Interleukin 6 -174 g/c promoter polymorphism and risk of coronary heart disease: results from the rotterdam study and a meta-analysis.

OBJECTIVE Inflammation plays a pivotal role in the pathogenesis of atherosclerosis. Interleukin (IL) 6 has many inflammatory functions, and the IL-6 -174 G/C promoter polymorphism appears to influence IL-6 levels. Findings of previous studies on the relation between this polymorphism and risk of cardiovascular diseases are inconsistent. We investigated this polymorphism in relation to risk of coronary heart disease (CHD) in a population-based study and meta-analysis. METHODS AND RESULTS Participants (6434) of the Rotterdam Study were genotyped. Analyses on the relation between genotype and CHD were performed using Cox proportional hazards tests, and the association between genotype and plasma levels of IL-6 and C-reactive protein was investigated. All of the analyses were adjusted for age, sex, and common cardiovascular risk factors. A meta-analysis was performed, using a random effects model. No association between genotype and risk of CHD was observed. The polymorphism was not associated with IL-6 levels, but the C-allele was associated with higher C-reactive protein levels (P<0.01). Our meta-analysis did not show a significant association between the genotype and risk of CHD. CONCLUSIONS We conclude that the polymorphism is not a suitable genetic marker for increased risk of CHD in subjects > or =55 years of age.