In part four of our five-part series featuring Dr. Rebecca’s interview with David Stewart on the SuperAge podcast, “HRT, Estrogen and Menopause, New Scientific Findings with Dr. Rebecca Dunsmoor-Su”, she shares the three typical usage patterns of hormone replacement therapy, dispels the risks of HRT as they relate to breast cancer and cardiovascular disease and discusses why the risk of Alzheimer’s disease is so much higher for women.

What are the risks of HRT and is there a limit to using it?

David: Is there a time limit that one can be on HRT, or is it a lifetime?

Dr.Rebecca: Interestingly enough, we talked over the years about risks of HRT. So, a lot of women believe that HRT is going to cause them breast cancer or give them heart attacks. These are the two risks that we tend to talk about. I like to dispel those risks.

First of all, the breast cancer risk. I like to talk about the two hormones separately. Estrogen replacement does not cause breast cancer and I shout that from the rooftops. We have many studies that tell us that estrogen replacement does not cause breast cancer, it does not increase the incidence. The Women's Health Initiative, that big study that came out in 2002 that scared everybody away from hormones - they continued their estrogen only arm and then they actually published the results of the 18-year follow up last year, and they showed no increased risk in breast cancer in the women taking estrogen alone.

Now, obviously, we talked about the fact that women who have a uterus also need progesterone. The Women's Health Initiative showed that there was a slight increased incidence of breast cancer in progesterone users – or progestin users. They used Provera and they stopped to study for that. They also followed it up last year, 18 years later, and they can still see that slight incidence bump, and I'm talking slight, one additional cases of breast cancer in about a thousand-woman years which is how we study it, but they saw no increased risk in breast cancer mortality. So, the good news is this is low grade. But again, that was Provera. It's not what we tend to use now. Nowadays, we tend to use micronized progesterone, which is a little more body identical as we like to call it. I use those words because that separates it from the marketing of bioidentical which is generally the marketing of compounds which are less safe. I talked about body identical, which are estradiol and micronized progesterone, which are the molecules that the body used to make, but FDA regulated.

When we use micronized progesterone, we don't tend to see that bump in breast cancer risk. We have one big study out of France that has looked at 40,000 women on a micronized progesterone prescription up to five years and they saw no increased risk in breast cancer rates on that particular compound. I tell my patients, I can't say for sure. It doesn't increase your breast cancer risk. I think there's more study to be done on this progesterone, but I certainly don't think it increases significantly. One in eight women get breast cancer-that’s our baseline rate. Some women on hormone replacement therapy are going to get breast cancer. There's nothing we do about that. If you get it, you have to stop. But I tell people, there's a difference between association and causation. I think, we've assumed a causation that really isn't there for many years.

Then, we talk about cardiovascular risk. The Women's Health Initiative also made us worry about cardiovascular risk of stroke and heart attack. What we know from that in other studies is that, the risks of estrogen and progesterone are based on when you start, not how long you use it. So, if you start within five years of that last period, you can use your hormone replacement fairly indefinitely without increasing your risk. The risk of heart attack, stroke, all those things are based on when you start. And women who start hormone replacement therapy within five years of their last period actually reduce their cardiovascular risk, we talked about that. They also slightly reduce their colon cancer risk and they reduce their all-cause mortality over time. The North American Menopause Society is really clear - there is no set stop date for hormone therapy. You can use it as long as it's functional for you.  

Three typical use patterns of HRT  

Dr.Rebecca: In my practice, I see three different patterns really. Small group of my patients use it just to manage symptoms rather transition to menopause. Two to five years, they taper off, they feel fine, we're good. Another subset, use it through the age of retirement. They're very functional women, they don't like what it does to their brain when they come off their estrogen, they don't like the hot flashes in the workplace, they want nothing to do with it, they sleep better on it. So, we use it until they're 65, 70, 75 and then, we taper off and they do fine. And then, I have a small subset of women who feel better on hormone, and they're going to die with that hormone in their hands, and that's fine, too. [laughs] I'm happy to continue that journey with them as long as they don't have any other risk factors. They haven't developed breast cancer, they haven't developed heart disease, or anything else that would mean that they need to come off.

Women and increased Alzheimer’s risk

David: Do you have an opinion about why Alzheimer's risk is so much higher with women than with men?

Dr.Rebecca: I have a lot of opinions. I don't know how based on science they are. I can tell you what we know from the data and what we suspect. I don't know if we have the full story yet. We mentioned Dr. Mosconi. She's working on this at Weill Cornell Medical School, and I think, she's probably on the pathway of discovering exactly what's going on in the brain. But I think, there are a couple things about estrogen that we need to think about. Like I said, estrogen is an anti-inflammatory molecule, and it's anti-inflammatory everywhere including in the brain. So, I think, there's a certain amount of that anti-inflammatory effect that is beneficial for women.I think that sleep has a lot to do with it. When women are transitioning through menopause, we're talking about five, ten years of disrupted sleep. That's a lot of impact in the brain and I think that has a lot to do with it.

