Physical activity as a protective factor against depressive symptoms in older Chinese veterans in the community: result from a national cross-sectional study

BACKGROUND Physical activity is generally considered to be effective in reducing the prevalence of depression and promoting remission of its symptoms. However, large-scale epidemiological research on this issue is lacking in older Chinese adults. We performed a nationwide epidemiological survey to determine the relationship between physical activity and depressive symptoms in older Chinese veterans in the community, with adjustment for potential confounders. METHODS A cross-sectional study was conducted in a representative sample of 9,676 community-dwelling older Chinese veterans. Depressive symptoms were identified using the Center for Epidemiological Studies Depression Scale. Physical activity was self-reported using a one-year physical activity questionnaire. Information about covariates was obtained by questionnaire-based interview. Relationships between study variables and symptoms of depression were estimated using unadjusted and adjusted analyses. RESULTS The median age was 82.29 (interquartile range 80.25-84.60) years. In total, 81.84% of the study participants engaged in physical activity that was predominantly light in intensity. In unadjusted analyses, physical activity was associated with a significantly decreased likelihood of depressive symptoms (5.43% versus 18.83%, P<0.0001). Multivariate logistic regression with adjustment and controlling for confounders, physical activity was still inversely associated with depressive symptoms and was the only independent protective factor (odds ratio 0.57, 95% confidence interval 0.44-0.72, P<0.0001) among the associated factors in this study. In a univariate general linear model, there was a significant difference in Center for Epidemiological Studies Depression Scale score between subjects participating in active physical activity and those who did not (F=59.07, P<0.0001). CONCLUSION This study found an inverse relationship between physical activity and symptoms of depression in older Chinese veterans in the community. It was also indicated that the antidepressant effect of physical activity probably extended to the oldest-old, and the light-intensity physical activity was probably available for the same protective effect. This information could be used to devise further interventions to prevent or ameliorate symptoms of depression.