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

Abstract

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%CI). 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%CI: 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.