Men with heart disease who have high levels of hostility are more than twice as likely as men with more trusting personalities to get sick or require hospitalization for heart-related causes.

But researchers found no such association between hostility and recurrent heart disease in women.

As defined in the study, hostility does not necessarily mean aggression or anger, but instead having a personality characterized by suspicion of others, cynical views, and resentfulness towards and impatience with other people, said Dr. Donald Haas of the Mt. Sinai School of Medicine in New York City, the study’s lead author.

This personality type is a refinement of the heart disease-linked “type A” personality first described in the 1980s, he added.

Haas and his colleagues studied 139 men and 88 women with coronary heart disease. All had completed a personality test called the Cook-Medley Hostility scale.

Over the following four years, men with high hostility scores were more than twice as likely as those with low scores to become ill from or be hospitalized due to heart disease-related causes. However, women’s hostility levels had no relationship to their heart health.

People with hostile personalities, Haas noted, are less likely to follow instructions and may be less willing to adhere to their doctor’s recommendations, which may help explain the findings.

He pointed out that while past studies have tied hostility to heart health in women, the participants in these studies were volunteers, and thus perhaps less hostile than average. The current study, which included people randomly selected from the population, may provide a more accurate evaluation of heart risk and hostility, Haas said.

The mechanism responsible for the different gender effect is not clear, he said, although some research has suggested that men show a stronger response to stressful cues in the environment than women do.

While it’s much to early to say that treating hostility could improve heart disease risk - and it’s inaccurate to talk about “treating it,” since it’s a personality trait rather than a disorder - cognitive behavioral therapy has been shown to reduce hostility and to also lower blood pressure levels, Haas said. “It’s worth pursuing and studying.”

SOURCE: Heart, December 2005.