The National Institutes of Health has halted a large study on the long-term effects of estrogen therapy in healthy women, officials announced Tuesday, saying the hormone caused an increased risk of stroke.
But unlike the combination of estrogen and progesterone, which was tested in a parallel study, estrogen alone did not increase the risk of heart disease or breast cancer.
In fact, the overall risk of a serious health problem was the same for women who took estrogen as for those who took dummy pills, because the risks of estrogen were neutralized by the benefits–mainly, the prevention of hip fractures.
Nevertheless, the NIH concluded that “an increased risk of stroke is not acceptable in healthy women” and stopped the trial, according to Dr. Barbara Alving, director of the Women’s Health Initiative, which is a project of the NIH.
`Not a panacea for aging’
The take-home message from both hormone studies remains the same, doctors said Tuesday: If you need hormones to manage menopausal symptoms, take the lowest effective dose for the shortest possible time. If you’re thinking of taking hormones to improve your health–don’t.
“Hormone therapy isn’t really good for you,” said Dr. Henry Black, chairman of preventive medicine at Rush University Medical Center. “There’s no question it helps people through menopause. But it’s not a panacea for aging.”
Black said that data from the study will be analyzed carefully and that the subjects will continue to be followed. That could help identify some groups of women who might see greater benefit than risk from therapy.
“If you knew who would get fracture prevention and isn’t at risk for stroke–that could be an ideal candidate,” he said.
The Women’s Health Initiative’s trial of estrogen plus progesterone was cut off in July 2002, causing widespread panic among postmenopausal women. Sales of Prempro, the combination hormone pill used in the study, plummeted. Use of Premarin, the estrogen-only pill being studied in the parallel trial, also dropped. Even sales of hormone pills containing different forms and lower doses of the two hormones suffered.
The WHI study was designed to find out whether long-term hormone use in healthy women could prevent serious health problems, such as heart disease–as several small studies had suggested. Women who were suffering menopausal symptoms were excluded from the study, which was not intended to assess the risks or benefits of hormones for short-term symptom management.
Nevertheless, millions who were taking the drugs to alleviate menopausal symptoms ditched them for fear of getting heart disease or breast cancer. In an unintended development, even women in their 30s whose ovaries had been shut down by surgery or drugs–and who were thus thrown into premature menopause–stopped taking hormones.
“What is widely being lost in the panic over WHI is that its findings were never meant to apply to women under 50 without working ovaries,” said Dr. Linda Hughey Holt of the Northwestern University School of Medicine, a consultant to the Women’s Health Initiative. “It’s just common sense that those women should be given hormones … until they reach the age of natural menopause.”
Wyeth, the manufacturer of Prempro and Premarin, noted Tuesday with relief that Premarin apparently does not increase the risk of breast cancer, which should reassure some women who need to take the drug for treatment of menopausal symptoms or to prevent osteoporosis. The company also noted that the increased risk of stroke found in the study is already reflected in the labels of its estrogen products.
Risk similar in other study
The estrogen-alone arm of the study involved 11,000 healthy women age 50 to 79 who had undergone hysterectomies. Combined hormone pills are generally preferred for women with an intact uterus, because unopposed estrogen can cause cancer of the uterine lining.
The results are still being analyzed, and the findings will be published within two months.
In the meantime, a preliminary analysis of the estrogen-alone study found that the increased risk of stroke was similar to that in the combined-hormone study. In that trial, women taking hormones had about eight more strokes per 10,000 women per year than those taking placebo pills.
Both studies also found a lower risk of hip fractures due to bone-thinning osteoporosis. In the estrogen-progesterone trial, for every 10,000 women there were five fewer broken hips per year.
But the combined-hormone study also found seven more heart attacks and eight more cases of breast cancer per 10,000 women per year compared with those on placebos. No such increases were found in the estrogen-only trial.
Preliminary data from women over 65 also suggest hormones don’t help prevent memory loss, as was once hoped.
