However, the effect was not noted among women who believed their risk was low.
University of Rochester Medical Center researcher Dr. Robert Gramling found that men who believed they were at lower-than-average risk for cardiovascular disease experienced a three times lower incidence of death from heart attacks and strokes.
Gramling said a posisble reason the data did not support the same conclusion among women is that the study began in 1990 -- a time when heart disease was believed to be primarily a threat to men and women's judgments about how often heart attacks occur among average women might have been disproportionately low.
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.
Study participants were asked their risk of heart attack or stroke and almost half of the men who self-rated their risk to be "low" were classified by objective medical tests as having "high" or "very high" risk.
"It is not clear whether we should seek to disabuse people of optimistic 'misperceptions' in pursuit of changing behavior," Gramling said.
The study is published in the July-August issue of Annals of Family Medicine.