Aspirin helps prevent strokes in women

In a stunning example of gender differences in medicine, a major new study found that aspirin helps healthy women avoid strokes but makes no difference in their risk of heart attacks unless they're 65 or older -- the polar opposite of how the drug affects men.

Aspirin is recommended now for both men and women at high risk of heart disease. Many doctors have assumed it also prevented heart problems in healthy women because of research showing it helped healthy men.

The new study "raises issues about the dangers of generalization," said Dr. Paul Ridker of Harvard Medical School and Brigham and Women's Hospital in Boston, one of the researchers. "This is an issue we thought we already had an answer to."

The Women's Health Study was the first rigorous test of aspirin and vitamin E in women. It found that taking vitamin E did no good, adding to a large body of evidence that such supplements don't help and might even be harmful.

"Bottom line: There wasn't a benefit but there wasn't harm" from vitamin E in the new study, said Harvard epidemiologist Julie Buring. "The better thing to do is to have a heart-healthy diet."

Read more: Aspirin helps prevent strokes but not heart problems in women, study find