ApoE Polymorphisms and the Risk of Different Subtypes of Stroke in the Chinese Population: A Comprehensive Meta-Analysis.

BACKGROUND AND PURPOSE Numerous studies have evaluated the association between apolipoprotein E (ApoE) gene polymorphisms and the risk of different subtypes of stroke. However, the results remain uncertain, and few sources of data specific to the Chinese ethnic population contribute to these outstanding questions. Therefore, we performed a meta-analysis to derive a more comprehensive estimate of the association between ApoE polymorphisms and stroke risk in the Chinese population. METHODS Case-control studies in Chinese and English publications were identified by searching the PubMed, EMBASE, Web of Science, China Nation Knowledge Infrastructure Platform, Wanfang, and VIP databases and by hand-searching relevant journals and the reference lists of the retrieved articles. ORs and 95% CIs were applied to assess the strength of the associations. Subgroup and sensitivity analyses were performed to explore between-study heterogeneity. RESULTS Evidence of a significant association was found between the ApoE ε4 allele and different subtypes of stroke (for ischemic stroke (IS): OR 2.19, 95% CI 1.90-2.52, p < 0.001; for intracerebral hemorrhage (ICH): OR 2.08, 95% CI 1.57-2.75, p < 0.001; and for subarachnoid hemorrhage (SAH): OR 2.03, 95% CI 1.28-3.23, p = 0.003) among the Chinese population. In addition, a significant difference in the risk for different subtypes of stroke between ε4 carriers and ε3ε3 genotype carriers was found (for IS: OR 2.41, 95% CI 2.00-2.89, p < 0.001; for ICH: OR 2.41, 95% CI 1.68-3.47, p < 0.001; and for SAH: OR 2.04, 95% CI 1.21-3.45, p = 0.008). CONCLUSION The ApoE ε4 allele may predict an increased risk for different subtypes of stroke, including IS, ICH and SAH, in the Chinese population, and the results of this genotypic analysis may help to identify populations at an increased risk for stroke. Further studies with larger sample sizes are needed to confirm our findings.