 37. Percentage of Total Dietary Fiberl Intake Attributed to a Particular Food Source Calorie-Adjusted Nutrient/Food Densities1 Q i (Low) q 2 Q s 0 4 (H igh) P Value for Trend ! Dietary fiber Median intake (g/day) No. of cases Multivariate OR (95% Cl) 20.3 38 1.00 26.8 31 0.87 (0.51-1.51) 31.1 18 0.50 (0.27-0.94) 40.6 14 0J37 (0.18-0175) 0.00 % of total dietary fiber from: % gm % CONTROLS gm % gm % gm fruit 1711% 3.5 22.1% 5.9 26.6% 8.3 27.9% 11.3 grain 36.0% 7.3 34.1% 9 1 1 31.0% 9.6 28.0% 11.4 legumes 21:3% 4.3 22.4% 6.0 2211 ? /o 6.9 24:2% 9:8 vegetables 2516% 5.2 21.4% 5:7 2013% 6.3 19.9% 8:1 'Adjusted by conditional logistic regression for generation status and total calories by the multivariate nutrient density model. In the calculation Of the odds ratios, the group with the lowest Intake of dietary fiber from a given source served as the reference group. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Table 38. Cdlorectal Cancer Odds Ratios by Dietary Fiber intake as Reported on a i Questionnaire for Seven! Studies 1 .2 0 -i 1110 unn 1.00 0J96 1093 0 90 M - ® o c M O 0.83 0180 1 .7 7 a 0170 e o g 0 60 0.66 .0 .6 5 0.51 " AO-51 o 0.50 ? “ 0140 n u ° 0:30 0.50 0:20 0110 0.00 10 20 25 0 5 15 30 45 35 40 Dietary Fiberl intake (gm) - - ♦ - • M o n r o e — ■ — Fuchs A - Negri — X— Le Marchand —h*—- Howe — - Steinmetz - - H — Terry studies provided the median g/day intake by quintile or quartile: Terry’s, Fuchs’, Howe’s, and ours. For the other three studies, we estimated the median g/day intake from die reported interquartile or interquintile range. All seven studies adjusted for total energy intake, age, sex, as well as various other covariates. With the exception of the Terry and Fuchs studies, results from the other five referenced studies demonstrate a decreasing risk of colorectal cancer with increasing intake of dietary fiber. The median intake (g/day) of dietary fiber for each of the quartiles defined from controls within our Mexican-origin Latino population was 20.3,26.8,31.1, and 40.6 (from the lowest to highest quartile of dietary fiber intake). The multivariate odds ratios associated with each quartile were 1.00, 0.87,0.50, and 0.37 from the lowest to highest. Conversely, the median, energy-adjusted, dietary fiber intake (g/day) for each of the quintiles in the Nurses’ Health Study was 9.8, 13.1, 15.9, 19.1 and 24.9 from lowest to highest quintile and the multivariate relative risks associated with each quintile were 1.00,0.90,0.96, 0.93, and 0.95. The median gram intake in our reference group (20.3) roughly corresponds to the median gram intake (19.1) in the 4th quintile of the Nurses’ Health Study. The median gram intake in the highest quintile of the Nurses’ Study was 24.9 g/day, an amount that is less than the median gram intake in our 2n d quartile. In fact, the median gram intake of dietary fiber in all five quintiles, when averaged together, would be less than the median dietary fiber intake in our reference group. The median, energy-adjusted, dietary fiber intake (g/day) was even lower in the Swedish mammography study, namely 12.3, 15.6, 18.1 and 21.8 from lowest to highest quartile and the multivariate relative risks associated with each quintile were 1.0Q, 0.96,1.05, and 0.96 (Terry et al, 2001). Again, the median gram intake of dietary fiber from all four quartiles, when averaged together (17 g/day), would be considerably less than the median dietary fiber intake from the reference group in the Multiethnic Cohort Mexican American population. Negri et al. reported the upper outpoint of fiber intake (g/day) to create quintiles in their study, namely, 15.7,19.6, 23.2, and 27.9. The multivariate odds ratios associated with quintiles two 153 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. through five were 0.83,0.65, 0.58, and 0.51, respectively. If we line up the gram intake in each quintile from this study with our data, the risk estimates would be quite similar, if not identical. Our third quartile, representing a median intake of 31.1 g/day, has a corresponding odds ratio of 0.50 that is in line with the dietary fiber intake (g/day) and odds ratio for the 5th quintile in Negri’s study (Negri et al., 1998). In die study by Le Marchand et al. the interquartile range of fiber intake was 16-26 (g/day) for men and 15-22 (g/day) for women. Therefore, the highest quartile would correspond to about a median intake greater than 24 g/day if values for men and women were averaged. If we estimate that the median intake for the 4th quartile corresponds to 27-30 g/day then the odds ratio from this study (OR=0.7) is directly between the odds ratios for quartiles 2 and 3 (OR, 0.87 and 0.50, respectively) from our Mexican-origin Latino population for the same gram intake (Le Marchand et al., 1997). Howe et al. in an analysis of combined data from thirteen case-control studies reported a relative risk of 0.51 for a median intake of 31.2 grams of fiber per day (Howe et al., 1992). Again, the relative risk for this level of fiber intake is in agreement with Negri et al. and our study that report the same g/day of fiber intake. In fact, the odds ratios for various levels of dietary fiber intake are identical between the Negri et al. and Howe et al. studies. We also plotted (Table 39) the colorectal cancer odds ratios associated with varying amounts of insoluble fiber intake for three recent studies that examined this component separately: Negri et al., LeMarchand et ah, and ours. Results demonstrate a decreasing risk of colorectal cancer with increasing intake of insoluble fiber. In fact, the odds ratios corresponding to varying amounts of insoluble fiber are remarkably consistent across the three studies. To support the negative findings of their study, Fuchs et ah noted that three placebo- controlled randomized trials found no significant reduction of colorectal tumors among subjects who received fiber supplementation (Fuchs et ah, 1999; DeCosse et ah, 1989; MacLennan et ah, 1995; McKeown-Eyssen et ah, 1994). Recently, three additional randomized dietary intervention trials also found a lack of effect of a low-fat, high-fiber diet on the recurrence of colorectal adenomas (Schatzkin 154 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. © 2 © il 0 ) A 3 o 1 0 © a: (0 "3 o t_ © o c a a o 2 o o o o > « © -O 1? 00 I!/ C O o o >. o o C O o o o o 05 o o 0 0 o C O o o CM o o 9 I © J B U . © £ 3 O (0 © ■ b c c a j= CO © O ) © I CO < b o I ♦ i jepueg |epaio|oo joj open sppo 155 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. et al, 2000; Bonithon-Kopp et al, 2000; Alberts et al, 2000). While the results of these randomized trials are disappointing to investigators looking for short-term treatment effects, they do not necessarily diminish the findings of a protective effect of fiber seen in the epidemiology studies. DeCosse et al suggested that colorectal carcinogenesis occurs pyer a period of years and that preventive measures would, accordingly, require long-term exposure (DeCosse et al, 1989). Further, in two of the studies, dietary fiber intake averaged 22.2 and 25 g/day, an amount that is considerably less than the daily gram intake of some of the epidemiology studies (DeCosse et al, 1989; MacLennan et al., 1995). And although MacLennan et al found no statistically significant prevention of total new adenomas with the intervention, they found that the intervention may reduce the transition from smaller to larger adenomas, a step they hypothesize may define those adenomas most likely to progress to malignancy (MacLennan et al, 1995). The mean dietary fiber intake of subjects at baseline in the dietary intervention trials ranged from 17 g/day among females to about 21.7 g/day among males. The mean age of subjects ranged from 56 to 67 years in five of the six intervention trials (one study enrolled young subjects (mean age 35) with familial adenomatous polyposis). We think this information is important in light of the hypothesis that colorectal carcinogenesis occurs over a period of years and that preventive measures would, accordingly, require long-term exposure. Four years or less of fiber supplementation following fifty years or more of low dietary fiber intake seems unlikely to provide the protective effect of a lifetime of high dietary fiber exposure seen in the Mexican American population. Support for this hypothesis comes from the fact that the Mexican American cohort population also has a low incidence of polyps of the intestines (only about 2%-4% of the Mexican American cohort subjects reported polyps on the questionnaire; the mean age of respondents is comparable to the mean age of subjects in the randomized trials). Our results for Mexican Americans, combined with findings from the literature related to the dietary behaviors of the indigenous population of Mexico, support a 156 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. finding of a lifetime of high dietary fiber exposure that is protective not only of colorectal cancer but the occurrence of adenomas as well. Vegetables Our finding of a statistically significant inverse association between vegetable intake and colorectal cancer risk has strong support from previous studies. Among dietary factors, the most consistent and convincing observation in the literature (prior to 2000) has been the inverse association between vegetable consumption and risk (World Cancer Research Fund, 1997). An inverse association for one or more measures of vegetable intake was found in both genders in three of four prospective studies (Phillips and Snowdon, 1985; Thun et al, 1992; Steinmetz et al, 1994). The fourth study found a protective association for various measures of vegetable intake in females only (Shibata et al, 1992). Seventeen of twenty-one case-control studies found a reduced risk of colon cancer for higher consumption of at least one category of vegetable or fruit. Decreased risk is particularly consistent for raw vegetables and green vegetables (World Cancer Research Fund, 1997). A meta-analysis of sixteen case-control studies of vegetable consumption and risk of colon cancer reported a combined OR of 0.48 (0.41-0.57) for highest versus lowest quintiles of vegetable intake (Trock et al, 1990). Our analysis found a similar effect (OR, 0.45; 95% confidence interval, 0.24 - 0.87) for the highest versus lowest quartile of vegetable intake. Recently, an analysis in Italy that combined two case-control studies with a total of 1,953 colorectal cancer cases, compared the effect of consumption of different types of vegetables and fruit to better understand which constituents may be related to risk (Franceschi et a l.,_ 1998). They found that most vegetables were inversely associated with colorectal cancer risk. High total intake of raw vegetables was associated with a statistically significant reduction of colon cancer (OR=0.74) for the difference between the 20th and 80th percentile of weekly servings (Franceschi et al, 1998). 157 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Conversely, results from a recent analysis of prospective data are non-supportive of the vegetable association (Michels et al., 2000). Hie investigators used data from two large cohorts: the Nurses’ Health Study (88,764 women) and the Health Professionals’ Follow-up Study (47,325 men) to investigate the association between fruit and vegetable intake and the incidence of colorectal cancer. Measures of the consumption of fruit and vegetables were grouped in five categories: < 1.5 (1 serving/day), 1.5-2.4 (2 servings/day), 2.5-3.4 (3 servings/day), 3.5-4.4 (4 servings/day), and > 4.5 (5+ servings/day). The measure of fruit and vegetables combined were grouped in five categories: < 2.5 (2 serving/day), 2.5-3.4 (3 servings/day), 3.5-4.4 (4 servings/day), 4.5-S.4 (5 servings/day), and 5.5 or more (6+ servings/day). Michels et al. concluded that frequent consumption of fruit and vegetables does not appear to confer protection from colorectal cancer. Furthermore, they did not find evidence of any appreciable benefit from any specific sub-group of fruit or vegetable intake, e.g., citrus fruits or green leafy vegetables. Beta-carotene One possible reason for the protective effect of vegetables on colorectal cancer risk includes the presence of potentially anticarcinogenic substances such as carotenoids. Although we found no statistically significant association between P-carotene and colorectal cancer in our data, there appears to be modest protection from high intake. There have been several reports of a low risk associated with a high intake of carotenoids, micronutrients found primarily in fruits and vegetables (van Poppel, 1993). Five case-control studies reported that higher intakes of P-carotene were associated with a lower risk of colorectal cancer (La Vecchia et al, 1988; Lee et al., 1989; Freudenheim et al., 1990; Whittemore et al, 1990; Zaridze, 1993). However, three case-control studies (Tuyns et al., 1987; Peters et at., 1992; Meyer and White, 1993) and one prospective cohort study (Bostick et al., 1993) found no association. The difficulty with examining the role of carotenoids in relation to colorectal cancer risk is the probability that the protective factor in foods containing p-carotene could be non- 158 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. starch polysaccharides or starch, rather than a particular micronutrient (Key, 1994). For example, Howe et al. found that P-carotene, ascorbic acid, and dietary fiber were each inversely associated with risk. However, after adjustment for each factor, only the inverse association of dietary fiber remained strong and statistically significant (Howe et al., 1992). It is also unclear whether the association between P-carotene and colorectal cancer could be due to other phytochemicals that are present in fruits and vegetables high in carotenoids (World Cancer Research Fund, 1997). Vitamin C We found a statistically significant inverse association between vitamin C and the risk of colorectal cancer. However, as with other constituents that are abundant in vegetables and fruit, the protective effect of vitamin C on colorectal cancer risk may be due to the fiber, carotene, or other component of these plant foods. In the literature, high dietary vitamin C intake may reduce the risk of colorectal cancer, but at present, the evidence is not sufficient (World Cancer Research Fund, 1997). Dietary Fat Our finding of a statistically significant increased risk of colorectal cancer from total fat intake has limited support in the literature. Two case-control studies have found a statistically significant increased risk associated with total fat intake [Freudenheim et al., 1990 (rectal only); Peters et al., 1992] and one cohort study found that intake of total fat in the highest quintile was associated with a twofold increase in the risk of colon cancer (Willett et al, 1990). However, of eleven studies which attempted to separate the effect of total fat from total calorie intake on the risk of colorectal cancer, four of five cohort studies (Bostick et al, 1994; Giovannucci et al, 1994; Goldbohm et al, 1994; Kampman et al, 1996) and three case-control studies found no association (Tuyns et al., 1987; Benito et al., 1990; Meyer and White, 1993). Two recent studies have also not provided support for the risk associated with dietary fat. The combined analysis of data from thirteen 159 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. case-control studies found no evidence of an increased risk with higher dietary fat intake after adjustment for total energy intake (Howe et al, 1997). Additionally, Le Marchand et al. reported that intakes of total fat were not related to the risk of colorectal cancer in a case-control study in a multiethnic population in Hawaii (Le Marchand et al., 1997). Saturated or Animal Fat We found evidence of an increased risk of colorectal cancer from higher saturated fat intake although the overall trend was non-significant. In the judgment of the scientific panel of a recent review of colorectal cancer, saturated fat may possibly increase the risk of colorectal cancer (World Cancer Research Fund, 1997). Five cohort studies have reported on animal and or saturated fat in relation to colorectal cancer risk. One early study of Japanese men living in Hawaii reported a decreased risk of colon cancer but a moderately increased risk of rectal cancer associated with high intake of saturated fat (Stemmermann et al., 1984). Conversely, a large cohort of female nurses found the relative risk for the highest compared to the lowest quintile of fat intake was 1.9. However, the positive association no longer remained when the analysis controlled for red meat consumption (Willett et al, 1990). A weak increase in risk (RR=1.4) for colon cancer was also reported for the highest quintile of saturated fat intake in Dutch women but no association was found for men (Goldbohm et al., 1994). The two other cohort studies found no association between saturated and/or animal fat intake and colorectal cancer risk with relative risks ranging between 0.9 and 1.2 (Bostick et al, 1994; Giovannucci et al., 1994). Additionally, sixteen case-control studies have examined associations of colorectal cancer and saturated/animal fat intake. Results are inconsistent as well. Of seven studies reporting solely on colorectal cancer, four found that a higher intake of saturated fat was associated with a higher risk (Sandler et al., 1993; Miller et al., 1983; Whittemore etal, 1990; Zaridze et al., 1993). The other three reported that intakes of saturated fat were not related to the risk of colorectal cancer (Lee et al, 160 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1989; Benito etal., 1991; Le Marchand etal., 1997). However, of the latter studies, Le Marchand reported an inverse association for the polyunsaturated fat/saturated fat (P/S) ratio for both genders (Le Marchand et al, 1997). Of the eight additional studies reporting on colon cancer, five reported an increase in risk with higher intakes of saturated fat (Dales et al, 1979; Jain et al., 1989; Potter and McMichael, 1986; West et al., 1989; Gerhardsson de Verdier et al., 1999) while three found no association between saturated fat and colon cancer risk (Tuyns et al, 1987; Peters et al, 1992; Meyer and White, 1993). One study found evidence of a modest increased risk of colorectal cancer in die highest quartile of saturated fat intake but the overall trend was not significant (De Stefani et al, 1997). Red Meat We found no statistically significant association between red meat intake and colorectal cancer risk in our study population. The pattern we observe — colorectal cancer risk actually decreases as gram intake of red meat increases — reflects the changing pattern of intake we observed in the migrant analysis between Mexico-born and US-bom subjects. As more of our cancer cases are US-bom and intake of red meat is decreasing among this nativity group compared to Mexico-bom subjects, a smaller proportion of cases are consuming larger quantities of red meat. Of the seven cohort studies that have examined the association of meat consumption with colorectal cancer risk, five found no increase in risk associated with meat consumption (Phillips et al, 1985; Thun et al., 1992; Goldbohm et al, 1994; Knekt eta/., 1994; Bostick et al., 1994). Conversely, the Nurses’ Health Study found red meat consumption remains positively associated with colon cancer after controlling for dietary fat (Willett et al., 1999). The relative risk of colon cancer in the Nurses Health Study was considerably higher at 2.49 for women who ate beef, pork, or lamb as a main dish every day than for women reporting consumption less than once a month. A similar association with red meat consumption was reported in the Health Professionals Eollow-Up Study 161 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. (Giovannucci et at., 1994). Of the four cohort studies that examined processed meat, two found a statistically significant increased risk of colorectal cancer (Willett et at., 1999; Goldbohm et at., 1994) and one found a weak increased risk (Bostick et at., 1994). A comprehensive review of the literature found sixteen of twenty-six case-control studies conducted in Greece, Canada, Australia, Italy, Belgium, United States, Spain, Sweden, Argentina, and the Netherlands reported a statistically significant increased risk associated with one or more measures of higher meat consumption (World Cancer Research Fund, 1997). Two studies reported weak increases in risk (Steinmetz and Potter, 1993; Sandler et at., 1993), while seven reported essentially null findings (Macquart-Moulin et at., 1986; Lyon and Mahoney, 1988; Lee et at., 1989; Peters et at., 1989; Zaridze et at., 1993; Centonze et at., 1994). Recently, Le Marchand et al. found that intakes of red meat were associated with the risk of cancer in the right colon in men, but not in women (Le Marchand et at., 1997). Six of the ten case-control studies that examined the relationship of colorectal cancer and processed meat found statistically significant elevated risks (Young and Wolf, 1988; Wohlleb et al, 1990; Geihardsson de Verdier et al, 1991; Bidoli et al, 1992; Peters et at., 1992; Le Marchand et al, 1997). The remaining four studies reported no association (Peters et at., 1989; Benito etal., 1990; Steinmetz et al, 1993; Centonze