Mechanisms Linking the Number of Chronic Diseases to Health-Related Quality of Life in Older Adults: The Roles of Disability, Depressive Symptoms, and Social Support

This study used longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS; <i>n</i> = 7,900, aged ≥60) to examine the mechanisms linking the number of chronic diseases with health-related quality of life (HRQoL) in older Chinese adults. Chronic diseases were significantly associated with reduced HRQoL (<i>β</i>_total = -0.01, 95% <i>CI</i>: -0.011, -0.009). Disability and depressive symptoms jointly mediated 69% of this effect through independent (<i>β</i>_disability = -0.0027, 95% <i>CI</i>: -0.0031, -0.0022; <i>β</i>_depressive = -0.0034, 95% <i>CI</i>: -0.0039, -0.003) and chain mediation (<i>β</i>_{disability-depressive} = -0.0008, 95% <i>CI</i>: -0.0009, -0.0006). Notably, informal social support moderated this negative relationship (<i>β</i> = 0.002, 95% <i>CI</i>: 0.001, 0.003), while formal social support had no significant impact (<i>β</i> = -0.0002, 95% <i>CI</i>: -0.001, 0.002). This study highlighted the need for interventions targeting management of disability and depressive symptoms, while leveraging informal care networks to mitigate HRQoL decline in the elderly.