Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and susceptibility to ischemic stroke: A meta-analysis

Associations between 5,10-methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and ischemic stroke have been reported (Ariyaratnam et al., 2007; Banerjee et al., 2007; Casas et al., 2004), but the results of these studies are inconsistent. To investigate the possible associations between the MTHFR gene polymorphism and ischemic stroke, we performed a meta-analysis. Nineteen case-control studies associated with MTHFR gene C667T involving 2223 cases and 2936 controls were included. Heterogeneity among studies was evaluated with I2 and Egger's test and an inverted funnel plot was used to assess publication bias. Odds ratio (OR) was observed to identify the associations. Statistically significant association with ischemic stroke was identified for allele T polymorphism of MTHFR [fixed-effects OR = 1.28, 95% confidence interval (95% CI): 1.17-1.40, P < 0.00001] and marginally significant association was detected with genotype CT of MTHFR (fixed-effects OR = 1.13, 95% CI: 1.01-127, P = 0.04) and genotype TT of MTHFR (fixed-effects OR = 1.43, 95% CI: 1.20-1.70, P < 0.001). The results suggested that the MTHFR C667T genetic polymorphism was significantly associated with increased risk of ischemic stroke.