Objectives: Studies examining whether glutathione S-transferase M1 (GSTM1) polymorphisms are associated with Parkinson's disease (PD) have reported inconsistent results. To clarify those inconsistencies, a meta-analysis was performed.
Methods: The electronic databases were searched for all publications regarding the association. Studies were included if they met the eligibility criteria. The strength of the association between GSTM1 polymorphisms and PD risk was measured by odds ratios (ORs) and 95% confidence intervals (CIs) in the recessive genetic model (null genotype vs. present genotype). Subgroup analyses by ethnicity and OR type were performed.
Results: A total of 22 publications (23 studies) were included. There were 14, 7 and 2 studies with Caucasians, Asians and Latinos, respectively. OR types were 15 and 8 studies with crude and adjusted ORs, respectively. The combined results of the overall analysis showed that the GSTM1 null genotype was not significantly associated with PD risk (ORrandom-effects = 1.06, 95% CI = 0.95-1.19). In subgroup analyses by ethnicity, no significant associations were found in Caucasians, Asians or Latinos individually. Similarly, there were no associations in the subgroup analyses by OR type. There were no obvious publication biases in any of the comparisons.
Discussion: The results of this meta-analysis suggest that the GSTM1 null genotype is not significantly associated with PD risk.
Keywords: Glutathione S-transferase M1 (GSTM1); Meta-analysis; Neurodegenerative movement disorder; Parkinson’s disease (PD); Polymorphism.