Hormone Therapy Does Not Increase Mortality Risk, Major Study Confirms

A major new study published by the British Medical Journal has found that menopausal hormone therapy (MHT)—commonly known as hormone replacement therapy or HRT—does not increase the overall risk of death in women, according to research examining nearly a generation of Danish women over an average of 14 years.

The nationwide register-based cohort study analysed data on 876,805 Danish women aged 45 and older, of whom 104,086 had used MHT. The findings align with updated 2024 guidance from the National Institute for Health and Care Excellence (NICE), which recommends hormone therapy for women experiencing moderate to severe menopausal symptoms without medical contraindications.

The Danish study followed women from their 45th birthday until July 2023, recording 47,594 deaths across the cohort. When raw figures were examined, women who used MHT had an incidence of 54.9 deaths per 10,000 person-years, compared with 35.5 per 10,000 person-years for those who never used it. However, this raw comparison did not account for other factors that might influence mortality, such as age, income, education, and existing health conditions including diabetes and heart disease.

Once researchers adjusted for these influential factors, the difference in mortality risk virtually disappeared. The adjusted hazard ratio was 0.96, meaning that MHT users actually had a slightly—though not meaningfully—lower mortality risk than non-users. No increase in specific causes of death was found, including cardiovascular mortality, cancer-related deaths, or stroke.

Crucially, duration of use made no meaningful difference. Women who used MHT for less than one year showed a marginal increase in mortality (hazard ratio 1.01), but this decreased substantially with longer use, reaching an 11 per cent reduction in mortality risk between five and 9.9 years of use, and a 10 per cent reduction after 10 or more years of continuous treatment.

The study revealed an important finding for women who had undergone surgical removal of both ovaries (bilateral oophorectomy) between ages 45 and 54 for non-cancerous reasons. In this group, women who used MHT experienced a 27 to 34 per cent lower mortality risk compared with those who did not use hormone therapy. Women in this group who took MHT had a median age at death of 60.9 years, compared with 56.6 years for those without treatment—a difference of more than four years.

This finding reflects the significant biological impact of losing ovarian function during the prime working and family years, and suggests that hormone replacement in such cases offers genuine health benefits.

The research provides robust support for existing medical guidance. NICE’s 2024 menopause guidance confirms that MHT does not increase overall life expectancy but emphasises that it can significantly improve quality of life for women suffering moderate to severe menopausal symptoms. The therapy is not recommended for women with certain contraindications, including personal history of breast cancer, stroke, or blood clots, or those with uncontrolled high blood pressure.

Professor Amy Dwyer, a National Breast Cancer Foundation Research Fellow, noted that the study provides “reassuring real-world evidence that appropriately prescribed hormone therapy does not increase a woman’s overall risk of death.” She emphasised that for women with significant menopausal symptoms—particularly those experiencing early surgical menopause—”the balance of evidence suggests that hormone therapy can be both safe and beneficial.”

In the UK, the average duration of MHT use is approximately six years, which falls within the period where the Danish study showed reduced mortality risk. However, MHT use rates in Denmark were 11.9 per cent compared with higher rates among White British women, meaning some findings may not be directly comparable to the UK population.

The study was strengthened by its large size, near-complete follow-up records, and focus on a specific birth cohort, reducing the risk of bias. Researchers controlled for numerous confounding factors, and sensitivity analyses confirmed the robustness of the findings.

Key Takeaways

• A study of over 800,000 women found no increased mortality risk associated with menopausal hormone therapy after accounting for health factors
• Duration of use, even for 10+ years, did not increase mortality risk
• Women who underwent surgical removal of both ovaries before age 55 and used MHT experienced a 27-34 per cent reduction in mortality risk
• No unequivocal differences were found in specific causes of death, including cardiovascular disease and cancer

What This Means for Kent Residents

Women in Kent experiencing moderate to severe menopausal symptoms should feel reassured by this large-scale evidence that hormone therapy does not increase their risk of premature death. Kent and Medway NHS Trust’s women’s health services, along with local GP practices, can discuss MHT as a treatment option for eligible women. Those seeking advice about whether MHT is appropriate for their individual circumstances should speak with their GP, who can assess personal risk factors and explore all available treatment options. The NHS also offers menopause symptom management through structured programmes available across Kent primary care services.