David: Wow, okay. So, I'm going to paraphrase here and tell me if I got this wrong. But it seems like with HRT, unless you fall into one of these groups where you have a preexisting condition, and you can't do it - this seems like a really good thing all around. If for nothing else, just the sleep. Like not sleeping for ten years like, oh, my gosh, that's going to cause all kinds of problems.

Dr.Rebecca: Right. I don't disagree with you. I think, we have been told a scary story of hormone replacement therapy. Before the Women'sHealth Initiative published, that was not the story we were telling. We were telling women it was great for them. Those of us who've been working in this space a long time have gone back to that story for the most part. I think that was the Women's Health Initiative, and the way it was published, and the way it was recorded was a bit of a blip in that story. The way I'd like to think about it is that, menopause probably had a function when it started. Very few species go through menopause. It's us and a couple of great whales. That's pretty much it. There's a whole sort of grandmother theory about why we would do this. And the theory is that, the grandmothers are the repository of knowledge within these societies, and risking them in childbirth as they age doesn't make sense, so they stopped being able to reproduce, so they can continue to pass on knowledge. That's a great theory. There's no way to prove that. But sounds good. I like it.

But the one thing I do think about is, when menopause is fine and functional, if you're going to live to be 65, you got 10 years to survive your menopause, you're going to be okay. We live to 95, 100, 105 now. And that's a long time. That's almost half your life without the hormones that sort of keep things going. So, I think that we need to adjust like, I think people have been fed this line that, it's better to just go through this natural and normal transition. Well, it's natural normal, but so is dying by 65. We're in a different place now. So, we need to think about our long-term health, and estrogen may actually help with that long-term health. Not everybody needs it. People do live to 85, 90, 95 without hormone replacement therapy, but it can be beneficial for many women.

David: So, if somebody comes to you and they're non-symptomatic, they're not having any of the sort of sleep disorders, mood stuff, weight gain, but they come to you and they say, "Huh, I've read this stuff about hormones and long-term brain health. Should I be doing this? Not so much my current status but my longevity, essentially? 

Dr.Rebecca: The answer if they're just talking about brain health is, I don't know if we know for sure. We have some studies that point at increased exposure to hormone over a woman's lifetime being protective of her brain and reducing the risk of dementia and Alzheimer's dementia specifically. In that, we're talking about a couple of studies. There's an observational study called The Cache County Study out of Utah, where they just looked at this county and watched everybody age, and one of the publications that they did was they counted up women's years on estrogen, they counted their pregnancies, their breastfeeding, their hormone use, all those things, and showed that women with more estrogen exposure had a reduced risk of Alzheimer's disease.

Then, there's Dr. Mosconi's study, which was recently published, which looks at women who've had exposure to contraceptives, or hormone replacement therapy, things like that, and more exposure showed decreased risk. There are other studies that show that HRT increased the risk of dementia. The Women's Health Initiative showed an increased risk of dementia. Now, there are some issues with how that study was designed, a lot of those women were 10 or more years into menopause when they were started on hormones, there's the whole idea of blood clotting and could there be small strokes in the brain, there are a lot of issues. But I have to be honest with these patients and say, there's data on both sides.

Some data says that, it's harmful, some data that says, it's helpful. My take on all that data is, I think, there's more help than harm if we use it correctly. If you start within five years of that menopause, if you take it continuously, if we use it through the skin rather than orally, because through the skin, there's a lower risk of blood clots. There are ways that we can do it safely and I am happy to prescribe someone hormone therapy for health benefit as long as they understand that is actually what we consider an off-label use. Hormone therapy is FDA approved to treat hot flashes and protect your bones. That's it. We know all these other things. So, we can have that conversation and do the prescribing based on that, but definitely, we're in a somewhat of a gray area.

The menopause journey is different for everyone, but you don’t have to go it alone.  Learn more about whether HRT is right for you by tapping into the expertise of our integrated care team.  You will access both natural and prescription therapies approved by physicians who specializes in menopause.

Continue to part 5 for Dr. Rebecca’s take on whether intermittent fasting is beneficial, why strength training is key for women, and the importance of supporting your bones starting in your 30s.

Don’t miss the entire series of Dr. Rebecca’s interview with SuperAge on HRT:

And be sure to listen to the full podcast episode at


Gennev Staff

July 6, 2022

Medically Reviewed By

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