The mediating effect of activities of daily living (ADL) disability on the association between depressive symptoms and cognitive impairment in older adults: a national study

Abstract Background Numerous studies have demonstrated a correlation between depressive symptoms and a higher likelihood of cognitive impairment among older adults. Little is known about the underlying pathway connecting these two conditions. Objective This study aimed to investigate whether functional ability potentially mediates the relationship between depressive symptoms and cognitive impairment. Methods A total of 6623 Chinese older adults aged 60 years and above from the 2018 China Longitudinal Healthy Longevity Survey (CLHLS) were included in this study. Binary logistic regression was conducted to examine the relationships among cognitive impairment, depressive symptoms, and ADL disability while accounting for all confounding factors. Mediation analyses were performed to examine whether activities of daily living (ADL) disability mediate the relationship between depressive symptoms and cognitive impairment via PROCESS macro version 4.0. Results The results indicated that the relationship between depressive symptoms and cognitive impairment was significantly mediated by ADL disability (estimated indirect effect = 0.024, bootstrapped SE = 0.011, bootstrapped standard 95% CI = 0.004–0.050). When stratified by gender, the mediating effect of ADL ability was observed only in men (estimated indirect effect = 0.034, bootstrapped SE = 0.019, bootstrapped standard 95% CI = 0.002–0.075). Conclusion This study revealed that ADL disability could partially mediate the relationship between depressive symptoms and cognitive impairment in older adults. Furthermore, there may be a gender difference in this mediating role, indicating that enhancing physical function in men experiencing depressive symptoms potentially help prevent cognitive decline.