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TUESDAY, Aug. 26, 2003 (HealthDayNews) -- Older women can get the bone-building benefits of estrogen by taking about a quarter of the usual dose, perhaps minimizing some of the potential dangers associated with hormone therapy, a new study has found.
The lean dose led to substantial gains in bone mineral density over the course of the three-year study, building the skeleton at the hip, wrist and spine. Although the study was too small to determine if the treatment reduced a woman's risk of fractures, even slight increases in bone mass can prevent breaks.
"Small increases in bone mineral density result in decreased fracture risk with other [drugs]," says study leader Dr. Karen Prestwood, an aging researcher at the University of Connecticut. The low dose "may be beneficial to bone but have a lower side-effect profile" than stronger preparations, she adds. Her findings appear in the Aug. 27 issue of the Journal of the American Medical Association.
If true, that would be comforting to many women.
Estrogen has been the workhorse for the treatment and prevention of osteoporosis. The hormone helps prevent the body from cannibalizing the skeleton for calcium -- the result of the loss of estrogen associated with menopause.
However, estrogen therapy, particularly in combination with progestin, has come into question lately. It's been well known that estrogen triggers uterine cancers, but several studies have found the combination of hormone supplements can cause breast cancer while failing to reduce the heart problems for which some women have been taking them.
Recently, newer drugs have arrived that also reduce the risk of fractures, though these have side effects many women can't tolerate.
Prestwood's group followed 167 women who were at least 65 years old at the start of the study. About two thirds had low bone mass, a condition called osteopenia, and a third had full-blown osteoporosis. Roughly half were given .25 milligrams a day of an estrogen preparation called 17 beta-estradiol, the form that circulates in the human body, and the rest took dummy pills.
By the end of the trial, women on estrogen saw their bone mineral density rise by 1.2 percent on a whole-body scan compared with women on the sham treatment. The increase was three times greater at the hip, 2.6 percent at the head of the femur, and 2.8 percent in the spine. At the same time, blood markers of bone turnover -- the skeleton consuming itself -- declined in the women taking estrogen compared with the other group.
The findings agree with previous research showing that scaling back estrogen doesn't sacrifice its bone-saving effects. But this is the first long-term study to show the benefits of such a low dose with 17 beta-estradiol. The dose was half the amount prescribed for Premarin, which is derived from horses, that doctors consider low, Prestwood says.
While the study didn't find any increase in breast cancers among women taking estrogen, it wasn't large enough to detect such a risk, Prestwood says. The researchers did find that women on low-dose estrogen had less incontinence, a frequent remnant of menopause.
Dr. Wulf Utian, executive director of the North American Menopause Society, says it's "wishful expectancy" to suppose that lower doses of estrogen will cause fewer side effects than higher amounts.
"The problem is that the expectation will be that there will be fewer risks, but the only way we're ever going to prove that is with outcome studies," Utian adds.
More information
Try the North American Menopause Society or the Women's Health Initiative. For more on osteoporosis, visit the National Osteoporosis Foundation.
