Hormone Replacement Therapy Revisited
Low-Dose HRT May Protect Against Bone Loss Without Life-Threatening Side Effects
Aug. 26, 2003 -- Women at risk for bone-thinning osteoporosis may be able to take hormone replacement therapy for its bone-preserving benefits without increasing their risk for heart disease and breast cancer. Intriguing new research offers the hope that very low doses of estrogen or estrogen plus progestin can improve bone density with few unwanted side effects.
If confirmed, the early findings could once again open the door to the routine use of hormones for the prevention of osteoporosis. That door was closed just over a year ago, when the government-funded Women's Health Initiative (WHI) was stopped early after researchers concluded taking the combination estrogen-progestin treatment Prempro put women at increased risk for breast cancer, heart attack, strokes, and blood clots.
New findings from the WHI, published earlier this month, suggest the risk may be even greater than previously thought. Hormone therapy was found to almost double a woman's risk of having a heart attack during the first year of treatment.
Most doctors now recommend hormone replacement therapy only for short periods and only for middle-aged women seeking relief from the symptoms of menopause. Heart attack risk is very low among women of this age group, so short-term hormone therapy is not a major concern.
The newly reported study, published in the Aug. 27 issue of TheJournal of the American Medical Association, followed a group of higher-risk, older women who were treated with low doses of hormone therapy for three years, solely to prevent bone loss.
Lead researcher Karen M. Prestwood, MD, says she began researching lower estrogen doses in the mid 1990s, at a time when hormone replacement therapy was widely touted as a panacea for protecting older women from the diseases of aging.
"Many of my older patients on estrogen experienced troubling side effects like breast tenderness and fluid retention, and I began looking at lowering the dosage in an effort to prevent these side effects," the University of Connecticut assistant professor of medicine tells WebMD.
The study included only women over the age of 65, randomly assigned to receive either placebo or the equivalent of one-fourth of a conventional dose of hormone replacement therapy -- estrogen alone in women who had had hysterectomies and estrogen with progestin in women who still had their uterus.
"We saw significant positive effects on bone density in the treatment group, compared to those in the placebo arm of the study," Prestwood says. "The effect was comparable to some of the other drugs [used in the prevention of osteoporosis]."
But Prestwood adds that it is unclear whether the estrogen dosage used in the study protects older women from fractures -- the most important goal for an osteoporosis prevention. She says a larger and longer study is needed to answer this question.