No association between myeloperoxidase gene rs2333227 G > A polymorphism and Alzheimer's disease risk: a meta-analysis and trial sequential analysis

Evidence suggests that there is a close association between myeloperoxidase (MPO) gene rs2333227 G>A polymorphism with Alzheimer's disease (AD) susceptibility. We conducted a meta-analysis to explore the precise association between MPO rs2333227 G>A polymorphism and AD susceptibility. Online databases were searched and the relevant information was collected. Crudeodds ratios with 95% confidence intervals were calculated. Trial sequential analysis (TSA), heterogeneity analyses, accumulative analyses, sensitivity analyses, and publication biasestests were performed. Overall, nine publications (ten independent case-controls) were included in this meta-analysis, involving 3260 participants. Pooled results revealed no significant association between MPO rs2333227 G>A polymorphism and AD susceptibility was observed. TSA showed that the present meta-analysis remained inconclusive due to insufficient evidence. In summary, the current meta-analysis indicated that the MPO rs2333227 G>A polymorphism may not be acausalfactor in the development of AD.