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Charlotte Libov, M.D., physician advocate for women’s heart health, explores the myths concerning women and heart disease which were promulgated in medical schools throughout most of the past century. First, women are NOT largely "immune" to heart disease. Second, if a woman DOES suffer a heart attack, she may not be elderly, as previously assumed.
These relatively new clarifications of the mythic nature of women’s heart treatment show that heart disease is actually the biggest killer of American women, with over 240,000 dying annually. At least 21,000 of these women are under the age of 65. Women with a negative heart history in the family, and particularly if high blood pressure is present, need to take proactive steps such as quitting smoking, reaching and maintaining a normal weight, and engaging in a healthful program of exercise to minimize their risk of serious coronary consequences.
Women who are postmenopausal should discuss the use of estrogen-replacing hormones. While further studies are being done, current data shows that women who take estrogen are half as likely to suffer heart attacks or die from heart disease. But there are risks associated with hormone replacement, such as elevated probability of acquiring breast cancer. How does a woman decide what to do?
The Harvard Medical School’s Harvard Heart Letter recommends that a balance be achieved between risks and benefits, when women are deciding whether or not to take estrogen replacements. The major benefits of postmenopausal estrogen therapy are a reduction in the risk of heart disease and osteoporosis, as well as the symptomatic relief from postmenopausal symptoms like hot flashes and vaginal dryness.
The potential risks are increased chances of breast cancer and endometrial cancer (cancer of the uterus), although the latter risk seems to disappear if the woman takes progesterone along with the estrogen 12 or more days a month.
What do current studies show? Assessing the risk factors of almost 50,000 nurses in the Nurses’ Health Study verified that women taking estrogen replacements lowered their risk of coronary artery disease by half. A further “meta-analysis” by Harvard researchers who combined the results of 30 epidemiologic studies revealed that estrogen therapy reduced the risk of CAD by 44%--close enough to “half” to cause physicians to take notice.
The Harvard Heart Letter finds this study particularly compelling because as many as one-third of all women 65 and over have coronary artery disease, and CAD is the leading cause of death in this group. Some experts speculate that women who take estrogen replacements tend to be healthier in ways that decrease their heart-disease risk, such as engaging in additional exercise, eating healthier diets, or seeing their physicians more frequently. Some of these factors could be responsible for the lowering of heart disease risk, yet there are clearly biologic reasons why estrogen should be good for the heart. For one thing, women on estrogen therapy continually have a significant increase in HDL, the good cholesterol, and a comparable decrease in the bad cholesterol, LDL.
Studies have also shown the positive effects of estrogen on the reactivity of blood vessels. That is, women who received injections or powerful oral doses of estrogen showed a significant dilatation of their blood vessels in response to certain stimuli, a factor that might be expected to protect the heart by providing increased blood flow. Also, it is thought that estrogen replacement may possibly decrease blood clotting, one of the factors thought to precipitate a heart attack. For example, estrogen users show lower levels of fibrinogen, a protein involved in blood clotting. Also, estrogen may improve the body’s response to insulin; since insulin resistance is another independent risk factor for heart disease, this is an added benefit. Some studies show that women taking estrogen report a lowered blood pressure, although this is not a definitive finding at this time.
Physicians are currently calling for more studies to look at the combination of progestin-estrogen therapies on heart health in women, since most studies thus far have focussed on estrogen replacement primarily. But another big plus factor for taking estrogen replacements is estrogen’s amazing ability to prevent bone loss density, and possibly even to increase bone density in many women. Since one in six women has a hip fracture during her lifetime, and many more have vertebral fractures, the increased bone density could be a major health factor overall. Recently, other medications that are not estrogens have become available to treat women with osteoporosis who should not take female hormones.
Exactly who are the women who should consider avoiding female hormones? Postmenopausal women who still retain their uterus and take estrogen therapy by itself have six times the likelihood of incurring endometrial cancer, a powerful warning. But when progestin is added to the prescribed dosage of estrogen, the risk seems to disappear. Thus, the concomitant use of progesterone with estrogen appears to protect against endometrial cancer.
Breast cancer risk however remains controversial. One study showed that women on some sort of estrogen therapy have a 40% increased risk of incurring breast cancer, and the risk appears to increase when the hormones have been taken for five or more years, putting women in the 60-65 year old range at particular risk. This factor remained solid, whether the treatment was for estrogen alone or estrogen in combination with progestin.
Another study is more reassuring, although the study involved a smaller number of participants. In it, researchers argued that there was no increased risk of breast cancer among women who took hormones for more than eight years. Probably the most significant factor for women considering hormone therapy is their personal histories. With a clear cut family history of breast cancer, which affects one women in nine over a lifetime and accounts for 45, 000 deaths of US women each year, women should consider the statistics soberly.
With no family history of breast cancer, whether or not heart disease history is present, women should probably be encouraged to consider estrogen replacement. With heart disease history in the family, women should probably be strongly encouraged toward hormone replacement in postmenopausal years.
The Women’s Health Initiative, a massive study which is looking at many aspects of female health, should prove enlightening. In one branch of the study 27,500 postmenopausal women will be treated either with estrogen alone, estrogen with progestin or with a placebo over a nine-year period. Investigators hope to more clearly define the role of hormone therapy as regards heart disease, osteoporosis, breast and endometrial cancer. Until results are in and fine-tuned, women should carefully consider the possibilities with their medical care providers and make the wisest choice available to them at this time.
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