Meta-analysis of GSTT1 null genotype and preterm delivery risk.

Glutathione S-transferase T1 (GSTT1) null genotype has been indicated to be correlated with preterm delivery (PTD) susceptibility, but study results were still debatable. Thus, a meta-analysis was conducted. PubMed, EMBASE, and CNKI were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strength of association in the random-effects model or fixed-effects model. Nine case-control studies with a total of 2526 cases and 4565 controls were eligible. The null genotype of GSTT1 was associated with a significantly increased risk of PTD when compared with present genotype (OR = 1.18; 95% CI 1.05-1.33; I(2) = 33). In the subgroup analysis according to ethnicity, significantly increased PTD risk was observed in Asians (OR = 1.20; 95% CI 1.01-1.33; I(2) = 0%) but not in Caucasians (OR = 1.32; 95% CI 0.89-1.97; I(2) = 77). This meta-analysis suggested that GSTT1 null genotype may be associated with the risk of PTD.