Lee Swanson Research Update

Folate May Cut Stroke Risk in Male Smokers

May 2008

Folate may cut stroke risk in male smokers

An increased intake of folate (folic acid) may reduce the risk of stroke by 20% for male smokers, according to information compiled by researchers and published in the American Journal of Epidemiology.

Researchers from the Karolinska Institutet (Stockholm), the Finnish National Public Health Institute (Helsinki) and the National Cancer Institute, US National Institutes of Health, used data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study concerning 26,556 male smokers ranging in age from 50 to 69.

Dietary intakes of the smokers were assessed using a validated food frequency questionnaire and intakes of folate, vitamins B-6 and B-12 and methionine from the diet were calculated. During 13.6 years of follow-up, the researchers documented 3,281 cases of stroke, including cerebral infarctions, intracerebral hemorrhages and subarachnoid hemorrhages.

Lead author of the study, Susanna Larsson, reported that men with the highest average intakes (410 mcg per day) of folate were 20% less likely to suffer a cerebral infarction than men with the lowest folate intakes (262 mcg per day), after adjusting for age and other cardiovascular risk factors.

"An inverse association between folate intake and risk of stroke is biologically plausible because folic acid supplementation lowers blood homocysteine, which in high concentrations may cause vascular damage (endothelial dysfunction, increased arterial intimal-medial thickness and increased arterial stiffness) and increased procoagulant activity," Larsson wrote. "Meta-analyses have estimated that a 3-micromoles per liter decrease in blood homocysteine concentrations is associated with a 19-24% lower risk of stroke."

However, researchers also discovered that intakes of B-6, B-12 and methionine were not associated with any type of stroke.

The study concluded: "These findings in men suggest that a high dietary folate intake may reduce the risk of cerebral infarction.:

American Journal of Epidemiology Published online ahead of print.

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