et al., 1994). Protein We found no association between protein intake and colorectal cancer risk. Of the five cohort and fifteen case-control studies that examined the relationship of protein and colorectal cancer, all five cohort and seven of the fifteen case-control studies also found no association (Willett et at., 1990; Bostick et al, 1994; Giovannucci et al, 1994; Goldbohm etal, 1994; Kampman et al, 1996; Kune et al, 1987; Tuyns et al, 1987; Lee et al, 1989; Freudenheim et al, 1990; Whittemore et al, 1990; Peters et al, 199?; Meyer and White, 1993). However, another seven of the fifteen case- 162 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. control studies reported that higher total protein intakes were associated with increased risk (Jain et al., 198Q; Potter and McMichael, 1986; Lyon etal., 1987; Slattery et al, 1988a, 1988b; Gerhardsson de Verdier et al., 1990; Benito et al, 1991). Legumes We found an appreciable reduction in risk for higher legume intake (OR, 1.00, 0.85, 0.46, 0.61 for the lowest to highest quartile), but the overall trend was not consistent nor statistically significant (p=Q.36). Aside from the contribution to overall dietary fiber intake, it appears that legumes have no independent effect on colorectal cancer risk. The published data relating colorectal cancer and the consumption of legumes is very limited and the results have been inconsistent. For every published report that shows a decrease in risk with greater intake of legumes, there is another report that shows an increased risk or no association. Two studies combined legumes with nuts and seeds (Heilbrun et al., 1989; Kune et al, 1987), while one cohort study found the consumption of legumes in their population to be low and homogeneous (Steinmetz et al., 1994). An ecologic mortality study found an inverse correlation between colon cancer and consumption of legumes (McKeown-Eyssen and Bright-See, 1984). The consumption of legumes in our study population of Mexican-origin Latinos is neither low nor homogeneous. Perhaps with a larger sample size this finding will become statistically significant. Dietary Cholesterol and Eggs Our findings of increased risk of colorectal cancer from total dietary cholesterol and from eggs have support in the literature, although overall results remain mixed. In nine of eleven colon cancer and six of eight rectal cancer studies, higher egg consumption has been associated with an increased risk although findings were only statistically significant in three of the colon cancer and two of the rectal cancer studies (Steinmetz and Potter, 1994; World Cancer Research Fund, 1997). In two 163 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. prospective cohort studies, neither found an association between dietary cholesterol intake and the risk of colorectal cancer (Giovannucci et al, 1994; Bostick et al, 1994). In a combined analysis of thirteen case-control studies, a weak increase in risk (OR=l .3 adjusted for total energy) was associated with higher dietary cholesterol (Howe et al, 1997). In a case-control study in Hawaii, Le Marchand et al. found the association of eggs and colorectal cancer to be dose-dependent, not explained by known confounders; the finding is consistent between genders and among ethnic groups (Le Marchand et al, 1997). Additionally, a case-control study in Uruguay found a statistically significant increased risk between dietary cholesterol and colorectal cancer when adjusted for age, sex, total energy, and other covariates, e.g., vitamin D, calcium, and folate intake (De Stefani et al, 1997). Calcium High calcium intake has been hypothesized to provide a protective effect for colorectal cancer although die evidence suggests only a weak overall decrease in risk. Our data suggest that high intake of calcium may afford some protection, but the overall trend is non-significant. Eight cohort studies and at least sixteen case-control Studies have examined this association (World Cancer Research Fund, 1997; De Stefani et a l, 1997). Sixteen estimates of relative risk were reported in the cohort studies of which only one was statistically significant with a relative risk below unity (Garland et al, 1985). Of the twenty-six or more odds ratios reported by the case-control studies, seven showed a statistically significant decrease in risk, one showed a statistically significant increase in risk, and eighteen showed no association. A meta-analysis reported an overall relative risk of 0.89 for data from twenty-four studies (Bergsma-Kadijk et al, 1996). In a case-control study conducted in Uruguay, calcium intake was associated with a statistically significant decrease in risk of colorectal cancer (OR=0.41) for the highest quartile of intake (De Stefani et al, 1997). 164 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Methods o f Cooking Meat Sugimura and Sato were the first to propose that specific heterocyclic amines from heavily cooked meats were important in the etiology of colon cancer (Sugimura and Sato, 1983). Since then results have been mixed. One study reported an elevated odds ratio for colorectal cancer associated with the most frequent consumers of fried meat (Gerhardsson de Verdier et al., 1991). Similarly, Schiffrnan et al. reported a 3.5 fold increase in risk for subjects eating well-done meat (Schiffinan et al., 1989). Similar findings were reported in a case-control study of colorectal adenomas (Probst- Hensch et al., 1997). Conversely, Augustsson et al. found that intake of heterocyclic amines is unlikely to increase the incidence of colorectal cancer in the dietary range of their study population (Augustsson et al., 1999). For high intakes, their data are consistent with human carcinogenicity, but they caution their measurement precision was extremely low. Although our preliminary data suggest an association between colorectal cancer and fried or barbequed meat, we will be able to examine these factors in more detail in the data currently being collected from a follow-up questionnaire. Questions about cooking methods (pan-fried, oven-broiled, barbequed) and about how “brown” the outside of the meat was cooked were included to specifically address this question. Heterocyclic amines from heavily charred meats are metabolized by the enzymes N- acetyltransferase and CYP1 A 2 (World Cancer Research Fund, 1997). Increased risk of colon cancer has been observed in rapid acetylators in four of five studies. In two of die studies, the association was found only in meat eaters (Lang et al., 1995; Roberts-Thomson et al., 1995). Again, this association will be examined in detail in the Genetic Susceptibility biological specimen study. Diabetes Our finding of an increased risk of colorectal cancer from a previous diagnosis of diabetes has limited support in the literature to date. Prior to 1997 several studies found no association (O’Mara et al., 1985; Adami et al., 1991; Ragozzino et al., 1982; Kessler, 1970). Recently, however, 165 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Hu et al. reported a significant positive association between history of diabetes and risk of colorectal cancer in women participating in the Nurses’ Health Study (Hu et al., 1999). The covariate adjusted relative risk was 1.43 for colorectal cancer and 1.49 for colon cancer in this prospective analysis. In the only previous prospective study, the risk of colorectal cancer among persons with diabetes was 1.30 for men and 1.16 for women (Will et al., 1998). However, although this study had a 13-year follow-up period, diabetes was not updated at any time during that period. Two recent case-control studies have suggested a positive association. In a large, multi-center case-control study conducted in Italy, history of diabetes afforded a slight increased risk of colorectal cancer (LaVecchia et al., 1997). The multivariate odds ratio was 1.3 (95% Cl, 1.0-1.6) for colorectal cancer. A population based case- control study in Hawaii found an increased risk of cancer in the left colon with a history of diabetes in both men and women; odds ratios were 1.9 and 3.0 respectively (LeMarchand et al., 1997). The possible association between history of diabetes and colorectal cancer risk is particularly intriguing in light of recent evidence of beneficial effects of high dietary fiber intake in patients with type 2 diabetes (Chandalia et al., 2000). Further, a prospective study conducted in older Iowa women found a strong inverse association for total grain, whole-grain, total dietary fiber, and cereal fiber with incidence of diabetes (Meyer et al., 2000). Alcohol We found no association between colorectal cancer risk and alcohol consumption in our study population. Our results have limited value to this question because the amount of alcohol currently consumed overall in this population is low (interquartile range: 0 - 4.5 daily grains) and the percentage of alcohol calories is low (interquartile range: 0 - 1.5%). 166 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Physical Activity/Inactivity The role of other lifestyle behaviors (physical activity, obesity, and alcohol) believed to be associated with colon cancer risk has been investigated extensively. In particular, reduced physical activity has emerged as the one behavior that is associated most consistently with an increased risk of colon cancer. The association has been shown in both genders. Studies examining occupational activity, leisure time activity, total physical activity, and participation in college athletics have all shown a reduced risk associated with greater physical activity. The time at which physical activity, or lack thereof, may confer its greatest impact has not been established, although several studies (Vena et al., 1985; Lee et al., 1991; Slattery et al., 1997) indicate the importance of lifetime activity. In a recent study by Slattery et al. lack of lifetime vigorous leisure-time activity was associated with increased risk of colon cancer for both men and women (Slattery et al., 1997). A recent review of published literature observed about a 50% reduction in colon cancer incidence among those with the highest level of activity across several studies that used different measures of physical activity including occupational or leisure-time activity (Colditz et al, 1997). Le Marchand et al. found an inverse association with hours spent in lifetime recreational physical activity, although the statistically significant trend was seen in men only. In females, an inverse association was present for usual daily physical activity (Le Marchand et al., 1997). Studies that controlled for diet and other known risk factors for colon cancer support this association. We were only able to look at daily vigorous work and sedentary hours in our data because of the problems described above with our question about moderate activity. While we found no association between daily vigorous work and colorectal cancer risk in our combined data for males and females, our data suggest a possible protective effect among males. Importantly though, the mean age of our study population (56-64 years) may preclude us from finding a statistically significant effect for this factor even with additional cases and controls. 167 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Our finding of a statistically significant increased risk of colorectal cancer from increasing sedentary hours has been observed previously. Garabrant et al. found that among 2,950 population- based colon cancer cases in Los Angeles, men with sedentary jobs had a colon cancer risk at least 1.6 times that of men whose jobs required a high level of activity (Garabrant et al, 1984). Risk increased as activity level decreased. This gradient was consistently seen within each socioeconomic stratum and within each ethnic group (whites, blacks, immigrant and US-born Latinos). Le Marchand et al. reported there was a suggestion of a direct association between the number of years spent in sedentary or light work jobs and cancer of the right colon (OR, 1.0,1.6,1 .8 among males and 1.0, 0.8,2.1 among females) for tertile of years of sedentary work (Le Marchand et al,, 1997). In a population- based case-control study of colorectal cancer among Chinese in North America and the People’s Republic of China, colon cancer was elevated among men in sedentary occupations (Whittemore et al, 1990). In both countries and in both genders, risks for cancers of both the colon and rectum increased with increasing time spent sitting. Colorectal cancer odds ratios among Chinese-American men reporting 5-9 hours and 10 or more hours sitting were 2.4 (P<. 05) and 3.9 (P< 001) respectively, compared with men reporting less than 5 horns sitting. Our finding among men of an increased risk of colorectal cancer with increasing sedentary hours is remarkably consistent with the findings of Whittemore et al. Colorectal cancer odds ratios among Mexican-origin men reporting 6-8 hours and 8.5 or more hours of sitting were 2.4 (P<. 04) and 2.6 (P<. 01) respectively. Methodology The findings of our study should be interpreted in light of the following potential strengths or weaknesses. Our results are unlikely to be due to imprecise or biased measures of food/nutrient intake. First, the performance of the FFQ was assessed in a calibration sub-study that compared diet reported from the questionnaire with three 24-hour dietary recalls. The correlations between nutrient intake from the 24-hour recalls and nutrient intake as reported on the FFQ, a standard measure of 168 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. validity of the study instrument, were generally highly satisfactory (Stram et al., 2000). Second, even though these data are examined with case-control methods, the prospective study design from which it originates precludes bias attributable to differential recall between colorectal cancer cases and controls. Qur results are also unlikely to be due to differences in language versions of die questionnaire. First, recognizing that one criticism of a cross-language analysis might be that between group differences reflect an artifact of differences in the language version of the questionnaire, rather than true between group differences, we conducted an extensive review and analysis of the subject responses. As a result, we excluded three foods from the nutrient calculations for all Latinos. We also calculated the nutrient content of die three “stir-fly?” questions separately so that we could see the impact of including or excluding them in future analyses. Second, we adjusted for generation status, an indirect measure of language, in all analyses except die multivariate analysis. We cannot mle out that our findings are due to some measured or unmeasured confounding factor that we failed to consider. This is of primary concern in a study of diet and disease. One factor that came to mind in assessing our findings related to dietary fiber was com or specifically, com tortillas. We tested for an association between these factors and colorectal cancer and found no direct association. The odds ratios (adjusted for generation status and total energy intake) for com tortillas were 0.81, 0.69, and 0.81 from the lowest to highest quartile. Potential bias in the ascertainment of colorectal cancer cases within our cohort needs to be considered. While every effort is made to identify all incident cancers occurring within the cohort, we are, nevertheless subject to the quality of our matching criteria when performing linkages with the Los Angeles Cancer Surveillance Program (CSP) and the California Cancer Registry (CCR). We attempted to assess that quality by examining the percentage of cases and controls that have a social security number (SSN) in our tracking database. We have SSN for 100% of our cases. This high percentage is because we obtain this information from our linkages for subjects who are missing this 169 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. identifier. We learned SSN in this manner for 21% of colorectal cancer cases in our study. The other sources for SSN among cases include; 74% came directly from the subject in the original questionnaire; 3% came from the subject’s participation in a sub-study, e.g., the calibration study; and 2% came from a linkage with a credit reporting service. Among controls, we are missing SSN for 5% (20/404) of our study population. The other sources for SSN among controls include: 80% came directly from the subject in the original questionnaire; 2% came from a tumor registry or social security death index linkage; and 13% came from a linkage with a credit reporting service. Although we are missing SSN on 5% of the controls in our study population, this percentage is unlikely to have been missed in our tumor registry linkages. Four times per year, we match the LA cohort with the CSP. Additionally, once per year we link our cohort with the CCR. For both linkages, we submit multiple records per individual if there exists alternate social security numbers, alternate dates of birth, or alias names. Four passes are done for each linkage using name, date of birth, and gender in addition to social security number. While the majority of our cases are ascertained with social security number, we also ascertain cases with the other three variables as evidenced by the fact that 21 of the 101 cases in our study were originally ascertained without a social security number. The social security numbers we do have on study participants are also believed to be highly accurate as we find few discrepancies in our linkages. When discrepancies are found, we store both numbers for future linkages and submit multiple records. Another potential bias may be related to differential access to health care between cases and controls, specifically colorectal cancer screening, resulting in undiagnosed cancers in the control population for a longer period of time. This is a concern especially in the migrant population where recent immigrants may not utilize health care options as readily as US-bom residents and screening through colonoscopy or sigmoidoscopy would affect incidence. We attempted to assess this concern by comparing the percentage of cases and controls, by place of birth, who reported having a mammogram and/or PAP smear on the questionnaire. Among cases, 87% of US-bom and 65% of 170 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Mexico-born females reported ever having a mammogram, whereas among controls, 89% of US-bom and 71% of Mexico-born females reported ever having a mammogram- While there is a difference in reported mammograms between nativity groups, controls actually report a slightly higher percentage of mammograms than cases. Likewise, among cases, 96% of US-bom and 94% of Mexico-born females reported ever having a Pap smear whereas among controls, 81% of US-bom and 71% of Mexico-bom females reported ever having one. An additional 10% of US-bom controls and 15% of Mexico-born controls left the Pap question missing. This differential reporting for Pap smear between cases and controls may be important. Unfortunately, we do not have a measure (such as mammogram) for assessing access to health care among men from the original questionnaire. We do, however, ask specifically about screening, e.g., colonoscopy, PSA blood test, mammogram, and Pap smear, in a follow-up questionnaire. We will be able to examine this issue in more detail when the complete data analysis is commenced and we can utilize data currently being collected from the follow-up questionnaire. Nevertheless, given the severity of disease in colorectal cancer patients, the fact we found no effect for education (a variable likely to be correlated with screening), and the fact that we used a June 1998 cut off date (a date for which we believe we have complete case ascertainment), we think biased ascertainment due to differential access to health care or screening is unlikely. CONCLUSION In this analysis, we had the opportunity to examine the association of colorectal cancer with food/nutrient intake in an important minority population not previously studied, Latinos of Mexican- origin now residing in the southwestern United States. Of particular interest, we were able to examine the association of colorectal cancer and dietary fiber intake where findings from both prospective and case-control studies have been inconsistent. The Mexican American population has a broad range of dietary fiber exposure, extending over a lifetime, which is not seen in other ethnic populations. Thus, 171 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Mexican Americans are an ideal population in which to study the dietary fiber association with colorectal cancer. In our case-control study (nested within a prospective study), we found strong evidence that high intake of all standard measures of fiber (dietary fiber, total NSP, soluble NSP, and insoluble NSP) reduced the risk for colorectal cancer. Fiber from vegetables and fiber from grain seem to afford the greatest protection, although fiber from legumes may contribute to the highly significant finding of a protective effect for dietary fiber. Aside from the contribution to overall dietary fiber intake, it appears that legumes have no independent effect on colorectal cancer risk. Total vegetable intake showed an inverse association with colorectal cancer risk. We