Adiponectin gene polymorphisms and risk of gestational diabetes mellitus: A meta-analysis

Background Adiponectin (ADIPOQ) is an important factor involved in the regulation of both carbohydrate and lipid metabolism. Polymorphisms in the ADIPOQ gene are known to influence an individual's predisposition to metabolic syndrome and type 2 diabetes. Moreover, women with gestational diabetes mellitus (GDM) are at an increased risk of developing type 2 diabetes. Several studies have been conducted previously to assess the association between ADIPOQ polymorphisms and GDM; however, the results of the association are inconclusive. Aim To quantitatively evaluate the association between ADIPOQ +45T/G, +276G/T, and -11377C/G polymorphisms and the risk of GDM. Methods A systematic search of EMBASE, PubMed, CNKI, Web of Science, and WANFANG DATA was conducted up to October 20, 2018. We calculated merged odds ratios (ORs) with 95% confidence intervals (CIs) using a fixed-effects or random-effects model depending on the between-study heterogeneity to evaluate the association between AIDPOQ +45T/G, +276G/T, and -11377C/G polymorphisms and the risk of GDM. Subgroup analysis was performed by ethnicity. Publication and sensitivity bias analyses were performed to test the robustness of the association. All statistical analyses were conducted using Stata12.0. Results Nine studies of +45T/G included 1024 GDM cases and 1059 controls, five studies of +276G/T included 590 GDM cases and 595 controls, and five studies of -11377C/G included 722 GDM cases and 791 controls. Pooled ORs indicated that +45T/G increased GDM risk in Asians (allelic model: OR = 1.47, 95%CI: 1.27-1.70, P = 0.000; dominant model: OR = 1.54, 95%CI: 1.27-1.85, P = 0.000; recessive model: OR=2.00, 95%CI: 1.43-2.85, P = 0.000), not in South Americans (allelic model: OR = 1.21, 95%CI: 0.68-2.41, P = 0.510; dominant model: OR = 1.13, 95%CI: 0.59-2.15, P = 0.710; recessive model: OR = 2.18, 95%CI: 0.43-11.07, P = 0.350). There were no significant associations between +276G/T (allelic model: OR = 0.88, 95%CI: 0.74-1.05, P = 0.158; dominant model: OR = 0.91, 95%CI: 0.65-1.26, P = 0.561; recessive model: OR = 0.82, 95%CI: 0.64-1.05, P = 0.118) or -11377C/G (allelic model: OR = 0.96, 95%CI: 0.72-1.26, P = 0.750; dominant model: OR = 1.00, 95%CI: 0.73-1.37, P = 0.980; recessive model: OR = 0.90, 95%CI: 0.61-1.32, P = 0.570) and the risk of GDM. Conclusion Our meta-analysis shows the critical role of the ADIPOQ +45T/G polymorphism in GDM, especially in Asians. Studies focused on delineating ethnicity-specific factors with larger sample sizes are needed.