Hot flashes can range from irritating to debilitating, but they may also be a sign of something worse: As women go through menopause, hot flashes may signal a higher risk of heart disease and heart attacks, according to new data presented Friday at the annual meeting of the North American Menopause Society in San Diego.

These findings, based on more than 400 participants in the ongoing prospective Study of Women's Health Across the Nation (SWAN), agree with previous studies linking the two. Researchers aren't sure why that might be the case.

SWAN researcher Dr. Karen A. Matthews of the University of Pittsburgh in Pennsylvania and colleagues studied the women, all of whom were between 42 and 52, and did not have any known heart disease.

They found that women with hot flashes were more likely to have thickening of their carotid arteries, blood vessels in the neck whose health has been linked to heart disease in other studies.

Earlier findings among the same women had shown that some with hot flashes had significant cholesterol plaques in those arteries. Such plaques can rupture, leading to blockages in the brain's arteries - a stroke - or hint that the heart's arteries have similar plaques that can break off and cause a heart attack.

These findings, Matthews noted, don't mean that hot flashes cause heart disease, or vice versa. However, they do suggest that the two are linked somehow.

"We are intending to follow this up and figure out why this is so and some of the explanations that would be important for prevention and intervention," she added.