Interleukin‐6 gene polymorphism is an age‐dependent risk factor for myocardial infarction in men

Abstract

Several studies show that inflammatory components may contribute to atherosclerosis and increase the risk for myocardial infarction (MI). Interleukin-6 (IL-6) is a key pro-inflammatory and immune-modulatory cytokine of relevance for cardiovascular diseases. In this case-control study, 200 patients with MI and 257 healthy controls were genotyped for the polymorphism present in -174 promoter region of the IL-6 gene. Plasma concentrations of IL-6 and C-reactive protein (CRP) in a group of patients and controls were measured. The -174 C allele was associated with an increased risk of developing MI (OR = 2.886, c.i. = 1.801-4.624, P = 0.0001) in older patients, while no association was found in younger ones. The IL-6 plasma levels were higher in patients with MI carrying the CC genotype than in GG patients (CC carriers, IL-6 = 2.97 pg mL(-1) vs. GG carriers = 1.81 pg mL(-1), P = 0.016). A positive correlation of IL-6 levels with those of CRP in serum from patients with MI was also found. Data from this study suggest that the C allele of the promoter polymorphism in the IL-6 gene is a risk factor for MI in the elderly, and the production of the IL-6 is differentially affected by different genotypes of the IL-6 -174 promoter polymorphism.