Aspirin Won't Prevent 1st Heart Attack in Women

Low-Dose Aspirin Reduces Stroke in Women, but Vitamin E Has No Benefit

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March 7, 2005 (Orlando, Fla.) -- Doctors often advise daily aspirin therapy in high-risk people to prevent heart attacks. However, a new study shows that when low-dose aspirin treatment is given to women it doesn't prevent first heart attacks in women.

Low-dose aspirin therapy reduces the risk of stroke in women aged 65 or older, but does not prevent first heart attacks, according to the results of a 10-year long study of 40,000 women.

Also, the study shows that taking vitamin E supplements for 10 years does not reduce either risk. It's a finding that researcher Paul Ridker, MD, of the Women's Health Study, tells WebMD, "should be just about the last word on vitamin E."

"We've had seven studies," says Ridker, "and none have shown a benefit so it really is better to eat your fruits and vegetables than to take a pill."

Ridker, and colleague July Buring, ScD, a professor of medicine at Harvard Medical School, presented the study at the American College of Cardiology 2005 Scientific Session.

At the same time, the low-dose aspirin study was published online by the New England Journal of Medicine.

The study enrolled healthy women aged 45 to 80. Half of the women were told to take 100 mg of aspirin every other day and half took a dummy aspirin pill every other day. The women were given either 600 IU of vitamin E every other day or a vitamin E placebo every other day.

After 10 years, women taking aspirin had a 17% reduction in the risk of stroke. Yet there was no protection against heart attacks or death from heart disease in women taking aspirin.

While Ridker and Buring didn't express surprise about the vitamin E findings, both say they were surprised by the aspirin results. "This is the exact opposite of what we see in men -- aspirin prevents the risk of heart attack in men but has no impact on stroke," says Ridker.

Buring added that the new results pertain only to prevention of heart attacks or stroke in people who have not had a heart attack or stroke.

Weighing the Risks of Aspirin Therapy

For people who have had heart attacks, low-dose (81 mg-325 mg) aspirin is still recommended as a way to reduce risk of second heart attacks. "And that recommendation is for men and women," she says. Also, for someone having a heart attack -- man or woman -- the recommendation is still to take an aspirin to limit the damage of the attack.

Cardiovascular disease, which includes heart attack and stroke, is a leading cause of death in the U.S. Heart disease is responsible for more than 900,000 deaths annually in the U.S. Aspirin can stop blood clots from forming, and block blood flow to the heart and brain, which can cause heart attacks and strokes.

Otherwise, Ridker and Buring say that the decision to take aspirin "should be a decision between a woman and her doctor, who can weigh the risks and benefits."

For women over the age of 65, it appears that the benefit of stroke prevention with aspirin's use may outweigh the risk of bleeding, says Buring. Not surprisingly, given the increased bleeding risk associated with aspirin use, women taking aspirin had more gastrointestinal bleeding episodes than women taking the placebo.

American Heart Association's Take

The American Heart Association responded to the study findings with the following statement pointing to their guidelines for aspirin use:

"These guidelines included recommendations for aspirin use among women at varying levels of risk, and advised that the routine use of aspirin in low-risk women was not recommended pending the results of ongoing trials."

Lori Mosca, MD, chair of the AHA's writing group for the guidelines, says the results of this study support the recommendations. She explains that while the new study results show a benefit for aspirin therapy in healthy women aged 65 or older, "we will have to balance this benefit with the risk of serious gastrointestinal bleeding and the potential for increasing hemorrhagic strokes."

Robert Harrington, MD, Duke University School of Medicine, tells WebMD that the study results provide guidance for women and their physicians. "The message is clear, aspirin does reduce stroke in women aged 65 or older, so we need to talk about prophylactic aspirin use in our women patients in that age group."

The study was funded by the National Heart, Lung, and Blood Institute.

WebMD Health News


SOURCES: American College of Cardiology, 2005 Scientific Session, Orlando, Fla., March 6-9, 2005, Late breaking Clinical Trials: A randomized study of low-dose aspirin in the primary prevention of cardiovascular disease in 39,876 women: The Women's Health Study; A randomized trial of vitamin E in the primary prevention of cardiovascular disease in 39,876 women: The women's health study. New England Journal of Medicine, 2005: pp 352. Paul M. Ridker, MD, Women's Health Study. Julie E. Buring ScD, professor of medicine, Harvard Medical School, Boston. Lori Mosca, MD, American Heart Association. Robert Harrington, MD, Duke University School of Medicine.

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