MONDAY, Feb. 13, 2006 (HealthDay News) -- Estrogen therapy appears to do no harm -- or good -- when it comes to heart health in postmenopausal women.
According to the latest results from the mammoth Women's Health Initiative (WHI), the hormone did not diminish or increase the risk for coronary heart disease.
The hormone may, however, reduce this risk in women aged 50 to 59, according to the study, which appears in the Feb. 13 issue of the Archives of Internal Medicine.
But past research has found that estrogen therapy can cause other problems, including a greater risk of stroke.
"It was neutral with regard to heart disease," said study author Dr. Judith Hsia, a professor of medicine at George Washington University, in Washington, D.C.
"But you also have to bear in mind that there still is an increased risk of stroke, dementia and blood clots in the legs and a reduced risk for fractures," Hsia added. "The [U.S.] Food and Drug Administration recommendation that estrogen should not be used for the purpose of heart disease still applies, and the recommendation that women who need to take it for menopausal symptoms should take the lowest dose for the shortest duration possible still holds."
Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, said the new finding "doesn't change anything. Although there was a trend for younger women, it hasn't definitively proven it. We're trying to get women to understand that they have to take more than maybe a pill to reduce their risk for heart disease."
The WHI included two clinical trials that looked at whether hormone therapy with estrogen alone reduced the risk of coronary heart disease in postmenopausal women.
This estrogen-only research was stopped early in March 2003 because the treatment appeared to increase the risk of stroke. The new findings are the final results for that trial.
The estrogen/progestin arm of the Women's Health Initiative (WHI) was also halted early when researchers found the regimen increased the risk of invasive breast cancer and blood clots in the legs and lungs, in addition to not protecting women from heart disease and stroke.
In the wake of the WHI study, the American Heart Association recommended that long-term hormone therapy not be used to protect against cardiovascular disease, and that its use for other reasons "should be cautiously considered with the advice of a physician."
Recent research has suggested that when a woman begins the therapy may be key to whether or not it will protect her from heart disease. According to that research, women who start hormone-replacement therapy (HRT) when they are younger, near the onset of menopause, have about a 30 percent lower risk of coronary heart disease, compared with women who never use hormones. However, women who start HRT 10 years or more after menopause, or after the age of 60, gain no cardiovascular benefit from the therapy.
Some of the new findings may help support that conclusion.
For this trial, 10,739 women, aged 50 to 79, who had undergone a hysterectomy were randomly chosen to take conjugated equine estrogens or a placebo. Estrogen cannot be given on its own to women who still have a uterus because of the increased risk of endometrial cancer.
Over a follow-up period of 6.8 years (the trial was originally scheduled to go on for 8.5 years), the risk for coronary events, including heart attacks and coronary death, were similar in both groups of women.
There was a hint of a lower risk in women in the 50-to-59 age range, which was quickly picked up by Wyeth, maker of the estrogen therapy Premarin.
"Timing may, in fact, be key," Dr. James Pickar, Wyeth's assistant vice president of clinical research and development, said at a news conference Friday. "Menopausal hormone therapy continues to be the best treatment of menopausal symptoms and prevention of post-menopausal osteoporosis and, as this new information continues to emerge, we hope this will encourage women to speak with their doctors and discuss their individual risk-benefit profile."
Dr. Lila Nachtigall, a professor of obstetrics and gynecology at New York University School of Medicine, said, "You do have to individually evaluate women for all risks and benefits, but this puts us in a much happier position to help women."
Pickar said Wyeth is in "regular discussions" with the FDA to determine any labeling changes.
For now, the same recommendations hold: Take the lowest dose possible for the shortest amount of time if hormone therapy is needed for menopausal symptoms, such as hot flashes.
"It really doesn't change anything, and I think at this point women have voted with their feet," Hsia said.
Visit the National Heart, Lung, and Blood Institute for more on the Women's Health Initiative.