Despite evidence that an aspirin a day can ward off heart attacks, many high-risk people - especially women - are not taking the drug, a large U.S. survey shows.

The study of more than 97,000 adults found that women were 30 percent less likely than men to take aspirin to prevent cardiovascular diseases like heart attack and stroke, and the difference was present even among adults at high risk.

But aspirin use was fairly low among high-risk men and women alike - surprisingly so, lead study author Dr. Catherine Kim of the University of Michigan in Ann Arbor told Reuters Health.

Among the 12,000-plus participants at high risk of cardiovascular complications, 58 percent of men said they were taking aspirin daily or every other day. That figure was 45 percent among women.

High-risk women were, however, slightly outdoing men when it came to making diet changes for their heart health, according to findings published in the American Journal of Preventive Medicine.

The study was based on data from a federally funded survey of 97,387 adults in 20 states. Respondents were considered to be at high risk of cardiovascular problems if they had ever suffered a heart attack or stroke or had coronary heart disease or diabetes. Those with two or more risk factors-including smoking, High cholesterol or high blood pressure-were put in the “intermediate-risk” group, and the rest were deemed “low risk.”

Kim said the findings on aspirin use suggest that both men and women at high risk of cardiovascular disease should talk to their doctors about using the drug. And, she pointed out, “everybody should be dieting and exercising more.”

Overall, high-risk women were the ones most likely to be cutting fat and cholesterol from their diets, with about 80 percent saying they had done so. Rates were lower among men and among women in the other two risk groups, and the percentage of people who said they were trying to exercise more often hovered around 60 percent in all groups.

The reason for the gender difference in aspirin use is unclear, Kim said. The survey asked participants whether they took aspirin, and not whether a doctor had prescribed it, so the researchers don’t know what kind of advice doctors were giving.

Aspirin is not for everyone, and it can cause side effects like stomach upset and ulcers. Among participants who did not take aspirin regularly, women were more likely than men to say that stomach problems or other conditions prevented them from taking the drug.

But Kim said that while a higher rate of side effects may be a “contributor” to the sex difference in aspirin use, it probably doesn’t fully explain the disparity.

It’s possible, she and her colleagues note in the report, that women and their doctors perceive their cardiovascular risk as being lower than men’s, and therefore think aspirin use unnecessary.

Past surveys have suggested that fewer than half of all women are aware that cardiovascular disease is the leading killer of women in the U.S.

SOURCE: American Journal of Preventive Medicine, July 2004.