Interleukin-10 (IL-10) is a cytokine with pleiotropic properties. Limited biochemical and clinical evidence suggest a link between IL-10 and coronary heart disease (CHD). However, more data are needed to clarify the relationship between IL-10 and risk for CHD events.
Methods: The present study was a secondary analysis of the estrogen replacement and atherosclerosis (ERA) trial, a randomized clinical trial that examined the effects of hormone replacement therapy on post-menopausal women with known coronary atherosclerosis. IL-10 concentration, measured at baseline, was treated as both a continuous and categorical variable. Cox proportional hazards models were used to compute hazard ratios as estimates of relative risk for CHD events.
Results: There were 71 events over an average 3.2 year follow-up. Incident rates were higher for individuals with IL-10 concentrations equal to or greater than the median level (1.04 pg/mL) compared to those individuals below the median level (30% versus 18.5%, p=0.02). The cumulative incidence of CHD events was significantly greater in individuals with IL-10 concentrations >or=1.04 pg/mL (p=0.01). A one standard deviation increase in baseline IL-10 concentration was associated with a 34% greater risk of a CHD event (HR 1.34 [1.06-1.68], p=0.01). This elevated risk was not altered by interleukin-6, C-reactive protein, or additional cardiovascular risk factors. IL-10 concentration and risk for CHD events was most pronounced in diabetics (HR 2.4 [1.46-3.83], p=0.0005).
Conclusion: In the ERA trial, elevated IL-10 concentration was associated with an increased risk for future cardiovascular events in post-menopausal women with established coronary atherosclerosis. Further study of the relationship between IL-10 and the pathogenesis and progression of atherosclerosis and cardiovascular events is warranted.