The interleukin-6 G(–174)C promoter polymorphism in the LURIC cohort: no association with plasma interleukin-6, coronary artery disease, and myocardial infarction

Abstract

IL-6 plasma levels are predictive of major cardiovascular events. Recently a G/C polymorphism at position –174 in the promoter of the IL-6 gene has been associated with differences in both the IL-6 transcription rate in vitro and IL-6 levels in vivo. We examined the association of this polymorphism with coronary artery disease (CAD) and previous myocardial infarction (MI) in 2559 patients with angiographically documented CAD with (n=1365) and without (n=1194) MI and in a control group of 729 individuals in whom CAD had been ruled out angiographically. Assuming dominant or recessive modes of inheritance, carriers of the G allele had odds ratios of 0.98 (95% CI 0.79 – 1.20) and 0.96 (95% CI 0.80 – 1.14), respectively, for CAD, and almost identical ones for previous MI. In subgroups stratified for low cardiovascular risk, the IL-6 promoter polymorphism was also not related to the risk of CAD or MI. In addition, the plasma concentration of IL-6 did not differ between groups with different IL-6 genotypes in 942 randomly selected individuals. We conclude that the IL-6 G(–174)C polymorphism is not associated with the risk of CAD or MI and does not contribute to cardiovascular risk stratification.