Polymorphisms of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) and endometriosis risk: a meta-analysis

Published data on the association between the glutathione S-transferases (GSTs) gene polymorphisms and endometriosis risk are inconclusive. We performed a meta-analysis to clarify the association of GSTM1 and GSTT1 polymorphisms and endometriosis risk. A comprehensive search was conducted to examine all the eligible studies of GSTM1 and GSTT1 polymorphisms and endometriosis risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. A total of 18 case-control studies were included in the meta-analysis of GSTM1 (2593 cases and 2732 controls) and GSTT1 (2520 cases and 2508 controls) genotypes. The overall results showed that the GSTM1 null genotype was related to an increased risk of endometriosis (OR = 1.55, 95% CI = 1.38-1.73). Similarly, for GSTT1 null polymorphism, moderate significantly increased risk was found (OR = 1.30, 95% CI = 1.13-1.50). In the subgroup analysis by ethnicity, significantly increased risks were also found among Caucasians and Asians for null GSTM1 genotype, and Asians for null GSTT1 genotype, but no correlation was noted in Caucasian populations for GSTT1 polymorphism. This meta-analysis provides strong evidence that the GSTM1 and GSTT1 polymorphisms are associated with the development of endometriosis.