For older women, the difficult question of whether to take estrogen for the rest of their lives has grown even more complicated.
On Wednesday, researchers reported new evidence that estrogen supplements after menopause may cut the risk of Alzheimer’s disease in half. Today, another study is coming out suggesting that long-term use increases the risk of dying from breast cancer by nearly half.
Women often take estrogen for a couple of years to ease the hot flashes and other symptoms of menopause, and there is little doubt about the safety of this limited use.
More controversial, however, is the idea that women should keep on taking the pills because of estrogen’s other well-known benefits: It clearly protects the heart and keeps bones from growing brittle, and might also ward off Alzheimer’s.
Estrogen also increases the risk of breast cancer, although by just how much has been unclear. Nevertheless, since heart disease is so much more common than breast cancer in older women, many doctors and their patients assumed that the benefits far outweighed the risks.
The latest study, published in today’s issue of the New England Journal of Medicine, attempted to see what estrogen supplements do to women’s risk of death. It is the first to assess how this risk changes over time.
Like other studies, it found that estrogen dramatically reduces older women’s risk of dying from a heart attack. But it found that the risk of breast cancer gradually increases. And after a decade of use, the increasing cancer deaths begin to wipe out the advantages of avoiding heart trouble.
Researchers say these studies emphasize the need for making the decision about long-term estrogen on a person-by-person basis, taking into consideration each woman’s risk of heart trouble, breast cancer and other diseases.
The Boston study involves 121,700 women in the Nurses Health Study, including 3,637 who died during 18 years of follow-up.
It found that the risk of dying from any cause was 45 percent lower than expected among nurses who took estrogen supplements for less than five years. Between five and 10 years of use, the risk was 40 percent lower.
However, after more than 10 years on estrogen, the risk of death was just 20 percent lower. This is because these women’s risk of dying from breast cancer was 45 percent higher than nonusers’.
Wyeth-Ayerst issued a statement Wednesday saying that whether hormone replacement therapy raises the risk of breast cancer “remains an inconclusive topic.”