Apolipoprotein E Gene Polymorphism in a Chinese Population with Vascular Dementia: A Meta-Analysis

BACKGROUND: Apolipoprotein E (ApoE) gene has been reported to be associated with the development of vascular dementia (VD); however, results from observational studies are conflicting. METHODS: We surveyed all case-control studies on ApoE gene and VD patients with comprehensive search and review of the references. A meta-analysis was performed to demonstrate the association of ApoE gene with VD by random effects models. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI). RESULTS: A total of 18 studies including 935 patients and 1,686 controls were eligible and abstracted. ApoE ε3/4 and ε4/4 genotype, as well as ε4 allele (OR = 1.95, 95% CI: 1.52-2.49; OR = 3.47, 95% CI: 1.85-6.51 and OR = 2.12, 95% CI: 1.64-2.74, respectively) were associated with an increased risk of VD, while ApoE ε3/3 genotype and ε3 allele (OR = 0.65, 95% CI: 0.53-0.79 and OR = 0.65, 95% CI: 0.53-0.80, respectively) trended to protect against VD. There was no significant difference in ApoE ε2 allele frequency, ε2/2, ε2/3 or ε2/4 genotype between VD and controls (OR = 0.85, 95% CI: 0.61-1.17; OR = 0.89, 95% CI: 0.39-2.01; OR = 0.82, 95% CI: 0.61-1.09 and OR = 1.03, 95% CI: 0.57-1.84, respectively). CONCLUSIONS: Our results support a genetic association between ApoE polymorphism and VD in the Chinese population.