Link between depression and heart attack due to behavior

Study results have shown that people with depression are at increased risk of heart attack and heart failure because they are less likely to take regular exercise.

Scientists have known for some years that people who are depressed are at increased risk of heart attack and other cardiac events, however the reason why this should be has remained unclear. However, according to results of a study by Mary A Wooley and colleagues, the increased risk is due to behavioral factors.

The researchers analyzed data obtained from 1,017 people with heart disease, 199 of which had symptoms of depression. Results showed that 10% of depressed participants had a cardiac event (e.g. heart attack, heart failure, stroke, transient ischemic attack) during the study period, compared to just 6.7% of non-depressed participants, meaning that depressed participants were 50% more likely to have a cardiac event.  However, results also showed that depressed participants were more likely to smoke, were less likely to take their medications as prescribed, and were less physically active. After the researchers factored these behaviors into their calculations the risk of a cardiac event in depressed participants was similar to that in non-depressed participants.

The researchers concluded: "These findings raise the hypothesis that the increased risk of cardiovascular events associated with depression could potentially be preventable with behavior modification, especially exercise." Adding: "Exercise training can improve both depressive symptoms and markers for cardiovascular risk."

Whooley MA, de Jonge P, Vittinghoff E, et al. Depressive symptoms, health behaviors, and risk of cardiovascular events in patients with coronary heart disease. JAMA 2008;300:2379-2388.