Bone study gives estrogen therapy another chance
With many women shying from hormone replacement therapy because of potential risks of heart attack, stroke and cancer, some doctors are seeking safer ways to take advantage of estrogen’s bone-preserving benefits.
They’ve been experimenting to see if lower doses can protect bone density without the cardiovascular and cancer risks that led federal officials to halt the Women’s Health Initiative study three years early. That study of 16,000 women found that taking estrogen plus a progestin conferred no protection against heart disease and instead increased disease risks.
Some women subsequently went cold turkey; others opted only for short courses of hormones. But that left many fearing a disabling effect of low estrogen: bone-thinning that can lead to spinal and hip fractures, and sometimes death.
“There may still be some role for estrogen so that we don’t need to throw it out completely, and a lower dose may be the answer,” said lead study author Dr. Karen M. Prestwood, a University of Connecticut geriatrician.
She and her colleagues used ultra-low-dose estrogen -- about one-fourth of the standard treatment -- in a study of 167 healthy women age 65 and older. They found that taking just 0.25 milligram of estrogen daily for three years increased bone density of the hip by 3.6%, the spine by 2.8%, and the body overall by 1.2%, according to findings in the current Journal of the American Medical Assn. In addition, the treatment decreased bone turnover, in which more bone breaks down than builds up.
Results of the study, funded by the National Institute on Aging, probably will stir additional debate about whether estrogen has a place in treating some effects of menopause.
Earlier research by Prestwood had found that the 0.25-milligram dose reduced bone turnover as much as a full dose, leading to the most recent study in which participants who had undergone hysterectomies received estrogen alone or a placebo. Women with an intact uterus also got tiny doses of progesterone for two weeks every six months to guard against potentially dangerous thickening of the uterine lining.
The clinical trial used 17-beta estradiol, a natural estrogen; other studies have used conjugated equine estrogen, which is derived from the urine of pregnant mares. All 167 participants took calcium and vitamin D.
Dr. Robert P. Heaney, a long-time specialist in bone biology at Creighton University in Omaha, Neb., said Prestwood’s work might help swing the pendulum back toward selectively using low-dose estrogen.
“It pushes one step further the study we published about four years ago showing that half the usual dose of estrogen still produced a very strong bone benefit if you gave plenty of calcium and vitamin D,” he said. “They got quite a nice effect.”
