Association of physical activity and sedentary behaviour with depressive symptoms in Chinese adults

This study aims to examine the independent and joint associations of physical activity (PA) and sedentary behaviour with depressive symptoms. A population-based cross-sectional study conducted in China included 17,861 adults. PA and sedentary behaviour were assessed using the International Physical Activity Questionnaire. Depressive symptoms were determined by the 9-item Patient Health Questionnaire score >= 10. Logistic regression models were used to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs). The prevalence of depressive symptoms among all participants was 20.6% (3679/17861). Higher levels of PA were inversely associated with depressive symptoms, whereas prolonged sedentary behaviour was associated with increased odds of depressive symptoms. The positive associations between sedentary behaviour and depressive symptoms remained significant, regardless of PA levels. In joint analyses, the depressive symptoms OR comparing adults who reported low level of PA with the highest tertile of sedentary behaviour to those reporting high level of PA with the lowest tertile of sedentary behaviour was 1.99 (95% CI 1.64 to 2.40). This study indicated that high level of PA may not offset the increased risk of depressive symptoms associated with high amounts of sedentary behaviour, and therefore these behaviours should be considered jointly to obtain optimal prevention effects.