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38
Across the 7 cities, a total of 14,434 students and their parents provided consent and
filled out questionnaires. Participants who have completed responses to all measures of
interests were included in the current study. The final sample therefore consisted of 9023
(62.51%) students and their parents who responded to the questionnaires.
Measures
Sedentary behavior
A total of 4 items adapted from the Youth Risk Behavior Surveillance Survey
(YRBSS) were used to measure time spent on 2 sedentary activities: watching TV/video
and using a computer outside of school.(16) For each sedentary activity, participants were
asked to report how much time they spent on school days and on a usual weekend or
holiday, respectively. Reponses to the questions ranging from “none/hardly any”, “< 30
minutes”, “30 - 59 minutes”, “1 – 1.99 hours”, “2 – 2.99 hours”, “3 – 3.99 hours”, and “
4 hours”. The responses were converted into minutes. Minutes spent on an average day
for each sedentary activity were then calculated via the following equation: minutes spent
on an average day = [(minutes spent on school days)*5 + (minutes spent on an average
weekend)*2] / 7. Finally, total minutes spent on sedentary behaviors were obtained by
summing the minutes spent on an average day for watching TV/video and for using a
computer outside of school.
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 49 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 38 Across the 7 cities, a total of 14,434 students and their parents provided consent and filled out questionnaires. Participants who have completed responses to all measures of interests were included in the current study. The final sample therefore consisted of 9023 (62.51%) students and their parents who responded to the questionnaires. Measures Sedentary behavior A total of 4 items adapted from the Youth Risk Behavior Surveillance Survey (YRBSS) were used to measure time spent on 2 sedentary activities: watching TV/video and using a computer outside of school.(16) For each sedentary activity, participants were asked to report how much time they spent on school days and on a usual weekend or holiday, respectively. Reponses to the questions ranging from “none/hardly any”, “< 30 minutes”, “30 - 59 minutes”, “1 – 1.99 hours”, “2 – 2.99 hours”, “3 – 3.99 hours”, and “ 4 hours”. The responses were converted into minutes. Minutes spent on an average day for each sedentary activity were then calculated via the following equation: minutes spent on an average day = [(minutes spent on school days)*5 + (minutes spent on an average weekend)*2] / 7. Finally, total minutes spent on sedentary behaviors were obtained by summing the minutes spent on an average day for watching TV/video and for using a computer outside of school. |