found strong evidence that total dietary cholesterol, eggs, and dietary fat (particularly polyunsaturated fat) each increase die risk of colorectal cancer in univariate analyses. We also show some evidence that heterocyclic amines from heavily cooked meats may play an important role in colorectal cancer etiology. Importantly, we found strong evidence that a sedentary lifestyle contributes to an increased risk of colorectal cancer among males. In a stepwise logistic regression analysis only three risk factors entered the model and remained statistically significant in the nested case-control data: dietary fiber and cholesterol adjusted for total energy intake, and sedentary hours. The results of this analysis demonstrated that dietary fiber and sedentary hours are independent risk factors for colorectal cancer whereas the effects of cholesterol are diminished by inclusion of fiber in the model. We used these three risk factors to determine how much of the difference in the colorectal cancer incidence rates between Mexico-bom and US-bom subjects we could explain. Our data suggest that among males, dietary fiber and sedentary hours explain 29% of the difference in rates whereas among females, these two risk factors explain 64% of difference in rates between nativity groups. If we add cholesterol to the model, adjusted for total energy, our data shows that 36% and 72% of the difference in rates, for males and females respectively, can be explained by these three identified risk factors. We found this to be 172 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. remarkable given that the incidence rate among US-bom males is twice that among US-bom females. This suggests that the combined effect of dietary fiber, cholesterol, and sedentary hours on the risk of colorectal cancer is the same for males and females but we have yet to identify other risk factors among males that are contributing significantly to the doubling of the colorectal cancer incidence rate not seen in females. Food intake patterns in Mexico and the impact of the contemporary American culture on the dietary practices of the Mexican American population supports evidence of dietary adaptation to a new range of foods and changes in the mean intakes of certain nutrients which contribute to an increasing incidence rate of colorectal cancer following migration. However, the level of acculturation, determined by factors such as age at migration, number of years in the US, educational attainment, and employment opportunities, has a large role in determining whether new foods are incorporated into the diet or traditional food practices are retained. The large-scale mass immigration of Mexicans during the last three decades, the geographic closeness to Mexico, and the increasing availability of Mexican foods in California also play major roles. The level of acculturation may have a larger impact on males if they are exposed more readily to the contemporary American culture through their occupation. Lifetime daily vigorous work, a factor that we didn’t measure on the first questionnaire, is one plausible explanation for the difference in colorectal cancer incidence observed in the Multiethnic Cohort between males and females. Consistently, previous studies have shown a reduced risk associated with greater physical activity. Although the time at which physical activity may confer its greatest impact has not been established, several studies indicate the importance of lifetime activity. The question about current vigorous work on the first questionnaire provides evidence for this hypothesis. Overall, 46% of Mexican American males reported no current vigorous work compared to 74% of Mexican American females. Conversely, 23% of males report four or more hours of vigorous work per week compared to 5% of females. Given the mean age of our study population, we 173 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. realize that, if anything, the percentage of subjects reporting lifetime vigorous work would more than likely increase. Even so, it is unlikely that the striking difference between males and females would diminish. Alcohol intake is also a plausible explanation for the divergent pattern of colorectal cancer incidence between males and females. The published data on alcohol intake show that this factor more than likely increases the risk of colorectal cancer. Previous studies show the general pattern of alcohol consumption among males in Mexico is best characterized as high quantity per occasion but in moderate frequency. Cross cultural studies have found that Mexican males who migrate to the US shift their pattern of alcohol use to die American pattern of frequent drinking but continue the pattern of consuming a large quantity per occasion (Caetano and Medina Mora, 1988). In contrast, Mexican migrant women do not change their pattern of alcohol use characterized by abstinence or infrequent drinking. The current sample size in the nested case-control analysis precluded us from being able to examine the association of heavy, frequent drinking on colorectal cancer risk. Further, given that the mean age of our male study population is 65 years, and previous studies have found that as age increased alcohol consumption decreased (Marks et al., 1990; Markides et al., 1990), we will not be able to examine this risk factor among Mexican Americans until many more years of follow-up have accrued. Lifetime alcohol intake, another factor we didn’t measure on the first questionnaire, may also play a more important role in the etiology of colorectal cancer than current alcohol use. Nevertheless, it is clear that the impact of these factors needs to be examined separately in both males and females when we accrue sufficient numbers of colorectal cancer cases and the complete data analysis is commenced. 174 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. PART IH. GRANT PROPOSAL OVERVIEW AND SPECIFIC AIMS A large and compelling body of epidemiological and experimental data implicates estrogens in the etiology of human breast cancer. The premise being that estrogen and progestin are die primary determinants of cell proliferation in breast epithelium and that cell proliferation is a prerequisite for many of the genetic changes necessary for a cell to transform to a malignant phenotype. The role of diet in the causation of breast cancer is less clear. However, there is suggestive evidence that dietary fiber may play an important role in the enterohepatic metabolism of estrogens and is therefore an important determinant of circulating estrogen levels in the body. In this grant, we propose to investigate the hypothesis that high dietary fiber, either in total or a specific fraction (e.g., soluble fiber from legumes or insoluble fiber from grain) lowers circulating estrogen levels through enterohepatic estrogen metabolism and potentially alters breast cancer risk. A highly regulated biosynthetic and metabolic process determines total circulating estrogen levels (see figure 8 below). In premenopausal women, the ovaries accomplish estrogen synthesis in a in te s tin a l m e ta b o lis m genetic - disposition enterohepatic metabolism of estrogen bloavallable circulating estrogen | s o lu b le adipose tissue in s o lu b le N S P » f live r m e ta b o B sm ovary d ietary fiber tightly controlled system involving genetically determined cytochrome P450 enzymes and dehydrogenases. In postmenopausal women, estrogens are largely produced through the peripheral aromatization in adipose tissue. In the 1980s it was hypothesized that fiber may have a beneficial effect on breast cancer. The rational involved modulation, by dietary fiber, of the enterohepatic re-circulation of estrogens 175 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. (Cohen, 1999). It was proposed that direct binding of hormones by fiber within the intestinal lumen prevents estrogen re-absorption (Rose, 1993; Goldin et al., 1982) and thus lowers circulating levels in the body. We propose to investigate the relationship between dietary fiber, circulating estrogen levels, and breast cancer risk among Latinas enrolled in the Multiethnic/Minority Cohort Study o f Diet and Cancer (MEC). These women provide a unique and scientifically important group to study because Latinas have lower breast cancer rates of any major racial/ethnic group in the US and they consume a broader range of dietary fiber. Two generations of Mexican-origin postmenopausal women numbering nearly 7,000 are currently enrolled in the cohort and are being followed for cancer and other disease outcomes. Baseline data on dietary fiber have been collected, as well as blood and urine samples. Fiber intake of Latinas in the MEC (20-40 grams/day) is higher than what is reported by most racial/ethnic groups ( 10-20 grams/day) making this population well suited to test the fiber- estrogen-breast cancer hypothesis. This minority population provides a unique and exceptional opportunity to understand the biological relationship between dietary fiber and estrogen metabolism and potentially provides a plausible dietary mechanism for altering a woman’s risk of breast cancer. To investigate this hypothesis, we propose the following specific aims; (!) (2) (3) 176 To investigate the correlation between serum biomarkers of dietary fiber intake (the lignans enterolactone and enterodiol) and fiber intake measured by a food frequency questionnaire. To determine the effect of fiber intake, including the biochemical measures of enterplactone and enterodiol and fiber measured by the FFQ, on blood concentration To examine the association between dietary fiber intake and breast cancer risk within the Mexican American Latina population of the MEC and the possible risk modifying effects of obesity, family history, reproductive characteristics and hormone replacement therapy (HRT). R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. BACKGROUND AND SIGNIFICANCE A. Racial/Ethnic Variation, Endogenous Estrogen Levels, and Breast Cancer Etiology The large international variation in breast cancer incidence rates (1999 World Health Organization figures: United States 20.0 per 100,0000, Denmark 27.6, Venezuela 20.3, Cuba 14.9) suggests that both genetic and environmental factors, such as diet, may be important determinants of breast cancer risk. Among women living in the US, Latinas experience the lowest breast cancer incidence rates (69.4 per 100,000) compared to all other major racial/ethnic groups including whites (113.2), African-Americans (99.3), and Asians (72.6), representing a 39% difference in risk between the two extremes (Latinas residing in the US compared to whites). While differences in rates across racial/ethnic groups may be explained by variation in genetic predisposition, our finding that US-bom Latinas and non-US-bom Latina immigrants have the lowest rates of breast cancer in our cohort relative to non-Latina whites, even after adjustment for known risk factors of breast cancer, suggests environmental factors are influencing disease occurrence [see Table 40 in the Preliminary Studies section]. Figures from the World Health Organization also show that breast cancer mortality rates are much lower among women bom in Mexico (9.3 per 100,000; WHO, 1999) than US bom Latinas. While there are few published studies that have investigated the role of circulating estrogen levels and breast cancer risk among Latina women, there are numerous studies describing circulating estrogen levels among Asian and white women. These two groups traditionally have been selected for studies of estrogen and breast cancer risk, because of the extremes in their breast cancer rates: high incidence rates of breast cancer occur among Western European and US-bom women, while low rates occur among Japanese women bom in Japan and Chinese women in China. The most carefully completed international studies of these racial/ethnic groups support the role of estrogens, especially estradiol (E2 ), in the pathogenesis of breast cancer. In the early 1970’s, MacMahon et al conducted a series of studies with young women in Asia and North America, in which they found that total urinary estrogen (collected on day 21 of the menstrual cycle) was 36% higher in North American than Asian women (MacMahon et al., 1974). Similarly, in two recent studies, E2 levels were higher among US 177 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. white than Asian women (Bernstein et al., 1990; Shimizu et al, 1990). Specifically, Bernstein and colleagues observed that E2 levels were 20% higher among premenopausal women living in Los Angeles compared with women in Shanghai (Bernstein et al., 199Q). In a comparison of postmenopausal women, E2 levels were 36% higher in Los Angeles women than Japanese women living in Japan (Shimizu et al, 1990). A meta-analysis of twenty-nine epidemiologic studies of endogenous hormone levels and post-menopausal breast cancer, also implicate estrogens in the etiology of breast cancer (reviewed in Henderson & Feigelson, 2000; Thomas et al., 1997). Six prospective studies from the meta-analysis show that women who subsequently developed breast cancer had an overall 15% higher mean concentration of estradiol in their blood than control women who did not develop breast cancer. Similar differences were seen in die case-control studies included in the quantitative review (Thomas et al, 1997). A subsequent publication from the Nurses’ Health Study (Hankinson et al, 1998) evaluated the relationship between plasma hormone levels and risk of breast cancer in postmenopausal women. They observed statistically significant positive associations for breast cancer risk and circulating levels of estradiol, estrone, estrone sulfate, and dehydroepiandrosterone sulfate. The median level of estradiol was 14% higher in breast cancer cases than control women. Breast cancer risk factors (e.g:, early menarche, late menopause, alcohol consumption, postmenopausal obesity, hormone replacement therapy, young age at first full terra pregnancy, parity, prolonged lactation, and physical activity) have been hypothesized to indicate measures of the cumulative exposure to estrogen (Henderson and Feigelson, 2000). For example, early menarche and late menopause increase the number of ovulatory cycles over a woman’s lifetime. Prolonged lactation and parity are associated with periods of anovulation thus reducing lifetime exposure to estrogen. It is hypothesized that postmenopausal obesity increases the risk of breast cancer through increased production of estrogen from the conversion of androstenedione to estrone in adipose tissue. Alcohol may increase breast cancer risk by any number of potential biological mechanisms including increased plasma estrogen levels (Hankinson et al., 1995; Gavaler and van Thiel, 1992) or increased aromatization of androgens to estrogen (Purohit, 2000). The influence of physical activity on the 178 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. cumulative exposure to estrogen may be manifested by the delay of the onset of menstruation and the frequency and nature of ovulatory cycles (reviewed in Friedenreich and Rohan, 1995). B. Dietary Factors and Endogenous Estrogen Levels Epidemiologic studies also have shown that diet may influence the menstrual cycle and circulating estrogen levels. Importantly, vegetarians, known to consume as much as 2-3 times more fiber than non-vegetarians, have been shown to have a significantly higher percentage of menstrual irregularity (Pederson et al., 1991; Pirke et al., 1986) and significantly lower blood estrogen levels (Goldin et al., 1982; Pirke et al., 1986; Barbosa et al., 1990; Persky et al., 1992; Bennett and Ingram, 1990). Several intervention studies among premenopausal women have found evidence that a low fat/high fiber diet reduces blood estrogen levels. Woods et al reported significant decreases in serum estrone sulfate levels (-36%) after dietary modification to a low-fat (25% of calories) high-fiber (40 g/day) diet among 17, healthy premenopausal women (Woods et al., 1989). Goldin et al. found that a low-fat (20-25% of calories) high-fiber (40 g/day) diet was associated with significant decreases in serum concentrations of estrone (-9%), estrone sulfate (-30%), testosterone (-12.2%), androstenedione (-9.7%), and SHBG (-14.7%) and near significant decreases in estradiol (-10.4%) and free estradiol (- 10.4%) among 48 pre-menopausal women (Goldin et al-, 1994). High fiber alone caused significant decreases in estradiol (-11%) and SHBG (-11.1%). Schaefer et al. investigated the effects of a low-fat (16-18% calories as fat) high-fiber (mean 40 g/day) diet on plasma lipid and lipoprotein levels and serum sex hormone levels in 22 normal premenopausal women. They found that the diet produced a 25% decrease in estrone sulfate levels during the follicular phase of the menstrual cycle (Schaefer et al., 1995). Bagga et al. reported a significant reduction in serum estrone and estradiol levels after two months of a low-fat (10% calories from fat) high-fiber (25-35 g/day) diet in twelve premenopausal women (Bagga et al., 1995). Decreases ranging from 18% to 26% in mean levels of estradiol and estrone in pooled samples were observed during the follicular and luteal phases of the menstrual cycle. Woods and colleagues reported significant decreases in serum estradiol (-8.5%) and estrone 179 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. sulfate (-16.2%) levels after dietary modification to a low-fat (20% of calories) high-fiber (40 g/day) diet among 21 premenopausal African American women (Woods et al., 1996). Finally, Rose et al. found that during the luteal phase, lOg and 20g supplements of wheat bran resulted in statistically significant decreases in estrone. Serum estradiol was reduced in the lOg supplement group; the 20g supplement group showed a significant decrease in estradiol at 1 month but not at 2 months (Rose et al., 1997). Evidence of an association between dietary fiber and circulating estrogen levels among postmenopausal women is scarce. In contrast to earlier studies in premenopausal women, Stark et al. found no association between wheat bran supplementation and hormone levels in postmenopausal African-American non-users and current users of ERT (Stark et al., 1998). In an earlier observational study, Heber et al. observed a 48% decrease in serum estradiol among 13 postmenopausal women given free access to a low-fat (less than 10% of calories) high-fiber (35-45g/day) diet in a residential cafeteria setting (Heber et al., 1991). An early study by Prentice and colleagues provides indirect evidence of an association between dietary modification and circulating estrogen levels among postmenopausal women (Prentice et al., 1990). They found a statistically significant 17% reduction in average estradiol levels after 10-22 weeks of participation in a low-fat diet intervention program. The overall evidence suggests that dietary fiber might have a significant effect on circulating estrogen levels in the body among premenopausal women (Adlercreutz, 1990; Rose, 1993; Woods et al, 1996; Bagga etal., 1995; Goldin etal., 1994; Schaefer et al, 1995). Among postmenopausal women, the role of dietary fiber needs further study. C. Mexican-Origin Latinos: Dietary Fiber and Breast Cancer Risk The importance of study of breast cancer risk in a Latino population of Mexican origin is based on the fact that the incidence in Mexico is among the lowest in the world. Now, one of the fastest growing ethnic groups in the US, Latina women, primarily of Mexican origin, have the lowest breast cancer incidence rate of any of the major racial/ethnic groups. One might hypothesize that dietary factors play an important role. 180 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. It is well recognized that the traditional Mexican diet1 is rich in dietary fiber. Today, corn and beans remain the most important dietary staples in Mexico. Although com stands out as the primary grain, wheat and other grains are consumed frequently. Rice and pasta, introduced by the Spaniards, continue to be an important component of the Mexican diet as are vegetables and fruits. Following migration to the United States, researchers have found that significant changes occur in food intake patterns. Although limited, the findings of dietary studies among Mexican immigrants support evidence of dietary adaptation to a new range of foods and consequently, changes in the mean intakes of certain nutrients (Guendelman and Abrams, 1995; Romero-Gwynn et al, 1993; Chavez et al, 1994; Elder et al, 1991; Jones et al, 1997). However, while acculturation has caused changes in the diet of Mexicans in die United States, many food traditions have also been retained. The preservation of traditional food consumption habits, such as die high intake of com tortillas, rice, and beans, is facilitated by a geographic closeness to Mexico and the ever-growing availability of Mexican foods and products in the United States (Romero-Gwynn, 1993). A traditional diet high in dietary fiber, through its effect on circulating estrogen levels, provides support for the biological mechanism by which women in Mexico and Mexican-origin Latinos residing in the US haye some of the lowest rates of breast cancer in the world. Support for this hypothesis comes from several studies conducted in the US that have observed that Mexican Americans are consuming a higher intake of dietary fiber compared with non-Latino whites (Elder et al, 1991; Winkleby et al, 1994; Alaimo etal, 1994; Jones etal, 1997). D. The Influence o f Dietary Fiber on Estrogen Metabolism The beneficial effect of fiber in cancer etiology had its origins in the work ofBurkitt and colleagues in the early 1970s by examining the association with colon cancer and disorders of the gastric-intestinal tract (Burkitt et al, 1974). In the 1980s it was hypothesized that fiber may have a beneficial effect on breast cancer. The rational involved modulation, by dietary fiber, of the 'Most of the knowledge about the nutritional status of Mexicans during the past forty years comes from the Instituto Nacional de la Nutrition Mexico (INN or National Institute of Nutrition) founded in 1957. 