Background and purpose: Folate, vitamin B6, and B12 deficiency are related to elevated blood homocysteine level. However, the effects of intakes of these vitamins on risk of stroke are still uncertain. This study examines intakes of folate, vitamin B6, and B12 in relation to risk of ischemic and hemorrhagic stroke.
Methods: We enrolled 43 732 men, aged 40 to 75 years, who were free of cardiovascular diseases and diabetes at baseline. Participants were followed from 1986 to 2000. Dietary information was assessed every 4 years using a detailed and validated semiquantitative food frequency questionnaire. The main outcome measures were incident ischemic and hemorrhagic strokes.
Results: A total of 725 incident strokes, including 455 ischemic, 125 hemorrhagic, and 145 unknown types of stroke, were documented during the 14-year follow-up. After adjustment for major lifestyle and dietary factors, intake of folate was associated with a significantly lower risk of ischemic but not hemorrhagic stroke. The multivariate relative risk of ischemic stroke was 0.71 (95% CI, 0.52 to 0.96; P for trend=0.05) for men in the highest quintile of intake compared with those who in the lowest quintile. Intake of vitamin B12, but not B6, was also inversely associated with risk of ischemic stroke.
Conclusions: Our findings suggest that increased folate intake is associated with decreased risk of ischemic stroke in men.