People who are antagonistic, competitive and aggressive may be at greater risk of having a heart attack or stroke. Researchers from the National Institute on Aging in Baltimore studied 5,614 Italians from Sardinia who ranged in age from 14 to 94. The participants answered a standard personality questionnaire that included six facets of agreeableness: trust, straightforwardness, altruism, compliance, modesty and tender-mindedness. The researchers then measured the thickness of their carotid (neck) arteries - the thicker people's arteries the greater their risk of stroke or heart attack. Those who scored highest for antagonistic traits had greater thickening of their neck arteries and three years later they continued to be at more risk - especially if they were manipulative and quick to express anger. Those who scored in the bottom 10% of agreeableness and were the most antagonistic had a 40% greater risk of arterial thickening. In general men had more thickening of their arterial walls than women but if women were antagonistic they had the same risk as men. The researchers also measured the participants' blood pressure, cholesterol and blood sugar and used statistical tools to take these variables 'out of the equation' in their analysis.
You can find out more about this research by clicking on the link in the title of this post.