Hormone Replacement Therapy May Boost Women's Hearts

Women who take hormone replacement therapy (HRT) during menopause appear to have changes in heart structure and function that may be associated with a lower risk of heart disease, suggest the results of a novel UK study.

Using data from a nationwide health database, the team found that women who took HRT for a median of 8 years had smaller left ventricular (LV) and atrial heart chambers, and a lower LV stroke volume compared with women who did not use HRT. Significantly smaller LV and LA chamber volumes are linked to favorable cardiovascular outcomes, say the authors.

The research, published online March 8 in PLoS One, also indicates that the effect was more pronounced in older women, with the greatest benefit of HRT seen in women who were in their late 60s and older when their hearts were imaged.

Lead author Mihir Sanghvi, MD, William Harvey Research Institute, National Institute for Health Research (NIHR) Biomedical Research Centre at Barts, Queen Mary University of London, UK, said: "This is the first study to look at the relationship between the use of menopausal hormone therapy and subtle changes in the structure and function of the heart, which can be predictors of future heart problems."

The study used the gold-standard of cardiovascular MRI, whereas previous research into the effects of HRT on the heart have focused on atherosclerotic burden as detected by cardiac CT, he and his coauthors explain.

In a statement by his institution, he added that the results show HRT "is not associated with any adverse changes to the heart's structure and function, and may be associated with some healthier heart characteristics."

This is an important issue, he said, because millions of women use HRT and "current evidence of its effect on heart health is conflicted and controversial."

Ashleigh Doggett, senior cardiac nurse at the British Heart Foundation, which funded the study, nevertheless noted that the effect of HRT on heart health is "still unknown," and that the study "adds to our understanding by suggesting that the treatment does have a positive effect on the heart's structure, which should give reassurance to women taking the treatment."

But she emphasized that women should not take HRT "specifically to improve their heart health, as this study doesn't consider all of the ways this therapy affects our cardiovascular health. For instance, there is some evidence to suggest that HRT may increase your risk of blood clots, meaning more research is still needed to get a complete picture."

Nevertheless, she advised, "For most menopausal women — especially those under the age of 60 — the benefits of taking HRT outweigh any potential risks. However, each woman's situation is different so please speak to your general practitioner about whether HRT is appropriate for you."

HRT Associated With Improved LA and LV Structure

To definitively examine the impact of HRT on heart structure and function, researchers conducted a cross-sectional study using the UK Biobank, an ongoing, large-scale, population-based study.

The resource includes questionnaire data, physical measurements, and biological samples taken from over 500,000 individuals aged 40 to 69 years between 2006 and 2010. In addition, imaging studies were performed in 100,000 of the original participants, including cardiovascular MRI.

For the current analysis, the team selected 1604 women who underwent cardiovascular MRI and had gone through, or were going through, menopause. In addition, they were free of known cardiovascular disease.

Of the participants, 513 (32%) had used HRT for 3 years or more, while 1091 had never used it. The median length of HRT use was 8 years, and mean age of initiation was 47.6 years. At the time of imaging, 78 women (15.2%) women were still taking HRT.

Participants who had taken HRT were significantly older than the non-HRT group, at a mean age at baseline of 65.4 vs 61.3 years, and had a lower median age of menopause, at 50 vs 51 years. There were no significant socioeconomic differences between the groups.

HRT users were found to have a significantly lower left ventricular (LV) end-diastolic volume than nonusers, at a mean of 122.8 vs 119.8 mL and an effect size of –2.4% (P = .013), and a significantly smaller LV stroke volume, at 72.1 vs 74.3 mL and an effect size of –3.1% (P = .004).

Left atrial maximal volume was also significantly smaller in HRT users vs nonusers, at 60.2 vs 57.5 mL and an effect size of –4.5% (P = .012).

There were no significant differences in LV end-systolic volume, LV mass, and LV ejection fraction between the groups.

Of note, the timing of commencement of HRT in relation to the onset of menopause had no discernible impact of LV or LA volumes, the researchers note.

HRT use "was not associated with adverse, subclinical changes in cardiac structure and function. Indeed, significantly smaller LV and LA chamber volumes were observed which have been linked to favorable cardiovascular outcomes," the authors reiterate.

These findings, they add, represent "a novel approach to examining" HRT's effect on the cardiovascular system.

Greater the Age at Imaging, the Bigger the Improvement in Structure

The team found that age significantly modified the association between HRT use and cardiac parameters. So the biggest reductions in heart chamber size occurred in the oldest women who were imaged and had taken HRT, compared with women of the same age who were imaged and didn't take it.

Hence, in women aged 67 to 77 years, those who took HRT had a change in LV end-diastolic volume of –6.2% compared with women who didn't take HRT (P < .0001). For LV stroke volume, the percentage was –6.4% (P < .0001), and for left atrial maximal volume, it was –10.1% (P = .0002).

Fung was supported by the Medical College of Saint Bartholomew's Hospital Trust. Lee and Petersen were supported by the NIHR Cardiovascular Biomedical Research Centre at Barts and received a SmartHeart Engineering and Physical Sciences Research Council program grant. Neubauer and Piechnik are supported by the Oxford NIHR Biomedical Research Centre and Oxford British Heart Foundation Centre of Research Excellence. Aung is supported by a Wellcome Trust Research Training Fellowship. Petersen, Neubauer, and Piechnik received funding from the British Heart Foundation.

PLoS ONE. 2018;13:e0194015. Full text

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