People who have intense, long-lasting periods of anxiety might be courting a heart attack, warn researchers.
The study, led by Biing-Jiun Shen, Ph.D., an assistant professor of psychology at the University of Southern California in Los Angeles, shows that longstanding anxiety markedly increases the risk of heart attack, even when other common risk factors are taken into account.
"What we're seeing is over and beyond what can be explained by blood pressure, obesity, cholesterol, age, cigarette smoking, blood sugar levels and other cardiovascular risk factors," Shen said.
The role of anxiety in hiking heart attack risk also goes beyond the effects of depression, anger, hostility, Type A behaviour and other negative emotions.
Type A personality, also known as the Type A Behaviour Pattern, is a set of characteristics that includes being impatient, excessively time-conscious, insecure about one's status, highly competitive, hostile and aggressive, and incapable of relaxation.
"These psychological factors are important in predicting the risk of heart disease, but anxiety is unique. Older men with sustained and pervasive anxiety appear to be at increased risk for a heart attack even after their levels of depression, anger, hostility and Type A behaviour are considered," Shen said.
In the study, the researchers analysed data from the Normative Aging Study, which was designed to assess medical and psychological changes associated with aging among a group of initially healthy men. Each of the 735 men participating in the new analysis completed psychological testing in 1986 and was in good cardiovascular health at the time.
Although most people think of anxiety as intense worry, the researchers looked much deeper, examining four different measures of anxiety.
The first anxiety scale measured psychasthenia, or excessive doubts, obsessive thoughts and irrational compulsions. The second anxiety scale measured social introversion, or anxiety, insecurity, and discomfort in interpersonal and social situations. The third anxiety scale measured phobias, or excessive anxieties or fears about animals, situations or objects. The fourth anxiety scale, manifest anxiety, measured the tendency to experience tension and physical arousal in stressful situations.
Separate sections of the psychological test measured hostility, anger, Type A behaviour, depression, and negative emotions.
Study participants also completed questionnaires about health habits such as smoking, alcohol consumption and daily diet, and had a medical exam every three years over a follow-up period that averaged more than 12 years.
The results showed that men who tested at the highest 15th percentile on any of the four anxiety scales, as well as on a scale combining all four, faced an increase in the risk of heart attack of approximately 30 to 40 percent.
Those who were found to have even higher levels of anxiety on psychological testing faced an even higher risk of heart attack.
This finding held true even after the findings were adjusted for standard cardiovascular risk factors, health habits, and negative psychological and personality traits.
"The good thing about anxiety is that it's very treatable. If someone is highly anxious—if they're suffering from panic attacks or social phobia or constant worry—we recommend therapy. Although more research is needed, we hope that by reducing anxiety, we can lower the future risk of heart attack. This is one more reason to seek help," Shen said.
The study is published in the Journal of the American College of Cardiology (JACC).