Correlation of rs9331888 polymorphism with Alzheimer's disease among Caucasian and Chinese populations: a meta-analysis and systematic review

Clusterin polymorphism (rs9331888) was reported to be associated with the susceptibility to alzheimer's disease (AD). Nevertheless, the results were inconclusive. To derive a more precise estimation of this association, this meta-analysis was conducted. We've conducted a comprehensive search of PubMed, Embase, CNKI and AlzGene database for case-control studies published throughout October, 2016 that evaluated the role of rs9331888 gene variants in AD patients. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated to assess the strength of associations between the rs9331888/C > G polymorphism and AD disease. A total of 9 studies were enrolled in the Meta Analysis. The overall analysis revealed a significant association between the rs9331888/C > G polymorphism and AD disease in the recessive model (GG vs. GC + CC: OR = 1.11, 95% CI: 1.05-1.18; P < 0.01). Sub-group analysis revealed that the Caucasian populations which with recessive model (GG vs. GC + CC: OR = 1.12, 95% CI: 1.06-1.2; P < 0.01) were dramatically related to AD, while no significant association was found in the Chinese populations among the five genetic models. Our meta-analysis demonstrated that the rs9331888/C > G polymorphism in the clusterin gene might contribute to AD susceptibility especially in Caucasian populations. Whereas the relationship of the polymorphism to the disease in Chinese populations was still in controversial. Additional well-designed studies, with larger sample sizes, are required to further elucidate this association.