The Biggest Killer of Women: Heart Attack

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At director Dr. Bernadine Healy's instigation, the NATIONAL INSTITUTES OF HEALTH is preparing to launch the Women's Health Initiative, a $500 million, 14-year study of 140,000 postmenopausal women. The study will explore the effects of diet, smoking and other factors on women's risk of developing heart disease, stroke, osteoporosis, and breast and colon cancers. The study will also evaluate the effects of hormone replacement therapy: providing women with supplemental estrogen or with estrogen plus progestin after menopause.

Some studies have already suggested that these supplements reduce the risk of heart disease by as much as 30% to 50%, but cardiologists and their patients sometimes shy away from them; larger doses, like those used in early birth-control pills, are known to increase the risk of endometrial and breast cancer. Still, many doctors, considering the even greater risk of coronary- artery disease in the absence of estrogen, now endorse the supplementary therapy. One strong advocate is Framingham's Castelli, who calls the evidence of its efficacy in protecting against both heart disease and osteoporosis "overwhelming."

For all the hubbub about estrogen, its workings are still somewhat mysterious. "We attribute the rise in heart disease to menopause, in which the estrogen supply is diminished," says Columbia's Giardina. "Yet we really don't know how estrogen works." The hormone is known to promote higher levels of HDL, the "good cholesterol" that helps keep arteries clear. Yet estrogen increases HDL by only 10% or 15%, and Giardina suspects that is not enough to account for the dramatic difference in heart disease rates between men and premenopausal women.

Part of the answer may lie in a report published two months ago in Circulation, an American Heart Association journal. In a study of some 1,900 men ages 42 to 60, Finnish researchers determined that the risk of heart attack was greater among men with high blood levels of iron than in those with lower readings. For each 1% increase in the amount of ferritin (a protein that binds iron), the risk of heart attack increased by 4%. The reason, many doctors suspect, is that iron may interact with LDL, "the bad cholesterol," in a way that promotes the formation of plaque on arterial walls.

Healy finds the Finnish study "very provocative." It suggests that at least part of estrogen's protection is indirect: by triggering the monthly menstrual flow, which carries away iron, it reduces levels of the metal in the bloodstream and lessens the threat of heart attack. When periods cease after menopause, the reasoning goes, iron begins to accumulate and the risk rises.

Besides taking estrogen supplements, "women themselves can do a lot to reduce their risk of heart disease," says Dr. Millicent Higgins, associate director of epidemiology and biometry at the National Heart, Lung and Blood Institute. She recommends that women have their blood pressure checked and treated if it is found to be high, eat diets low in fat, exercise, lose excess weight and stop smoking. But most important of all, she says, is that "women need to be aware that they can have heart attacks."

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CREDIT: [TMFONT 1 d #666666 d {Source: American Heart Association, based on the Framingham Heart Study}]CAPTION: RISING RISK

Heart attacks in the U.S. in thousands*