Association Between Obesity, Physical Activityand Mental Health Among Junior High School Students In Xuzhou

Background Obesity contributes to the onset and maintenance of various serious health problems in adolescents. In addition, mental health is found to be predictive of developing obesity, even impacts the life quality in adulthood. According to decreasing of physical activity among adolescents in21centry, insufficient physical activity (PA) has been one of the main public health problems. Because regular PA can reduce the incidence of depressive and anxiety symptoms, lessen the perceived psychosocial stress. So this research is focus on the relationships between PA, obesity and mental health among adolescents in Xuzhou.Objectives To describe prevalence of obesity, physical activity(PA), and mental health among junior high school students in in Xuzhou, Jiangsu province, and to test the relationships between obesity, PA and self-reported psychological problems among adolescents.Methods A cross-sectional survey was conducted in junior high schools of Xuzhou city in China. In2011, all the participants from5junior high schools were instructed to self-report informations on sociodemographic data, dietary intake, self-reported PA, self-reported sedentray behaviors (including ST) and psychological health (including depressive symtoms, anxiety symptoms). Meantime, height and weight were measured to calculate body-mass index (BMI). Adolescents were classified as obese according to Chinese age and gender-specific cutoff points.Descriptive analyses were performed on adolescents’sociodemographic characteristics. The Pearson chi-square tests were used to compare the proportions of the independent variables versus dependent variables. Logistic regression analyses were used to analyze the possible factors affecting obesity and PA, and furthermore explore the effects of obesity and PA on adolescents’ psychological problems.Results A total of3103valid questionnaires and physique measure were retained for analysis(Male51.1%, Female48.9%). The prevalence rates of overweight and obesity were20.9%and17.1%. The prevalence rates on depressive symptoms was14.6%, anxiety symptoms was16.6%in Xuzhou city. Adolescents self-reported rates of participating in sufficient moderate, vigorous and insufficient PA were12.9%、36.1%and60.5%, respectively. And approximately11.1%of the adolescents were exposed to ST for more than2h·d-1. After adjusting on screen time, obesity and other potential confounders, participants who had insufficient PA was positively associated with depressive (OR=1.18,95%CI=1.02-1.37) and anxiety symptoms (OR=1.15,95%CI=1.01-1.30). Insufficient PA as a moderate effect enhanced the association between obesity and depressive symptoms in junior high school students OR from1.33to1.50.Conclusion Obesity and insufficient PA were closely related to the presence of mental health among junior high school students in Xuzhou. Insufficient PA moderated the association between obesity and depressive symptoms in junior high school boys.