Many women avoid hormone replacement after menopause because they fear it will increase their risk of breast cancer. However, they may not realize that they face a much higher risk of dying from heart disease than any type of cancer, and that taking hormones is something that may decrease that risk. In this post I am going to review why there is good reason to believe that estrogen is good for the heart.
What type of heart disease does estrogen help?
There are many forms of heart disease, such as congenital malformations, heart valve problems, and diseases that attack the heart muscle itself (which is what we’ve seen with many Coronavirus infections). But the most common type of heart disease is coronary artery disease (CAD). CAD is caused by a buildup of “gunk” known as plaque inside an artery. 
Plaque is composed of cholesterol, protein, calcium, and other ingredients. It begins as a small deposit and gets progressively larger over time.
There are three major coronary arteries, and branching from these are progressively smaller arteries. This network of blood vessels delivers the nutrients and oxygen needed by the heart cells to survive.
As plaque builds up, it can become unstable and suddenly rupture and completely plug a segment of one of these arteries. Without blood, the area of the heart downstream from the blockage quickly becomes permanently damaged, causing a heart attack. A large heart attack can be fatal. Multiple smaller heart attacks can weaken the heart to such a degree, it can lose its ability to effectively pump and circulate blood. This leads to congestive heart failure. CAD and its consequences account for the bulk of problems affecting the heart.
The beneficial effects of estrogen on the heart
Prior to menopause, women are less likely than men to develop CAD. Much of this is due to the fact that estrogen plays a large role in preventing plague. Some of the beneficial effects are that:
- Estrogen decreases the level of “bad cholesterol” which is low-density lipoprotein (LDL). LDL is toxic to the lining of the arteries and promotes the development of plaque.
- Estrogen inhibits inflammation. Inflammation is another factor that comes into play in causing plaque.
- Estrogen has anti-oxidative effects meaning it can combat free radicals, which are electrically charged particles that damage the lining of the arteries in a process known as oxidation.
- Estrogen stimulates the production of nitric oxide. This chemical is made in the lining of the arteries and keeps the arteries from constricting and plays other roles in preventing plaque formation.
When the estrogen level falls, as it does with menopause, these beneficial effects on the arteries are lost. This allows plaque to begin accumulating rapidly after menopause. I offer a much more detailed explanation of how estrogen affects the heart in my book, The Estrogen Question: Know Before You Say “No” to HRT.
Studies on estrogen and heart disease and why there is controversy
As described in previous posts, the most famous study on hormone replacement was the Women’s Health Initiative (WHI), which was done in the 1990’s. This study was undertaken primarily to confirm what had previously been believed, that HRT would help decrease the risk of heart attacks. However, when the results of the WHI were published it 2003, they caused an uproar, because the conclusion was opposite what was anticipated. The WHI concluded that using HRT increased the risk of heart disease.
This shed doubt on the benefit of estrogen for the heart. However, it has become apparent there are some major flaws in the way the study conclusions have been applied. The main issue is that the average age of the women enrolled in the study was 63, and some even older than 70. This is much older than when women typically go through menopause. Yet the conclusions and recommendations have been applied to all women, regardless of their age.
Over the last ten years we have learned that hormones behave differently if they are given to women who have gone for years without them. So most experts in menopause now agree that the WHI study’s results should only apply to older women who are given hormones ten or more years beyond menopause. As for women around the age of 50, the vast majority of studies done before and after the WHI have revealed that in this age group, estrogen decreases the risk of heart disease. I reference these studies and describe them in more detail in my book.
(What is interesting is that when data from the WHI was examined more closely, it showed that women who were younger when they started HRT showed less evidence of plaque build-up on the coronary arteries over a five-year period!)
Is HRT approved for preventative treatment of heart disease?
Despite the more recent studies and the extensive research on the beneficial effects of estrogen on preventing plaque, the current guidelines do not recommend HRT as a preventative treatment for heart disease. This is primarily because the guidelines continue to use the WHI as the basis for this decision. Many experts in menopause feel this is inappropriate.
Fortunately, HRT is approved for hot flash treatment, so women taking estrogen for this reason will also benefit from a heart perspective.
Know Before You Say “no” to HRT
The decision to take hormone replacement is a complicated one and each women needs to look at her own personal goals and medical situation. When assessing the benefits and risks of HRT, an awareness of the effects of estrogen in preventing heart disease should be strongly considered.
Hi Dr. Rice
I am 75 and have been on HRT since age 45 when I had a complete hysterectomy/oopherectomy. Initially, I was on descending doses of Premarin and for the last 5 years, I have been using the transdermal dots. Question: Am I continuing to benefit from the heart protective effects of estrogen and how long can I continue to use Estrace dots.
Hi Dr. Kate! Your question is an excellent one, and is yet another area where more research is needed. Depending on whom you ask this question, you likely will get conflicting answers. But here is the best response I can give.
There is no question that estrogen promotes many effects in the heart and arteries that prevent heart disease. This has been shown in many animal studies, as well as from data in human studies. As we age, it is likely that estrogen will continue to exert these positive effects and decrease the risk of building up plaque. Many studies involving thousands of women have shown that women who start HRT at the time of menopause have lower rates of heart attacks than women who don’t take HRT. In some studies, the women who took hormones the longest, like many years, lived longer and had fewer deaths due to heart disease.
The problem is that it appears that if a woman has developed a lot of plaque, taking hormones may harm the plaque and cause it to become unstable, which can lead to a heart attack or stroke. This is likely what happened in the WHI study. Most of the women in this study were over the age of 60 and many had underlying cardiac risk factors. So they may have had a fair burden of plaque to start with.
So, here is the bottom line. If a woman has healthy arteries and is taking estrogen, odds are she will continue to get cardiac benefits from it. However, if she has developed a fair amount of plaque, estrogen may cause problems. Some menopause experts recommend doing tests, such as a calcium score of the heart, or ultrasound of the carotid arteries to asses if a woman has a high plaque burden. Others look at cardiac risk assessment calculators, such as the American Heart Association’s calculator to assess cardiac risk. If a woman’s risk is less than 7.5% she likely has little or no plaque.
It is also important to note that in the WHI study, which many doctors use as a basis to advise older women not to take hormones, the risk of a heart attack was very low, less than one in 1,000. This needs to be weighed against all the other benefits of taking HRT. And as a final note, the position statement from the North American Menopause Society reads:
“Hormone therapy does not need to be routinely discontinued in women aged older than 60 or 65 years and can be considered for continuation beyond age 65 years for persistent hot flashes, quality of life issues, or prevention of osteoporosis after appropriate evaluation and counseling of benefits and risks.”
Keep holding the torch high, Dr. Rice! This is such important information for women approaching menopause…critical information for long-term health and longevity. At age 71, I only wish I’d known then what I know now.
Thank you Susan! Onward!