The Ripple Effect: A Serial Mediation Analysis of Multimorbidity and Depressive Symptoms Among Women in Midlife in China

Purpose: Multimorbidity is a primary risk factor for depressive symptoms, particularly among women in midlife. Guided by stress process theory, this study investigated the underlying mechanisms of this association by testing a serial mediation model involving functional limitations, self-rated health, and life satisfaction. Methods: This study conducted a secondary analysis using data from the fifth wave of the China Health and Retirement Longitudinal Study (CHARLS)-2020. The final analysis included 4,106 women aged 45– 60 years. Multimorbidity was defined as a self-reported diagnosis of two or more out of 14 chronic somatic conditions, and depressive symptoms were assessed using the Center for Epidemiological Studies-Depression (CES-D) scale. The serial mediation analysis was conducted in SPSS using the PROCESS macro via bootstrapping. Results: The prevalence of multimorbidity and depressive symptoms among women in midlife was 10.35% and 41.50%, respectively. Our findings highlight a specific cascade of effects, where functional limitations, self-rated health, and life satisfaction serially and partially mediated the association between multimorbidity and depressive symptoms (total effect c=1.206, 95% CI=0.986 to 1.426; direct effect c′=0.421, 95% CI=0.220 to 0.622; total indirect effect ab=0.785, 95% CI=0.655 to 0.918). However, life satisfaction alone showed no significant mediating effect on the association between multimorbidity and depressive symptoms (a3b3=0.046, 95% CI: − 0.022 to 0.113). Among the seven mediation pathways, self-rated health accounted for the largest mediation effect of the total effect (30.60%), followed by functional limitations (14.26%) and a combination of self-rated health and life satisfaction (8.04%). Conclusion: Our findings offer a comprehensive insight into the complex relationship between multimorbidity and depressive symptoms through various mediating mechanisms under a well-developed theoretical framework. These findings hold significant implications for the prevention and intervention efforts for depressive symptoms among women in midlife, underscoring the pivotal role of alleviating functional limitations, improving self-rated health, and enhancing life satisfaction. Plain Language Summary: Why was this Study Done? Women in midlife often face “multimorbidity”, a well-known risk factor for depression, yet we do not fully understand the step-by-step process of how physical illness leads to mental health challenges. Our team wanted to map the pathway between these conditions to identify where doctors and family members can best provide support. What did the Researchers do and Find? We analyzed data from over 4,100 women in China aged 45 to 60. We looked at how their chronic illnesses affected their daily physical abilities, how they viewed their own health, and how satisfied they felt with their lives. Our study found that:Over 41% of the women experienced symptoms of depression.Physical illness does not just impact mood directly; it creates a “domino effect.” Chronic conditions often lead to functional limitations (difficulty with daily tasks), which causes women to view their health more poorly, eventually lowering their overall life satisfaction.How a woman feels about her health (her self-rated health) was the most powerful factor linking chronic illness to depression. What do these Results Mean? These findings show that supporting the mental health of women in midlife requires more than just treating physical symptoms. To prevent depression, healthcare providers and policy-makers should focus on:Helping women maintain their physical independence in daily life.Providing psychological support to improve how women perceive their own well-being.Creating programs that boost general life satisfaction. By addressing these “middle steps”, we can help break the link between physical illness and emotional distress.