Interleukin-6 promoter polymorphism and cardiovascular risk factors: The Health 2000 Survey

Abstract

Objective Inflammatory factors modify the risk of cardiovascular diseases and atherosclerosis. The single base genetic polymorphism in the promoter region of inflammatory cytokine interleukin-6 ( IL6 −174 G>C, rs1800795) is associated with the variation of IL-6 production. The aim of this study was to investigate whether IL6 −174 G>C is associated with the risk factors and early markers of atherosclerosis. Methods As part of Finnish Health 2000 Study, we performed carotid artery ultrasound examinations, IL6 −174 G>C genotyping and cardiovascular risk factor determination for 1334 subjects aged 46–76 years. Results In men, serum total cholesterol was higher in IL6 −174 GG (5.70 ± 0.88 mmol/L) than in the GC (5.51 ± 0.98 mmol/L) or CC (5.38 ± 0.97 mmol/L, mean ± SD, p = 0.0059) groups. The same order was seen in LDL-C (GG 3.64 ± 0.83 mmol/L, GC 3.41 ± 0.88 mmol/L, CC 3.30 ± 0.91 mmol/L, p = 0.0017). The opposite association was observed with plasma fasting glucose levels (GG 5.93 ± 0.97, GC 6.11 ± 1.34, CC 6.34 ± 1.59 mmol/L, p = 0.043) and BMI (GG 26.8 ± 3.42, GC 27.5 ± 4.32, CC 28.0 ± 3.81 kg/m 2, p = 0.027). IL6 −174 allele C homozygous men indicated a trend towards higher systolic blood pressure. IL6 −174 G>C was not associated with carotid artery compliance, intima media thickness or CRP. The effect size of IL6 −174 G>C on cardiovascular risk factors was not significant in women. These results suggest that IL6 −174 G>C modifies the levels of several metabolic risk factors of atherosclerosis in men.