Nonlinear threshold and association of depressive symptoms with pain in middle-aged and older Chinese adults: a cross-sectional and cohort study

Previous studies have demonstrated a correlation between depressive symptoms and pain events, but the dose-response relationship remains unclear. This study aimed to explore this dose-response and potential non-linear relationship between depressive symptoms and pain in middle-aged and older Chinese adults. Utilizing data from the China Health and Retirement Longitudinal Study (CHARLS), both cross-sectional (n = 16,356) and longitudinal cohort analyses (n = 8204) were conducted. Multivariable logistic regression, Multivariable cox regression, restricted cubic spline (RCS), and threshold effect modeling were employed. After adjusting for demographic characteristics, lifestyle factors and multiple chronic diseases, a significant positive association was found between CESD-10 score and pain (cross-sectional OR = 1.15, 95% CI: 1.14-1.16; longitudinal HR = 1.05, 95% CI: 1.05-1.06). Besides, this association exhibited a nonlinear pattern: it was more pronounced at lower CESD-10 scores (below 13 in cross-sectional study and below 10 in longitudinal study) and attenuated at higher scores though remained significant. Subgroup analysis confirmed the consistency of this association across various strata defined by age, sex, and the presence of conditions such as hypertension or diabetes. The findings indicate that even subclinical depressive symptoms are significantly associated with an increased risk of pain, underscoring the importance of early screening and intervention for mild depressive mood in the context of pain management.