Gender- and puberty-dependent association between physical activity and depressive symptoms: national survey among Chinese adolescents

Background: The study aims to understand the possible gender difference in the associations between physical activity and depressive symptoms during pubertal transition. Methods: Participants were 30,399 children and adolescents of Han ethnicity from urban and rural areas in 8 cities in China. Physical activity (PA) and depressive symptom was assessed by adapted Youth Risk Behavior Survey and Children Depression Inventory (CDI), respectively. Pubertal development was assessed by trained physicians. Results: In China, over 30% boys and 40% girls reported having no vigorous PA (VPA) or moderate PA (MPA) in the past week. In girls, participating in VPA 1 to 2 days/week showed protective effect for depressive symptoms; whereas in boys, participating in MPA 1 to 2 days/week showed protective effect for depressive symptoms at and after genital stage III (G3). Conclusions: Moderate frequency (1 to 2 days/week) in PA undertaken might be encouraged to prevent depressive symptoms among adolescents.