Associations of cardiometabolic disease and depression with changes in instrumental activities of daily living disability among middle-aged and older adults

This study examined the independent and joint associations of cardiometabolic disease (CMD) and depression with changes in instrumental activities of daily living (IADL) disability among middle-aged and older adults. Longitudinal data were obtained from 16,780 individuals aged ≥ 45 years in the China Family Panel Studies from 2012 to 2020. Changes in IADL disability were assessed using transitions and trajectories. Mixed-effects models, Cox proportional hazards models, and multinomial logistic regression were applied, and joint associations were evaluated using multiplicative and additive interactions. CMD and depression were associated with higher IADL disability scores. Single CMD, cardiometabolic multimorbidity (CMM), and depression were associated with increased risks of new-onset and persistent disability, a higher likelihood of severe disability trajectories, and a lower likelihood of recovery. The combination of CMM and depression showed evidence of multiplicative and additive interaction for IADL disability scores, with a broadly consistent adverse additive interaction pattern across new-onset disability, persistent disability, and severe disability trajectories. These findings suggest that CMD and depression are independently associated with adverse changes in IADL disability, with CMM and depression showing an additional adverse joint association. Integrated management of physical and mental health may help reduce disability in ageing populations.