Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 55 11 2018 01 02 665 671 EN Danyal Imani Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Ramazan Rezaei Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Bahman Razi Department of Hematology, School of Align Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Shahab Alizadeh Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. Mahdi Mahmoudi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran. AND Rheumatology Expert Group (REG), Universal Scientific Education and Research Network (USERN), Tehran, Iran. 2017 02 05 2017 04 25 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. https://acta.tums.ac.ir/index.php/acta/article/view/6205 https://acta.tums.ac.ir/index.php/acta/article/download/6205/5021