Previous studies have indicated an association between elevated levels of total homocysteine and stroke and heart disease, according to background information in the article. Folic acid, pyridoxine (vitamin B6), and cobalamin (vitamin B12) reduce plasma homocysteine levels. The effectiveness of homocysteine-lowering therapy to reduce the risk of stroke has not been confirmed by randomized trials.

James F. Toole, M.D., of Wake Forest University School of Medicine, Winston-Salem, N.C., and colleagues conducted a double-blind randomized controlled trial from September 1996 to May 2003 to determine whether high doses of folic acid, vitamin B6, and vitamin B12, reduce the risk of an additional stroke over a 2-year period, compared with low doses of these vitamins. The study included 3,680 adults who had experienced a nondisabling stroke. It was conducted at 56 university-affiliated hospitals, community hospitals, private neurology practices, and Veterans Affairs medical centers across the United States, Canada, and Scotland.

Patients were randomly assigned to receive once-daily doses of the high-dose formulation (n = 1827), containing 25 mg of vitamin B6, 0.4 mg of vitamin B12, and 2.5 mg of folic acid; or the low-dose formulation (n = 1853), containing 200 micrograms of vitamin B6, 6 micrograms of vitamin B12, and 20 micrograms of folic acid.

Mean reduction of total homocysteine was greater in the high-dose vitamin group than in the low-dose group, but there was no treatment effect on any end point. The chance of an event (stroke, CHD [coronary heart disease] or death) within 2 years was 1
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Contact: Jonnie Rohrer
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JAMA and Archives Journals
3-Feb-2004