181 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. enterohepatic re-circulation of estrogens (Cohen, 1999). It was proposed that direct binding of hormones by fiber within die intestinal lumen prevents estrogen re-absorption (Rose, 1993; Goldin et al, 1982). The enterohepatic metabolism of hormones plays an important role in die regulation of steroid levels in the body. This is particularly true for estrogens, which are excreted in high amounts in the bile (Adlercreutz et al, 1987). It is estimated that between 20 and 50% of the estrogen metabolites fiom the liver are excreted in bile and reach the intestinal lumen mostly in a biologically inactive conjugated form. About 80% are then reabsorbed. However, a prerequisite for effective re absorption is hydrolysis of the conjugates. Estrogens are mostly reconjugated in the intestinal mucosa, but are also partly reabsorbed in the unconjugated, biologically active form. Evidence has suggested that dietary fiber may bind estrogens in the intestinal lumen, prevent re-absorption, and thus lower circulating levels of estrogen in the body (Goldin et al, 1982). Another proposed mechanism involves direct binding of fiber to unconjugated estrogen within the gut (Rose, 1992; Adlercreutz et al, 1990). Shultz et al designed in vitro experiments to examine the extent that steroid hormones bind to natural fiber (e.g., bran or oat hulls) and to purified fiber (e.g., cellulose or lignin). Of the fibers tested, each bound die following percentage of unconjugated hormones: lignin 87%; wheat and oat bran 45% each; com bran 44% and oat hulls, 32% (Shultz and Howie, 1986). The conjugated steroid was less likely to bind than the unconjugated steroids. Arts and colleagues found lignin bound almost all estradiol present in vitro; oats bound 83% and wheat bran bound 82% of estradiol (Arts et al, 1991). The results of these two studies suggest that the components of fiber in the diet should be considered separately when evaluating in vivo metabolic effects. Further, Whitten et al. found that insoluble fiber has a high affinity for binding estradiol and estrone in vitro (Whitten and Shultz, 1988). Yet even with this early evidence suggesting that various components of fiber have different steroid-binding capability, most studies investigating the effect of dietary fiber intake on endogenous hormone levels have not examined dietary fiber components separately. It has also been suggested that the biological mechanism by which dietary fiber modulates estrogen metabolism is fiom foe high intake of plant lignans. There is evidence that plant lignans and 182 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. isoflavonoids, after being converted by intestinal bacteria to hormone-like compounds with weak estrogenic activity, may influence estrogen formation, metabolism and biological activity in the body (Adlercreutz, 1995; Adlercreutz and Mazur, 1997). The mammalian lignans enterolactone and enterodiol are produced in die intestine from precursors in plant lignans (Setchell et al, 1981). Blood enterolactone concentration depends on the intake of lignan-containing food and die activity of the intestinal microflora, e.g., antibiotic treatment decreases the production of enterolactone for weeks (Vanharanta et al, 1999). Thompson and colleagues determined the production of enterolactone and enterodiol from common plant foods. They found that whole legumes, cereal bran, whole grains, fruits, and vegetables produce the highest amount of lignans (Thompson et al., 1991). Vegetables produced the second highest concentration of lignans when the data were expressed on a moisture- free basis. It has therefore been suggested that enterolactone and enterodiol may play a role in the cancer-protective effect of vegetarian diets (Thompson et al, 1991). Further, in addition to their estrogenic activity, it is proposed that many of these plant compounds can interfere with steroid metabolism and bioavailability (Denis et al, 1999; Adlercreutz et al, 1993). E. Dietary Fiber and Breast Cancer Risk Published reports of epidemiology studies examining dietary fiber and breast cancer risk are equivocal (reviewed in Rose 1990, Adlercreutz et al, 1992; Hunter and Willett, 1993; Clavel- Chapelon et al, 1997; La Vecchia and Chatenoud, 1998; Cohen, 1999). Relatively few studies have examined the association and the results are mixed. Three prospective cohort studies of breast cancer have investigated fiber intake, yet only one found a protective association (Rohan et al, 1993). The Nurses’ Health Study with 1,439 breast cancer cases as well as a study in New York with 344 breast cancer cases found no association (Willett et al., 1992; Graham et al, 1992). An analysis of combined data from ten case-control studies found a weak, but statistically significant protective association (Howe et al, 1990). Several other case-control studies have also reported protective associations for various measures of fiber such as non-starch polysaccharides, soluble NSP, cellulose, crude fiber, and fiber from vegetables and fruit (Van ‘t Veer et al, 1990; Zaridze et al, 1991; 183 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Baghurst and Rohan 1994; Yuan et al., 1995; Freudenheim et al., 1996; De Stefani et ah, 1997; Ronco et ah, 1999; La Vecchia et al., 1997). Conversely, Witte et al. found no association for dietary fiber and breast cancer risk in a familial matched case-control study of premenopausal bilateral breast cancer (Witte et al, 1997). Investigators have proposed that perhaps these inconsistencies are because of the heterogeneous nature of fiber products and differences in the ways in which fiber is measured and quantified (World Cancer Research Fund, 1997; La Vecchia 1998; Potter, 1999). The inconsistencies could also be due to the magnitude of absolute gram intake of dietary fiber. In die multi-center case- control study conducted in Italy the cut point for die highest quintile of daily dietary fiber intake was 21.1 grams (La Vecchia et ah, 1997). The energy-adjusted, dietary fiber intake (g/day) for each of the quintiles in the Nurses’ Health Study were <=11.0,12-14,15-17,18-21, >=22 g/day from lowest to highest quintile. These amounts are in agreement with data from NHANES2 III for non-Latino white populations in the United States (Alaimo et al., 1994). In comparison, die median intake (g/day) of dietary fiber for each of die quartiles defined from controls within our Mexican American population is 20.3, 26.8,31.1, and 40.6 g/day (from the lowest to highest quartile of dietary fiber intake). In fact, of all the ethnic groups represented in the MEC, Latinos consume more dietary fiber than any other race/ethnic group (Kolonel et al., 2000). The mean daily intake, age-standardized to the overall cohort, is 30.6 g for Latinos, 25.6 g for African Americans, 22.2 g for Japanese Americans, and 24.5 g for whites. Overall, results from epidemiological investigations make it clear that studies on breast cancer risk cannot be carried out without careful dietary evaluation in addition to hormonal investigation (Adlercreutz, 1990). 2 National Health and Nutrition Examination Survey (1988-1994) - a federal survey conducted by the National Center for Health Statistics that provides population dietary estimates through standardized data-collection, standardized food composition databases, and continued research to improve dietary assessment. 184 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. PRELIMINARY STUDIES A. Incident Breast Cancer Among Postmenopausal Women in the Multiethnic Cohort Breast cancer incidence rates in the Multiethnic Cohort Study (MEC) calculated after an average of five years of follow-up present a divergent pattern of disease between racial/ethnic groups (see Table 40). US-bom Latinas and non-US-bom Latina immigrants have the lowest rates of breast cancer relative to non-Latina whites. Even after adjustment for known risk factors of breast cancer, non-US-bom Latinas still have lower rates. TABLE 40. Incident Breast Cancer Cases in the Multiethnic Cohort W* A J L-US L-NUS Total All postmenopausal w om en # Women # Breast cancer cases Relative rates 20,796 372 1.00 18,527 294 0.83 23,638 418 0.97 10,205 144 0.76 9,976 85 0.50 83,142 1313 W om en w ith natural m enopause or bilateral oophorectom y # Women 14,771 # Breast cancer cases 252 Relative rates 1.00 Adjusted rates for 'known' risk factors 1.00 10,222 154 0.81 0.96 17,426 303 1.00 1.00 6,364 92 0.80 0.94 5,900 58 0.60 0.77 54,683 859 *W=non-Latina White; A=Afiican-American; J=Japanese-American; L-US=US-bom Latina; L-NUS=non-US-bom Latina We further sub-divided the Latina population to examine breast cancer rates in the total Mexican-origin Latina population. In fact, the age-standardized rate of breast cancer in 2n d generation US-bom Mexicans, i.e., both parents were bom in Mexico, is double (289.5) the incidence rate (141.2) in Mexico-bom immigrants to California. The reasons for the strong differences in risk by migration status are still unknown. The variation in exposure to environmental risk factors following migration, particularly dietary factors, is a plausible explanation. B. Significant Differences in Intake Patterns Between Latino Subgroups Daily gram intake of three selected traditional Mexican foods and several nutrients are shown in Table 41 for three Latino subgroups, Mexican American Latinos, other Central or South 185 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Americans, and Caribbean or Cubans. Mexican Americans have been divided into two groups based on nativity. This table demonstrates the difference in intake between national origin Latino groups. TABLE 41. Daily Mean'lntake of Traditional Mexican Foods and Selected Nutrients by Latino Subgroup ------------------- US-bom Central America- Cuba or FOOD/NUTRIENT (Mexico-born parents) Mexico-born born Caribbean-born Refried Beans (g) 20.2 26.5 17.2 3.8 Boiled Dried Beans (g) 19.4 34.9 25.4 24.1 Com Tortillas (g) 20.4 53.9 33.3 2.5 % Calories from Fat 32.0 30.2 28.3 28.1 Daily Total NSP (g) 21.Q 26.3 23.2 18.2 NSP from Grains (g) 5.4 5.3 4.7 4.5 MSP from Vegetables2 (g) 9.3 13.2 10.6 7.5 Daily Alcohol (g) 2.9 1.5 1.8 1.9 'age-standardized to combined population for all Latina subgroups; '‘includes legumes Other researchers have also observed that while dietary patterns of Cuban Americans and mainland Puerto Ricans share some similarities with die dietary patterns of Mexican Americans, the data from the Hispanic Health and Nutrition Examination Survey (HHANES) show significant differences in consumption patterns of traditional and contemporary foods among the three Latino subgroups (Aguirre-Molina & Molina, 1994; Romero-Gwynn & Gwynn, 1994). Studies based on HHANES data have found significant differences in macronutrient and micronutrient intakes, including alcohol, as well (Loria et al., 1995; Looker et al., 1993; Black and Markides, 1994; Caetano, 1988). The interpretation and comparison of dietary analyses from studies where Latino subgroups have been combined becomes very difficult at best. First, grouping may mask important differences. Second, before populations can be compared they must share a uniform definition (Hayes-Bautista, 1980; Hayes-Bautista & Chapa, 1987; Lowenstein, 1981). Therefore, only those Latinos of Mexican national origin who are currently residing in Los Angeles will be included in our study population. First-generation (Mexico-bom) immigrants and second-generation (US-bom) Mexican Americans will be eligible for selection. While we suspect that most of our third-generation (or higher) Latino cohort members are most likely of Mexican descent, we could not verify this from the questionnaire. 186 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. And we have sufficient numbers of 1st and 2n d generation Mexican Americans allowing us to impose strict selection criteria for this study. G. Range o f Dietary Fiber Exposure in Mexican-Americans 1116 differences in intake o f various measures of fiber that we can expect from this study population are shown in Table 42 below. The three categories shown are based on nutrient density (intake/total calories) quartiles o f total NSP intake. Eliminating subjects from the bottom half o f quartile two and the top half of quartile three created the middle category. This increased the spread o f fiber intake between groups for this comparison. TABLE 42. Median intake of certain nutrients and foods by category of NSP intake Median intake NSP Density Quartilei (Low) NSP Density QuartileS2-3 NSP Density Quartile^ (Midpoint) (High) Calories 2037 2107 1970 % Calories from fat 35% 32% 26% % Calories from alcohol 0.001% 0.001% 0.001% NSP (gm/day) 13.1 21.0 30.1 Insoluble NSP 7.4 11.9 16.9 Soluble NSP 5.7 9.2 13.5 NSP from fruit 2.3 4.7 8.1 NSP from grain 3.6 4.2 4.4 NSP from legumes 2.5 4.5 4.9 NSP from vegetables 3.5 5.2 7.2 Boiled or refried beans 15.8 24.8 40.3 White bread 17.8 7.1 3.5 Whole wheat bread 1.6 4.1 8.9 Com tortillas 26.6 35.7 26.6 The range of dietary fiber intake in this population provides an exceptional opportunity to test the hypothesis that high fiber intake or a particular fraction, e.g., soluble fiber from legumes or insoluble fiber from grain, effects estrogen metabolism, lowers estrogen circulatory levels, and thereby provides a plausible explanation for the lower incidence rates of breast cancer in this Latina sub-population. 187 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. RESEARCH DESIGN AND METHODS The study is designed to (1) investigate the correlation between serum biomarkers of dietary fiber intake, i.e., the mammalian lignans enterolactone (Enl) and enterodiol (End), and fiber intake measured by a food frequency questionnaire (FFQ); (2) to determine the effect of fiber intake on blood concentration levels of endogenous estrogens, their urinary metabolites, and androgens; and (3) to examine the association between dietary fiber intake and breast cancer risk within the Mexican American Latina population of the MEC and the possible risk modifying effects of obesity, family history, reproductive characteristics and hormone replacement therapy (HRT). Healthy, postmenopausal, Mexican American women will be selected from an existing prospective cohort study. A fasting, morning blood specimen and overnight urine sample will be obtained from 300 women selected on the basis of the baseline dietary fiber value from the FFQ and history of never use of hormone replacement therapy. Correlation analysis methods will be utilized to first gain an understanding of the relevant relationships between different measures of fiber intake and various hormone values. Fiber intake will then be divided into quintiles and analysis of covariance (ANCOVA) will be used to test mean differences in serum and urine hormone levels by category of fiber intake with adjustment for potential confounders. A. Dietary and Hormonal Biomarkers o f Interest To better study the role of dietary fiber in estrogen metabolism we propose to measure Enl and End in serum. These compounds, formed by intestinal bacteria from the plant lignans matairesinol (MAT) and secoisolariciersinol (SEC), respectively, are ingested with common plant foods- It has been shown that enterolactone correlates significantly with dietary fiber intake (unpublished results Kilkkinen, 2000). This will not only enable validation of measures of fiber intake quantified from a FFQ but also allow analyses of the correlation between these biomarkers and hormones of interest. R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The steroid hormones of interest in this study are estrone (Ei), total estradiol (E2 ), bioavailable E2 {i.e., free E2plus albumin-bound E2 ), conjugates Ei sulphate, E] glucuronide, E2 sulphate, E2 glucuronide, SHBG, testosterone, dehydroepiandrosterone sulfate (DHEAS), androstenedione, urinary metabolite fractions (Ei, E2 , and estriol (E3 )), 2-hydroxyestrone and 16a- hydroxyestrone. While prospective studies with at least 50 cases have been consistent in showing a significant positive relationship of total E2 with the risk of postmenopausal breast cancer, results have been inconsistent with respect to the proportion of free or bioavailable (free + albumin bound) E2 as an additional predictor of risk. Although E! is biologically less active than E2 , it is the principal estrogen formed in postmenopausal women. The production rate of this estrogen is about 40 ug/day compared to 6 ug/day for E2 (Stanczyk 1997). Estrone levels in circulation in vivo are approximately 30 pg/mL as compared with 15 pg/mL for E2. In fact, the major contributor to circulating estradiol is from estrone (Stanczyk, 1997). The estrone conjugate, estrone sulphate (E|S04 ), may be important in that it accounts for 40- 50% of the circulating estrogen in vivo, has a concentration 10 times higher than that of estrone or estradiol (Ruder et al., 1972) and it contributes to our understanding of total estrogenicity in women. Significant decreases of estrone sulphate in several studies examining the effects of a low-fat, high- fiber diet (Woods et al., 1989; Goldin etal., 1994; Schaefer et al., 1995) could reflect reduced production of estrone and estradiol. Or as Woods and colleagues suggested, it may represent a shift in the metabolism of Ei and E2away from sulfation toward other estrogen metabolites, e.g., estriol, 2- hydroxyestrone, or 16a-hydroxyestrone (Woods et al., 1989). Reduced estrone sulphate may also be an indicator of interrupted enterohepatic circulation because estrone sulfate, like other estrogen conjugates, is excreted in the bile (Adlercreutz et al., 1979). A study examining the association of estrone sulphate levels and breast cancer risk found approximately twice the level in breast cancer cases compared with matched controls (Prost et al., 1984). Fishman and colleagues found lower levels of glucuronide conjugates and a compensatory increase in estrogen sulphate conjugates among women with a family history of breast cancer compared with matched controls (Fishman et al., 1983). 