Aug. 17, 2010— -- People with antagonistic or disagreeable personalities have thicker arterial walls that may make them more prone to heart attacks and strokes, researchers said.
The carotid artery lining was significantly thicker in people who rated low on a scale of agreeableness, reported Angelina Sutin of the National Institute on Aging in Bethesda, Md., and colleagues.
In a study of 5,614 residents of the Italian island of Sardinia, those ranking in the lowest 10 percent of agreeableness were 1.4 times as likely to have thickening in their lining of their carotid artery, the researchers found. This held true even after the researchers adjusted for cholesterol levels, smoking status and other risk factors.
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The researchers also found that an antagonistic personality predicted increased thickening over approximately three years of follow-up.
"Antagonistic individuals, especially those who are manipulative and aggressive, have greater increases in arterial thickening, independent of traditional cardiovascular risk factors," Sutin and colleagues wrote in the American Heart Association journal Hypertension.
The effect of personality appeared to be greater in women than in men, the researchers found. The carotid artery lining thickness in women with disagreeable personalities was similar to the average in men, who normally have significantly thicker arterial walls.
Previous studies have linked cardiovascular disease with certain personality types, notably the hard-charging "Type A" personality. Subsequent research showed that hostility was a major contributor to these findings, Sutin and colleagues reported.
They also cited some earlier studies linking various antisocial behavior patterns to arterial thickening. But these focused on specific populations, including poor young adults, women transitioning to menopause and men with untreated high blood pressure.
"Large, population-based samples are needed to test whether these associations hold across different demographic groups," Sutin and colleagues wrote.
Their sample came from an ongoing, prospective study in Sardinia designed to uncover genetic and environmental factors associated with complex and age-related health problems. Approximately 62 percent of the population in four towns has participated in the study.
One of the questionnaires included in the study was the Revised NEO Personality Inventory (Italian translation), a self-assessment that includes 48 items covering six traits associated with agreeableness: trust, straightforwardness, altruism, compliance, modesty, and tendermindedness. Each is rated on a five-point scale from "strongly agree" to "strongly disagree."
Carotid artery thickening was assessed by ultrasound at the time of enrollment and approximately three years later. The follow-up measurement was performed in 83 percent of participants.
Other risk factors included in the statistical analysis were age, sex, education, waist circumference, systolic and diastolic blood pressure, LDL and HDL cholesterol, triglycerides, fasting plasma glucose and insulin, smoling status, and use of antihypertensive, statin, or diabetic medications.
Sutin and colleagues found that agreeableness scores were significantly associated with initial arterial thickness and with changes during the three-year follow-up. The specific traits of straightforwardness and compliance were most strongly associated with the arterial thickness.
On the other hand, when the researchers looked at the risk of being in the top quartile of arterial thickness, high agreeableness scores did not appear to have a protective effect in participants from either gender.
Dr. Redford Williams of Duke University in Durham, N.C., who was not involved with the study, commented that the findings highlight the largely unappreciated role of psychological factors in cardiovascular disease risk.
"Psychological and social factors are just as strong, as this study clearly documented, in putting people at higher risk of heart disease and other health problems," he said in an interview.
Williams noted the degree of cardiovascular event risk suggested by the study findings as associated with antagonistic personality traits was comparable to that of high LDL cholesterol, hypertension, or smoking.
"We really need, in this country and around the world, to begin to focus on ameliorating the effect of psychosocial risk factors just as we are on the physical risk factors," he said.
He suggested that patients with these traits should consider anger-management training, though he cautioned that cardiovascular benefits remain uncertain.
"I think we need the clinical trials -- carefully done, randomized clinical trials -- to make sure the kinds of anger-management training we might employ really are not only reducing anger, but reducing the rate of disease development. That's the gold standard we have to hit," Williams said.
But he adds, "It's certainly not going to hurt you to learn how to manage anger better."