Depressive symptoms increased the risk of dying from stroke, but coronary heart disease (CHD) was not associated with increased death, researchers report in the November issue of Stroke. “I believe this is the largest, well-controlled study to consider both coronary heart disease and stroke in relation to depression,” said Brooks B. Gump, PhD, MPH, an associate professor of psychology at the State University of New York, Oswego, NY.
Data for this study of 12,866 men from across the country comes from the Multiple Risk Factor Intervention (MRFIT) Trial, which is based at the University of Minnesota, Minneapolis. The men were average age 46 and had no evidence of coronary heart disease at the start of the seven-year study. They were considered to have above-average risk because of multiple risk factors for heart and blood vessel disease. In the sixth year of the study, the subjects answered a questionnaire to identify depressive symptoms. Symptoms were rated on a four-point scale, beginning at 0, which meant rarely experiencing symptoms, and ending at 3, which meant experiencing symptoms most of the time.
Researchers then followed them for the next 19 years, tracking deaths and the cause of deaths, said co-author Karen A. Matthews, PhD, a professor of psychiatry, psychology and epidemiology at the University of Pittsburgh and the director of the Pittsburgh Mind-Body Center. After adjusting for age, blood pressure, alcohol consumption, and other factors that could influence the results, the researchers found that men in the top quintile, or one-fifth, of depression scores had a 15 percent increase in all-cause death, a 21 percent increase in cardiovascular disease death and double the risk of stroke death, compared with men in the lowest quintile for depression, Dr. Gump said.
Although about 22 percent of these high-risk men had developed cardiovascular disease by the year they answered the questionnaire on depression, an analysis showed that the relationship between depression and cardiovascular disease was found regardless of cardiovascular disease history, Dr. Gump said. Still, the current study is unable to rule out the possibility that silent strokes might have contributed to the increased risk of depressive symptoms and cardiovascular disease deaths.
About half of all earlier studies on this issue had found a positive association between depressive symptoms and mortality, one-fourth found the opposite, and another fourth showed different mortality-depression associations for men and for women. Those inconclusive findings may have been because the number of subjects was too small to be able to consider both stroke and heart disease deaths separately, he said.
Men who were slightly depressed (the second and third quintiles) had a 22 to 24 increased risk of stroke in the next 19 years compared with those with no depressive symptoms. Men in the fourth quintile had a 75 percent greater risk and those in the top quintile had a 103 percent increase in risk.