189 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. Hydroxylation products of E2 metabolism, i.e., 2-hydroxyestrone (20HEi) and 16a- hydroxyestrone (16aGHEi), have different biological activities that may distinguish their effect on breast cancer risk (Schneider et at., 1982). The two main pathways for metabolizing E2 are via 16a- hydroxylation mid via 2-hydroxylation of Ei- There is some date suggesting that 16aOHE| is more biologically active than 20HEt (Fishman et at., 1995; Van Aswegen et at., 1989) and that women who metabolize more Ei through the 16a pathway may have a prolonged estrogenic effect of El (Bradlow et al., 1986; Bradlow et at., 1986). It has also been suggested that the estrogen metabolite ratio of urinary 2QHEi:16aOHEi represents an important biomarker of breast cancer risk, i.e., die lower the ratio the higher the risk (Kabat et al., 1997). Other studies examining this association have been inconsistent (Ursin et at., 1997; Osborne eta/., 1993; Adlercreutz et al, 1989; Meilahn etal, 1998; Ursin et al, 1999; Ursin et al, 2001). Androgens may be involved in breast carcinogenesis as precursors of estrogen, i.e., the biosynthesis of estrone and estradiol occurs from androstenedione and testosterone, respectively (Stanczyk, 1997) or they may play an independent role (Speroff et al, 1994). Studies examining androgens have not been consistent. Woods and colleagues found a significant increase of androstenedione with a significant decrease in E2 and E 1 SO4 levels among premenopausal African American women consuming a low-fat, high-fiber diet (Woods et al, 1996). However, an earlier, dietary intervention study by Goldin et al found a significant decrease in serum concentrations of testosterone, androstenedione and SHBG among premenopausal women when changed to a low-fat, high-fiber diet (Goldin et al, 1994). Androstenedione levels were positively associated with postmenopausal breast cancer risk in die Breast Cancer Serum Bank data (Dorgan et al, 1997; Dorgan et al, 1997) but not in the Washington County (Maryland) cohort of 51 cases (Helzlsouer et al, 1994) or the Nurses’ Health Study (Hankinson et al, 1998). Most studies have shown a positive association of testosterone with the risk for postmenopausal breast cancer that is attenuated by adjustment for estradiol (Hankinson et al, 1998; Dorgan etal, 1996; Zeleniuch-Jacquotte et al, 1997; Dorgan etal, 1997; Dorgan et al, 1997; Thomas et al, 1997). Testosterone has a much higher affinity for SHBG than E2 and can block 19Q R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. hepatic synthesis of this protein (Siiteri et al, 1981). The concentration of dehydroepiandrosterone sulfate (DHEAS) was associated with postmenopausal breast cancer in the Breast Cancer Serum Bank cohort (Dorgan et al., 1997) and the Nurses’ Health Study (Hankinson et al., 1998). However, the NYU Women’s Health Study found no association (Zeleniuch-Jacquotte et al, 1997). While most early studies evaluated only one or two of the major circulating estrogens, recent studies have clearly shifted to examining the levels of both circulating estrogens and androgens in relation to breast cancer risk (Hankinson et al, 1998; Zeleniuch-Jacquotte et al, 1997; Dorgan et al, 1997; Dorgan etal, 1997; Thomas et al., 1997). This approach provides a complete profile of circulating estrogen and androgen levels, and importantly, allows investigators to examine the balance of hormones in the body as well as the effects of metabolism. B. Description o f the Multiethnic Cohort We are currently in the second funding cycle of a National Institutes of Health R01 funded grant to establish the Multiethnic/Minority Cohort Study o f Diet and Cancer (RO1 CA54281 -06: Laurence N. Kolonel, Principal Investigator). The design and implementation of this large cohort study in the populations of Hawaii and Los Angeles has been described in detail elsewhere (Kolonel et al., 2000; Stram et al, 2000; see Appendices K and L). Briefly, participants entered the cohort from 1993 to 1996 by completing a 26-page, self-administered mail questionnaire that asked about the normal intake of approximately 180 foods and beverages (see Appendix M). The dietary component comprises the major portion of the questionnaire and covers all the major sources of nutrients for each of the ethnic populations. In addition, the questionnaire included information on demographic factors (including ethnicity, education, and migrant status), personal behaviors (smoking, solar exposure, and physical activity), history of prior medical conditions (e.g., high blood pressure, heart attack or angina, diabetes, and stroke), use of medications, family history of common cancers, and, for women, reproductive history and the use of oral contraceptives or hormone replacement therapy. All questionnaires were processed by optical scanning and the information was stored in a structured database. An extensive editing process of the questionnaire responses has been completed and a 191 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. computerized tracking system to keep the mailing lists current, to monitor participation in the study and to manage follow-up activities has been implemented. The Department of Motor Vehicles driver’s license file was used as the primary source of potential subjects. In 1996, we successfully accomplished our primary goal with the establishment of a cohort of 215,251 men and women who are being followed for cancer and other disease outcomes. Follow-up is being accomplished by computer linkage with the population-based SEER cancer registry in Los Angeles, the statewide California Tumor Registry, state death files, social security death index, and foe State of California, Office of Statewide Health Planning and Development hospital discharge database. We are well positioned to follow this cohort for all disease outcomes, as well as overall mortality, as we have social security number, a critical identifier, on 98.7% of our entire cohort. Further, only 2.7% of Los Angeles cohort members have migrated from foe state of California since foe study’s inception in 1993. C. Selection o f Subjects Table 43 shows foe distribution, by age and birthplace, of foe female Latina cohort in Los Angeles. With foe exception of US-born cohort members, Table 43 is restricted to cohort members whose parents were both bom in foe same country as themselves. There are approximately 2,500 US- bom females with one parent bom in Mexico and one parent bom in foe US and considerably smaller numbers with other combinations. TABLE 43. Distribution of foe Latina Cohort by Age and Birthplace, Los Angeles Birthplace of Cohort Member No. % No. % No. % Total 45- 54 55-64 65- 75 — U.S. both parents bom in U.S. 1,176 23.0% 1,294 14.0% 638 12.0% 3,108 both parents bom in Mexico 462 9.0% 2,138 23.1% 2,224 41.9% 4,824 Mexico 2,562 50.1% 3,649 39.5% 1,573 29.6% 7,784 Central or South America 803 15.7% 1,751 18.9% 672 12.7% 3,226 Cuba or Caribbean Islands 114 2.2% 411 4.4% 202 3.8% 727 Total 5,117 9,243 5,309 19,669 - - ... --- 192 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. As mentioned previously, only those Latinos of Mexican national origin or descent who are currently residing in Los Angeles are eligible for selection. To determine the population from which a sub-sample of study participants will be drawn, only Mexico-born and US-bom Mexican American women (both parents bom in Mexico) who were aged 45-64 at cohort entry and reported being postmenopausal on the questionnaire are included. We excluded 228 subjects of mixed race; specifically, Latino Indian, Latino Asian, and Latino white in order to minimize any potential confounding genetic or environmental effects. This resulted in a sample of 6,950 postmenopausal women. TABLE 44. Sample selection Total Latinas in Multiethnic Cohort residing in Los Angeles 23799 Total Mexico-bom or US-bom Mexican American 12252 Exclude premenopausal women, mixed race/ethnicity, >=age 65 at baseline (5302) Age 45-64, postmenopausal, and not of mixed race/ethnicity 6950 Exclude ever users of estrogen as reported on the FFQ (3181) Exclude women whose age at natural menopause can not be determined (1290) Total Mexican American females residing in Los Angeles available for selection 2479 In order to understand the role of dietary fiber in estrogen metabolism, “ever users” of estrogen (n=3,181) as reported on the questionnaire were excluded. Women who reported that their menstrual periods stopped because of surgery, radiation, or medication (n=l,042), women who reported the removal of one or both ovaries (n=218), and women whose age at menopause was missing on the questionnaire (n=30) were excluded to enable the adjustment for age at menopause in the analysis. There are 2,479 Mexico-bom and US-bom Mexican American women who met the inclusion criteria. Measurement “error” of dietary values from a self-administered food frequency questionnaire (FFQ) has to be taken into account when defining the appropriate study population. Therefore, to ensure that we end up with a substantial number of subjects in both the high and low comparison groups of dietary fiber intake, validated by the serum biomarkers enterolactone and enterodiol, most (80%) subjects will be selected from of the highest and lowest quintiles of fiber intake measured by the baseline FFQ. Approximately 20% will be drawn from the middle. As our 193 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. required sample size is only 300 women, these strict criteria will still allow an ample number of subjects for selection and will ensure a broad range of dietary fiber exposure. At the time of analysis, subjects will be excluded if they were taking antibiotics or other prescription drugs at the time of their blood collection that may affect the Enl, End, or hormone assays. Subjects will also be excluded if they report current use of estrogen at blood draw that was not reported on the original food frequency questionnaire. D. Assessment o f Dietary Fiber Intake Using a Food Frequency Questionnaire The methods for diet assessment have been described in detail elsewhere (Kolonel et al., 2000). In brief, we developed the FFQ based on the methods used for many years by the University of Hawaii for eliciting dietary information from personal interviews. This method asks the respondent to report how often they ate a particular food item during the past year and the usual portion size. Usual intake for food items was reported by marking one of the eight following frequencies: never or hardly ever; once a month; 2 to 3 times a month; once a week; 2 to 3 times a week; 4 to 6 times a week; once a day; 2 or more times a day. For beverage items, usual intake is reported by marking one of nine frequencies, the same eight as above plus 1 additional (4 or more times a day). Photographs showing three different portions are included to assist the respondent in estimating intake. The FFQ included 164 questions on foods, 13 questions on beverages, and 5 questions about condiments added to food such as salt, catsup, and sour cream. The performance of the FFQ, by correlation analysis, was assessed in a calibration sub-study. The methods and findings have been described in detail elsewhere (Stram et al., 2000). Briefly, we collected three 24-hour dietary recalls from a random sample of cohort subjects of each sex/ethnic group to calibrate the dietary information from the FFQ. The correlation between nutrient intake from the 24-hour recalls and nutrient intake as reported on the FFQ is used as a standard measure of validity of the study instrument. The calibration sub-study also aided in the development of the food composition table by providing intake measurements of ethnic specific foods and it provided data that will be used for correction of risk estimates in nutrient analyses. Assuming that a 24-hour dietary 194 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. recall provides an unbiased estimate of a single day’s diet, a regression equation calculated from the average of 3 dietary recalls can be used for imputing an estimate of true nutrient consumption from the FFQ nutrient value. E. Development o f the Food Composition Table An extensive food composition database for use in nutritional epidemiology studies had been developed and maintained at the Cancer Research Center of Hawaii for several years. For the current Multiethnic Cohort Study, additional data on foods consumed by Latinos were added. To better understand the role of dietary fiber in the etiology of disease, several measurements of intake were included. Dietary fiber is the sum of lignin and “non-starch polysaccharides” (NSP) in foods. It is not a single entity, but rather a mixture of many complex organic substances whose single common property is their ability to resist digestion in the human stomach and small intestine. NSP is the sum of the polysaccharide fiber components: cellulose, hemi cellulose, pectin, gum, and mucilage (see Appendix D). NSP can be further categorized as insoluble or soluble. Insoluble NSP is the structural building material in the plant cell wall and does not dissolve in water. It is found in such foods as whole grains, wheat and com bran, brown rice, and broccoli and other cruciferous vegetables. Soluble NSP is involved with plant cell structure and metabolism and is found in fruits, legumes and peas, oatmeal, barley, and soybeans. The NSP values (total, insoluble, and soluble) reported in this analysis were obtained by the Englyst procedure, which aims to measure plant cell wall NSP as the sum of the chemically identified constituent sugars. This measurement reflects the plant cell-wall material that is characteristic of the high fiber diet embodied in the dietary fiber hypothesis. The Englyst procedure (Englyst et al, 1994) is an extension of the work of McCance and Widdowson and later, Southgate. It measures NSP using enzymic-chemical methods allowing fiber to be divided into soluble and insoluble fractions as well as into individual fiber components, cellulose and noncellulose polysaccharides, and into individual constituent sugars (arabinose, xylose, mannose, galactose, and glucose) and uronic acids. 195 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The “dietary fiber” measurements reported in this analysis are those published in the USDA tables and are primarily obtained with the Association of Official Analytical Chemists (AOAC) Prosky procedure. The aim of this procedure is to measure NSP and lignin. However, it has been demonstrated that this method gives dietary fiber values feat represent NSP, lignin, some starch, Maillard reaction products, and degradation products formed as a result of heat processing (J Assoc Pub! Analysts, 1996). Further, detailed analysis of fee gravimetric residue showed feat fee AOAC Prosky procedure underestimates fee NSP content of foods by 12% on average and feat from 5 to 42% of fee residue material remains unidentified and not accounted for as lignin. F. Collection, Processing and Storage o f Blood Specimens from the Sub-cohort No additional subject recruitment or specimen collection will be required for this proposed study. Blood and mine specimens are currently being collected as part of a National Institutes of Health funded grant “Genetic Susceptibility to Cancer in Multiethnic Cohorts " 5 U01 CA063464: Brian E Henderson, Principal Investigator. The purpose of this grant is to collect biological specimens from men and women participating in fee Multiethnic Cohort o f Diet and Cancer Study to evaluate fee genetic component of racial/ethnic variability in cancer risk and fee interplay between genes and environment. Specimens are collected by personal home visit and current participation rates are over 67% among Latinas. We will, however, change fee current protocol in order to obtain overnight urine samples. We decided to collect complete, overnight urine rather than a first morning void because fee former will reduce intersubject variability due to differences in specimen collection, e.g., time since last urine excretion may affect fee assay result. In advance of fee blood collection appointment, we will send fee subject a collection kit (a urine collection container, a small cooler, and two packs of blue ice) along wife specific instructions for proper collection and storage. A reminder call will be made to fee subject the day before their appointment. Instructions regarding fee fasting and urine protocols will again be given at feat time. Subjects will be asked to place fee blue ice in the freezer until fee evening before their appointment for blood draw. On feat evening, subjects will be requested to fast from 9:00 196 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. pm, to empty their bladder before going to bed, and then to collect any urine passed during the night as well as their first urine upon rising in the morning. They are requested to store the mine container, with die blue ice, in their bathroom as a reminder to collect their urine during the night. Our colleagues in Hawaii pilot tested this protocol among 23 female MEC members mid found that all 23 were successful. The date and time(s) of urine collection will be recorded on the collection form. After collection, the phlebotomist will label five 2-cc cryovials with printed labels containing the subject’s ED. After mixing die urine, a plastic pipette will be used to transfer approximately 2cc of urine to each cryovial. The vials will be stored in freezer boxes at -20C. G. Determination o f Biochemical Markers ofFiber Intake Serum levels of enterolactone can be measured by time-resolved fluoroimmunassay: method for the determination of enterolactone is presented in Adlercreutz et al, 1998. The reliability of serum measurements is presented in Zeleniuch-Jacquotte et al, 1998. Results suggest that serum measurements of this compound could be a useful tool in prospective epidemiological studies with access to blood (serum) specimens. The reliability coefficient of a single measurement of enterolactone has been shown to be 0.55. [To be expanded in collaboration with Adlercreutz & colleagues] H. Assays o f Serum Hormones Serum hormone assays will be conducted in the Reproductive Endocrine Research Laboratory at USC under the supervision of our collaborator, Dr. F. Stanczyk. Dr. Stanczyk’s laboratory has extensive experience in measuring steroid hormone levels using well-validated methodology. The pertinent assay methods are described below: Estrone (E|) and estradiol (E2 ) are measured by a previously described radioimmunoassay (RIA) method (Probst-Hensch et al., 1999). The estrogens will be extracted from 0.6 ml serum with ethyl acetate: hexane (3:2) and then separated by Celite column partition chromatography. 197 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Approximately 1,000 dpmof3H-Ei, and of 3H-E2 will be added to the serum prior to the extraction step in order to follow procedural losses. Intraassay and interassay coefficients of variation, determined in pooled serum samples are approximately 7.5% and 12.5%, respectively. Bioavailable E2 will be analyzed in 0.3 ml of serum by first determining its percentage of the total E2 concentration, using ammonium sulfate precipitation (Stumpf et al., 1981). Dehydroepiandrosterone-sulfate (DHEAS) and Ei andE2 conjugates (E, sulphate, Et glucuronide, E2 sulphate, E2 glucuronide) are measured directly in serum by specific RIA (Lobo et al, 1981; Ranadive et al., 1998). SHBG will be measured directly in serum by a highly specific radioimmunoassay using a commercial kit (Diagnostic Systems Laboratories, Webster, TX). Androstenedione and testosterone will be analyzed in serum by RIA (Dorgan et al., 1997; Goebelsmann et al., 1973; Goebelsmann et al., 1974). Follicle-stimulating hormone (FSH) will be measured in serum by a highly specific chemiluminescent immunoassay on women <56 years of age to validate menopausal status. One in every 10 specimens (10%) is repeated (with laboratory personnel blinded to whether it is a repeat) to confirm die reproducibility of our results. I. Assays of Urinary Metabolites Assays of the urinary metabolites of Ej, E2 , and estriol (E3 ), will be conducted in die Reproductive Endocrine Research Laboratory at USC under the supervision of our collaborator, Dr. F. Stanczyk. Metabolites are measured by a previously described radioimmunoassay (RIA) with preceding high-performance liquid chromatography-RIA (Gentschein et al, 1997). Each sample of urine is acidified and subjected to P-glucuronidase/aryl sulfatase hydrolysis before subjection to chromatography and separation of E|, E2 , and E3. One in every 10 specimens (10%) is repeated (with laboratory personnel blinded to whether it is a repeat) to confirm the reproducibility of our results. The two metabolites, 2-hydroxyestrone (2OHE0 and 16a-hydroxyestrone (16aOHEi), will be measured in 0.4 ml of serum simultaneously to avoid interassay variation, using competitive enzyme immunoassay (EIA) kits (Estramer, Immuna Care Corp., Bethlehem, PA). Klug et al, 1994, 198 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. describe this method. In brief, monoclonal antibodies to the estrogen metabolites will be immobilized directly to die solid phase, and die metabolite standards will be conjugated to alkaline phosphatase enzyme. Each urine sample (0.2 ml) will be acidified and subjected to P-glucuronidase/aryl sulfatase hydrolysis before assay. The 2QHEi and 16aOHEi kits were validated by comparing values obtained with these kits to values obtained by gas chromatography-mass spectroscopy. The interassay and intraassay coefficients of variation were between 7% and 13%. Creatinine values above 0.20 mg/mL are considered necessary to obtain adequate reproducibility of the 20HE; and 16aOHEi assays. J. Sample Size and Data Analysis To determine the sample size for this study, we used preliminary data from the Multiethnic Cohort Study for postmenopausal Latinas. The mean estradiol level was 17.93 with a standard deviation of 5.63 pg/mL among 90 subjects. This estimate is in agreement with the median (15 pg/mL) estimate of plasma concentration of E2 in postmenopausal women from the Reproductive Endocrine Research Laboratory at USC under the supervision of Dr. F. Stanczyk. By personal communication, the measurement of E2 could have a four-fold range in postmenopausal women, as there is substantial inter-subject variation. In order to detect a 10% decrease in E2 among women in the highest quartile of dietary fiber intake compared with women in the lowest quartile, with a significance level of 0.05 and power of 0.80,148 women would be required in each of the two groups for a total sample size of approximately 300 women. We also calculated sample size with our estimate of estrone among Latinas (mean=39.067; std. dev.