In 1959, cardiologists Meyer Friedman and Ray Rosenman observed in top medical journals that competitive, deadline-driven, hypervigilant men-so-called Type A personalities-faced a significantly increased risk for coronary heart disease.
Yet ensuing large epidemiological studies failed to confirm the connection, and most health psychologists abandoned the concept in the late 1980s in favor of a component often found in Type A people: hostility.
A meta-analysis presented by German researcher Michael Myrtek, PhD, in his chapter on heart disease, Type A and hostility in the recently published APA book "Contributions Toward Evidence-based Psychocardiology: A Systematic Review of the Literature" (see "One heart-many threats") confirms that there is no significant association between Type A personalities and heart disease, but that there is a connection between hostility and coronary heart disease.
"The consensus is really that it is not all aspects of Type A behavior, but just the hostility component," says Redford Williams, MD, director of the behavioral medicine research center at Duke University School of Medicine.
David Krantz, PhD, chairman of the department of medical and clinical psychology at Uniformed Services University, agrees: "You can be ambitious. You can be time pressured. But if you're not hostile and angry, your risk is lower," he says.
Today, the heart disease-hostility link has gained significant credence among investigators, even though the exact nature of the connection remains up for debate. One hot-button issue is that several studies have linked hostility with other well-established risk factors like smoking, obesity, depression and socioeconomic status. But, with the help of technological advances, researchers have also discovered evidence that hostility contributes independently to the pathogenesis of heart disease through lipid accumulation, increased blood pressure and heart rate and platelet physiology.
Psychologists conceptualize hostility as consisting of three components: the emotion, the expression and the cognition-so-called cynical mistrust. Most research has focused on the cognitive hostility aspects of distrust, antagonism and general manipulativeness and how these traits relate to medical measures like blood pressure and heart rate or traditional cardiac risk factors like smoking.
A study co-authored by Krantz in the July issue of Psychosomatic Medicine (Vol. 67, No. 4, pages 546-52) found that in 506 women with suspected artery disease, those with higher hostility scores were more likely to have subsequent coronary events like hospitalizations for angina, nonfatal myocardial infarction, stroke and congestive heart failure in the next three to six years. This remained true even after the investigators adjusted for other risk factors, suggesting that hostility indeed constitutes an independent risk factor.
Another study published in the February issue of Neuropsychobiology (Vol.53, No.1, pages 26-32) found a positive association between increased hostility and increased plasma homocysteine levels, which is also considered an independent risk factor for coronary heart disease.
In another example of high-tech experimentation, University of Pittsburgh School of Medicine (UPSM) researchers used carotid-artery imaging to evaluate a connection between intimal-medial thickening-a measure of subclinical atherosclerosis-and hostility in white and African-American middle-aged women. They found that each one-point increase in hostility scores predicted a significantly higher intimal-medial thickening. The results were published in the November issue of the American Heart Journal (Vol.152, No. 5, pages 982.e7-13).
"These new technologies allow one to measure atherosclerosis in healthy people way before there are any symptoms of the disease and offer opportunities to examine the associations between hostility with sub-clinical disease," says study co-author Karen Matthews, PhD, professor of psychiatry, epidemiology and psychology and director of the cardiovascular behavioral medicine research training program at UPSM.
Hostility's complex role
Other research points to hostility's overlap with other well-established psychological and physical risk factors.
For example, a recent study published online in Psychosomatic Medicine examined hostility, depression, anxiety and trait anger as it related to coronary heart disease in U.S. Air Force Veterans. The study concluded that while each individual psychological attribute was a significant predictor of coronary disease, it was really the co-variation of the four traits that posed the biggest risk.
Meanwhile, a meta-analysis published in the July issue of Health Psychology (Vol.25, No.4, pages 493-498) found a relationship between hostility and the following measures: triglycerides, body mass index, waist-to-hip ratio, glucose levels, socioeconomic status, alcohol consumption and smoking. The results suggest hostility plays a complex role in the etiology of heart disease.
Such findings lead the study's lead author Jerry Suls, PhD-a health psychologist at the University of Iowa-to believe future research should focus on the connections among the different risk factors. "It probably isn't wise to split the traditional physical risk factors for cardiac risk from the psychological ones because there is so much connection between the two types," he says.
Nadja Geipert is a writer in Los Angeles.