Activity Limitation and Risk of Incident Depression Among Middle- Aged and Older Adults in China: Evidence From a Nationally Representative Longitudinal Study

Background With global population aging, depression has become a major public health issue. Although physical inactivity often coexists with depressive symptoms, longitudinal evidence on its impact on depression incidence in low- and middle-income countries remains limited. Objective This study aimed to examine the association between baseline activity limitation and incident depression among middle-aged and older adults in China, and to explore moderating effects of demographic and socioeconomic factors. Methods Data were from the China Health and Retirement Longitudinal Study (CHARLS). A total of 8,406 participants aged ≥ 45 years without depressive symptoms at baseline were followed from 2018 to 2020. Activity limitation was defined as difficulty in at least one Activities of Daily Living (ADL) or Instrumental Activities of Daily Living (IADL). New-onset depression was identified using CESD-10 cutoff scores. Multivariate logistic regression with sequential adjustments and subgroup analyses were performed. Results Over two years, participants with baseline activity limitation had a significantly higher cumulative incidence of depression (22.3%) compared with those without (11.7%, p < 0.001). After adjusting for confounders, activity limitation remained an independent risk factor (OR = 1.35, 95% CI: 1.12–1.62). The association was stronger among men (OR = 1.65, 95% CI: 1.17–2.34), older adults (aged ≥ 60), and those with lower education. A significant interaction was found between activity limitation and gender (P = 0.005). Conclusions Activity limitation is an independent risk factor for incident depression in Chinese middle-aged and older adults. Men and individuals with lower socioeconomic status warrant particular attention. These findings support integrating functional assessments into geriatric mental health screening.