=17.77; n=90). With 300 subjects, we can detect a 15% decrease in E| levels among women in the highest quartile of dietary fiber intake compared with women in the lowest quartile, with a significance level of 0.05 and power of 0.80. The reliability coefficient of a single measurement of enterolactone has been shown to be 0.55 (Zeleniuch-Jacquotte et al., 1998). Assuming errors in the measurement of both enterolactone and E2 with a reliability coefficient of 0.55 for each, we can detect a correlation of 0.3 between true enterolactone and true E2 with 300 subjects. This translates to an observed correlation between the two values of 0.165. With 300 subjects, we can also detect an observed correlation of 0.165 between 199 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. one measurement of serum enterolactone and fiber intake measured from the FFQ. This is assuming a reliability coefficient of 0.55 for both measurements, i.e., the square of die correlation of 0.75 for the dietary fiber density measurement from the FFQ (Stram et al, 2000). The first aim is to investigate the correlation between serum biomarkers of dietary fiber intake, i.e., the lignans enterolactone and enterodiol, and fiber intake measured by the FFQ using correlation analysis methods. All standard measures of fiber intake, e.g., dietary fiber, NSP, insoluble and soluble fractions, and NSP from various food sources will be utilized. Correlation coefficients, regression slopes and intercepts, and standard errors are calculated from the sum of squares of deviations of each variable from their means, and the sum of cross-product of deviations (Epilog Plus: Statistical Package for Epidemiology and Clinical Trials, version 3. Epicenter Software, Pasadena, CA). All pairs of non-missing values are used in foe analysis. The transform log((l+r)/(l- r)) is used to convert foe distribution of the correlation coefficient r to an approximately normal distribution for calculation of confidence limits. The second aim is to determine foe effect of fiber intake on blood concentration levels of endogenous estrogen and their urinary metabolites. Fiber intake is defined as foe FFQ value and as foe biomarker values of Enl and End. Fiber intake from foe FFQ will be quantified both as an absolute amount (g/day) and as a nutrient density, i.e., adjusted for total calorie intake. Insoluble and soluble fractions as well as fiber from various food sources, e.g., fruit, vegetables, legumes or grain, will be utilized. Correlation analysis methods described above will be utilized first to gain an understanding of foe relevant relationships between different measures of fiber intake and various hormone values. Fiber intake will then be divided into quintiles and analysis of covariance (ANCOVA) will be used to test mean differences in serum and urine hormone levels by category of fiber intake. Non-dietary factors that will be considered as potential confounders in foe analysis include age, weight, height, body mass index, age at menarche, age at first birth, age at menopause, parity, and physical activity. Adjustments for dietary factors include alcohol intake, percent of calories from fat, and total calorie intake. 200 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. HUMAN SUBJECTS A. Gender and Minority Inclusion The participants in the study will include 300 Latina females of Mexican heritage residing in California. They will be identified from subjects who volunteered to participate in the Multiethnic Cohort Study by completing a 26-page mailed questionnaire from 1993 to 1996. They were age 45 to 64 at the time of their recruitment into the Multiethnic Cohort Study. B. Consent To establish the cohort, subjects were sent a cover letter explaining the study along with the questionnaire. Spanish versions of both die cover letter and questionnaire were included along with the English version in every mailing packet to a Spanish sumamed individual. Participation was voluntary; there was no direct contact by phone or in person to attempt to persuade subjects to respond. Receipt of a completed questionnaire was evidence of a desire to participate in the study and was taken as a formal indication of consent. Only persons already in the cohort will be contacted to participate in the blood collection component of the study. Initial contact will be by mail and followed by telephone for recruitment into the study. Prior to collection of a blood sample, the phlebotomist wiU orally describe the purpose of the study and the process of blood collection. The consent form, explaining the purpose of the study, the blood collection procedure, risks and benefits, confidentiality, offer to answer questions, withdrawal rights, and injury rights will be signed in duplicate by the subject. A copy of the consent will be given to the subject to keep. The Institutional Review Board of the University of Southern California has approved the consent form. It stresses the patient’s bill of rights including the opportunity to consent freely to the study without the use of coercion and the opportunity to withdraw at any time without affecting future medical care. C. Potential Risks The major risk of participating in the study will be pain and discomfort resulting from the venipuncture. A small bruise may occur or the subject may experience slight bleeding after the blood 201 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. is drawn. No other physical risks are involved. Certain cohort members may view the potential loss of confidentiality a risk. We have extensive experience in maintaining confidentiality of information in epidemiological studies and believe that the risk is very low. Nevertheless, because of the potential loss of confidentiality, there is a minimal psychological risk associated with providing a blood sample. D. Measures Taken to Minimize Potential Risks Protecting the confidentiality of research data of an individual is of paramount concern to all personnel involved in die study. The following safeguards are in place at USC: (a) information from the questionnaires as well as data obtained through computer linkage is kept in secure computer files containing identification numbers only; (b) names are kept in a separate file, which is used only to re contact the subjects for follow-up purposes; (c) only authorized staff members, currently die project manager and the programmer, have knowledge of how to link the computer files; (d) the original questionnaires have been discarded with the exception of the section useful for re-contacting the subjects (these files are kept locked at all times and only authorized personnel are allowed access); (e) any data that is provided to investigators for analysis purposes does not contain any personal identifying information; (f) every employee who has access to confidential information has signed an individual pledge of confidentiality; and (g) no subject will ever be identified in any publication of the findings of the study. E. Risk vs. Benefits While our cohort members themselves will not benefit directly from the study, the potential benefits are nevertheless numerous. We have established a large cohort of Latina women, a minority group that is currently under-represented in epidemiological research. This cohort provides a unique opportunity to study dietary factors that may contribute to the risk of breast cancer or other chronic diseases. This cohort is particularly suited for this type of analysis as environmental exposures and disease outcomes vary widely between the migrant groups that make up our study. 202 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. In view of the minimal risks to die participants and the substantial potential for the study to yield important and useful data to the scientific community for the ultimate prevention of chronic diseases, the benefits from the proposed study should greatly outweigh the risks. 203 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. REFERENCES Abrams B, Guendelman S. Nutrient intake of Mexican-American and non-Hispanic white women by reproductive status: Results of two national studies. J Am Diet Assoc. 95(8):916-918, 1995. Adami HO, McLaughlin J, Ekbom A, Berne C, Silverman D, Hacker D, Persson 1 . Cancer risk in patients with diabetes mellitus. Cancer Causes & Control 2(5):307-314, 1991. Adlercreutz H, Martin F, Jarvenpod P, Fotsis T. Steroid Absorption and enterohepatic recycling. Contraception 20:201-223,1979. Adlercreutz H, Fotsis T, Heikkinen R, Dwyer JT, Woods M, Goldin BR, Gorbach SL. Excretion of the lignans enterolactone and enterodiol and of equol in omnivorous and vegetarian postmenopausal women and in women with breast cancer. Lancet 2:1295-99,1982. Adlercreutz H, Eotsis T, Bannwart C, Wahala K, Makela T, Brunow G, Hase T. Determination of urinary lignans and phytoestrogen metabolites, potential antiestrogens and anticarcinogens, in urine of women on various habitual diets. J Steroid Biochem 25(5B):791-797, 1986. Adlercreutz H, Hockerstedt K, Bannwart C, Bloigu S, Hamalainen E, Fotsis T, Ollus A. Effect of dietary components, including lignans and phytoestrogens, on enterohepatic circulation and liver metabolism of estrogens and on sex hormone binding globulin (SHBG). J Steroid Biochem 27(4-6): 1135-1144,1987. Adlercreutz H, Fotsis T, Hockerstedt K, Hamalainen E, Bannwart C, Bloigu S, Baltonen A, Ollus A. Diet and urinary estrogen profile in premenopausal omnivorous and vegetarian women and in premenopausal women with breast cancer. 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Alvarez, Robert R., Jr. “Changing Patterns of Family and Ideology among Latino Cultures in the United States.” In Handbook of Hispanic Cultures in the United States: Anthropology. Ed. Thomas Weaver. University of Houston, Houston, TX. 1994. Arts CJ, Govers CA, van den Berg H, Wolters MG, van Leeuwen P, Thijssen JH. In vitro binding of estrogens by dietary fiber and die in vivo apparent digestibility tested in pigs. J Steroid Biochem 38(5):621-628,1991. Augustsson K, Skog K, Jagerstad M, Dickman PW, Steineck G. Dietary heterocyclic amines and cancer of the colon, rectum, bladder, and kidney: a population-based study. Lancet 353:703- 707,1999. Axelson, ML. The Impact of Culture on Food-Related Behavior. Ann Rev Nutr 6:345-363, 1986. Bagga D, Ashley JM, Geffrey SP, Wang HJ, Barnard RJ, Korenman S, Heber D. Effects of a very low fat, high fiber diet on serum hormones and menstrual function. Implications for breast cancer prevention. Cancer 76(12):2491-2496,1995. Baghurst PA, Rohan TE. 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Food and Culture in southern Illinois, a Preliminary Report. Am Soc Rev. 7:645-60, 1942. 205 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Bennett FC, Ingram DM. Diet and female sex hormone concentrations: an intervention study for the type of fat consumed. Am J Clin Nutr 52(5):808-812, 1990. Bergsma-Kadijk IA, van’t Veer E, Kampman E, Burema J. Calcimn does not protect against colorectal neoplasia. Epidemiol 7:590-597,1996. Bernstein L, Yuan JM, Ross RK, et al. Serum hormone levels in pre-menopausal Chinese women in Shanghai mid white women in Los Angeles: results from two breast cancer case-control studies. Cancer Causes Control 1:51-58,1990. Bernstein L, Ross RK. Endogenous Hormones and Breast Cancer Risk. Epidemiol Rev 15(l):48-64, 1993. Berry EM, Zimmerman J, Peser M et al. Dietary Fat Adipose Tissue Composition, and the Development of Carcinoma of the Colon. JNCI 77:93-97,1986. Beto JA, Sheth G, Rewers P. 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Further reproduction prohibited without permission. Zeleniuch-Jacquotte A, Adlercreutz H, Akhmedkhanov A, Toniolo P. Reliability of serum measurements of lignans and isoflavonoid phytoestrogens over a two-year period. Cancer Epidemiol Biomarkers Prev 7:885-889,1998. Zeleniuch-Jacquotte A, Bruning PF, Bonfrer JM, Koenig KL, Shore RE, Kim MY, Pasternack BS, Toniolo P. Relation of serum levels of testosterone and dehydroepiandrosterone sulfate to the risk of breast cancer in postmenopausal women. Am J Epidemiol 145:1030-1038,1997. 225 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX A. NUTRITION MONITORING IN THE UNITED STATES A dozen different United States federal agencies conduct and analyze nutrition-monitoring activities (Woteki, 1995). The two agencies with the greatest responsibility for these tasks are the Human Nutrition Information Service of the US Department of Agriculture (USD A) and the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (GDC) of the US Department of Health and Human Services (DHHS). The Departments of Defense, Labor, Commerce, and State also conduct nutrition surveys but they are usually limited to a specific population they serve. The activities of these six federal departments are collectively referred to as the National Nutrition Monitoring and Related Research Program (NNMRRP) which was enacted by the passage of the Nutrition Monitoring and Related Research Act of 1990 (Woteki, 1995). This act requires development of a comprehensive, ten-year plan for coordinated nutrition monitoring and research. The goal is to improve dietary assessment methodology and population dietary estimates through better coordination and timing of national surveys, standardizing data-collection methods, conducting research to improve dietary assessment methods and standardizing food composition databases used for analyses (Briefel, 1994). The most frequently cited federal nutrition surveys are the Nationwide Food Consumption Survey (NFCS) conducted by the USDA and the National Health and Nutrition Examination Survey (NHANES) conducted by the NCHS. The USDA has conducted the NFCS approximately every ten years since 1936. It consists of a national survey of food consumption using a sample of households in the forty-eight contiguous states. The person most knowledgeable about food purchased and prepared in the household is interviewed about the amounts of food used in the house during a seven-day period. Since 1965, individual household members have also been asked to do a 24-hour dietary recall of the previous day and then asked to keep a diary of foods eaten for two days, i.e., the current and following day. The outcome variables for individuals include intakes of food and nutrients. 226 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. The USDA began a smaller survey in 1985 called the Continuing Survey of Food Intakes by Individuals (CSFII). The purpose was to provide more coverage of the population in the years between die decennial surveys. In die 1985-1986 survey, ages were restricted to men and women aged nineteen to fifty years and children ages one to five. The goal was to obtain six 24-hour dietary recads collected at approximately two-month intervals over the course of a year from each participant. In the 1989-1991 survey, one 24-hour dietary recall plus a two-day diary was obtained from persons of all ages. Dietary intake data covered all days of the week. Whites, blacks and Hispanics (undefined) were included. Health examination surveys conducted by NCHS were mandated by the National Health Survey Act of 1956 (McDowell, 1994). These surveys commenced in 1960 with a nutritional assessment component added for the first time in 1970. At this time the name of the program was changed to NHANES. Three national nutrition surveys under the name NHANES have been conducted to date. Each survey used probability sampling to select a representative sample of the United States civilian, non-institutionalized population. NHANES I was conducted in 1971-1974. In 1976-1980, NHANES II was conducted using a single 24-hour dietary recall for persons aged six months to seventy-four years. The major ethnic/racial groups interviewed were blacks and whites. Subjects were asked to report all food and beverage consumed in the 24-hour period before the interview day. Almost all recall days were weekdays. A person’s recall was considered unsatisfactory if the person refused to participate, was not available at the time of the scheduled interview and could not subsequently recall two major meals, or if there was incomplete 24-hour recall data regarding types or amounts of food for the entire day. Of the over twenty thousand adults and children examined in NHANES n, only 1.11 % had unsatisfactory recalls (Lanza, 1987). The NHANES II food composition database was developed by NCHS and consisted of data from manufacturers, USDA, and other sources. Alcohol was included in the calculation of total calorie intake. 227 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. NHANES HI (1988-1994) used a single 24-hour dietary recall for persons two months and older and a food frequency questionnaire for persons twelve years and older. In order to improye the overall dietary intake estimates, 24-hour dietary recalls included weekend days for the first time. Self-reported race and ethnicity were used to classify person as non-Latino white, non-Latino black, Mexican American, or ‘other.’ This survey was designed as a six-year survey and was conducted in two three-year phases. The NHANES III dietary assessment was developed with input from experts in the fields of nutrition, public health, biostatistics, and epidemiology to meet the nutrition research objectives. In 1988, NCHS contracted with the University of Minnesota’s Nutrition Coordinating Center to develop an automated dietary interview and coding system called the Dietary Data Collection (DDC) System (McDowell, 1994). This system provided a standardized interview format and automated probes for the interviewers. USDA food codes were used and nutrients were calculated using the USDA Survey Nutrient database. Many brand specific food codes were added to the USDA nutrient database and hundreds of new foods with reduced fat, sodium and sugar content were also added. A large number of ethnic foods, particularly Mexican American foods, were added and significant changes were made to the nutrient composition table. For example, the revised cholesterol content of eggs was incorporated based on updated nutrient composition data. As under reporting has been documented in previous studies, ratios of energy intake to basal metabolic rate were calculated for adults based on published formulas. These results suggested a more complete reporting of intake in the NHANES III survey compared to earlier surveys (McDowell, 1994). A special survey of Mexican Americans, Puerto Ricans, and Cubans, aged twelve to seventy- three years, residing in the continental US was conducted in 1982-1984 (HHANES) also by NCHS. The sample consisted of9,455 Mexican Americans from the southwestern states of Texas, New Mexico, Colorado, Arizona, and California (representing 84% of the total Mexican American population in the United States in 1980), 2,125 Cubans from Dade County, Florida (representing 57% of the total Cuban population in 1980), and 3,525 Puerto Ricans from the New York City 228 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. metropolitan area including New Jersey and Connecticut (representing 59% of the total Puerto Rican population in 1980). (Delgado, 1990) A single 24-hour dietary recall was administered in mobile examination centers by trained bilingual interviewers. Response rates were 70%-75% for Mexican Americans and Puerto Ricans and 60% for Cubans. HHANES was designed to provide baseline nutritional information for Latino subgroups comparable to other surveys conducted by NCHS, particularly NHANES II (Delgado, 1990). By design, both surveys included recalls from weekdays only. However, in order to increase response rates in HHANES, some recalls were from weekend days. Few or no recalls were completed for weekend days for Puerto Ricans and Mexican Americans whereas 14% of recalls for Cuban Americans were from weekend days. The HHANES nutrient database was developed by the Human Nutrition Information Service of the US Department of Agriculture. It is also important to note that unlike the previous NHANES surveys, HHANES was not designed as a national Latino survey. HHANES was restricted to three regions of the country in order to facilitate a cost efficient and iogistically feasible operation of the survey (Delgado, 1990). Therefore, national estimates for Latino subgroups can not be drawn based on the survey’s findings. Although HHANES was not designed as a national survey, NCHS estimates that it represented approximately 76% of the total 1980 US Latino population aged 6 months through 74 years (Delgado, 1990) and it does allow inferences to the majority of Latinos of these three ethnic subgroups (Block, et al., 1995). However, limitations of this survey include the lack of important traditional foods and food preparations as well as the fact that food items were frequently collapsed into categories which do not apply to Latin American diets (Romero-Gwynn, 1994). The National Health Interview Survey (NHIS) is a multistage survey conducted annually by NCHS using a national probability sample of households in the forty-eight contiguous states. Within each household, one adult aged eighteen years or older was administered the core questionnaire and one supplement. The 1987 NHIS was administered to 44,123 persons and included blacks, Latinos, 229 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. whites, and ‘other,’ where race/ethnicity was based on self-identification. Latinos were over-sampled to provide more stable estimates and to permit the description of dietary characteristics of this population. This was accomplished by interviewing up to three Latino adults per household in three large metropolitan areas (New York, Miami, and Chicago) rather than a single adult as was the case with the other race/ethnic groups included in the survey. A Spanish language version of the questionnaire was available for subjects who spoke only Spanish. In 1987, the National Cancer Institute in collaboration with NCHS and the Census Bureau, sponsored the Cancer Risk Factors Supplement to the annual NHIS. The purpose of the supplement was to provide information on behavior, knowledge, and attitudes related to cancer prevention. One supplement, the Cancer Control Study questionnaire obtained information on tobacco use and attitudes, use of screening for cancer prevention, and beliefs about diet and its relationship to cancer. The Epidemiology Supplement obtained information on cancer risk factors and included the NCI (Block) food frequency questionnaire. Because so much information was to be collected, participants were randomly assigned to receive one of the two supplemental questionnaires. The overall response rate was 82% to the core questionnaire and two supplemental survey questionnaires. The 1987, NHIS dietary questionnaire was administered to over twenty-two thousand persons in which individuals were asked to recall the usual frequency of consumption of fifty-nine foods, beverages and alcohol during the preceding twelve months. Serving size was included (small, medium, or large) as were questions about the consumption of skin on poultry and fat on red meat. The foods included in the food frequency questionnaire (FFQ) were selected because they represented the major contributors of energy and eighteen major nutrients. The fruits and vegetables selected represent 80% or greater of total population intake of vitamin C and P-carotene. Some frequently consumed fruits and vegetables, such as bananas and string beans, were not included because they do not make a major contribution to the selected nutrients. High fiber cereals and beans were included as well as meat, meat products, starches, dairy products, fats and popular snack foods. The full-length 230 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. one hundred item questionnaire on which this shorter questionnaire was based has been validated in several studies. In validations against multiple days of dietary records, the shorter questionnaire not only performed almost as well as the longer version, but also represents 80% or more of the nutrients on the NHANES II database. It is important to point put, however, that the NHANES II database is representative of the black and white populations only. A second NHIS study was conducted in 1992. However, fee Hispanic samples differed in ethnic distribution between the 1987 and 1992 surveys. 