People who are aggressive may be at higher risk for heart attack or stroke, a new study suggests.

The study of 5,614 Italians in Sardinia found that those who scored high for antagonistic traits like competitiveness and aggression on a standard personality test had more thickening of their neck arteries compared with those who were more agreeable.

The thickness of this carotid artery is considered a risk factor for heart attack and stroke, researchers said in Monday's online issue of the journal Hypertension: Journal of the American Heart Association.

"People who tend to be competitive and more willing to fight for their own self-interest have thicker arterial walls, which is a risk factor for cardiovascular disease," Angelina Sutin, the study's lead author and a postdoctoral fellow with the U.S. National Institute on Aging in Baltimore, Md., said in a news release.

"Agreeable people tend to be trusting, straightforward and show concern for others while people who score high on antagonism tend to be distrustful, skeptical and at the extreme, cynical, manipulative, self-centered, arrogant and quick to express anger," she added.

When researchers followed up with study participants three years after the initial tests, they found they found the link between artery thickening and antagonism had persisted.

The findings are consistent with research in more urban regions and might apply to others in the world, the researchers said.