How Menopausal Hormone Therapy Affects Heart and Brain

Short-term hormone therapy during menopause (MHT) has no long-term cognitive effects when administered to women in early postmenopause. This is the conclusion of a study published in the open access journal PLOS Medicine by Carey Gleason of the University of Wisconsin-Madison, USA, and colleagues.

Menopausal Hormone Therapy and Brain Health

While MHT can alleviate the distressing symptoms of menopause, many women and doctors are hesitant to start such therapy due to possible risks. Previous research has linked one form of hormone therapy with mild cognitive impairment and dementia in women over 65 years of age, leading to investigations into the importance of age and timing of therapy on cognitive impairment. Other studies have suggested that transdermal estrogen might have long-term cognitive benefits. In the Kronos Early Estrogen Prevention Study (KEEPS), women in early postmenopause with good cardiovascular health were randomly assigned to receive one of two types of MHT (oral or transdermal estrogen) or a placebo.

After four years, no cognitive benefits or harms were found in those women receiving MHT compared to the placebo group. However, the long-term cognitive effects of MHT have not yet been sufficiently researched. In this new follow-up study – the KEEPS Continuation Study – researchers have revisited the participants almost ten years later to repeat a series of cognitive tests. Although MHT did not protect against cognitive decline, short-term therapy did not have any long-term negative cognitive effects in 275 women. These results may reassure women considering menopausal hormone therapy, while adding to the growing body of research that highlights the importance of timing for MHT. Further research is needed to examine whether these results are transferable to women at higher cardiovascular risk.

Early Hormone Therapy Use Reduces Risk of Future Coronary Heart Disease

The potential health effects of hormone therapy (HT) have been the subject of intense debate for more than a decade, particularly in relation to coronary heart disease. A study from Sweden suggests that the effects depend on when women started taking HT. Researchers have found that there is a difference in the onset of coronary heart disease depending on when a woman starts taking hormones and when she enters menopause. The authors collected data from five population-based Swedish cohort studies with a total of 74,352 participants.

The differences in percentiles were estimated in the number of event-free years between the exposed group and the unexposed group. Adjustments were made for the age of the participant, the age at which menopause began, the level of education, body mass index, smoking status, type of menopause, diabetes, hypertension and dyslipidemia. Finally, it was found that early hormone therapy (within five years of the onset of menopause) was associated with a reduced risk of future coronary heart disease, while late hormone therapy was associated with an increased risk.

Positive Effects on the Heart

Some research even suggests that menopausal hormone therapy can have a positive effect on the female heart. Women who use menopausal hormone therapy appear to have heart structure and function associated with a lower risk of heart failure, according to a study led by Queen Mary University of London. Extensive data suggested that MHT had a protective effect on the heart, leading to MHT being routinely prescribed to prevent heart disease. However, the results of subsequent studies that sought to confirm this have been mixed.

To settle this long-standing question, researchers have used data from UK Biobank – a database of health questionnaires, biological samples, and physical measurements from over 500,000 people. UK Biobank has cardiovascular MRI data – the gold standard for imaging and analyzing heart structure and function – that could help address the lack of detailed data on the effects of MHT on cardiovascular health.

Using data from UK Biobank, the experts were able to show that the use of menopausal hormone therapy is not associated with adverse changes in heart structure and function and may be associated with some healthier traits. The study, published in the journal PLOS ONE, examined left ventricular (LV) and left atrial (LA) structure and function in 1,604 postmenopausal women without known cardiovascular disease, 32% of whom had received at least three years of hormone replacement therapy. The researchers found that hormone replacement therapy was not associated with adverse changes in cardiac structure and function. In fact, significantly smaller LV and LA chamber volumes were observed, which in other situations have been associated with favorable cardiovascular outcomes, including lower mortality and a lower risk of heart failure. They also looked at LV mass – one of the most important features observed on cardiovascular imaging, with an increase in LV mass predicting a higher incidence of cardiovascular events and mortality. Importantly, they found no significant difference in LV mass between the two groups of women.

However, women should not take MHT specifically to improve their heart health, as this study does not take into account all the effects of this therapy on cardiovascular health. For example, there is evidence that MHT can increase the risk of blood clots, which means that further research is needed to get the full picture. For most women going through the menopause – particularly those under the age of 60 – the benefits of hormone replacement therapy outweigh the potential risks. However, every woman’s situation is different, so it is always worth discussing with your doctor whether hormone replacement therapy is right for you or whether other alternatives are preferable.