In what is believed to be the first direct comparison of blood cell testing in both sexes of 81 milligrams of acetyl salicylic acid a day, Hopkins researchers found aspirin therapy prevents the clumping together of these clot-forming cells, called platelets. Clots in blood vessels of the heart and brain can cause heart attacks and strokes.

However, while the drug's overall effects on blood cell function were the same for men and women, the investigators found that women's platelets reacted somewhat more strongly to aspirin before the start of therapy, and remained so even after treatment.

The study findings appear in the Journal of the American Medical Association online March 21, and challenge the conclusions from several other recent studies, including the federal Women's Health Study, which showed low-dose aspirin had no effect in preventing heart attacks in women, even though it worked in men. Previous results, the researchers say, were not likely caused by the failure of aspirin to prevent platelets from clumping together and forming blood clots in women.

"Women are clearly benefiting from taking aspirin and should continue to take it to improve their cardiovascular health," says study senior investigator Diane Becker, M.P.H., Sc.D., a professor at The Johns Hopkins University School of Medicine and Bloomberg School of Public Health. "Aspirin has been proven by all previous studies to lower the risk of stroke and, as our latest findings show, it also reduces platelet aggregation that can lead to potentially fatal clots in blood vessels."

"Our results show that aspirin does what it is supposed to do in both men and women," says platelet biologist and study co-author Nauder Faraday, M.D., an associate professor at Hopkins. "
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Contact: David March
dmarch1@jhmi.edu
410-955-1534
Johns Hopkins Medical Institutions
21-Mar-2006