Association between multimorbidity and childhood socioeconomic status with depressive symptoms among middle-aged and older adults in rural western China

This study aims to examine the association between multimorbidity and depressive symptoms among rural middle-aged and older adults in Ningxia and the interaction effect of childhood socioeconomic status. On the basis of the 2022 Ningxia Rural Household Health Survey, we analysed a sample of 5567 individuals aged 45 years and older. Propensity score matching and ordered logit regression were conducted to estimate the relationship between multimorbidity and depression; multiple matching methods were used for robustness checks; and interaction effects were examined to assess childhood socioeconomic influences. After full adjustment, both ordered logit and propensity score matching models indicated that multimorbidity was significantly associated with more severe depressive symptoms (β = 0.295, P < 0.01; β = 0.288, P < 0.01). Heterogeneity analyses revealed variation in the association across subgroups, with the largest coefficient estimates observed for male (β = 0.491, P < 0.01), those aged 75 years and older (β = 0.708, P < 0.01), and individuals with no formal schooling (β = 0.418, P < 0.01). Childhood hunger experience (β = -0.627, P < 0.05) and father's education (β = 0.692, P < 0.05) demonstrated a significant interaction effect in the relationship between multimorbidity and depressive symptoms. The negative interaction effect association was significant among individuals with childhood hunger, whereas a positive interaction effect association was observed in those with paternal education levels. Our findings emphazize a robust link between multimorbidity and depressive symptoms in later life, with childhood hunger and paternal education serving as significant moderators of this association.