Call it coffee klatch research. Or book group medicine. Or just plain winging it.
By whatever name, women of a certain age are trying to figure out for themselves — and with each other — the answers to a midlife question doctors won’t have good answers to for years:
If you’re taking postmenopausal estrogen and cut your dose, say, in half, can you lower the risk of breast cancer that goes with the normal dose — many women’s biggest fear — yet still get the benefits to your heart and bones and ward off hot flashes?
Two new studies — still unpublished, but presented at recent scientific meetings — suggest that women who lower their estrogen are on the right track, though it goes without saying that you shouldn’t do this without checking with your doctor first.
The studies suggest — and that’s really suggest, not prove — that low-dose estrogen may indeed provide at least some of the well-established benefits of the stan-
Don’t change dosage without checking with a doctor
dard dose estrogen regimen, most notably protection against osteoporosis.
Nobody has a clue yet whether lowering estrogen will also reduce the increased risk of breast cancer associated with hormone use, though that hypothesis is both logical and appealing to millions of women who have been scared silly since last year, when a big Harvard research project, the Nurses’ Health Study, documented the increased risk.
The Harvard study found that menopausal women who took estrogen alone raised their risk of breast cancer by about 30 percent, and that those who also took another hormone called progestin raised their risk about 40 percent.
Women who have not had hysterectomies often take progestin with estrogen to avoid the increased risk of uterine cancer that taking estrogen alone poses. In the Harvard study, the risk of breast cancer was increased only among women who had been taking hormones for five years or more.
The troubling Harvard study is a prominent peak in a mountain range of conflicting data on estrogen therapy. There are many good reasons to take estrogen — it reduces the risk of heart disease (which kills six times more women than breast cancer), raises “good” cholesterol and lowers “bad” and clearly wards off osteoporosis.
Estrogen may also protect against Alzheimer’s disease, and it reduces symptoms like hot flashes and vaginal dryness.
Yet many women shy away from hormone therapy because of the added, albeit modest, increased risk of breast cancer.
In the larger of the new studies, Dr. Morris Notelovitz, director of the Women’s Medical and Diagnostic Center in Gainsville, Fla., tested 406 post-menopausal women on various doses of an estrogen pill called Estratab for two years.
All of the women, including those receiving a placebo (a lookalike drug with no estrogen), took 1,000 milligrams a day of calcium, and none took progestin. During the study, neither the women nor the doctors knew who was getting which dose.
The results, presented in September at the North American Menopause Society meeting in Chicago, were very encouraging.
The low dose of 0.3 milligrams a day — half the usual dose of 0.625 mg — increased bone mineral density in the spine and hip without increasing the risk of endometrial hyperplasia, or pre-cancerous cells in the uterus.
The Florida study, if confirmed by other research, means not only that Estratab, which is derived from plant estrogens, can protect bones, but that it can do so without apparently raising the risk of uterine cancer, says Dr. Joseph Mortola, director of reproductive endocrinology at Cook County Hospital in Chicago and a participant in the study.
More work needs to be done, he cautions, but the Florida study, which was funded by Solvay Pharmaceuticals, the maker of Estratab, means some women may be able to avoid taking progestins like Provera to protect the uterus. Progestins can cause bloating, depression and other side effects.
Still, because the data are preliminary, he says, any woman with a uterus who takes only estrogen, even at low doses, and does not take progestin should have an annual endometrial biopsy to make sure she has not developed uterine cancer.
And while it is not yet clear whether low-dose estrogen carries a lower risk for breast cancer, Mortola says the Florida study did find that low-dose estrogen may help protect the heart as well as the bones.
Low-dose estrogen, he says, seemed to have a positive effect on blood lipids — raising good cholesterol and lowering bad, although this finding was not statistically significant.
The low-dose estrogen also reduced hot flashes and vaginal dryness, Mortola noted.
A drawback of the Florida study is that it did not look at Premarin, the estrogen supplement that is derived from horse urine and used most often by American women.
But a small study of about two dozen women by Dr. Karen Prestwood, a specialist in osteoporosis and an assistant professor at the University of Connecticut Health Center, did.
In data presented this fall to the American Society for Bone and Mineral Research, Prestwood found that women taking only 0.3 milligrams a day of Premarin got roughly the same protection against bone loss as those taking 0.625 milligrams.
In related research, Prestwood studied another estrogen formulation called Estrace, a synthetic form of estradiol, the main type of estrogen found in the body.
As long as women also took 1,500 milligrams a day of calcium, low doses (0.5 mg) Estrace — the equivalent of 0.3 mg of Premarin — protect against osteoporosis, she found.
Dr. Isaac Schiff, chief of obstetrics and gynecology at Massachusetts General Hospital, says the new studies follow the logic used for years with birth control pills — reducing the dose to decrease side effects yet still achieve contraception.
“The same thinking is carrying over to estrogen replacement therapy,” he says, adding that the findings are “taking us to a new plateau.” Still, he does not recommend low dose estrogen for everyone, though he does prescribe it for some patients.
There may one more benefit to low dose estrogen, though it has yet to be proved, says Dr. Joann Manson, co-director of women’s health at Brigham and Women’s Hospital in Boston.
A small study by Boston researchers showed recently that women who take estrogen and drink alcohol may raise blood levels of estrogen to more than three times the intended dose.
This study focused on Estrace, not Premarin, and the hormone users drank quite a bit — the equivalent of three glasses of wine.
Yet the emerging data suggest that women who drink may want to ask their doctors if they should switch to low dose estrogen.
No matter what the doctor says, it’ll make for an interesting discussion at your next coffee klatch.
SIDEBAR:
Variations on a theme
Estrogen pills and patches — and their dosages — as approved by the US Food and Drug Administration:
- Estrogen-only pills
- Premarin: 2.5 milligrams, 1.25 mg, 0.9 mg, 0.625 mg or 0.3 mg.
- Estratab: 2.5 mg, 1.25 mg, 0.625 mg, or 0.3 mg.
- Estrace: 2 mg, 1 mg or 0.5 mg. (The latter is roughly equivalent to 0.625 mg of Premarin.)
- Ogen: 1.5 mg.
- OrthoEst: 1.25 mg, 0.625 mg or 0.615 mg.
- Menest: 2.5 mg, 1.25 mg, 0.625 mg, 0.3 mg.
- Estrogen-progestin combination pills
- PremPro: one tablet contains 0.625 mg of estrogen and 0.5 mg of medroxyprogesterone (Provera)
- PremPhase: a two-tablet combination regimen containing 0.625 mg of estrogen and 0.25 mg of medroxyprogesterone. [CORRECTION – DATE: Monday, December 23, 1996: CORRECTION: Because of inaccurate information supplied by the FDA, dosages for two estrogen-progestin pills described by Health Sense columnist Judy Foreman last Monday were incorrect. The amount of medroxyprogesterone in is 5 mg; in PremPhase it is 2.5 mg.]
- Estrogen patches (which last from 3 to 7 days)
- Vivelle, which provides daily doses of 0.1mg; 0.075 mg; 0.05 mg; or 0.0375 mg.
- Estraderm, which provides daily doses of 0.1 mg or 0.05 mg.
- FemPatch, which provides a daily dose of 0.025 mg.
- Climara, which provides daily doses of 0.1 mg or 0.05 mg.