As the number of women over 60 gradually increases, the debate over the benefits and risks of using estrogen replacement therapy (ERT) in menopause has heated up. Scientists are still trying to determine the value of this treatment.
Q: What are the proven benefits of estrogen replacementherapy?
A: Estrogens given around the time of menopause will definitely reduce the hot flashes or flushing and the osteoporosis that occur during this period of change. Although aging will still cause bone loss, the rapid loss in bone density that occurs around the time of menopause does not occur and so women experience only the gradual decline, which is common to both sexes.
Q: What are the risks of ERT?
A: Use of estrogen clearly increases the risk of endometrial cancer (cancer of the lining of the uterus). It also possibly increases the risk of breast cancer. Fortunately, the cancers of the endometrium have a good survival rate in most patients (when detected early enough) and they can be prevented by the use of combined estrogen and progesterone hormonal therapy. We know less about the effects on the risk of breast cancer.
Q: Why are new questions regarding ERT being raised today?
A: Some scientists believe that ERT may reduce the risk of cardiovascular disease, which increases in women after menopause. Not all studies, however, have reported these beneficial effects. Plus, in all studies to date the women have been given the therapy for reasons other than the prevention of heart disease.
The question arises as to whether the women on therapy had a different risk for cardiovascular disease even before they ever took the hormone. Studies have shown, for example, that the women on therapy are generally thinner, and this may reduce their risk.
Q: What issues remain about the hormonal therapy itself?
A: Most of the reported risks and benefits from therapy have been gathered on women who received oral estrogens. Hormones received orally must pass through the liver before going to the target organs.
Doctors are now giving the hormone through the skin to allow it to enter the bloodstream directly, bypassing the liver altogether. This would reduce the possible risk of blood clots and high blood pressure, although these have never been a reported problem with menopausal estrogen therapy.
There are direct changes in the blood fats of women on estrogen therapy, which should make their heart disease risk lower. Cholesterol and fats are carried in the blood with proteins in "packages" called lipoproteins. The so-called "bad" low-density lipoproteins (LDL) carry most of the cholesterol and cause the buildup of atherosclerotic plaques in arteries. High-density lipoproteins (HDL) carry cholesterol to the liver, where it is broken down and consequently is considered a "good" cholesterol. Estrogen use will improve a woman's blood-fat profile by increasing the HDL and decreasing LDL.
This profile is thought to reduce the risk of cardiovascular disease. For this reason, several years ago men who had a heart attack were given estrogen to reduce their risk of having another. While their cardiovascular profile changed for the nTC better, their risk of death from heart disease did not. Thus, blood changes alone are not enough to prove that the observed changes in heart disease are from estrogen therapy.
The addition of a progesterone hormone to the estrogen treatment raises additional questions. This hormone causes the blood-fat profile to look more like that of people at risk of heart disease in some studies.
Also, the combination of estrogen and progesterone may cause vaginal bleeding for some women. So, while the therapy with both hormones may reduce the risk of endometrial cancer, the effects on cardiovascular diseases are not well known.
Q: What is the bottom line?
A: The medical community still has many questions to answer before the optimum treatment of women in menopause is known. Currently, many women are receiving estrogen therapy to improve menopause symptoms such as hot flashes, and to prevent against osteoporosis that becomes much more common after menopause.
The use of this therapy is definitely a question that deserves thoughtful discussion with your doctor to determine what the best course is for you.
Dr. Genevieve Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is a founding director of the school's Institute for Women's Health Research and Policy.