Association Between IL6-174 G/C Polymorphism and Graves' Disease: A Systematic Review and Meta-Analysis

Several studies have evaluated the association between interleukin-6 (IL-6) -174 G/C polymorphism and Graves' disease (GD); however, the results have been inconsistent. In the current study, a meta-analysis was performed to assess the association of IL6 -174 G/C polymorphism with Graves' disease. Medline, EMBASE, and Web of Science databases were searched to identify all eligible studies published before August 2016. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated to assess the strength of association in dominant, recessive, allelic, homozygotes contrast, and heterozygotes contrast models. A total of four case-control studies with 554 GD cases and 1201 healthy controls were included in this meta-analysis. In the combined analysis, the results showed significant association between the IL6 -174 G/C polymorphism and the risk for GD in dominant model (OR=1.39, 95% CI: 1.07-1.80), recessive model (OR=2.75, 95% CI: 1.01-7.55) and homozygote contrast model (OR=3.25, 95% CI: 1.1-9.58). No publication bias was found in the current study (all P>0.05). The meta-analysis results suggested that the IL6 -174 G/C polymorphism was indicated to be associated with the risk of GD. Further studies are warranted to confirm these results.