Impact of life satisfaction on chronic diseases in aging populations: Exploring the mediating effects of depressive symptoms and frailty

BACKGROUND: This study investigates the relationship between life satisfaction and chronic disease development in older adults, with depressive symptoms and frailty serving as mediating factors. METHOD: This study utilized data from the 2011 and 2018 China Health and Retirement Longitudinal Study (CHARLS), comprising 7809 middle-aged and older Chinese adults. Life satisfaction (including health, marriage, children relationship satisfaction, and air quality satisfaction) and chronic disease diagnosis were assessed, using self-reported questionnaires. Depressive symptoms were measured using the CES-D-10 scale, while frailty was evaluated by the FFP criterion. Negative binomial regression and logistic regression models were used to investigate associations among life satisfaction and chronic diseases, calculating incidence rate ratios (IRR) and odds ratios (OR). Additionally, mediation analysis was performed to examine whether depression and frailty mediated the relationship between life satisfaction and chronic diseases. Sensitivity and subgroup analyses confirmed the robustness of our findings. RESULT: Our results showed that life satisfaction was significantly associated with a reduced prevalence of chronic diseases in middle-aged and older adults (IRR = 0.87; 95 % CI: 0.85-0.88; p < 0.001). Significant associations were observed from four types of satisfaction, including satisfactions of health (IRR = 0.77; 95 % CI: 0.75-0.78; p < 0.001), marriage (IRR = 0.95; 95 % CI: 0.94-0.97; p < 0.001), children relationship (IRR = 0.93; 95 % CI: 0.91-0.95; p < 0.001) and air quality (IRR = 0.94; 95 % CI: 0.92-0.96; p < 0.001). Mediation analysis further revealed that depression and frailty partially mediated the relationship between life satisfaction and chronic diseases, accounting for 19.4 % and 7.3 %. CONCLUSION: These findings indicate that higher life satisfaction is associated with a lower burden of chronic diseases among middle-aged and older adults. Depressive symptoms and frailty statistically accounted for part of this association, emphasizing the need to address both psychological and physical factors to reduce burden of chronic disease burden in aging populations.