Study: Low-Dose Estrogen

 Use By Older Women

The first clinical trial to compare the effects of different doses of estrogen on bone turnover in older women has shown that lower doses of estrogen improve bone health, while minimizing side effects in healthy women aged 65 and older.

Principal investigator of the study, Karen Prestwood, MD, UConn Center on Aging, at UConn Health Center in Farmington, found that one-quarter of the current 1 mg dose of estrogen recommended as part of estrogen replacement therapy (ERT) is equally effective and has fewer side-effects in older women.

ERT has long been recognized to treat symptoms of menopause, reduce bone loss, and treat osteoporosis, but women frequently experience breast tenderness, fluid retention, headaches, and bloating. The results of this study indicate that older women may be able to reap the benefits of ERT without the side effects. This should be encouraging for women who may be avoiding taking estrogen because of possible adverse effects, said Dr Prestwood.

A group of 106 Caucasian, African-American, and Hispanic women over age 65 participated in the study. After 12 weeks, bone turnover had significantly decreased in the participants taking 0.25, 0.5, or 1 mg of estradiol, a form of estrogen. The group taking the lowest dose had no more side effects than the group taking a placebo, while the two higher doses had more side effects than the groups receiving the placebo or the lowest dose. Decreases in bone turnover among the women who took .25 mg of estradiol were the same as the decreases in the women who took 1 mg.

Bone turnover is the bone remodeling cycle in which new bone is formed as older bone is dissolved. Osteoporosis develops when more bone is dissolved than is formed. This process thins and weakens bones and puts individuals at serious risk for fractures, which commonly occur to the spine, wrist, and hip. More than 10 million Americans have been diagnosed with osteoporosis and about 18 million are likely to develop the osteoporosis.

“It is possible that different women require different doses of estrogen. It is also conceivable that the same woman may require different doses of estrogen at different times in her life,” said Dr Prestwood. “We need to better understand how to treat women individually,” she said.

However, she cautions women already being treated with the usual dose not to arbitrarily lower their doses. For women having problematic side effects, a lower dose may be something to consider, but only after discussing it with their physicians.

The study was conducted at the UConn Health Center by Dr Prestwood and Anne Kenny, MD, assistant professors of medicine, and Christine Unson, PhD, research associate, Claude Pepper Older Americans Independence Center at the UConn Center on Aging; and Martin Kulldorff, PhD, Department of Community Medicine. The Pepper Center is one of ten such centers funded by the National Institutes of Health conducting research on muscle/bone problems, especially osteoporosis.