Interleukin-6 gene polymorphisms and susceptibility to liver diseases: A meta-analysis

BACKGROUND: Several studies have explored the associations between interleukin-6 (IL-6) gene polymorphisms and the susceptibility to liver diseases, however, results remain ambiguous. The goal of this study was to conduct a meta-analysis to provide more credible evidence. METHODS: Studies identified in the PubMed, Cochrane Library, and EMBASE databases were used to perform a meta-analysis via the STATA software. Pooled odds ratios (OR) were calculated under fixed- and random-effects models to estimate the potential genetic associations. RESULTS: Twenty-five case-control studies involving 5813 cases and 5298 controls were included in this meta-analysis. Overall, the pooled results suggested that rs1800795 polymorphism was significantly associated with the risk of liver diseases in heterozygote (GC vs CC; OR = 1.57) and dominant (GG+GC vs CC: OR = 1.47) models; rs1800796 polymorphism was significantly associated with the susceptibility to liver diseases in heterozygote (GG vs GC; OR = 0.58) and recessive (GG vs GC+CC: OR = 0.68) models; rs1800797 polymorphism was significantly associated with genetic predisposition to liver diseases in homozygote (GG vs AA: OR = 1.63), heterozygote (GA vs AA; OR = 1.53) and dominant (GG + GA vs AA: OR = 1.61) models. A similar conclusion was found in the HBV, HCV, HCC, NASH and alcoholic liver disease of all ethnic populations for rs1800795; HBV and Asian subgroups for rs1800796; HCV and non-Asian subgroups for rs1800797. However, IL-6 rs2069837 and rs2066992 polymorphisms did not exhibit significant associations with the risk of liver diseases under any genetic models. CONCLUSION: This meta-analysis suggests that patients carrying G (rs1800795), C (rs1800796) or G (rs1800797) allele or genotypes of IL-6 may be more likely to suffer from liver diseases, which was ethnic-dependent.