Common Polymorphisms in the Interleukin-6 Gene and Myocardial Infarction Risk: A Meta-Analysis

BACKGROUND: Interleukin-6 (IL-6) plays a critical role in the development and progression of cardiovascular disease. Emerging evidence suggests that two common polymorphisms (-174 G/C and -572 G/C) in the IL-6 gene might have an impact on an individual's susceptibility to myocardial infarction (MI), but individually published results are inconclusive. This meta-analysis aimed to derive a more precise estimation of the relationship between IL-6 -174 G/C and -572 G/C polymorphisms and MI risk. METHOD: An extensive literary search for relevant studies was conducted in PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM), and China National Knowledge Infrastructure (CNKI) databases from their inception through August 1st, 2013. A meta-analysis was then performed using the STATA 12.0 software. The crude odds ratios (OR) with 95% confidence intervals (CI) were calculated. RESULTS: Eleven case-control studies were included with a total of 10,252 subjects, including 5429 MI patients and 4823 healthy controls. Our meta-analysis results indicated that IL-6 -174 G/C polymorphism may increase the risk of MI (C allele vs. G allele: OR=1.07, 95% CI: 1.01-1.14, p=0.018; GC+CC vs. GG: OR=1.14, 95% CI: 1.04-1.24, p=0.003; respectively). However, our results showed no significant association between IL-6 -572 G/C polymorphism and MI risk (C allele vs. G allele: OR=0.88, 95% CI: 0.75-1.03, p=0.098; GC+CC vs. GG: OR=0.87, 95% CI: 0.70-1.07, p=0.173; respectively). No publication bias was detected in this meta-analysis. CONCLUSION: The current meta-analysis suggests that IL-6 -174 G/C polymorphism may contribute to MI susceptibility. Thus, detection of IL-6 -174 G/C polymorphisms may be a promising biomarker for the early detection of MI. However, IL-6 -572 G/C polymorphism may not associate with the risk of MI.