Depression increases the risk of dying from heart disease, sometimes dramatically, according to research conducted in Holland and being published by a Wake Forest University faculty member in the March issue of Archives of General Psychiatry.
Brenda W.J.H. Penninx, Ph.D., and six colleagues from medical institutions in The Netherlands said that cardiac deaths following depression increased whether or not participants already had heart disease.
The 54-month observational study, which involved nearly 2,900 participants from 55 to 85 years old, found that among those without heart disease at the start of the study, heart disease deaths nearly quadrupled in participants with major depression. In those who already had heart disease when the study began, deaths from heart disease tripled in subjects with major depression.
"Our study is the first to directly compare the effect of depression on cardiac mortality in community-dwelling older subjects with and without cardiac disease," said Penninx, a member of the faculty of the J. Paul Sticht Center on Aging and Rehabilitation at Wake Forest and formerly with the Institute for Research in Extramural Medicine, Vrije University, Amsterdam.
"Prevention and treatment of depression may be one of the most effective targets for interventions aimed at reducing the risk for fatal cardiac events," she said.
The participants were selected at random from 11 Dutch municipalities for the Longitudinal Aging Study Amsterdam. Such studies differ from studies that focus on clinical patients because they encompass a sample of the community as a whole.
"This study shows that depressed older persons were significantly more likely to die because of cardiac disease during 54 months than non-depressed older persons," said Penninx.
She said that the increased risk of dying of heart disease "was present -- and similar -- in both subjects with and without cardiac disease."
Of course, the actual number of heart disease deaths was higher in the group with pre-existing heart disease than in those with no heart disease at the start of the study.
Participants who had minor depression also had an increased risk of dying of heart disease both among people with pre-existing heart disease and those without, but those increases were not statistically significant.
"Depression is common in older community-dwelling populations," she said. "The prevalence of major depression is our study was 2 percent, and a further 13 percent suffered from minor depression."
She called for clinical trials to determine whether more appropriate care for depressed patients could prevent heart disease deaths.
Penninx listed a number of possible explanations. Depression has been shown to impair the function of platelets in the blood and to decrease the variability of the heart rate. Unhealthy levels of a chemical called cortisol in the body and activation of the immune system, both stress responses to depression, may increase blood pressure and production of the body''s natural steroids and decrease insulin resistance, all of which increase the risk of heart disease.
Furthermore, she said, "Unhealthy lifestyles are more common among depressed persons."
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