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.