While most women perceive breast cancer as their greatest health threat, in the United States, heart disease is the No.1 killer of women, as well as of men. An American woman is 10 times more likely to die from heart disease than from breast cancer. Because many women take statins, a class of drugs that lower cholesterol, how well these drugs work for women who are also taking hormone replacement therapy is an important question.
One of the main purposes of the Women’s Health Initiative (WHI), a large U.S. study of 161,000 women that was initiated in 1991, was to determine whether long-term hormone therapy could prevent heart disease in women and prolong life in addition to controlling postmenopausal symptoms.
The end result, released in 2002, was not the expected result.
The WHI showed that for every 10,000 women per year who used estrogen and progestogen (compared to the women who were not taking any hormones or were taking estrogen alone), there were actually seven additional myocardial infarctions (heart attacks) and eight additional strokes. Overall, hormone replacement was associated with higher heart-health risk in this study.
But what we now appreciate is that, in many ways, the study design was flawed. For one, the average age of women in WHI was 63, and more than 70 percent of the women enrolled were over the age of 60.
Age Matters for Heart Disease Risk During Menopause
A re-evaluation of the study results showed that estrogen users between ages 50 and 60 did not increase their risk of cardiovascular disease. They actually decreased their risk of coronary heart disease and overall mortality. This is an important finding because menopausal women in this age group are the ones who are the most symptomatic — and the most likely to take hormone therapy.
Other studies have confirmed that it is not only the age at which women take hormone therapy, but also the type of estrogen that matters. Beta estradiol and transdermal estrogens seem to have cardiovascular advantages over the conjugated equine estrogen that was used in WHI.
There was another important issue. WHI did not identify who was taking statin drugs, and who was not.
New Data on the Difference Statins Can Make
A new Swedish study, published in the journal Menopause, attempts to answer the question of statins’ effects on heart disease risks for women taking hormone replacement therapy.
In this study, 40,000 women took statins along with beta estradiol, compared to 38,000 who did not. Over four years, the number of deaths and cardiovascular events, such as heart attack and stroke, were recorded. The rate of death from any cause was 33 per 10,000 person-years for women who used hormone therapy with statins compared with 87 per 10,000 person years for women who used statins alone — a significant difference.
The bottom line? If a woman chooses to take hormone therapy, it appears the best time to start is at the onset of menopause. The type and route of estrogen make a difference. In addition, for women at risk for cardiovascular disease, taking a statin may decrease the risk of coronary heart events that may occur early on in hormone therapy.
In spite of this information, at this point, hormone therapy is not recommended to treat or prevent cardiovascular disease. But, as we continue to gather data, the estrogen pendulum is swinging again. Many women can feel a lot more comfortable about taking systemic estrogen — not only relieve menopause symptoms but maybe even to prolong life.