Objective: To evaluate whether hyperhomocysteinemia is an independent risk factor for silent brain infarction (SBI), and to determine the relationship between homocysteine and folate in each type of methylenetetrahydrofolate reductase (MTHFR) polymorphism, in order to identify a way of reducing the risk for SBI.
Methods: The authors enrolled 161 patients with SBI and 126 healthy people, checked their fasting homocysteine and folate levels, and analyzed for the MTHFR C677T polymorphism.
Results: The mean plasma homocysteine level in patients with SBI (12.17 +/- 5.35 micro mol/L) was significantly higher than in normal healthy people (9.37 +/- 4.11 micro mol/L; p < 0.05). By subgroup analysis, based on the classification of plasma homocysteine levels as high (>or=11.77 micro mol/L), moderate (8.71 to 11.76 micro mol/L), and low (<or=8.70 micro mol/L), the adjusted OR (AOR) of the high group for SBI was significantly greater than that of the low group (AOR, 4.78; 95% CI, 2.45 to 9.33). The homocysteine level showed a significant inverse correlation with folate level only in patients with SBI with the MTHFR 677TT genotype (p < 0.05).
Conclusions: This study demonstrates that hyperhomocysteinemia is an independent risk factor for SBI, and provides the possibility of reducing the risk for SBI in the MTHFR 677TT genotype by folate supplementation.