Page 122 |
Save page Remove page | Previous | 122 of 172 | Next |
|
small (250x250 max)
medium (500x500 max)
Large (1000x1000 max)
Extra Large
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
|
111
is likely that the larger variations in activity levels introduced by the self-reported nature
of the 3DPAR might dilute the differences in activity levels between MetS group. Future
studies with a larger cohort of both MetS and non-MetS individuals are needed to further
investigate this explanation.
Strengths and Limitations
The strengths of this study include the use of both objective and subjective physical
activity measurements, the longitudinal design, and the use of growth curve modeling
that allowed us to model changes in activity patterns at the individual level. Some
limitations of this study warrant consideration. First, only the baseline MetS was
measured. As we know that MetS status is subject to change across puberty,(211) the
potential dynamic changes in MetS status throughout the year was thus not taken into
account when assessing the association between MetS and activity levels. Second, the
relatively small overall sample size and the uneven sample sizes of MetS, pubertal
Tanner stage, and ethnic groups may preclude more detailed exploration of findings and
impede the generalizability of our results. Third, measurement bias of activity levels
could exist considering the self-reported nature of 3DPAR and the fact that the accuracy
of the accelerometry is dependent on activity type (e.g., cannot adequately capture
swimming, biking, and other activities). Fourth, although no significant differences on
demographic characteristics were found between completers and dropouts, bias due to the
high attrition rate may have occurred in the current study.
Object Description
| Title | The vicious cycle of inactivity, obesity, and metabolic health consequences in at-risk pediatric populations |
| Author | Hsu, Ya-Wen |
| Author email | ywxxbirdy@yahoo.com; yawenhsu@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Preventive Medicine (Health Behavior) |
| School | Keck School of Medicine |
| Date defended/completed | 2011-03-09 |
| Date submitted | 2011 |
| Restricted until | Restricted until 26 Apr. 2012. |
| Date published | 2012-04-26 |
| Advisor (committee chair) |
Chou, Chih-Ping Spruijt-Metz, Donna |
| Advisor (committee member) |
Unger, Jennifer B. Azen, Stanley Paul Palinkas, Lawrence A. |
| Abstract | PURPOSE: This dissertation examined the associations between physical activity, sedentary behavior, overweight, and the metabolic syndrome (MetS) in at-risk pediatric populations in the United States and in China. Study 1 identified the independent influences of physical activity, sedentary behavior, and other weight-related correlates on overweight status in Chinese youth. Study 2 explored the influences of physical activity and sedentary behavior on MetS in US minority youth. Study 3 compared the longitudinal trends of physical activity and sedentary behavior between youth with and without MetS in a sample of US minority female youth.; METHODS: Participants were youth (ages 8-18 years) in the United States and in China. Study 1 used baseline data from of a longitudinal smoking prevention and health promotion study conducted in the 7 large cities in China for Chinese youth ages 11-18 years. Study 2 used baseline data from three related pediatric obesity studies that share a set of common methods and measures (US Latino and African American youth ages 8-18 years). Data for Study 3 are from a longitudinal, observation study for Latina and African American female youth ages 8-11 years at baseline.; RESULTS: In Study 1, Chinese youth were more likely to be overweight if they spent more time being sedentary, slept <7 hours/night, were male, were younger, participated more in vigorous physical activity, had higher levels of parental education, better self-perceived health status, a higher frequency of vegetable intake, and a lower frequency of sweet/fast food intake. In Study 2, lower levels of moderate-to-vigorous physical activity (by accelerometry) and higher levels of sedentary behavior (by 3-day physical activity recall) are associated with increased the metabolic risk independent of each other and body composition. In Study 3, a significant decline in MVPA and an increase in sedentary behavior were observed over one year. Sedentary behavior as measured by accelerometry increased 23.42 minutes/per quarterly visit, adding up to 93.68 minutes/per year more in youth with MetS than in those without.; CONCLUSION: Overweight-related correlates seem to play different roles in the Chinese culture than in Western cultures. Findings from this dissertation support a vicious cycle of increasing inactivity, obesity, and metabolic complications. These findings, coupled with longitudinal evidence of the effects of activity levels on obesity and MetS, suggests that physical activity and sedentary behavior could function as antecedents as well as consequences of overweight or MetS in youth. |
| Keyword | Chinese youth; metabolic syndrome; minority youth; obesity; physical activity; sedentary behavior |
| Geographic subject (country) | USA; China |
| Coverage date | 1970/2010 |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m3779 |
| Contributing entity | University of Southern California |
| Rights | Hsu, Ya-Wen |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Hsu-4455 |
| Archival file | uscthesesreloadpub_Volume23/etd-Hsu-4455.pdf |
Description
| Title | Page 122 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 111 is likely that the larger variations in activity levels introduced by the self-reported nature of the 3DPAR might dilute the differences in activity levels between MetS group. Future studies with a larger cohort of both MetS and non-MetS individuals are needed to further investigate this explanation. Strengths and Limitations The strengths of this study include the use of both objective and subjective physical activity measurements, the longitudinal design, and the use of growth curve modeling that allowed us to model changes in activity patterns at the individual level. Some limitations of this study warrant consideration. First, only the baseline MetS was measured. As we know that MetS status is subject to change across puberty,(211) the potential dynamic changes in MetS status throughout the year was thus not taken into account when assessing the association between MetS and activity levels. Second, the relatively small overall sample size and the uneven sample sizes of MetS, pubertal Tanner stage, and ethnic groups may preclude more detailed exploration of findings and impede the generalizability of our results. Third, measurement bias of activity levels could exist considering the self-reported nature of 3DPAR and the fact that the accuracy of the accelerometry is dependent on activity type (e.g., cannot adequately capture swimming, biking, and other activities). Fourth, although no significant differences on demographic characteristics were found between completers and dropouts, bias due to the high attrition rate may have occurred in the current study. |
