Adiponectin polymorphisms and non-alcoholic fatty liver disease risk: A meta-analysis

Background and Aim: The adiponectin polymorphism has been implicated in susceptibility to non-alcoholic fatty liver disease (NAFLD), but the results remain inconclusive. The aim of this meta-analysis is to investigate the association between adiponectin polymorphisms and NAFLD risk. Methods: All eligible case-control studies published up to September 2013 were identified by searching PubMed, Web of Science, and CNKI. Effect sizes of odds ratio (OR) and 95% confidence interval (95% CI) were calculated by using a fixed- or random-effect model. Results: A total of 10 case-control studies were included; of those, there were nine studies (1223 cases and 1580 controls) for +45T>G polymorphism, seven studies (876 cases and 989 controls) for +276G>T polymorphism, and three studies (299 cases and 383 controls) for -11337C>G polymorphism. Overall, a significantly increased risk was found for +45T>G and -11377C>G polymorphism (+45T>G: OR = 1.45, 95% CI: 1.06-2.00 for recessive model, OR = 1.48, 95% CI: 1.07-2.06 for GG vs TT; -11377C>G: OR = 1.52, 95% CI: 1.10-2.09 for dominant model, OR = 3.88, 95% CI: 1.29-11.68 for GG vs CC), while for +276G>T polymorphism, we found a significantly decreased risk between them (OR = 0.65, 95% CI: 0.45-0.94 for recessive model, OR = 0.58, 95% CI: 0.40-0.84 for TT vs GG). In subgroup analysis by ethnicity, significant association was detected among Asians for +276G>T polymorphism, but not for +45T>G polymorphism. Besides, none of the three adiponectin polymorphisms was associated with the serum adiponectin levels. Conclusion: This meta-analysis suggests that adiponectin +45T>G and -11377C>G polymorphisms might be a risk factor for NAFLD, while +276G>T polymorphism may be a protective factor for NAFLD among Asians.