Mental stress + heart disease: Stronger presence in women under 50

Researchers have found that women younger than 50 with a recent heart attack are more likely to experience restricted blood flow to the heart (myocardial ischemia) in response to psychological stress.

The finding may partly explain why younger women who are hospitalized after a heart attack face a greater risk of complications and dying, compared to men of the same age.

The results are scheduled to be presented Wednesday, Nov. 20 at the American Heart Association Scientific Sessions meeting in Dallas.

Researchers at Emory University have been studying the responses of patients who recently had a heart attack to exercise stress and mental stress, in the form of public speaking on an emotional topic. They have found that women age 50 and below are more likely to experience mental stress-induced ischemia, compared to men of the same age (52 percent compared to 25 percent).

The MIMS (Myocardial Infarction and Mental Stress) study included 49 men and 49 women, age-matched pairs who all had a heart attack in the last six months. Their ages ranged from 38 to 59. Among study participants older than 50, there were no significant sex differences in mental stress-induced ischemia;, however, men older than 50 had a rate of exercise-induced ischemia that was twice as high as women of a similar age.

"This is the first study to examine the cardiovascular effects of psychological stress as a possible mechanism for the greater mortality after myocardial infarction among younger women," says study leader Viola Vaccarino, MD, PhD, professor and chair of the Department of Epidemiology, Rollins School of Public Health.

"We saw a dramatic difference in mental stress-induced ischemia specifically in younger women. In addition, when ischemia was graded in a continuous way, we saw that it was twice as severe among the younger women."

Women who experience a heart attack before age 50 are relatively rare, suggesting that perhaps those who do simply have more severe heart disease. However, even when investigators adjusted for different rates of traditional heart disease risk factors such as smoking and diabetes, the disparity remained. In fact, women tended to have less severe coronary artery disease, measured by examining the degree of blockage in their coronary arteries.

One possible explanation the Emory investigators considered was a higher burden of psychosocial stress, Vaccarino says. In the study, the younger women were more often poor, of minority race, with a history of sexual abuse and with higher levels of depressive symptoms.

"Yet if we look at the statistics, factors such as poverty, race and depression do not explain the difference," she says. "Yes, women have more stressors. But our data show that women also may be more vulnerable to the effects of mental stress on the heart."

"This could be an added stimulus to the medical community to pay more attention to the emotional factors in cardiac patients. We are now taking a closer look at potential physiological factors that account for the additional susceptibility in younger women."