'Hie proportion of Mexican Americans increased from 43.5% to 53.9% with proportionately fewer Puerto Ricans, Cubans and other Latin Americans. The distribution by language version also changed significantly between 1987 and 1992. These points need to be considered when comparing fee results of fee two surveys. Many of fee studies reported in fee literature use data from fee NHANES, HHANES, CSFH and NHIS national nutrition surveys. It is important to understand fee design in order to assess fee comparability of these studies. 231 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. APPENDIX B IMMIGRATION OF LATINOS ORIGINATING FROM CENTRAL AND SOUTH AMERICA In recent years, die newest Latino immigrants have come from Central American countries, particularly El Salvador, but also Guatemala and Nicaragua. Many of these people are political refugees, escaping the war, violence, and poverty in their home countries. As other immigrant groups before, many Central Americans immigrate in search of jobs and a better standard of living for their families. The 1990 census estimates there are 698,000 ‘other- Latinos residing in Los Angeles County of which 64.9% are estimated to be originally from Central America and 13.7% from South America, not including Brazil. The remaining 21.1% are classified as ‘other.’ These numbers make them the second largest Latino ‘subgroup’ living in Los Angeles. Unfortunately, government reports do not contain separate statistics for the Central/South American immigrant group by country of origin. PUERTO RICAN AND OTHER CARIBBEAN IMMIGRATION In 1917, three weeks before the United States entered World War I, Congress passed the Jones Act, granting US citizenship to all Puerto Ricans. This Act provided that Puerto Ricans could not vote in presidential elections but they could be drafted to fight for the United States. Although Puerto Ricans had been migrating to the urban areas of northeastern United States since the late nineteenth century when the US acquired Puerto Rico from the Spaniards, it was not until 1925 that Puerto Rican colonias appeared in New York City. In the 1940s when the island economy became increasingly industrialized and moved away from agriculture, the labor pool could not be absorbed. The island people were essentially pushed to the United States. In the late 1950s American markets were experiencing a labor shortage and therefore recruited island residents. This resulted in the largest influx of Puerto Ricans, men and women, to the United States. However, the 232 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. industries that offered jobs in the 1950s declined in the 1970s and 1980s and the Puerto Bicans were left without jobs. As a result, the standard of living for Puerto Ricans has significantly deteriorated since the 1970s. The poverty rate is highest for Puerto Ricans of all Latino subgroups (R am irez, 1995). Puerto Ricans constitute the second largest Latino group, numbering 2.3 million, in the United States (Ramirez, 1995). The largest proportion of immigrants reside in northeastern metropolitan areas such as New York, New Jersey, and Connecticut. Small proportions also reside in Illinois, Florida, and Pennsylvania. Only 5% reside in California. The Cuban migration to the United States has occurred in waves. The first wave took place in the early 1900s when an estimated 79,000 Cubans of all social classes settled primarily in Florida. The second wave occurred when Fidel Castro came to power in 1959 and an estimated 273,000 Cubans primarily from the professional class sought exile (Aguirre-Molina, 1994). Tie third wave of Cuban migration began in 1980 when 118,000 people representing a mix of social and educational classes sought asylum in die United States through the Peruvian embassy (Aguirre-Molina, 1994). The Cubans are distinguished from other immigrant groups by the assistance they received from the United States federal government. The government established refugee funds for housing, food and health services all of which enabled their settlement into the United States. Cubans have the lowest percentage of families living below the poverty rate of all Latino subgroups. The majority of Cubans in the United States live in Florida (59%) followed by New Jersey (10%), New York (10%) and California (8%) (Aguirre-Molina, 1994). The population in Los Angeles totals 47,534, or 1.4% of the total Latino population in Los Angeles (1990 census). 233 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. NUTRITIONAL/FOOD CONSUMPTION PRACTICES OF LATINOS ORIGINATING FROM LATIN AMERICA Latinos represent a diverse blend of nationality, religion, culture, ethnicity, and socioeconomic status. This diversity is evident in the nutritional/food consumption habits and customs in the Latin American and Caribbean countries from which current US Latino residents originated. Food Consumption in Other Central and South American Countries The countries of Central America each have their own special cuisine that is surprisingly unique to each country (Marks, 1990). Although El Salvador, Honduras, Nicaragua, and Costa Rica shared a common origin, their diets took different directions. The cuisine of the Guatemala Maya was in reality two separate cuisines, one of the highland Indian and the other of the Spanish colonial. A third cuisine developed on Guatemala’s Caribbean coast where indentured labor from India and Africa was brought in by the British to work in the forests and sugarcane fields of British Honduras (present day Belize). These people developed a tropical style based on seafood, bananas, and coconut milk. Geography plays a vital role in dietary patterns of Central America. The people of the tropical lowlands eat differently from the people of the mountainous highlands. However, a common theme throughout Central American countries reflects their Indian origins. Com, tortillas, beans, squash, hot chiles, and tomatoes are basic. Beans may be red, white, or black, the latter being the most popular. After the arrival of the Spanish, foods of Europe and Asia such as wheat bread and rice were incorporated into the staple diet. Small french bread rolls are baked and sold all over Guatemala. Combread and Sunday bread (bread made with wheat and rice flour, flavored with cheese and sour cream) are common. Guatemala, with the largest number of Indians, has developed its cooking in direct proportion to their number, leaning heavily on the turkey, fruits, and vegetables that 234 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. originated in Central America. El Salvador and Honduras depend less on Indian influence and more on Spanish methods. Nicaragua, with its Miskito Indians, a Caribbean coastal group, has a mixture of foods. Costa Rica is an almost exclusively non-Indian nation and the cooking is based on die fertile tropical countryside and indigenous adaptation of the foods of the region. There is, of course, overlapping in the recipes of the different countries. All of the Central American countries along the Caribbean coast, use coconut milk, for example, in preparing bread, chicken, and fish dishes. The cuisine of South America represents the continent’s blend of cultures. The native Quechua Indian influence was predominant in South America prior to the Spanish and Portuguese conquests. With the arrival of the Spanish came the second strong influence on the region’s cuisine. The black Africans who were brought in by the Spanish as slaves introduced the third major influence in South America. In the nineteenth and twentieth centuries there have been additional influences, primarily the Italians in Argentina and the Germans in Chile. It is very much a Creole cuisine: a mixture of Europe and Africa. However, the influence of die Quechua Indians is the dominant factor in the food culture today. Quechuas are often referred to by die title of their leader, the Inca. The differences in foods in South America, like Central America, are influenced by geography, specifically, which side of the Andes the country is on and how the mountains are actually arranged within the country. In Peru, the mountains are easily terraced or cultivated and the Incas were able to create an advanced agricultural base. They built aqueducts that carried water great distances over land but also high up into the mountains. The Andes in Chile rise straight up from the edge of the seacoast not allowing for an agricultural economy. It is a long, coastal country with some of the most magnificent seafood due to the plankton rich, cold Humboldt current that runs off its shores. Chile also has die perfect climate for grapes and Chilean wine is valued throughout the world. The Incas are credited with discovering, developing, and breeding hundreds of varieties of com, potatoes, and hot peppers. Dehydration was used by the Incas to preserve foods. Chuno are potatoes sun dried for several weeks. The result is a soft, light, white potato on the inside from which 235 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. some of the finest starch is made. Air dried strips of llama meat called charqui are a staple of the Quechua Indians. Other animals and birds were domesticated and cultivated by the Indians, long before the arrival of the Spanish: wild pigeon or squab, duck, and rabbit. Rabbit is still one of the major meats of South America. Deer and wild boar are found, as is a large South American guinea pig native to the Andes (cuy) which is very much a staple today (Rojas-Lombardi, 1991). In South America no proper meal starts without hot soup. Chupe, or chowder, is prepared with a combination of fish, shellfish, meat, poultry, beans, grains, potatoes, squash or corn. Pureed soups are also found everywhere in South America. They are called cream soups even though cream is never used. Instead they are thickened with starchy vegetables, beans or grains. Poultry is an important part of the South American cuisine including duck, squab, quail, pheasant, chicken, and turkey. The duck is native to die Americas and the Inca developed methods to preserve its meat by freeze-drying it. Rabbit, cuy, and viscacha (hare) are also popular in the South American diet. The cuy is a domesticated animal raised for food and often weighs three to five pounds. The viscacha thrives in the wild especially in Argentina. Rabbit is bought in the market, usually whole, and is prepared in a variety of ways, from simple frying to complex dishes. It was not until colonial times that the cow, pig, lamb, goat, and sheep were introduced in South America and they soon had a profound effect on the cuisine of the region. Today, pork is extremely popular in every country of the continent. The production of beef in Argentina ranks among the highest in the world supplying all of its neighboring countries. For the people of Argentina and Uruguay, meat is so much a part of their food culture that no meal is served without it. Mondongo (tripe) is common and beef heart is a popular dish in Peru. Pigs’ feet is the main ingredient of a popular traditional dish from Ecuador. Lamb and goat are popular dishes in the South American culture. What beef is to Argentina, seafood is to Chile. Fish, shellfish, anchovies, clams, mussels, and other seafood are tire predominant food of this country. Other South Americans are passionate about seafood as well as die region is rich in fish, both freshwater and saltwater. Vegetables in South 236 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. America are an integral part of the meal. They are used in soups, stews, and in combination with meat and seafood. But most often they are served by themselves. Potatoes were a staple food of the early cultures of South America and continue to be one of the most important vegetables today. Sweet potatoes are popular, as is yucca, also called cassava or manioc, which is cultivated throughout the tropical regions. It is a starchy vegetable with a distinctly sweet taste and dense texture. Peppers were cultivated in South America as far back as 7000 years ago and they continue to be a major part of the cuisine. It is often the only vegetable and flavoring available for the people of the Andes. Peppers are eaten as vegetables both alone as in chile rellenos and in combination with other vegetables. Squash, native to South America, is among the most nutritious foods and is a standard item in every market. The most popular variety is the zapallo, a hard-shelled or winter squash that resembles the North American butternut squash in taste and texture but not in color or shape. It is grown in Colombia, Ecuador, Pem, Bolivia, northern Argentina, and northern Chile. The lima bean, named after the city of Lima, Pem was cultivated by the ancient people of the Andes because the common bean did not perform well at high elevations. Com has long been an integral part of the diet of South Americans. Countless varieties of different colors and textures are grown extensively. Hominy, a variety of com with large white kernels, is called mote by the Qnechuas Indians. Quinoa, although usually referred to as a grain, is the seed of an annual herb of the Chenopodium family. The seeds are large and are found in clusters at the ends of the plant’s stalks. Quinoa is extremely hardy and thrives under conditions few other crops can tolerate. This ability to survive has made it a strong staple food today as it was during the Inca empire period. Quinoa is high in protein and other nutrients and is often prepared with diced vegetables, beans, or chopped roasted nuts and fresh herbs. Fruits are often consumed as dessert for all South Americans. Puddings, pastries, pastelitos, poached fruit, and other sweets are part of the cuisine but are often eaten in the morning with coffee, in the afternoon with tea, or as a snack especially before bedtime. Traditionally, the best sweets are made and sold by convents. This tradition dates back to colonial times and is still alive today. Mazamorra 237 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. morada is a classic pudding, popular in Peru and Ecuador, characterized by its purple color which comes from purple com. Frijol Colado is a traditional bean pudding usually made with die yellow canary bean. Red kidney beans are also used. Quinoa combined with raisins, whole milk, cream, sugar and coconut makes a delicious popular pudding. Food Consumption in Cuba and Other Caribbean Island Countries Prior to Spanish colonization, the indigenous people of the Caribbean used cassava, squash, beans, sweet potatoes, tomatoes, chili peppers, bananas, plantains, papayas, and pineapples. The Spanish who colonized the region, the Africans who were brought in as slaves, and the Chinese, who came as laborers, have all had an impact on the cuisine. Today, rice is the main staple in the Caribbean. They inherited their love of rice from Eastern and Western influences alike. From the Chinese, they acquired dependence on white fluffy rice as an accompaniment at almost every meal (O’Higgins, 1994). Short grain white rice is preferred and is frequently eaten with small red beans or black beans in Cuba. In Puerto Rico, rice and beans are generally eaten twice a day. Per capita consumption is seven ounces of rice and three to four ounces of beans per day (Sanjur, 1986). Caribbeans consume both pork and beef. Beef in the form of tasajo, or jerked beef, was among the provisions carried by Columbus when he landed on the islands in 1492. The cattle thrived and eventually spawned an export market. The meat was salted to preserve it. Sirloin or flank steak marinated in orange and lime juice and then pan fried is popular. Pork, although introduced by the Spanish, was also loved by the Chinese who came as contract laborers to Cuba. Roasted suckling pig is a favorite. Chicken and poultry are common in the diets of Caribbeans. Although several types of seafood are eaten in the Caribbean, dried salt cod has been traditionally preferred over fresh fish. However, red snapper is plentiful in the waters surrounding the islands as is lobster, crab, and shrimp. Cubans and Puerto Ricans consume few leafy vegetables although vegetables such as plantains, black-eyed peas, yucca, broccoli, cabbage, cassava, chilies, 238 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. green beans, okra, potatoes, sweet potatoes, squash, tomatoes, and yams are consumed frequently. Fresh com has been an essential part of the Cuban diet and Swiss chard is plentiful and eaten often. Tortilla, in Cuba, means omelet and they are usually eaten as the midday meal. No Indian tortillas, as in Mexico, are available. Fritters are a very popular and important side dish. Finally, like in South America, hot soup is served almost every day. A rich soup is usually served at the beginning of the midday meal and stew like soups are common for die evening meal. 239 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. APPENDIX C RELATIONSHIP OF BASAL METABOLISM TO CALORIE INTAKE AND PHYSICAL ACTIVITY Physiologists have partitioned energy expenditure into die following four components: (1) basal metabolic rate, i.e., the minimum energy it takes to keep the resting, awake body alive; (2) thermogenic effect of food, i.e., energy required to digest, metabolize, absorb and store carbohydrate, protein, and fat; (3) physical activity; and (4) adaptive thermogenesis, i.e., the capacity to conserve or expend energy in response to variable intake of food or temperature extremes (Willett, 1990). To determine a person’s basal metabolic rate (BMR) a person must just have woken up, be in a warm room, stay as relaxed as possible, and must not have eaten for 12 hours (Wardlaw and Insel, 1993). Oxygen consumption and carbon dioxide output are measured for 20 to 30 minutes and the values are used to calculate kcalorie use. Within the general population there is a variation in BMR of about 23% to 3Q% depending on factors such as gender, age, body surface area, temperature, and thyroid hormone levels. Resting metabolic rate (RMR) is calculated when measuring energy use under less stringent conditions (Wardlaw and Insel, 1993). Although RMR is usually slightly higher than BMR, the difference is often less than 3%. The terms are often used interchangeably. BMR usually represents approximately 70% of daily energy expenditure in sedentary individuals, about 60-65% in moderately active individuals, and less in more physically active individuals. Physical activity, on the other hand, accounts for about 20% in sedentary individuals, about 30% in moderately active individuals, and more in very physically active individuals. Thermogenic effect of food (TEF) and adaptive thermogenesis each represent approximately 5% to 10% of total calories (Willett, 1990). The energy requirement for TEF is higher for a carbohydrate or protein diet than for a fat diet for the reason that it takes less energy to turn absorbed fat into fat stores than glucose into glycogen or amino acids into protein (Wardlaw and Insel, 1993). Large meals have 240 R eproduced with perm ission of the copyright owner. Further reproduction prohibited without permission. also shown higher values for TEF compared to the same amount of food eaten over the course of many hours. In order to examine the performance of our FFQ in terms of measuring energy intake, we calculated an estimate of RMR using the Harris-Benedict