Estrogen, the Heart, and the Hype
What the Studies Really Show About MHT and Protecting the Heart
Many menopause and longevity influencers advocate for menopause hormone therapy (MHT) for the primary prevention of cardiovascular disease. However, if it were a done deal, the cardiology societies would be promoting MHT for this reason, and the Menopause Society would not have issued a statement last year specifically stating that MHT is not recommended for the primary prevention of cardiovascular disease.1 And no, the guidelines are not out of date; no pivotal research about the heart and MHT has been published since the 2022 Guidelines on Menopause Hormone Therapy.
We must be honest about what the data shows and doesn’t show, because not only do women deserve scientific rigor, but misinformation about MHT protecting the heart is being used to scare women with no symptoms into starting hormone therapy under false pretenses. Perhaps even more concerning is that the purported benefits of estrogen for the heart are used to dissuade women from taking statins. We have good data about statins being protective for women, so if a woman chooses MHT over statins for her heart, she may be losing out on the known protective benefits. We even had a session on the fact that statins work for women at the 2023 Menopause Society conference!
What does the literature tell us about MHT and protecting the heart? Given the rise in misinformation in this space, I thought it was time to expand the section on the heart and MHT in The Vajenda’s Hormone Therapy Guide, so people can be armed with more facts for their evidence-based decisions. You can find the Table of Contents for the guide here.
This is a long post because I want to discuss the major studies, so when they are cherry-picked down the road, you can be prepared (and also horrified at their abuse). But if reading the whole thing isn’t your jam, I’ve got you covered with a practical summary at the end! If you just want to cut to the chase, skip ahead to the “Putting It All Together” section.
The Background
The hypothesis that estrogen in MHT might protect the heart originated from observational studies and animal data, which led to several proposed mechanisms by which estrogen could protect cardiovascular health. A significant limitation of observational studies is that women who access MHT are typically wealthier, more physically active, healthier, and have better access to healthcare (much more so in the United States than in other countries)–all factors that are associated with improved cardiovascular outcomes.2 Social determinants of health are such an important variable that zip code is now included in the cardiovascular risk calculator, Prevent. And of course, animal data is, well, animal data. It’s great to find a potential mechanism this way, but we must prove that this mechanism applies to women taking a pharmaceutical.
Some Important Housekeeping: Combined versus Estrogen Therapy
This is very important. It is wrong to talk about “MHT protecting the heart,” because MHT is not a monolith. I consider this a red flag for someone who is misinformed or cherry-picking for an agenda. We need to be honest, because 2 mg of estradiol given orally without a progestogen may not be the same MHT for the heart as a 50 mcg patch combined with oral progesterone (for example), so lumping them all together is wrong medically and misleading to women and health care professionals alike. The dose, route, and type of estrogen may have different effects and the same with a progestogen.
The next time you see a broad “estrogen protects the heart,” as them what dose, what route, and what study? Make them show their work.
The Best Data
The best data for the heart would be randomized, double-blinded, placebo-controlled trials that show an impact on major cardiovascular events, like heart attack, stroke, or death from a cardiovascular cause. The only clinical trial that fits that bill is the Women’s Health Initiative (WHI), which was explicitly designed to test the hypothesis that Premarin-based MHT regimens were beneficial to protect the heart in otherwise healthy women. You can read more about the WHI here.
The results?
