Estrogen Linked to Lower Risk of Breast Cancer and Heart Attack

A new government-funded study has positive news for women who take estrogen to relieve hot flashes and other post-menopausal symptoms. The study, which appeared yesterday in the Journal of the American Medical Association (JAMA), reports and that certain women have a much lower risk of breast cancer and heart attack years after estrogen-only therapy. However, taking the two hormones estrogen and progestin has been linked to an increased risk of breast cancer and researchers emphasize that women and their doctors need to remain aware of this.

The study was part of the National Institute of Health‘s Women’s Health Initiative, a 15-year research program. It looked at 10,739 women who had had a hysterectomy, the surgical removal of the uterus. In the US, one-third of women in their 50s have had a hysterectomy. Says the New York Times Well blog:

While most women in the hormone study were taking combination hormone therapy, women without a uterus took estrogen alone or a placebo for about six years and were followed for nearly 11 years. The estrogen-only group was not given progestin, which is prescribed only to protect the uterus from the harmful effects of estrogen. Although all the women in the estrogen study stopped using the treatment in 2004, the investigators have continued to monitor their health, as is typical in large clinical trials.

The most surprising new finding relates to breast cancer. The women with hysterectomies who used estrogen alone had a 23 percent lower risk for breast cancer compared with those who had taken a placebo. This is in stark contrast to the higher risk of breast cancer shown in the estrogen-progestin part of the trial.

Again, the study’s authors emphasized that the results do not change recommendations for women who are taking the combination hormone therapy.

But new findings are reassuring news for women who only take estrogen for relief from post-menopausal symptoms, though an accompaning editorial to the study raised a number of caveats, noting that

…the design of the initiative, which is skewed toward older women and stopped all forms of hormone treatment after several years of use, does not match the way doctors typically prescribe treatment to women in their 50s at the onset of menopause.

In addition, the type of estrogen used in the study — conjugated equine estrogens, estrogen compounds derived from the urine of pregnant mares and marketed by Wyeth Pharmaceuticals under the brand Premarin — is a brand that is not being used as much by women. More women have been choosing to use estradiol, which is chemically similar to a woman’s natural estrogen.

The JAMA study’s researchers themselves point out that the benefits of estrogen differ depending on a women’s age, health and type of hormone used, with the data looking more favorable for younger women:

The data indicate that for every 10,000 women in their 50s, those using estrogen would experience 12 fewer heart attacks, 13 fewer deaths and 18 fewer adverse events like blood clots or stroke in a given year, compared with those taking a placebo.

But the risks of estrogen use were pronounced in older women. For every 10,000 women in their 70s, using estrogen would cause 16 extra heart attacks, 19 extra deaths and 48 serious adverse events.

Still, researchers also note that their new study offers further evidence that hormone treatment may have health benefits and that hormones are not simply good or bad; that, for some women, hormones may be, as Dr. Rowan Chlebowski, an author of the study and a medical oncologist at Los Angeles Biomedical Research Institute, says “a good choice.”


Photo of Estrogen patch by Belinda Hankins Miller from U.S.A. (my sanity depends on / This is Today 36) [CC-BY-2.0 (], via Wikimedia Commons


Maureen R.
M R6 years ago

It sounds like the study focused on women without a uterus who took estrogen benefited. What about all the women who have a uterus and take estrogen?

I agree with others who say keep it natural. Why not learn to breath better, do yoga, improve your diet, and attitude, and cut out activities that depress you, and stay away from people who make you feel low and terrible for being you. Get the environmental toxins out of your house. Stop exposing the body to endocrine system disruptors (BPA in plastic products, phthalates in plastics, no more TUPPERWARE and plastic storage containers, quit handling thermal paper and that includes cash register receipts that are coated with BPA!). There are so many ways to create a healthy life that don't cost a fortune but you must read and research and learn about them. This site is very useful for that, but this particular study doesn't impress me as being too hot. Remember how the CDC and FDA kept encouraging the use of flouride in our lives. Now they have reversed that opinion. Remember how the govt. encouraged the use of plastic cutting boards, then found that wooden were safest even for meats. I don't know why, but many govt sanctioned opinions just seem to be in the end poor advice.

Anja N.
Justin R6 years ago

Keep it natural - take nothing!

All is part of life. Our ancestors survived it and so will we. It is that constant brain-washing of advertisers which suggest how sick you feel.

Any chemical you take in will have side effects; I don't believe a word of any corporation.

Lil Judd
Lil Judd6 years ago

You couldn't pay me to take any form of estrogen. I don't trust a single American funded research result. Before I'd do anything like a hysterectomy etc I would get at least 2 or 3 opinions. In this country the doctors make money when they get us women to do hysterectomies, C-sections etc. I would get myself on a plane to good old Sweden & have the doctors there check me out. I'd trust the Government funded through taxes medical system there over the money greedy doctors, insurance companies, hospitals & HMOs in the US. It's insane what lies the US report as studies & facts. I can't stand what greedy Republicans have done to this country & the people here.

Yvette T.
Past Member 6 years ago

Premarin and mare urine...who would do that? We are so insane and so far astray from nature that we do not even see what once was obvious. Why do we use use use all animals? We are NOT healthy for this. Stop eating them, caging them, penning them etc unless they need us to help them to survive. Should they lose a limb, a fin, a tail or their families, for example, we can then come in and show them much love. We hate them now, and are only cruel and so disgusting. We think we are helping ourselves? We are NOT!

Sharon H.
Sharon H6 years ago

Leslea S.
I take Estradoil and have been for a few years. It works and I always have a clean mammogram report.

Emanuel v.
Emanuel v.6 years ago

Estrogen dominance through the pill, HRT, pseudoestrogens, xenoestrogens , phyto estrogens combine with disastrous effects on human health . We do not have to look far to see what all this hormonal manipulation is doing to the masses. Every one is getting ill either with circulation problems, neuromotor and neurologgical problr]ems, cancers of all description, endocrine disruption, heart disease, skeletal weaknesses, osteoporosis to name but a few. All the authorities, professionals and those with vested interests continue to apply the cop out word "SAFE" without bothering to check it out. They are killers , and for good reason. They are only implementing the depopulation programmme fostered by the UN through the WHO.,

Jamie Clemons
Jamie Clemons6 years ago

interesting I have always heard it the other way around that the combination was safer, but I guess they don't always tell you the truth.

Linda M.
Linda Moore6 years ago

I am a woman in my early 50's.Have been post-menopausal for 5 years and endured the torture of constant hotflashes and night sweats, mood swings,depression, lack of sleep,and anger for what seemed like forever.Last year I began low-dose estradial and progesterone. The relief was amazing , also for those around me! The risks in my case, were worth it.

Marilyn NO FWDS D.
6 years ago

I wonder what the results would have been for women who go through menopause the old fashioned way...naturally...without taking any kind of hormonal therapies.

Monique D.
Mon D6 years ago