The role of inflammatory markers in explaining the association between depression and cardiovascular hospitalisations.

This study investigated whether inflammation may explain the relationship between depression and incident cardiovascular hospitalisations. Participants (55-85 years) completed baseline depression and physical assessment. Those without self-reported cardiovascular events were followed prospectively for hospital admissions for angina, myocardial infarction and cerebral infarction (median 937 days). Across 5140 person-years of risk (N = 1692), there were 47 incident cardiovascular hospitalisations (2.8 %). Controlling for age and gender, interleukin (IL)-6, C-reactive protein (CRP), body mass index (BMI) and waist-to-hip ratio were associated with future cardiovascular events. Mediation analysis showed that CRP accounted for 8.1 % and IL-6 10.9 % of the effect of depression on cardiovascular events, and including the indirect effect in the model substantially reduced the direct relationship between depression and cardiovascular hospitalisations. BMI and waist-to-hip ratio accounted for indirect effects of 7.7 and 10.4 %, respectively. Inflammatory markers partly explain the association between depression and cardiovascular events, although other shared factors also likely contribute.