Association between education level and depressive symptom trajectories in middle-aged and older Chinese adults: a nationally representative cohort study

Abstract Background Previous studies reported that education level was associated with depressive symptoms, but its impact on various long-term depressive symptom trajectories has not been assessed. This study aimed to explore the association between education level and depressive symptom trajectories in middle-aged and older Chinese individuals. Methods We utilized data from the China Health and Retirement Longitudinal Study (CHARLS). Depressive symptoms across five waves from 2011 to 2020 were evaluated using the 10-item Center for Epidemiologic Studies Depression Scale (CESD-10). Group-based trajectory modeling (GBTM) was used to identify diverse patterns of depressive symptom trajectories. Multivariable logistic regressions were conducted to assess the association between education level and depressive symptom trajectories. Additionally, we conducted stratified analyses across clinically relevant subgroups and performed comprehensive sensitivity analyses to evaluate the robustness of our findings. Results A total of 6,173 participants were included in our study. Two depressive-symptom trajectories were identified based on the GBTM analysis. After adjusting for potential covariates, education level was inversely associated with depressive symptoms. Specifically, Individuals with middle school, high school, and college and above education had ORs of 0.70 (95% CI: 0.61–0.80, P < 0.001), 0.62 (95% CI: 0.51–0.75, P < 0.001), and 0.56 (95% CI: 0.34–0.95, P = 0.030), respectively, compared to those with an elementary school or below education. Moreover, stratified analyses across predefined subgroups and sensitivity analyses under different model specifications confirmed the robustness of the outcomes. Conclusions The findings suggest that higher education levels were associated with a more favorable trajectory of depressive symptoms. However, given the observational nature of this study, prospective or Mendelian randomization investigations are warranted to further examine this relationship.