The MTHFR C677T polymorphism contributes to an increased risk for vascular dementia: A meta-analysis

Background/aims: Vascular dementia (VaD) is the second common cause of dementia after Alzheimer's disease (AD) in later life. The methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism as a risk factor in VaD has been suggested, but direct evidence from genetic association studies remain inconclusive. We performed a meta-analysis pooling data from all relevant studies in order to determine the effect of the MTHFR C677T polymorphism on VaD. Methods: We applied a random-effects or fixed-effects model to combine odds ratio (OR) and 95% confidence intervals (95%Cl). Q statistic was used to evaluate the homogeneity, and Egger's test and Funnel plot were used to assess publication bias. Results: A total of 11 studies, comprising 672 cases and 1038 controls, were included worldwide. Publication bias was not observed. This meta-analysis demonstrated that the MTHFR T allele or TT genotype had an increased risk for VaD in general populations (OR, 95%Cl: 1.27, 1.01-1.59; 1.41, 1.06-1.88, respectively), and a significant association was found in allele contrast, recessive, and dominant model in Asian populations, but not in Caucasian populations. Conclusion: The MTHFR C677T polymorphism (mainly TT genotype) is associated with developing VaD in general populations or Asian populations, (C) 2010 Elsevier B.V. All rights reserved.