Physical activity, body mass index and mental health in Chinese adolescents: a population based study

The aim of the present study was to examine the association between physical activity, BMI level and mental health among Chinese adolescents.

Three thousand ninety-six adolescents aged 11 to 13 were analyzed from 6 middle schools of Xuzhou. Physical activity level was measured using self-designed questionnaires. BMI was calculated according to the results of these students' physical examinations. Anxiety symptoms were assessed by using the Screen for Child Anxiety Related Emotional Disorder, depression via the Children's Depression Inventory. Data were analyzed using chi-square test and logistic regression.

Adolescents' self-reported rate of insufficient physical activity was 58.1%. The overweight and obesity rates were 18.4%, 16.0%. The point prevalence rates on anxiety and depression were 15.2%, 11.5%. Insufficient physical activity was positively associated with anxiety and depression (OR [95%CI]: 1.31 [1.06-1.63]; 1.33 [1.04-1.70]). Obesity was positively associated with depression (OR [95%CI]: 1.48 [1.10-2.00]). IS-OB was positively associated with anxiety and depressive (OR [95%CI]: 1.71 [1.19-2.45]; 1.99 [1.33-2.97]).

Physical inactivity and overweight/obesity were negatively association with mental health of adolescents, respectively. Meanwhile, to explore the combined effects of physical inactivity and obesity would increase the risk of anxiety and depression in adolescents.