A meta-analysis of association between glutathione S-transferase M1 gene polymorphism and Parkinson's disease susceptibility

The aim of this meta-analysis was to evaluate whether there was an association between glutathione S-transferase M1(GSTM1) gene polymorphism and Parkinson's disease (PD) susceptibility by pooling published data. We performed comprehensive electronic database search for articles published between February12,2015 and April30 2016. The published case-control or cohort studies related to GSTM1 gene polymorphism and Parkinson's disease susceptibility were screened, reviewed, and included in this meta-analysis. The correlation between GSTM1 gene polymorphism and PD susceptibility was expressed by odds ratio (OR) and its corresponding 95% confidence interval (95% CI). Publication bias was evaluated by Begg's funnel plot and Egger's line regression test. All analysis was done by stata11.0 software. After searching the PubMed, EMBASE, and CNKI databases, seventeen case-control studies with 3,538 PD and 5,180 controls were included in the final meta-analysis. The data was pooled by a fixed-effect model for lack of statistical heterogeneity across the studies; the results showed GSTM1 null expression can significant increase the susceptibility of PD (OR=1.11, 95% CI: 1.01-1.21, P<0.05). Subgroup analysis indicated GSTM1 gene polymorphism was associated with PD susceptibility in the Caucasian ethnic group (OR= 1.15, 95% CI: 1.05-1.27, P<0.05) but not in the Asian ethnic group (OR=0.89, 95% CI:0.70-1.12, P>0.05). Begg's funnel plot and Egger's line regression test showed no significant publication bias. Based on the present evidence, GSTM1 null expression can significant increase the susceptibility of PD in persons of Caucasian ethnicity.