A new study published in the Journal of the American Medical Association says a regimen of one aspirin per day affects men and women very differently. "In women aspirin prevents strokes and doesn't have any real effect on heart attack, and in men aspirin prevents heart attacks, but has no effect on the prevention of strokes," says study author David Brown, professor at Stony Brook University Hospital Medical Center.

The study analyzed records of nearly 100,000 people who had no history of heart problems. "Our study found that aspirin treatment was associated with a 24 percent reduction in the risk of the most common type of stroke in women and a 32 percent reduction in heart attacks in men," Dr. Brown says.

Doctors recommend aspirin as a preventive measure for people with a history of heart disease because it promotes blood flow and helps prevent blood clots normally associated with cardiovascular disease or stroke. But Dr. Brown says patients must also consider another risk. "In both men and women there was an approximately 70 percent increase in the risk of bleeding associated with the taking of aspirin. And, it is known that the bleeding risk is dose related."

The study results were the same no matter what the aspirin dose. For that reason doctors recommend the lowest possible dose - or 81 milligrams - for people at high risk for heart problems like smokers, people with diabetes, high blood pressure, high cholesterol, or a family history of heart disease.