A screaming match may be heartbreaking in more ways than one. New research shows that high levels of hostility, anger and depression can predict a higher risk of heart disease in men. The study, published in the forthcoming August issue of the journal Brain, Behavior, and Immunity, is one of many linking hostility and heart health. But it is the first to examine what mechanisms the body is using to transform a psychological state, like anger, into a physical risk factor.
To explore the link between hearts and minds, researchers looked at how levels of inflammation in the body correlated to various personality traits, including a propensity for anger. "Inflammation is believed to be an important contributor when people get heart disease, diabetes and have high blood pressure," explains Edward Suarez, coauthor of the study and associate professor at Duke University Medical Center.
While inflammation is typically a healthy reaction of a functioning immune system, chronic, low-grade inflammation can be a sign of an adverse health condition. Researchers measured the levels of C3, a protein that is a biomarker of inflammation. Previous studies have shown that those with high levels of C3, are more likely to have a heart attack than those with low C3 levels.
At the outset of the study, 313 subjects were assessed for their levels of hostility, anger and depression. All of the participants were equally healthy, showing no signs of heart disease. Ten years later, those who had exhibited hostility, anger and depression had significantly higher levels of C3, indicating that they were at higher risk for heart disease and type II diabetes.
"We showed that psychological factors could, over time, push up levels of inflammation," says Stephen Boyle, Ph.D., coauthor of the Duke study. "We've provided more convincing argument that these factors are contributing to chronic, low-grade inflammation. The figures are pretty startling."
The study authors hope these results prompt cardiologists to evaluate a patient's level of anger and hostility along with other risk factors for heart disease. "In terms of risk reduction, it's important to explore who gets heart disease," says Suarez. "The traditional risk factors [like high blood pressure, obesity and smoking] only account for 50 percent of those who get the disease. There are a large number of patients where you would ask why they got it. Maybe its time to incorporate psychosocial, behavioral risk factors."
This isn't the first time researchers have explored the relationship between anger, hostility, depression and cardiovascular disease. "We know from a number of studies that individuals who are depressed or prone to anger respond to daily life stressors in a different way than those that are calm, cool and collected," says Suarez. And there have been definitive links between depression and heart disease. But even with the new evidence in the Duke study, researchers are still a ways away from a complete understanding of the relationship between anger and the heart.
Making the mind-body connection with anger is more difficult than it was with depression, say some researchers, because the medical community currently lacks a standardized definition of hostility. "Different authors have suggested different definitions," says Julie Schulman, an assistant professor of clinical psychiatry at Columbia University Medical Center. "There are quite a number of different tests. There are many questionnaires that don't necessarily agree with each other or mean the same thing."
Schulman's recent review of the relationship between hostility, anger and cardiovascular disease, published in the May/June issue of Cardiology in Review, says the personality traits have not shown to have a "meaningful clinical relationship." Cardiologists, Schulman says, would be better off focusing on traits that have more established links to heart disease, such as depression.
"If I have 10 minutes with a patient, the amount of time I want to spend talking with them about hostility is extremely low," she says. "So far the data shows that the effect is so small that we need to focus on other known risk factors." Those risk factors include smoking, sedentary behavior and diabetes—all have been strongly linked to heart disease in numerous studies.
Still, some cardiologists are saying that more results like these could change the way that heart disease is treated. Doctors typically focus on making lifestyle changes related to diet or exercise regimes, such as quitting smoking or eating less saturated fat. This new evidence may begin to change that. "This study will be a wakeup call to say, let's not ignore hostility," says Jennifer Mieres, a professor of cardiology at New York University who was not affiliated with the Duke Study. "Maybe in addition to the controlling the risk factors and trying to implement lifestyle changes, we should also be looking at adding behavioral modification or stress reduction."
No studies to date have looked at whether reducing hostility through meditation or other behavior-modification techniques could lead to a reduction in heart disease risk. That, says Boyle, "would be the ultimate test, if we used intervention to stop or slow down the risk." On both sides, researchers agree that further research is needed to shed light on how these psychological traits may, or may not, become physical risk factors.