Low Estrogen Linked to Heart Disease
Sex Hormone May Protect Women Prior to Menopause
Feb. 4, 2003 -- New research adds to the evidence that estrogen plays a complex role in heart disease risk. It suggests that estrogen and other sex hormones protect younger women who have not reached menopause against heart attack and stroke.
The findings may lead to a better understanding of why women who develop heart disease at an early age tend to have a worse outcome than men, lead researcher Noel Bairey Merz, MD, FACC, tells WebMD. They also suggest that women of different ages have very different responses to estrogen, which is now believe to increase heart disease risk among older women who have completed menopause.
"It is not at all unlikely that for one group of women estrogen is protective against coronary artery disease and for another group it is detrimental," Bairey Merz says. "We are just beginning to understand the complex role of these hormones, and the hope is that this understanding will lead to better ways to prevent and treat heart disease."
Bairey Merz and colleagues assessed sex hormone blood levels among 95 premenopausal women at risk for heart disease. The found that 69% of the premenopausal women who actually had coronary artery disease (CAD) had low estrogen levels due to abnormal functioning of the hypothalamus, the part of the brain that controls hormone production. These women also had low levels of the hormone estradiol and of follicle-stimulating hormone, which stimulates the ovary to produce estrogen. Less than a third of the women without CAD (29%) had low estrogen levels. The findings are reported in the Feb. 5 issue of the Journal of the American College of Cardiology.
The director of the Women's Health Program at Los Angeles' Cedars-Sinai Medical Center, Bairey Merz says studies in monkeys strongly suggest that stress can lead to significant reductions in estrogen levels. She adds that the women with low estrogen levels in this study tended to be more anxious and reported higher levels of stress.
"This study is very preliminary, and it certainly doesn't establish cause and effect," she says. "But it does suggest the possibility that estrogen deficiency, which might be caused by stress, is a risk factor for coronary artery disease in premenopausal women."
Heart specialist Robert Vogel, MD, says it is no surprise that estrogen appears to protect women who are still ovulating against heart disease. He says it is now believed that older women do not benefit because they have lost the estrogen receptors that allow them to respond to estrogen.
"The main message here is that age does count," the University of Maryland professor of medicine tells WebMD. "From a heart standpoint, premenopausal women are better off keeping their ovaries, and postmenopausal women need to be cautious about taking estrogen therapy."