A Danish study published in The BMJ has found that menopausal hormone therapy (HRT) does not increase the risk of death among women. The research tracked more than 800,000 women born between 1950 and 1977, excluding those with prior health conditions such as blood clots, liver disease, or certain cancers.
Researchers used nationwide registers to follow these women from their 45th birthday until July 31, 2023, with a median follow-up period of just over 14 years. Influential factors like age, number of children, education level, income, country of birth, and pre-existing conditions were considered in the analysis.
Of the total participants included in the main analysis, about 12% had used menopausal hormone therapy at some point. During the study period, roughly 5% died. When influential factors were not accounted for, mortality rates appeared higher among HRT users compared to non-users. However, after adjusting for these factors, no significant difference in all-cause mortality was observed between those who used HRT and those who did not.
The duration of hormone therapy use did not affect mortality risk—even after ten or more years—and there were no clear differences in deaths from heart disease, stroke or cancer between groups. Additionally, women aged 45 to 54 who had both ovaries removed for non-cancerous reasons saw a notable survival benefit when using hormone therapy; this group experienced a 27-34% lower risk of death compared to similar women who did not use HRT.
There was also an indication that transdermal forms of HRT (such as patches or gels) might be linked to slightly lower mortality compared to no treatment. However, researchers noted that further studies are needed to confirm this finding.
As this is an observational study rather than a randomized trial, researchers caution against drawing firm conclusions about cause and effect. They acknowledge limitations but emphasize the large sample size and robust results following additional analyses.
"In this large nationwide cohort study, menopausal hormone therapy was not associated with increased mortality. No unequivocal differences in cardiovascular specific or cancer specific mortality were found between groups," they stated.
The authors suggest that the improved survival seen among women receiving HRT after bilateral oophorectomy for non-cancerous reasons should encourage further discussion on offering hormone therapy following such surgery.
