title: Null genotypes of GSTM1 and GSTT1 contribute to increased risk of diabetes mellitus: a meta-analysis.
abstract: Diabetes mellitus (DM) is a common disease which results from various causes including genetic and environmental factors. Glutathione S-Transferase M1 (GSTM1) and Glutathione S-Transferase T1 (GSTT1) genes are polymorphic in human and the null genotypes lead to the absence of enzyme function. Many studies assessed the associations between GSTM1/GSTT1 null genotypes and DM risk but reported conflicting results. In order to get a more precise estimate of the associations of GSTM1/GSTT1 null genotypes with DM risk, we performed this meta-analysis. Published literature from PubMed, Embase and China Biology Medicine (CBM) databases was searched for eligible studies. Pooled odds ratios (OR) and corresponding 95% confidence intervals (95%CI) were calculated using a fixed- or random-effects model. 11 publications (a total of 2577 cases and 4572 controls) were finally included into this meta-analysis. Meta-analyses indicated that null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 were all associated with increased risk of DM (GSTM1: OR random-effects=1.60, 95%CI 1.10-2.34, POR=0.014; GSTT1: OR random-effects=1.47, 95%CI 1.12-1.92, POR=0.005; GSTM1-GSTT1: OR fixed-effects=1.83, 95%CI 1.30-2.59, POR=0.001). Subgroup by ethnicity suggested significant associations between null genotypes of GSTM1 and GSTT1 and DM risk among Asians (GSTM1: OR random-effects=1.77, 95%CI 1.24-2.53, POR=0.002; GSTT1: OR random-effects=1.58, 95%CI 1.09-2.27, POR=0.015). This meta-analysis suggests null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 are all associated with increased risk of DM, and null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 are potential biomarkers of DM.
authors.affiliation: Department of Endocrinology, Fujian Institute of Endocrinology, Union Hospital of Fujian Medical University, 29 Xinqu and Road, Fuzhou, Fujian 350001, China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhang
authors.forename: Hu
authors.initials: H
authors.lastname: Liu
authors.forename: Hongyi
authors.initials: H
authors.lastname: Yan
authors.forename: Guoliang
authors.initials: G
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
mesh_terms: D003920:Diabetes Mellitus / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012306:Risk
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1