Association Between cMIND Diet and Depressive Symptoms Among Chinese Older Adults: A Cross-Sectional Study

Background: With accelerated population aging, depressive symptoms in later life have become a major public health issue. The Chinese version of the MIND (cMIND) diet is a neuroprotective dietary pattern adapted to Chinese dietary habits. Previous studies have found that adherence to the cMIND diet is associated with lower levels of depressive symptoms, but the underlying statistical association patterns remain unclear. This study adopted a statistical moderated mediation framework to characterize cross-sectional associations, to examine the direct association between cMIND diet adherence and depressive symptoms, the statistical associational mediating pattern of social participation, and the exploratory moderating effect of exercise on the first segment of the statistical mediation chain. Methods: Data were drawn from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), including 8578 adults aged 65 years and older. Cross-sectional mediation and moderated mediation analyses were conducted using Model 4 and Model 7 of the PROCESS macro, with 5000 bootstrap resamples to test the significance of cross-sectional statistical indirect effects. Results: cMIND diet adherence was negatively associated with depressive symptoms (B = -0.414, p < 0.01). Social participation showed a statistical partial mediation pattern in this association, with the statistical indirect effect accounting for 14.02% of the total effect. Exploratory moderated mediation analysis showed that exercise moderated the first segment of the statistical mediation chain (B = 0.283, p < 0.01). The positive association between cMIND diet adherence and social participation was stronger among exercisers (simple slope = 0.635, p < 0.01) than among non-exercisers (simple slope = 0.352, p < 0.01). Correspondingly, the indirect association between cMIND diet adherence and depressive symptoms through social participation was stronger in the exercise group (indirect effect = -0.064, 95% CI [-0.079, -0.050]) than in the non-exercise group (indirect effect = -0.036, 95% CI [-0.045, -0.026]). Conclusions: Among Chinese older adults, higher adherence to the cMIND diet is significantly associated with lower levels of depressive symptoms, and this association shows a partial statistical mediation pattern linked to higher social participation. The positive association between cMIND diet adherence and social participation is more pronounced among adults who engage in regular exercise, which corresponds to a more pronounced statistical indirect association with depressive symptoms through social participation. As these findings are based on cross-sectional data and reflect only associational patterns, and given the limited effect magnitude, they provide only preliminary theoretical reference for the development of intervention strategies integrating dietary improvement and social participation promotion for late-life depressive symptoms.