In the first large population study of its kind, researchers at the University of Maryland School of Medicine have found that higher levels of the naturally-occurring substance called homocysteine increase the risk of stroke among younger women.
Deficiency in B vitamins or a genetic predisposition can cause higher levels of homocysteine, which is an amino acid. Results of the study are published in the August 1999 issue of the journal Stroke.
"We found that younger women who had the highest levels of homocystine had double the risk of stroke compared to women with lower levels," says Steven J. Kittner, M.D., M.P.H., professor of neurology, epidemiology and preventive medicine at the University of Maryland School of Medicine.
Dr. Kittner adds that it is possible to lower homocysteine levels by increasing the amount of folic acid and vitamins B6 and B12 in the diet. "We may have the potential to significantly improve the public health and reduce the risk of stroke and other forms of cardiovascular disease with nutritional intervention," Dr. Kittner says.
Stroke is the third leading cause of death in the U.S. and is a major cause of disability. Among women under age 45, stroke is more common than Multiple Sclerosis.
The study included 167 white and African-American women age 15 to 44 who had suffered an ischemic stroke in Maryland, Washington, D.C., southern Pennsylvania or Delaware. They were compared to 328 randomly selected women who had not had a stroke, but were matched with the participants for similar characteristics, such as age and location of residence. The researchers also looked at factors such as smoking, socioeconomic status and vitamin use, in addition to homocysteine levels.
The women in the study whose homocysteine levels were within the top 40 percent of the whole group had a 2.3 percent higher risk of stroke. When cigarette consumption, socioeconomic status and regular vitamin use were taken into account, the risk was still 1.6 percent higher.
"The magnitude of the increase in stroke risk was similar to that of smoking a pack of cigarettes per day. Even moderately higher homocysteine levels-those that would be considered normal among older people-conferred a greater risk of stroke among the women in our study," says Dr. Kittner.
He adds that the increased stroke risk from elevated homocystine levels was the same for both African-American and white women.
The next step is to find out whether it is possible to prevent stroke by lowering homocysteine levels. The University of Maryland School of Medicine is participating in a study to see if treating high homocysteine levels with B vitamins can reduce the risk of stroke or heart disease. In this new study, men and women of all ages who have had a recent stroke are randomly assigned to take multivitamins with or without a high dose of B vitamins.
Until the answers are in, Dr. Kittner recommends that people get their folic acid and B vitamins from eating a balanced, healthy diet that includes seven servings of vegetables and fruit each day, along with moderate consumption of meat and dairy products.
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