Quantitative assessment of the association between MTHFR C677T polymorphism and hemorrhagic stroke risk

Many studies have investigated the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and hemorrhagic stroke, but the impact of MTHFR C677T on hemorrhagic stroke is unclear owing to the obvious inconsistence among those studies. This study aimed to quantify the strength of the association between MTHFR C677T polymorphism and hemorrhagic stroke risk. We searched Pubmed, Emabse and Wangfang databases for studies investigating the association between MTHFR C677T polymorphism and hemorrhagic stroke risk. We estimated the pooled odds ratio (OR) with its 95 % confidence intervals (95 % CI) to assess this possible association. Meta-analysis of included studies suggested that TT genotype was obviously associated with increased risk of hemorrhagic stroke (OR (TT versus CC) = 1.84, 95 % CI 1.45-2.34; OR (TT versus CT) = 1.53, 95 % CI 1.23-1.90; OR (TT versus CT/CC) = 1.64, 95 % CI 1.24-2.00) compared with CC or CT genotypes of MTHFR C677T polymorphism. Subgroup analyses by ethnicity further identified the association above in both Asians and Caucasians. No evidence of publication bias was observed. Thus, meta-analyses of available data suggest an obvious association between MTHFR C677T polymorphism and hemorrhagic stroke risk, and TT genotype contributes to increased risk of hemorrhagic stroke.