Longitudinal Associations Between Physical Activity and Depressive Symptoms in Chinese Children: Evidence from the Tongji Mental Health Cohort Study

Background: We aimed to examine the associations between depressive symptoms and physical activity parameters (e.g., intensity, frequency, and duration) among Chinese school-aged children.

Method: Participants in this study were extracted from the Tongji Mental Health Cohort Study. The baseline survey was conducted in June 2020 involving 2588 school-aged children from two primary schools in Hubei Province, China. A total of 2435 children were followed up successfully in December 2020. The Children's Depression Inventory Short Form (CDI-S) was applied to evaluate depressive symptoms among school-aged children. The Physical Activity Rating Scale-3 (PARS-3) was adopted to estimate children's physical activity parameters including the intensity, frequency, and duration. Generalized estimation equation models were used to explore the longitudinal associations between physical activity and depressive symptoms among school-aged children.

Results: Engaging in moderate levels of physical activity (OR, 0.800; 95%CI, 0.692-0.924) or high levels of physical activity (OR, 0.808; 95%CI, 0.689-0.947) in the baseline survey was associated with a reduced risk of developing depressive symptoms in the follow-up survey compared with children engaging in low levels of physical activity. Stratified analyses revealed that the associations between physical activity and depressive symptoms exhibited a significant correlation among boys and children in the older age group (11-12 years). Our findings showed that engaging in physical activity more than once a week, with each session lasting 20 min or longer, was related to significant reductions in depressive symptoms by 43.8% and 22.3%, respectively.

Conclusion: Self-reported physical activity is positively associated with improved mental health among Chinese school-aged children, especially when considering parameters such as frequency and duration. The association between vigorous-intensity physical activity and depressive symptoms in children should be cautiously interpreted. Future research should continue to explore the effects of vigorous-intensity physical activity on depressive symptoms in children.