The National Institutes of Health said on Tuesday it had stopped a trial of women taking estrogen replacement therapy after finding the pills not only failed to improve their health but also may have slightly raised the risk of strokes.
It was the second broad trial of hormone replacement therapy to have been halted in two years. In July 2002, women taking estrogen and progestin were told to stop because of the risk of heart attack, stroke and some forms of cancer.


The trial stopped on Tuesday was a separate arm of the same trial, called the Women's Health Initiative. The 11,000 women in this part of the study were taking Wyeth Co.'s Premarin, an estrogen-only pill made from the urine of pregnant mares.

"After careful consideration of the data, NIH has concluded that with an average of nearly seven years of follow-up completed, estrogen alone does not appear to affect (either increase or decrease) heart disease, a key question of the study," the National Heart, Lung and Blood Institute, which organizes the Women's Health Initiative, said in a statement.

"At the same time, estrogen alone appears to increase the risk of stroke and decrease the risk of hip fracture. It has not increased the risk of breast cancer during the time period of the study."

ABOUT-FACE IN TREATMENTS

Menopausal women and their doctors were shocked when the Women's Health Initiative showed in 2002 that hormone replacement therapy did not, as had widely been believed, prevent heart disease.

Millions of women had been told taking hormone replacement therapy would ease the symptoms of menopause and help prevent heart disease, osteoporosis and memory loss.

Doctors hoped that somehow taking estrogen only would prove more benign, but Tuesday's announcement did little to support those hopes. Usually estrogen alone is taken by younger women who have had hysterectomies, as opposed to hormone combinations given to menopausal women.

"The increased risk of stroke in the estrogen-alone study is similar to what was found in the (Women's Health Initiative) study of estrogen plus progestin when that trial was stopped in July 2002," the National Heart, Lung and Blood Institute said. "In that study, women taking estrogen plus progestin had eight more strokes per year for every 10,000 women than those taking the placebo. The NIH believes that an increased risk of stroke is not acceptable in healthy women in a research study."

Last May, researchers found that combined hormone replacement therapy also slightly raised the risk of Alzheimer's disease and other forms of dementia. The Food and Drug Administration, which has been directing hormone replacement therapy makers to update their labeling with clear warnings, said it would act on the latest findings.

"FDA is advising women that post-menopausal hormone therapy has never received approval for prevention of heart disease, or cognitive disorders such as Alzheimer's disease or memory loss," the agency said in a statement.

"This potential risk is reflected in the current product label for Wyeth's estrogen therapy products," Wyeth said in a statement. "It should be noted that the 0.625 mg strength of Premarin was studied in the (Women's Health Initiative); today, Wyeth has a number of lower dose estrogen and estrogen plus progestin options widely available," the company added.

There are no statistics yet to show whether lower-dose hormones may be safer. The FDA said women with severe menopause symptoms should still be able to consider taking hormone replacement therapy, but only for the shortest time possible.

By Maggie Fox, Health and Science Correspondent