Depression mediates the association between physical inactivity and cognitive impairment in Korean older adults.

BACKGROUND: This study investigated the association between physical activity and cognitive impairment in older adults. METHODS: Data from 10245 Korean adults (4428 men and 5817 women) who participated in the 2008 baseline survey of the living profiles of older people survey were used for this analysis. Compared with low PA men, moderate PA men only had significantly lower odds-ratio (OR) and 95% confidence interval (95% CI) (OR=0.795, 95% CI: 0.654~0.965, P=0.021) for having cognitive impairment even after adjusting for measured covariates, which was no longer significant when additionally adjusted for depressive symptoms (OR=0.862, 95% CI: 0.707~1.051, P=0.143). RESULTS: Compared with low PA women, moderate- and high PA women had significantly lower risks of cognitive impairment (OR=0.830, 95% CI: 0.712~0.969, P=0.018 and OR=0.784, 95% CI: 0.651~0.943, P=0.010, respectively) even after adjusted for the measured covariates, which was no longer significant when additionally adjusted for depressive symptoms (OR=0.897, 95% CI: 0.776~1.049, P=0.173 and OR=0.919, 95% CI: 0.761~1.111, P=0.385, respectively). CONCLUSIONS: These findings suggest that depression mediates the inverse relationship between physical activity and cognitive decline among older adults.