INTERLEUKIN-6 PROMOTOR-634C/G POLYMORPHISM IS ASSOCIATED WITH ATRIAL FIBRILLATION IN ELDERLY HAN CHINESE PATIENTS WITH ESSENTIAL HYPERTENSION

Objectives There is an accumulating body of evidence indicating strong association between inflammation and the pathogenesis of atrial fibrillation (AF). Interleukin-6 (IL-6) is a pleiotropic cytokine, functions as a mediator of inflammatory response and has both pro-inflammatory and anti-inflammatory properties. Three single nucleotide polymorphisms (SNPs) in the IL-6 promoter region (−597G/A; −634C/G and −174G/C) have been reported to influence IL-6 transcription, and −174G/C was in tight linkage disequilibrium with −597G/A. The −174C allele is extremely rare and the −634C allele is common in eastern Asian populations. The aim of the present study is to investigate the association of −634C>G polymorphism of IL-6 gene with AF in elderly Han Chinese patients with essential hypertension (EH). Methods A total of 169 elderly patients with EH were eligible for this study. Patients with AF (n=75) were allocated to the AF group, and 94 subjects without AF to the control group. The PCR-based restriction fragment length polymorphism (PCR-RFLP) technique was used to assess the genotypes frequencies. Results The distribution of the IL-6 −634C>G genotypes (CC, CG, and GG) was 67.02%, 30.85%, and 2.13% in the controls, and 50.67%, 40.00%, and 9.33% in AF subjects, respectively (p=0.0312). The frequency of the G allele in the AF group was significantly higher than that in the control group (29.33% vs 17.55%, p=0.0103). Compared with the wild type CC, the G allele carriers (CG+GG genotypes) had increased risk of AF in both unadjusted (OR=1.98, 95% CI 1.06 to 3.69, p=0.0312) and adjusted analyses (OR=1.93, 95% CI 1.04 to 3.57, p=0.0364). Conclusions These findings suggest that IL-6 −634C>G polymorphism is associated with AF and the G allele is an independent risk for AF in elderly Han Chinese patients with EH.