The bidirectional association between the disability in activities of daily living and depression: a longitudinal study in Chinese middle-aged and older adults

Aim: Depression and disability in activities of daily living (ADL) are common in middle-aged and older adults. This study investigated the bidirectional relationship between depression and disability in ADL in Chinese middle-aged and older adults. Methods: Data from a baseline study of 17,596 participants from the China Health and Retirement Longitudinal Study (CHARLS) and two follow-up visits at 4 and 7 years were included. We designed Study A and Study B to explore the interaction between depression and disability in ADL in middle-aged and older people. Results: Individuals with disability in ADL at baseline had adjusted odds ratios (ORs) of 1.331 (1.118, 1.584) and 1.969 (1.585, 2.448) for developing depression compared with those without disability in ADL at the 4- and 7-year follow-ups, respectively. Individuals with depression at baseline had adjusted ORs of 1.353 (1.127, 1.625) and 1.347 (1.130, 1.604), respectively, for developing disability in ADL 4 and 7 years later. Conclusions: There was a bidirectional relationship between depression and disability in ADL. Depression increased the risk of disability in ADL, but this risk did not increase with time, whereas the effect of disability in ADL on depression increased with time.