Optimism is good for heart health, at least among men, a new study shows.

University of Rochester Medical Center researcher Robert Gramling, M.D., D.Sc., found that men who believed they were at lower-than-average risk for cardiovascular disease actually experienced a three times lower incidence of death from heart attacks and strokes.

The data did not support the same conclusion among women. One possible explanation for the gender difference, researchers said, is that the study began in 1990, a time when heart disease was believed to be primarily a threat to men. Therefore, women's judgments about how often heart attacks occur among average women might have been disproportionately low.

The study is published in the July-August issue of Annals of Family Medicine.

The 15-year surveillance study involved 2,816 adults in New England between the ages of 35 and 75 who had no history of heart disease. Researchers collected baseline data from 1990-1992; outcomes were obtained from the National Death Index records through December 2005.

Researchers were interested in measuring whether optimistic perceptions of risk might protect people from the fear-related coping behaviors (overeating comfort foods, too much alcohol, or avoiding the doctor) or the stress that can be associated with heart disease.

They asked people at the outset, "Compared with persons of your own age and sex, how would you rate your risk of having a heart attack or stroke in the next 5 years?"

Men's views were more discordant. Almost half of the men who self-rated their risk to be "low" would have been classified by objective medical tests as having "high" or "very high" risk. Most women who rated their risk to be "low" were far more accurate than the men.

"Clearly, holding optimistic perceptions of risk has its advantages for men," said Gramling, an assistant professor of Family Medicine and Community and Preventive Medicine.

If doctors are to accurately explain risks to patients, it's important for them to first understand how people perceive health risks. The study also pointed out that as genetic testing and advanced imaging continues to offer individuals more information about their future health, good communication is essential.

"It is not clear whether we should seek to disabuse people of optimistic 'misperceptions' in pursuit of changing behavior." Gramling said. "Perhaps we should work on changing behaviors by instilling more confidence in the capacity to prevent having a heart attack, rather than raising fears about having one."