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25
physical activity and lower levels of sedentary behavior may lead to poor metabolic
health outcomes, such as MetS. On the other hand, poor metabolic health may contribute
to declines in physical activity and increases in sedentariness. A recent study in a
nationally representative sample in youth aged 6 to 19 years showed that overweight
youth are significantly less active than normal weight youth, regardless of age.(10) This
suggests that, while inactivity certainly leads to poor metabolic outcomes such as
overweight or MetS, the presence of overweight or MetS might in turn lead to lower
activity levels and more sedentariness, resulting in a vicious circle of increasing inactivity
and worsening metabolic health - physical activity and sedentary behavior can thus be
conceptualized of as both antecedents and consequences of overweight or MetS. In order
to unveil the causal relationships between physical activity, sedentary behavior, and MetS,
more longitudinal investigations that allow for the study of temporal relationships are
needed.
In adults, there is longitudinal evidence indicating that low levels of physical
activity predict the development of MetS.(19, 56, 58, 89, 112) Leisure time physical
activity recorded in middle age man was a significant protector against MetS 28 years
later in life.(89) In another study of 393 adult men and women, increasing levels of
physical activity over a period of 5.6 years was found to reduce metabolic risk
independent of aerobic fitness and body fatness.(58) In children and adolescents,
however, there is a lack of relevant longitudinal research. Two pediatric studies were
found. Raitakari et al(170) showed that persistent physical activity lasting 6 years was
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 36 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 25 physical activity and lower levels of sedentary behavior may lead to poor metabolic health outcomes, such as MetS. On the other hand, poor metabolic health may contribute to declines in physical activity and increases in sedentariness. A recent study in a nationally representative sample in youth aged 6 to 19 years showed that overweight youth are significantly less active than normal weight youth, regardless of age.(10) This suggests that, while inactivity certainly leads to poor metabolic outcomes such as overweight or MetS, the presence of overweight or MetS might in turn lead to lower activity levels and more sedentariness, resulting in a vicious circle of increasing inactivity and worsening metabolic health - physical activity and sedentary behavior can thus be conceptualized of as both antecedents and consequences of overweight or MetS. In order to unveil the causal relationships between physical activity, sedentary behavior, and MetS, more longitudinal investigations that allow for the study of temporal relationships are needed. In adults, there is longitudinal evidence indicating that low levels of physical activity predict the development of MetS.(19, 56, 58, 89, 112) Leisure time physical activity recorded in middle age man was a significant protector against MetS 28 years later in life.(89) In another study of 393 adult men and women, increasing levels of physical activity over a period of 5.6 years was found to reduce metabolic risk independent of aerobic fitness and body fatness.(58) In children and adolescents, however, there is a lack of relevant longitudinal research. Two pediatric studies were found. Raitakari et al(170) showed that persistent physical activity lasting 6 years was |
