Frailty mediates the association between activities of daily living disability and depressive symptoms: a prospective cohort study

Background Globally, depression is a serious public health problem and it has a high incidence and recurrence rate. The underlying mechanism between the activities of daily living (ADL) disability and depression was not well understood. Our study aimed to explore the mediating role of frailty on the longitudinal association between ADL disability and depressive symptoms. Methods This study analyzed data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018. A total of 2,245 participants aged ≥45 years old were included. Linear regression, cox regression, and mediation analysis were used to explore the association of ADL disability with development of depressive symptoms and the potential mediating role of frailty. Results The results showed that both scores on ADL and frailty were positively associated with the risk of depressive symptoms (P<0.05). No interaction between ADL and covariates on depressive symptoms was found for all subgroups. The association between ADL disability and depressive symptom scores was partially mediated by frailty (mediated proportion = 16.05%) in the Chinese middle-aged and elderly population. Conclusion There were positive associations between both scores on ADL and frailty and new-onset depressive symptoms. Individuals with high scores on ADL disability had a higher risk of depressive symptoms, and frailty partially mediated this association.