Hormone Replacement Therapy Revisited
Low-Dose HRT May Protect Against Bone Loss Without Life-Threatening Side Effects
"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.
Women's health specialist Kathryn Rexrode, MD, agrees that such a study is warranted. Rexrode is an assistant professor at Boston's Brigham and Women's Hospital and Harvard Medical School.
"The exciting news from this study is that such a low dose of estrogen does have beneficial effects on bone," she tells WebMD. "Whether those effects will be sufficient to prevent fractures or whether this dosage reduces the unwanted side effects of hormone therapy has not been proven."
Though the Women's Health Initiative answered many questions about the use of hormone replacement therapy, Rexrode says it also left many questions unanswered regarding its role in both preventing and promoting disease.
"The idea that ultra-low doses of estrogen just might change the balance of risks and benefits for this therapy is certainly tantalizing," she says. "But the only part of the equation to be answered by this study is that this low dose does have a positive effect on bone."