3 studies examine effects of HRT
Following are brief overviews of the latest research articles on the use of hormone replacement therapy (HRT):
1. Estrogen use may prolong life, but length of use lessens benefits.
Use of estrogen following menopause may limit a woman’s chances of early death, but the survival benefit diminishes the longer she remains on the medication, according to a recent study from Boston.1 "In general, the benefits seem to outweigh the risks," says the study’s lead author, Francine Grodstein, PhD, of Harvard University’s department of epidemiology. "That doesn’t seem to be quite as true as for all people, though. Women with risk factors for cardiovascular disease had much more substantial benefits than women who had no risk factors."
Grodstein and her colleagues studied the effects of estrogen use among 3,637 women who died between 1976 and 1992 and 30,000 others. All of the participants were among 121,000 women in the Nurses Health Study, a large, prospective study begun in 1976.
After adjustment for confounding variables, the study revealed that current hormone users had a lower risk of death than those who had never taken hormones. However, the apparent benefit decreased over time because of an increase in mortality from breast cancer among long-term hormone users.
The study found that women with coronary risk factors, who comprised 69% of the group, had the largest reduction in mortality, with substantially less benefit for those at low risk for the disease.
The complexity in weighing the risks and benefits arises because the benefits of long-term therapy are offset by a 43% higher risk of dying from breast cancer after 10 years. Partly due to these risks for breast cancer, the life-preserving benefits of estrogen appear to decrease after 10 years of use.
2. Life expectancy increased by HRT.
The use of a diagnostic model developed by physicians from Boston’s New England Medical Center and Tufts University School of Medicine shows that among women at risk for breast cancer, the presence of even one risk factor for coronary heart disease tips the balance in favor of HRT.
Nananda Col, MD, MPP, assistant professor of medicine at Tufts University School of Medicine, and colleagues published their model in the Journal of the American Medical Association.2 In the article, the researchers examined the lifetime risks of developing coronary heart disease, breast cancer, hip fractures, and endometrial cancer and analyzed the impact of HRT on disease incidence.
"Our model predicts that HRT should increase the average life expectancy of most postmenopausal women," they write. "The only women not expected to gain from this treatment are those at greatest risk for breast cancer and the least risk for coronary heart disease."
The model looks only at the long-term risks and benefits of hormone therapy, Col says. "In this particular model, we are [asking,] If a woman wants to take HRT for whatever reason, what is the impact on her life expectancy and on her chances of developing heart disease, breast cancer, and hip fracture? How will it affect that? Will it make her live longer or shorter?’" she says.
3. ERT use reduces Alzheimer’s risk.
Women who use estrogen replacement therapy (ERT) appear to have a lower risk of developing Alzheimer’s disease, according to a recent study from Johns Hopkins University in Baltimore and the National Institute on Aging (NIA).3
Researchers found that women on ERT had a 54% reduction in their relative risk of developing Alzheimer’s disease. This finding was made through analysis of long-term health information on 472 women in the NIA’s Baltimore Longitudinal Study of Aging, a prospective multidisciplinary study of normal aging. Almost half of the women enrolled in the study had taken estrogen orally or through transdermal patches.
A total of 34 women developed Alzheimer’s disease; nine were estrogen users. In making their analysis, researchers factored in education levels, which have been demonstrated to affect the risk of Alzheimer’s development. Women who reported use of ERT still showed reduced risk for the disease. Scientists theorize that estrogen may play a factor in:
• reducing development of Alzheimer’s disease by stimulating growth of nerve cells;
• inhibiting levels of apolipoprotein E, a fatty acid also closely linked to heart disease;
• deactivating chromosome-damaging oxidants;
• increasing levels of acetylcholine and other neurotransmitters.
"Our findings support the notion that estrogen plays a very significant role in the brain," says one of the paper’s authors, Ann Morrison, MS, RN, who is affiliated with Johns Hopkins University’s Department of Neurology. "This study provides groundwork for future studies looking into the role of estrogen in actually delaying or treating Alzheimer’s disease."
A clinical randomized trial is needed, Morrison says, because at this point, it’s possible that the results demonstrated in the Baltimore study could be explained by variables other than estrogen.
"It’s really only the clinical randomized trial that will control for those variables and lead us to the level of certainty that we need to know that it’s just the estrogen and no other variable playing out here," she notes.
References
1. Grodstein F, Stampfer MJ, Colditz GA, et al. Postmenopausal Hormone Therapy and Mortality. NEJM 1997; 336:1,769-1,775.
2. Col NF, Eckman MH, Karas RH, et al. Patient-specific decisions about hormone replacement therapy in postmenopausal women. JAMA 1997; 277:1,140-1,147.
3. Kawas C, Resnick S, Morrison A, et al. A prospective study of estrogen replacement therapy and the risk of developing Alzheimer’s disease: the Baltimore Longitudinal Study of Aging. Neurology 1997; 48:1,517-1,521.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content