Hostility is a better predictor of coronary heart disease (CHD) in older men than a variety of other sociodemographic and physiological risk factors, including smoking, drinking, high caloric intake and high levels of LDL cholesterol, according to a new study published in Health Psychology (Vol. 21, No. 6).
The study focused on 774 white males who were recruited into the longitudinal Normative Aging Study in the 1960s. In 1986, the men were administered the Minnesota Multiphasic Personality Inventory, a subscale of which was used to measure their hostility, defined as a stable tendency to interpret the world and other people in a cynical and negative manner. Three years later, the men's health was assessed again. The authors found that the hostility scores obtained in 1986 predicted which men would suffer incidents of myocardial infarction, angina pectoris or ischemic heart disease in the following three years. Of those who experienced CHD, almost half had hostility scores in the 80th percentile of the sample as a whole.
The effect of hostility did not appear to be mediated by any of the other variables measured in the study, including the "metabolic syndrome," a cluster of risk factors that includes insulin resistance, high levels of triglycerides, hyperglycemia, high blood pressure and high waist-to-hip ratio. The only other significant predictor of CHD was HDL cholesterol, which acted as a protective factor.
"At least in this particular sample, it doesn't appear that hostility is having its effect on heart disease mediated through the metabolic syndrome," says Brown Medical School psychologist Raymond Niaura, PhD, the study's lead author. "That raises the question: How is it that hostility is affecting a person's risk for developing coronary heart disease? We speculate it may have to do with elevated stress hormones or other factors not measured in our study."
The study's brief follow-up period of three years could account for the fact that known risk factors, such as cigarette-smoking, did not significantly predict CHD. Niaura says he hopes that that a 15-year follow-up the team is working on now will have the statistical power to detect those relationships. Another limitation of the study was the homogeneity of the population studied, but, Niaura says, "At this point in time, I'd expect our findings to generalize to other populations because we don't have good evidence to the contrary."