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79
Self-reported physical activity data
3DPAR was used to assess self-reported activity levels.(164, 219) 3DPAR has been
validated in adolescents.(164) Students identified different activities (from a list of 71
activities provided) to describe their activity in half-hour intervals during a day from 7:00
am – 12:00 am for three days, and rated how much effort (intensity level) they put into
each activity (light, moderate, hard, or very hard). Activity types were converted into
half-hour blocks of either light, moderate, or vigorous physical activity using a
combination of the intensity ratings provided by the participants and the compendium of
physical activities.(1) MVPA ( 4 METs) was created to be consistent to the
accelerometry variable. Half-hour blocks spent watching television/movies, playing video
games/surfing the internet, and talking on phone were coded separately as sedentary
behaviors. Daily total time spent in MVPA and sedentary behavior was obtained by
summing over the half-hour blocks over one day. Mean minutes per day was then
obtained by averaging total minutes across three days.
Statistical analysis
Participants with complete data included in the present study were compared to
participants without complete data on demographic variables and MetS using
independent samples t tests or chi-square tests.
For the preliminary analyses, participants were dichotomized into those with and
without MetS. Independent sample t-tests and chi-square tests were conducted to
compare demographic variables between these two groups. Differences in MVPA and
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 90 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 79 Self-reported physical activity data 3DPAR was used to assess self-reported activity levels.(164, 219) 3DPAR has been validated in adolescents.(164) Students identified different activities (from a list of 71 activities provided) to describe their activity in half-hour intervals during a day from 7:00 am – 12:00 am for three days, and rated how much effort (intensity level) they put into each activity (light, moderate, hard, or very hard). Activity types were converted into half-hour blocks of either light, moderate, or vigorous physical activity using a combination of the intensity ratings provided by the participants and the compendium of physical activities.(1) MVPA ( 4 METs) was created to be consistent to the accelerometry variable. Half-hour blocks spent watching television/movies, playing video games/surfing the internet, and talking on phone were coded separately as sedentary behaviors. Daily total time spent in MVPA and sedentary behavior was obtained by summing over the half-hour blocks over one day. Mean minutes per day was then obtained by averaging total minutes across three days. Statistical analysis Participants with complete data included in the present study were compared to participants without complete data on demographic variables and MetS using independent samples t tests or chi-square tests. For the preliminary analyses, participants were dichotomized into those with and without MetS. Independent sample t-tests and chi-square tests were conducted to compare demographic variables between these two groups. Differences in MVPA and |
