Women warned
against estrogenThe hormone raises risk
of strokes and breast cancer,
a national study says
About 11,000 women taking estrogen in a national study, including 143 in Hawaii, have been told to stop taking the pills because of an increased risk of stroke.
Findings of the estrogen-only trial were similar to those in a companion study of women taking estrogen plus progestin, the National Institutes of Health reported yesterday.
The NIH stopped the 5.6-year combined-hormone trial in July 2002 before the targeted completion date because data showed increased risks of breast cancer, heart disease, stroke and blood clots outweighed benefits for reduced hip fractures and colorectal cancer.
After seven years of following women taking only estrogen, NIH reported yesterday that the hormone does not seem to increase or decrease heart disease but increases risk of stroke, which "is not acceptable in healthy women in a research study."
NIH said letters have been sent to all estrogen-alone participants -- healthy postmenopausal women who have had a hysterectomy -- informing them of the study results.
A total of 414 Hawaii women participated in the hormone replacement trials, 143 on estrogen alone (121 are still active) and 271 who were on estrogen plus progestin, said Dr. J. David Curb, University of Hawaii professor of geriatric medicine.
Curb, principal investigator in Hawaii for the Women's Health Initiative studies, said NIH stopped the estrogen-alone study Monday based on data up to November.
"NIH felt there was enough reason to stop," Curb said. "Overall, they felt it was unlikely that there would be anything new discovered in the year left in the study."
The estrogen-alone study was intended to see if long-term use of hormone therapy would prevent heart disease and hip fractures or change breast cancer risks in healthy postmenopausal women ages 50 to 79.
The hormone did decrease the risk of hip fracture, which was already known from other studies, and there was no negative effect on breast cancer, which occurred in the estrogen-progestin group, Curb said.
But no benefit appeared for heart disease -- the major question of the study -- while risk of stroke was higher, he added.
"These are really important studies," Dr. Ross Prentice, of the Fred Hutchinson Cancer Research Center and director of the Clinical Coordinating Center for the Women's Health Initiative trials, said in an interview here yesterday.
"For many years, there was strong belief and increasing belief that either estrogen alone or combined hormones would reduce the heart disease risk."
Based on the findings, he said, "This is quite important that women won't be advised in the future to initiate or continue hormone therapy primarily for heart-disease prevention."
However, hormone therapy is effective for controlling menopausal symptoms and will continue to be used for that, but for shorter periods, he said.
Prentice, a member of the Women's Health Initiative Data and Monitoring Board that reviews the data and oversees the safety of participants, discussed the findings in a talk yesterday at the Cancer Research Center of Hawaii.
A separate report will be issued on a related memory study involving women older than 65.
Preliminary data indicate increased risk of probable dementia for those on estrogen alone, compared with those on placebo, NIH said.
Similar results occurred in the estrogen-progestin study.