Polymorphism in the IL6 promoter region is associated with the risk factors and markers of subclinical atherosclerosis in men: The Cardiovascular Risk in Young Finns Study.

OBJECTIVE

Inflammatory factors modify the risk of coronary heart disease. Promoter region genetic polymorphism of inflammatory cytokine interleukin-6 (IL6 -174 G>C) is associated with the variation of IL-6 production. We investigated whether IL6 -174 G>C associates with the risk factors of atherosclerosis and carotid artery compliance (CAC) in young subjects.

METHODS AND RESULTS

As part of the Cardiovascular Risk in Young Finns Study, we performed carotid artery ultrasound examinations, IL6 -174 G>C genotyping and coronary heart disease risk factor determination for 2228 subjects aged 24-39 years. In men CAC was higher for IL6 -174 GG (2.10+/-0.65) than for GC (2.00+/-0.68) or CC (1.95+/-0.63, %/10mmHg, mean+/-S.D., p=0.0221). A similar association was observed for HDL cholesterol (GG 1.22+/-0.29, GC 1.15+/-0.27 and CC 1.14+/-0.28mmol/L, p=0.0015) and apolipoprotein A1 (apoA1) (GG 1.44+/-0.21, GC 1.40+/-0.20, CC 1.38+/-0.21mmol/L, p=0.0118). The opposite genotype effect was present in systolic (GG 127+/-13.1, GC 129+/-13.1, CC 130+/-14.3mmHg, p=0.0382) and diastolic blood pressure (GG 73.8+/-9.14, GC 75.1+/-8.68, CC 75.9+/-9.70mmHg, p=0.0374). The genetic effect size for these parameters was not significant in women.

CONCLUSIONS

IL6 -174 allele G homozygozity associates with beneficial profile of early predictors of atherosclerosis such as high CAC, HDL-C and apoA1 as well as low systolic and diastolic blood pressure in men.