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106
differences in both initial MVPA and initial sedentary behavior by MetS status were
found. There were statistically significant linear associations between longitudinal
changes in activity levels and visit. In the study sample, MVPA declined on an average of
2.17 minutes (-4.67%) per quarterly assessment (p=0.004), adding up to 8.68 minutes
(-18.67%) per year decline and sedentary behavior increased by 5.21 minutes (1.24%) per
quarterly assessment (p=0.002), adding up to 20.84 (4.97%) minutes per year increase,
after adjusting for age, ethnicity, pubertal Tanner stage, fat mass, and lean tissue mass.
When comparing the MetS-related rates of change in activity levels, sedentary behavior
increased 23.42 minutes/per quarterly visit, adding up to 93.68 minutes/per year more in
youth with MetS than in those without (p=0.014).
Table 4-5 shows the effects of baseline MetS status on initial levels and
subsequent changes in MVPA and sedentary behavior by 3DPAR. MVPA declined by
8.64 minutes in MVPA (-7.34%) per visit adding up to 34.56 minutes (-29.36%) over a
year in our sample (p=0.014). At the baseline, Latina youth spent an average of 54.89
minutes more in sedentary behavior than African Americans (p=0.008). Baseline MetS
status had no effects on either the initial levels or the subsequent rate of change in MVPA
and sedentary behavior over time.
4.4 DISCUSSION
This study is one of the few longitudinal studies to examine the developmental
trajectory of activity levels in minority adolescent girls. Consistent with other
studies,(165, 200) we observed both a significant decline in MVPA and an increase in
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 117 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 106 differences in both initial MVPA and initial sedentary behavior by MetS status were found. There were statistically significant linear associations between longitudinal changes in activity levels and visit. In the study sample, MVPA declined on an average of 2.17 minutes (-4.67%) per quarterly assessment (p=0.004), adding up to 8.68 minutes (-18.67%) per year decline and sedentary behavior increased by 5.21 minutes (1.24%) per quarterly assessment (p=0.002), adding up to 20.84 (4.97%) minutes per year increase, after adjusting for age, ethnicity, pubertal Tanner stage, fat mass, and lean tissue mass. When comparing the MetS-related rates of change in activity levels, sedentary behavior increased 23.42 minutes/per quarterly visit, adding up to 93.68 minutes/per year more in youth with MetS than in those without (p=0.014). Table 4-5 shows the effects of baseline MetS status on initial levels and subsequent changes in MVPA and sedentary behavior by 3DPAR. MVPA declined by 8.64 minutes in MVPA (-7.34%) per visit adding up to 34.56 minutes (-29.36%) over a year in our sample (p=0.014). At the baseline, Latina youth spent an average of 54.89 minutes more in sedentary behavior than African Americans (p=0.008). Baseline MetS status had no effects on either the initial levels or the subsequent rate of change in MVPA and sedentary behavior over time. 4.4 DISCUSSION This study is one of the few longitudinal studies to examine the developmental trajectory of activity levels in minority adolescent girls. Consistent with other studies,(165, 200) we observed both a significant decline in MVPA and an increase in |
