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

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 perpendicular to 1.59 mmol/L, p = 0.043) and BMI (GG 26.8 perpendicular to 3.42, GC 27.5 perpendicular to 4.32, CC 28.0 perpendicular to 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. (C) 2009 Elsevier Ireland Ltd. All rights reserved.