Exploring the relationship between BMI and cognitive function in older adults: The mediating role of recreational physical activity

This study investigates the associations among body mass index (BMI), recreational physical activity, and cognitive function in older adults, and examines whether recreational physical activity mediates the association between BMI and cognitive function. This cross-sectional study used data from 1213 adults aged 60 years and older from the 2011 to 2014 National Health and Nutrition Examination Survey. Multiple linear regression analyses were performed to evaluate the associations among BMI, recreational physical activity, and cognitive function. Mediation analysis was conducted to assess the mediating effect of recreational physical activity. Models were adjusted for age, sex, ethnicity, and smoking status. BMI was negatively associated with cognitive function in the fully adjusted model (β = -0.0074, 95% confidence interval [CI]: -0.0144 to -0.0004, P = .038). Recreational physical activity was positively associated with cognitive function (β = 0.0002, 95% CI: 0.0000-0.0003, P < .005), whereas BMI was negatively associated with recreational physical activity (β = -9.08, 95% CI: -12.80 to -5.36, P < .001). Recreational physical activity partially mediated the association between BMI and cognitive function, accounting for 16.95% of the total effect (P = .0320). Among older adults, higher BMI was associated with lower cognitive function, and recreational physical activity partially mediated this association.