Mediating effect of depressive symptoms on the relationship of chronic pain and cardiovascular diseases among Chinese population: Evidence from the CHARLS

Few studies have examined the direct or indirect effect of chronic pain on cardiovascular diseases (CVD) within Chinese population. The objective aimed to investigate the mediating role of depressive symptoms between chronic pain and CVD. 6522 participants from China Health and Retirement Longitudinal Study were included in this retrospective cohort study. The main endpoint was the occurrence of CVD. Weighted multivariate logistic regression was used to assess the association between chronic pain and depressive symptoms. Distribution-of-product method was employed to examine the mediation effect of depressive symptoms. Subgroup analyses were performed. 219 developed CVD at the end of follow-up period. After adjusting all confounding variables, chronic pain was associated with increased risk of depressive symptoms in total population [odds ratio (OR) = 3.85, 95%confidence interval (CI): 3.35–4.42]. Among total population, there was a positive association of chronic pain and CVD [risk ratio (RR)a = 2.00, 95% CI: 1.33–3.00] (total effect). After further adjusting depressive symptoms, the association between chronic pain and CVD was significant (RRb = 1.67, 95% CI: 1.16–2.41) (direct effect). According to the distribution-of-product test, we observed a mediating effect of depressive symptoms on the relationship between chronic pain and CVD with the percentage of mediation of 32.8%. The mediating effect of depression was observed in individuals of aged 45–65 years old, female participants, participants who never drinking and not have hypertension. Chronic pain was positively associated with CVD for Chinese population, and depressive symptoms was considered to mediate the association between chronic pain and CVD.