It's not surprising that a substantial percentage of patients experience depression after experiencing a heart attack or other cardiac event. But a new study reveals that depression may increase the risks of having and dying from coronary heart disease -- risks that appear to differ between men and women.

To examine the relationship between depression and coronary heart disease (CHD), researchers from Ohio State University analyzed data from 5,007 women and 2,886 men who took part in the first National Health and Nutrition Examination Survey. Researchers only looked at individuals with no history of CHD at the start of the study. Study participants were assessed for depression using a standard depression scale. They were followed over a 10-year period -- between 1982 and 1992.

Depressed women were more likely than non-depressed women to develop heart disease. In contrast, depressed men were not only more likely to develop heart disease, but they were more likely to die from it.

"In this sample, while controlling for possible confounding factors, depression was associated with an increased risk of CHD incidence in both men and women, as well as CHD mortality in men," the researchers concluded.

The findings, which appear in the May 8 issue of the Archives of Internal Medicine, are consistent with previous studies. However, "this is the first paper that has shown the relationship between depression and heart disease in women," said study author Judith A. Schwartzbaum, Ph.D., a professor with the division of epidemiology and biometrics.

Heart disease is the leading cause of death in the United States among men and women, and depression affects approximately 19 million Americans in any given year.

Researchers don't know why depression might increase the risk of heart disease or why depression appears to have a more serious impact on CHD mortality in men than in women.

Study authors speculate that lifestyle factors strongly linked to depression, such as cigarette smoking, may account for some of the increased risk. Depressed individuals may also be more likely to have irregular heart beats and conditions that lead to blood clots in the coronary arteries, which in turn lead to CHD. To explain gender differences, Schwartzbaum suggested that women might be better able to cope with depression, since they experience higher rates of depression than men.

"Future research should focus on defining the mechanism that links depression to elevated CHD risk in a non-coronary patient population," study authors recommended. "After specifying this relationship," they added, "interventions... to reduce the risk of CHD in depressed individuals can be tested."

(By Alicia M. Lukachko, M.P.H from American Council on Science and Health )