equation1 . This formula is used widely by registered dietitians for hospital patients, and considers weight, height, and age when determining resting energy expenditure. This formula has been found to yield reasonable estimates of RMR (Wardlaw and Insel, 1993). Harris-Benedict equation: 66.5 + 13.8*(weight in kg) + 5*(height in cm) - 6.76*(age in years) 241 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix D. Components of Dietary Fiber Perspectives in Nutrition (Wardlaw Inset); Lanza arid Butrum, J Am Diet Assoc (1986) Type/Component(s) Definition Food Sources Physiological Effects Definition: sum oflignin and non-starch polysaccharides irt foods: not a single entity but a mixture of many complex organic substances whose single common property is their ability to resist digestion in the human stomach arid smell intestine. All forms of dietary fiber come from plants. Lignins: noncarbohydrate ceil wSII component; imparts structural rigidity (woody tissue) to cell walls and acts a s bonding agent between cells. Other functions are to retard water from permeating across cell walls and to protect against attacks by microorganisms by impeding the penetration of enzymes into the cell wail. The woody fibers in broccoli are partly lignins. This compound generally will not dissolve in water and so is considered an insoluble fiber. Non-starch polysaccharides (NSP): roughly equivalent td the sum of the pblysacCharide fiber components (cellulose, hemicellulose, pectin, gum and mudlage) Insoluble NSP: structural bbilding materials in the plant cell wall wheat bran increases bblk im feces Cellulose A straight-chain polysaccharide of glucose molecules that is undigestible. Most abundant molecule in nature. Structural building material of cell wall. wheat products decreases intestinal transit time brown rice dilutes intestinal fecal contents broccoli Hemicelluloses , A group of insoluble fibers containing the monosaccSrides xylose,: galactose; arabinose, glucose, (some) & mannose. Structural bbilding material of cell wall. Generally have a much lower average number of units (50 to 20Q) than cellulose. At least 250 chemically different hemicelloses are known. Soluble NSP: Involved With plant cSII structure arid metabolism apples delays gastric emptying; slows glucose absorption from the small intestine; binds bile adds and Other organic mutagens; can lower serum Cholesterol by: (1) inhibiting absorbtion in the small Pectins Gums A group of soluble fibers containing chains Of galabturoriic add and Other monosaccharides. Pectins are fourid universally in the primary cell walls and intercellular layers in land plants. Intracellular cement Citrus fruits, apples, and sugar beet pulp are particularly rich sources. A substance secreted at the site O f plant injury by spedalized secretory ceils. bananas dtrus fruits carrots barley oatmeal legumes soybeans intestine (2) increases amount Of bile add that Mudlages A gelatinous substance of various plants (as legumes or seaweeds) that contain prbtein and polysaccarides; secretions bf plant seed is excreted ini the stool thereby requiring the liven to remove more cholesterol from the blood in older to make more bile add HemiceilUloses Cell wdl| polysaccharides that contain backbone O f 1 to 4 linked pyranoSide sugars. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix D. Components Of Dietary Fiber Perspectives in Nutrition (Wardlaw Insel); Lanza arid Butrum, J Am Diet Assoc (1986) Type/Component(s) Definition______________________________________________________________________ Food Sources Physiological effects______________ Noncelluloslc polysaccharides (NCF): non-starch polysaccharides fraction minus cellulose. This classification, used widely by British researchers encompasses hemicelluloses, pectins, gums and mucilages. to w Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix E. Comparison of the language version of the questionnaire for selected food items FOOD DESCRIPTION IN ENGLISH FOOD DESCRIPTION IN SPANISH Spanish English Spanis English (% distribution) (m ean daily intake) % Chang to £ Oriental Salted or Pickled Veaetables Salted, Pickled or Marinated Vegetables Never 48.1 81:7 (such as salted cabbage or leafy greens. (kim chee, jalapenos. cauliflower) 1-4 mo 24.9 6.3 tekuwanl kim chee) 2-7+wk 13.5 13 Cappuccino -1 cup or mug Coffee with Milk -1 cup Never 30.5 71:3 (includes cate au lait, caffe latte, cate con leche) (includes Cappuccino) 1^4 mo 10.1 7 3 2-7+wk 50.1 9:2 Stew, Curry, Pot Pie of Empanada Stews, Turnovers "Curry" or Empanadas Never 42.0 66:2 (with beef or lamb) (with beef, pods or lamb) M m o 37.1 23.6 2r7+Wk 8.3 1:2 Chow Mein, Chow Fun or Yakisoba Sppa de Pasta + Mexican or Oriental Style Never 11.5 48:2 (Oriental fried noodles) (like sopa de fideo (cooked vermicelli in a 1^4 mo 70.9 44:2 cream sauce), Chow Mein; Yakisoba) 2r7+Wk 12.1 15 Pumpkin or YelloW/Orange Winter Squash Pumpkin & Other YellowrOrange Squash Never 27.8 6311 1^4 mo 53.0 26:2 2-7+ wk 10.6 2:9 Milkshakes or Malts LicuadoS (blended fruit and milk) or Never 57.6 7413 irhilk shakes 1^4 mo 24.0 1416 2-7+wk 6.3 114 Pork and Greens or Laulaus Pork meat With Vegetables Never 46.0 6913 (like pork meat With verdolaoas (watercress 1^4 mo 40.8 1915 I family) or with cactus) ; 2f7+ Wk 1.8 014 2.5 0.3 -88.0% 20.4 3.3 -83.8% 18.1 5.2 -71.3% 14:8 4.5 -69.6 11.5 3.6 -68.7% 19.1 6.7 -64.S 8.1 2.9 -64.2% Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix E. Comparison of the language version of the questionnaire for selected food items I to l KJt FOOD DESCRIPTION IN ENGLISH FOOD DESCRIPTION IN SPANISH Spanish English (% distribution) Spanis English (mean daily intak% Chang Stiil-Fried Vegetables Vegetables, pan fried Never 22.3 45:3 29.9 12.6 -57.9% (no meat) (without meat) 1+1 mo 42.5 38.9 2r7+Wk 25.6 716 Dried Bean or Pea (Legump) Soup Crema of Sopa de Frijol (bean soup) Never 17.9 40.9 74.9 3211 -57.1% (such ad Portuguese bean, split pea) 1^4 mo 31.2 3617 2r7+Wk 41.5 16.0 Broth with Noodles or Rice Thin soup With Pasta. Rice or Tortilla Strips Never 6.6 2612 56:8 2611 -54.0% (such ad beef noodle, chicken rice, (such as chicken soup W ith rice or tortilla s o u p) 14imo 55.5 5612 wori tun mein) ; 2-7+wk 29.1 1110 Stir-Fried Chicken & Vegetables, or Fajitas ChiCken With Vegetables, pan fried Never 10.6 3118 2513 1117 -53.8% (such as slikiyakii nishime, chicken long rice) (such as fajitasi Chicken Mexican style, 1^4 mo 66.2 5710 chow mein) 2-7+wk 16.8 415 White or Purple Sweet Potatoes White! Purple or Sweet Potatoes Never 50.5 6611 5.6 2.7 -51.8% 14m o 33.5 2311 2-7+wk 3.4 114 Stir-Fried Beef or Poirk & Vegetables, Beef io it Pork with Vegetables, pan fried Never 12.2 3017 3211 1518 +5018% or Fajitas (such as beef broccoli, pork tofu, (such as fajitasi Steak picado. chop suey - 1r4mo 65.9 5916 chop suey, sukiyaki) Mexican style) 2-7+wk 16.6 414 Other Vegetables Other Vegetables Never 18.7 5216 9.9 5.0 14915% (such as white or summer squash, beets, (like small zucchini tvpe of squashl beets. 114 mo 63.1 35J4 eggplant) eggplant) 2-7+wk 12.1 516 Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. i Appendix! E. Comparison of the language version of thei questionnaire for selected food litems FOOD DESCRIPTION IN ENGLISH FOOD DESCRIPTION IN SPANISH Spanish English (% distribution) Spanis English (mean daily intak% Chang Jook Sopa "Jook" Never 58.3 61:8 6.4 1415 126.6% (rice gruel - may include meat, poultry, fish (made with rice Oriental style) 1+4 mo 23.2 2010 or vegetables) 2-7+wk 2.2 711 Potato, com, tortilla or Other chips Corn, potato or other chips or Chicharrones Never 45.1 I2416 1.3 3.1 138:5% or Chicharrones (pork rinds) 1+4 mo 41.5 59.6 2-7+wk 3.0 12J0 Gravy on meat, potatoes; lice Creams/Sauces Never 73.4 50.1 1.3 3.8 192:3% (made With the fat and juices that come from meat 1+4 mo 11.2 3715 when cooked) 2-7+wk 1:6 517 N ) O s Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix F. Calibration equation estimates for MALES (foil Mexico bom and US bom Latinos) NUTRIENT Intercept Slope AGE Intercept BMI intercept Age Slppe BMI Slppe R squared Total Calories 6.149 0.188 -0.006 40.007 0.161 Non-alcohol calories 6.121 0.188 r0:oo;r 40.006 0.155 % Protein 12.961 0.262 0.09: 0.116 % Saturated Fat 5.081 0J613 0.332 % Monounsaturated Fat 5.388 0.559 0.006 0.235 % POIyunsritunated Fat 4.384 0.350 0.04I 0.103 %Fat 13.220 0.587 01167 0.274 % Carbohydrate 30.129 0.429 -0.005 0.212 % Alcohol 4.664 0.578 0.393 Alpha carotene 131.022 0.399 -0.017 0.118 Beta carotene 437.289 0.350 0.150 Calcium 171.012 0.604 0.392 Cholesterol 93.277 0.303 2.87' 0.007 0.219 Dietary Fiber 4.508 0.496 -0.009 0.411 Folatin 88.608 0.364 0J831 -0.008 0.231 Lutein 509.169 0.096 0.159 Lycopene 40.302 0.834 55.666 40.042 0.367 Selenium 35.281 0.361 01202 0J43I 0.116 Insoluble NSP 1.758 0.388 0.004 40.0013 0.323 Soluble NSP 1.502 0.396 0.010 -0.009 0.330 Total NSP 3.187 0.399 0.003 40.0013 0.342 Vitamin A 1749.126 0.346 0.170 Vitamin B6 0.490 0.453 0.003 40.005 0.268 Vitamin B12 1.385 0.269 0.025 0.033 Vitamin C 24.152 0.512 40.020 0.271 Vitamin D 37.027 0.397 0.748 0L154 Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix F. Calibration equation estim ates for FEMALES (fori Mexico born and US born Latinos) NUTRIENT Intercept Slope AGE Intercept BMI Intercept Age Slppe BMI Slope R squared Total Calories ! 5J539 0:226 -0.005 0.000 0.108 Non-alcohol calories 5.402 0.242 -0.005 0.000 0.108 % Protein 10J953 0J373 01326 +0.017 0.149 % Saturated Fat 6.104 0.424 0.042 0.324 % Monounsaturated Fat 8:58^ 0J303 0.201 % Polyunsaturated Fat 4.692 0.394 -0.005 0.128 % Fat :21J04t) 0J336 +0.074 0.253 % Carbohydrate 42.835 0J20T +0.003 0.221 % Alcohol 8.105 0.472 0.269 Alpha carotene (Mexico) +40.116 0J61ti 0.006 0.149 Alpha carotene (US) 2901609 rOJ087 0.006 0.140 Beta carotene (Mexico) 660.720 0.346 241419 0.166 Bata carotene (US) 660.720 0J098 241419 0.166 Caidum 125.710 0.658 0.395 Cholesterol 90.540 0.383 41883 -0.031 0.167 Dietary Fiber (Mexico) 2.980 0.580 -0.049 0.002 0.371 Dietary Fiber (US) 9.536 0.122 +0104!) 0.002 0.371 Folacin 133.064 0.148 0l57( 0.249 Lycopene 939.743 0.178 0.071 Insoluble NSP 2.206 0.375 0.01( +01033 0.262 SolublO NSP 1.033 0.500 0.01; 0.326 TOtal NSP 2.868 0.440 0J02( 0.307 Vitamin A +64.788 0.826 145.15' 0.177 Vitamin A 3293.179 0.018 45.151 I 0.177 Vitamin B6 0.741 0.269 0.191 Vitamin B12 1.679 0.126 0.031 Vitamin C 39.047 0.471 -0.008 0.261 Vitamin D 28.456 0.692 0.175 Appendix G. Percentage of Mexico-born subjects reporting intake of core* foods/beverage food/beverage never 1-4 month 2-7+ week milk or cream added to coffee 97.2 com tortillas, com muffins/combread 5.8 14.1 79.3 coffee -regular or decaf -1 cup or mug 19.4 10.8 69.7 onions 15.7 16.1 66.0 bananas 5.8 30.7 62.8 salsa or hot chili peppers 18.8 23.1 55.4 oranges 8.5 37-7 52.9 sodas - regular or diet 17.8 30.5 51.8 tomatoes 14.3 36.7 48.5 white bread 18.2 39.2 41.7 orange or grapefruit juice 25.6 35.1 38.8 boiled dried beans or peas 15.2 45.2 38.7 cafe con leche 50.0 11.9 37.3 dried bean or pea soup 31.4 31.4 36.0 apples and applesauce 19.0 44.2 35.9 lowfat milk (1% or 2%) 52.6 12.1 34.6 light green lettuce or tossed salad 15.5 49.7 34.0 refried beans 25.0 41.9 32.5 whole wheat or rye bread 36.0 32.3 30.9 carrots 12.4 56.6 30.2 whole milk 53.7 16.9 28.9 rolls, buns, biscuits or flour tortilla 28.8 42-3 28.2 tomato or vegetable soup 17.0 56.8 25.Q broth with noodles or rice 19.7 54.7 24.5 Mexican or Spanish rice 12.0 63.4 23.6 cooked cereals 36.7 41.0 21.7 chili 35.5 42.1 21.7 other fruit juices or fruit drinks 41.3 36.8 21.4 other cheese, ie. American or cheddar 29.8 48.7 20.8 avocados and guacamole 14-1 65.8 19.4 pears 27.4 52.5 19.3 cantaloupe (in season) 22.3 58.1 19.0 white rice 23.6 56.8 18.8 any other fruit 37-9 43.0 18.6 tangerines or mandarin oranges 40.2 41.1 18.1 peaches 23.3 58.4 17.6 mangoes (in season) 29.8 52.0 17.6 other green vegetables (zucc/asp/okra) 28.3 53.4 17.6 broccoli 21.5 60.3 17.4 dark green lettuce 43.0 40.3 16.2 com 13.2 70.2 15.8 watermelon (in season) 26.1 57.8 15.5 beef steak, veal or lamb 17.6 66.1 15.5 249 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Appendix G. Percentage of Mexico-born subjects reporting intake of core foods/beverage Food/beverage never 1-4raontfr 2-7+ week lowfat cheese 48.3 36.0 15.1 cookies, brownies or fruit bars 45.0 39.5 15.1 eggs, cooked or raw 37.3 48.0 14.2 other cold cereals 48.4 37.1 14.2 mayonnaise in sandwiches 45.7 40.1 13.6 cottage cheese 43.9 42.0 13.6 green beans or peas 23.3 64.7 11.4 peanuts or other nuts 31.3 56.9 11.3 Arroz con Polio 22.5 65.9 10.7 dark leafy greens 40.3 48.5 10.6 roasted, baked, grilled, chicken 23.6 65.5 10.2 tegular or draft beer 67.5 22.7 9.4 fried chicken 24.0 66.9 8.3 french fried potatoes 31.3 60.9 7.3 Mexiran meat soup 15.2 77.3 6.4 baked or boiled white potatoes 30.7 62.8 5.8 light beer 78.5 16.3 5.0 tacos, tostadas, sopes, or taco salad (beef) 27.0 67.5 4.9 spaghetti 30.2 64.8 4.3 cheese enchilada 26.8 68.3 4.3 tacos, tostadas, sopes, or taco salad (chicken) 29.7 65.6 4.1 *The cote foods are defined as follows: 1. >=10% of population consumes the food item 2-7+ times per week (or) >=65% of population consumes it at least once per month 2. Foods were added to core diet based on information from the calibration study, i.e., the calibration sub-study determined that the food was a major contributor to calorie intake. 250 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Appendix H. Percentage of US-born subjects reporting intake of core* foods/beverages FoocUbevetage never 1-4 month 2-7+ week milk or cream added to coffee 97.2 coffee - tegular or decaf -1 cup or mug 23.6 7.4 69.0 onions 14.0 26.3 58.9 bananas 6.0 36.4 57.2 sodas - regular or diet 16.9 31.9 51.2 rolls, buns, biscuits or flour tortilla 9.9 38.9 50.9 salsa or hot chili peppers 18.0 31.2 49.6 tomatoes 9.0 41.9 48.8 light green lettuce or tossed salad 7.6 45.5 46.5 whole wheat or rye bread 22.2 32.8 44.7 oranges 10.4 44.8 44.5 white bread 23.0 34.1 42.5 margarine added to bread items 30.6 27.0 42.1 com tortillas, com muffins/combread 13.S 47.2 39.1 jowfat milk (1% or 2%) 44.7 16.8 38.1 orange or grapefruit juice 23.9 39.1 36.8 apples and applesauce 16.9 50.2 32.6 mayonnaise in sandwiches 26.9 43.9 28.7 carrots 11.3 61.2 27.1 eggs, cooked or raw 21.2 52.5 26.0 regular salad dressing or mayonnaise 32.8 42.3 24.6 cooked cereals 36.4 39.3 24.0 other cheese, ie. American or Cheddar 24-5 53.6 21.4 other fruit juices or fruit drinks 41.3 37.3 21.2 other green vegetables (zucc/asp/okra) 16.6 62.9 20.2 low calorie salad dressing 55.2 24.6 19.9 chili 37.Q 42.8 19.8 other cold cereals 37.8 42.3 19.6 refried beans 24.3 55.8 19.6 any other fruit 35.9 45.6 18.4 cookies, brownies or fruit bars 36.1 45.5 18.2 cantaloupe (in season) 20.2 61.4 18.2 boiled dried beans or peas 30.5 51.1 18.1 jam or jelly added to bread items 38.5 43.5 17.6 dark green lettuce 48.7 34.2 16.9 other bread 49.0 34.0 16.7 whole milk 68.9 14.5 16.4 potato, com, tortilla or other chips 24.6 58.9 16.2 broccoli 20.3 63.8 15.6 sweet rolls, croissants, doughnuts, etc. 33.8 50.6 15.3 watermelon (in season) 25.8 59.2 14.8 com 10.7 74.8 14.2 ice cream 29.4 57.0 13.4 251 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Appendix H. Percentage of US-born subjects reporting intake of core foods/beverages Food/beverage never 1-4 month 2-7+ week white dee 25.6 61.4 12.7 roasted, baked, grilled, chicken 24.4 63.1 12.1 crackers and pretzels 39.9 47.9 12.0 beefsteak, veal or lamb 21.4 66.5 11.8 Mexican or Spanish rice 13.8 74.2 11.5 peaches 27.6 60.7 11.4 green beans or peas 18.7 69.6 11.4 pears 36.2 52.5 11.0 popcorn 34.0 55.5 10.4 peanuts or other nuts 34.7 55.1 10.0 regular or draft beer 71.5 18.5 9.8 french fried potatoes 26.1 64.4 9.2 bacon 34.8 58.1 6.8 light beer 76.9 16.3 6.6 baked or boiled white potatoes 21.6 72.4 5.8 hamburgers 27.8 67.5 4.3 canned tunafish 28.6 67.0 4.0 spaghetti 19.2 77.3 3 2 tacos, tostadas, sopes, or taco salad (beef) 26.7 69.9 3.1 Mexican meat soup 26.7 70.5 2.3 cheese enchilada 33.9 63.9 1.9 *The core foods are defined as follows: 1. >=10% of population consumes the food item 2-7+ times per week (or) >=65% of population consumes it at least once per month 2. Foods were added to core diet based on information from the calibration study, i.e., the calibration sub-study determined that the food was a major contributer to calorie intake. 252 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix I. Percentage of Subjects Reporting Intake of Corel Foods/Beverages <=15 years Mexico bom 16r25years US-bom >=26 years % change M 1/1 u > Red Meat any beef item2 chili Poultry any chickerVturkey item3 teaum es dried bean or pea soup bdiled dried beans or peas refried beans Vegetables tomato or vegetable soup yellow vegetables^ e.g., com, squash Other frequently consumed green vegetable^1 tomatoes carrots Other green vegetables (zucchini/asparagus/okra) light green lettuce oit tossed salad Fruits tangerines peaches^ apricots, mangoes, or papaya avocados and guacamole pears oranges apples and applesauce bananas orange or grapefruit juice other firuit juices or frUit drinks cantaloupe 65 23 71 44 46 39 33 20 39 48 27 13 26 20 38 21 19 52 35 58 37 19 16 63 22 67 43 43 35 28 19 36 48 28 15 30 19 38 19 20 53 35 61 37 20 18 58 2 1 65 33 37 30 23 21 41 49 32 20 37 18 37 19 19 54 37 65 40 22 20 51 2 1 49 11 21 22 9 15 37 50 29 2 1 46 11 21 12 13 50 34 61 39 22 19 r22% r7% -32% -76% +54% -45% -72% r23% -4% 4% 5% 61% -45% -44% -43% ■+31% -5% -3% 4% 5% 15% 16% Reproduced with permission o f th e copyright owner. Further reproduction prohibited without permission. Appendix I. Percentage 6f Subjects Reporting Intake of Corel Foods/Beverages <=15 years Mexico bom 16-25 years US-bom >=26 years % Change Wftwft Pasta broth with noodles or rice white rice or arroz con polio Mexican or Spanish rice Breads and Cereals com tortillas, com muffins/combread white bread cold cereals cooked cereals whCle wheat or rye bread rbllpi buns, biscuits or flour tortilla Eggs. Milk & Cheese eggs, cooked or raw whCle milk American or Cheddar cheese lowfat milk (1 % or 2%) Margarine; Salad Dressing, etc. mayonnaise in sandwiches salad dressing (regular or low-cal) or mayonnaise margarine added to bread items Beverages regular sodas coffee (regular or decaf) -1 cup or mug beef (regular oriljght)! (Males only) diet sodas 33 29 25 83 40 27 16 25 19 14 40 19 24 11 10 11 48 67 116 11 29 28 24 83 41 27 17 26 23 12 33 20 31 12 12 13 48 73 19 13 22 26 23 78 42 33 25 34 31 15 25 21 38 14 21 23 37 80 22 18 7 14 13 46 42 37 27 44 51 26 18 21 40 27 37 42 28 83 24 27 -79% -51% -47% -45% 6% 38% 66% 77% 169% 85% -55% 9% 139% 251% 291% ^41% 23% 48% 146% “Food items consumed two or more times per week by St least 20% Cf the Mexico bom or US bom population nj ’dark green lettuce, broccoli, dark leafy greens, green beans or peas !j£ 2stew, curry or pot pie, stir fried beef, hamburgers, cheeseburgers, meat loaf or patties, beef steak, shortribs, tacos, enbhiladas ’stew, curry or pot pie, stir fried Chickea chicken wipgs, fried chicken, roasted or baked chitken, turkey, tacos, enchiladas Appendix J. Percent contribution of core* foods to specific nutrients by nativity status total total - - — -... beta dietary Mexico-born calories fat cajcium carotene fiber g ra in s & c e re a l 13.35 9.07 12.39 0.35 11.64 le g u m e s 6.00 5.76 3.28 1.64 17.88 fruit & fruit juice 11.19 4.07 5.94 14.77 23.99 v e g e ta b le s 2.35 1.58 3.53 34.94 8.49 rice & p a s ta 4.55 3.69 1.12 1.52 1.84 red m e a t 3.52 5.83 1.00 1.56 4-02 poultry 0.92 1.45 0.13 0.00 0.00 milk & c h e e s e 5.20 7.74 22.83 0.49 0.01 c o ffe e & s o d a 3.70 1.03 4.10 0.04 0.00 c o n d im e n ts 0.58 0.88 0.50 2.28 1.12 s n a c k s /d e s s e rt 1.88 3.53 0.47 0.00 1.43 alcohol 1.61 0.00 0.52 Q .O O 1.05 calibration stu d y fo o d s 8.86 14.13 11.38 3.45 4.93 Total 63.73 58.76 67.19 61.03 76.41 US-born total calories total fat calcium beta carotene dietary fiber g ra in s & c e re a l 14.48 9.12 11.23 0.25 15.63 le g u m e s 2.83 2.11 1.78 0.06 10.67 fruit & fruit juice 10.46 3.41 5.77 15.99 22.16 v e g e ta b le s 1.59 0.40 2.56 36.20 8.43 rice & p a s ta 2.12 1.16 0.45 1.11 0.99 red m e a t 3.42 5.53 1.01 1.76 4.14 poultry 1.11 1.70 0.17 0.00 0.00 milk & c h e e s e 6.21 9.76 22.16 0.67 0.02 co ffee & s o d a 3.55 2.05 4.55 0.03 0.00 c o n d im e n ts 2.44 5.85 0.67 2.79 1.21 s n a c k s /d e s s e rt 5.08 8.12 1.08 0.09 5.00 alcohol 2.02 0.00 0.69 0.00 1.28 calibration stu d y fo o d s 8.37 12.77 9.16 4.41 4.58 Total 63.70 61.99 61.28 63.35 74.10 •The core diet is specific to each group and is defined as follows: 1. >510% of population consumes the food item 2-7+times per week (or) >=65% of population consumes it at least once per month 2. Foods were added to core diet based on information from the calibration study, i.e., the calibration study determined that the food was a major contributor to calorie intake. 255 R eproduced with permission of the copyright owner. Further reproduction prohibited without permission.
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Monroe, Kristine Robinson
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The effects of dietary and other lifestyle behaviors on the risk of colorectal cancer among the Mexican -origin Latino population
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Epidemiology
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