Objectives: This study examines the extent to which depressive symptoms mediate the link between physical activity and cognitive function among older adults in China.
Methods: This study utilizes the 2013-18 China Health and Retirement Longitudinal Study (CHARLS) dataset, of which 3,658 subjects over the age of 50 satisfied inclusion criteria. Degree of physical activity, prevalence of depressive symptoms, and performance in cognitive function are measured by the International Physical Activity Questionnaire (IPAQ), Center for Epidemiological Studies Depression Scale (CESD), the Mini-Mental State Examination (MMSE) instruments. A structural mediation model was built to assess the degree to which depressive symptoms act as mediator between physical activity and cognitive function.
Results: Physical activity is positively and significantly associated with cognitive function (std β = 0.034, p-value = .007), while physical activity is negatively and significantly associated with prevalence of depressive symptoms (std β = -0.088, p-value < .001). Results indicate that depressive symptoms partially and significantly mediate the relationship between physical activity and cognitive function (std β = 0.003, p-value = .035). Total influence of physical activity on cognitive performance is evaluated to be 0.037 standard deviations (p-value = .035).
Conclusions: Findings uncover an underexamined mental well-being channel through which physical activity can positively influence late adulthood cognition.
Clinical implications: In recommending behavioral modifications to reduce risks of late adulthood cognitive decline, encouraging physical activity for older individuals is key, since it is both directly associated with better cognitive performance, as well as indirectly through lowering prevalence of depressive symptoms.
Keywords: Aging; China; dementia; depression; mini-mental state examination.