Good News: Menopause Hormone Therapy Doesn't Increase Dementia Risk

A comprehensive review of over one million women has found no evidence that menopause hormone therapy increases or decreases dementia risk, providing much-needed clarity on one of the most debated topics in women's health. This finding should reassure women and their doctors who have been navigating conflicting research for years.

What Did This Major Study Find?

Researchers from University College London led an international team to analyze the best available evidence on hormone replacement therapy (HRT) and dementia risk. Their systematic review, commissioned by the World Health Organization and published in The Lancet Healthy Longevity, included data from over 1,016,055 participants across one randomized controlled trial and nine observational studies.

The results were clear: no significant association existed between menopause hormone therapy and the risk of dementia or mild cognitive impairment. Even when researchers looked at different subgroups based on timing, duration, and type of hormone therapy, they still found no significant effects.

Why Does This Matter for Women's Health?

This research comes at a crucial time. The U.S. Food and Drug Administration recently removed "black box" warnings from menopause hormone therapy products, which had previously included disproven claims about potential long-term health risks, including increased dementia risk. However, the FDA also suggested that hormone therapy might reduce Alzheimer's disease risk—a claim this new review shows is also unsupported by evidence.

The findings are particularly important because dementia disproportionately affects women, even after accounting for women's longer lifespans. Lead author Melissa Melville, a Ph.D. student at UCL Psychology & Language Sciences, explained the significance: "Menopause hormone therapy is widely used to manage menopausal symptoms, yet its impact on memory, cognition and dementia risk remains one of the most debated issues in women's health."

What Are the Study's Limitations?

While the results are reassuring, researchers acknowledge several important limitations that affect how we should interpret these findings:

• Limited Trial Data: The scarcity of relevant randomized controlled trials means much of the evidence comes from observational studies, which provide relatively low certainty
• Diverse Populations Needed: More research is needed in women from ethnic minority backgrounds or those with early menopause and premature ovarian insufficiency
• Long-term Effects: High-quality, long-term research is still needed to fully understand the impacts of hormone therapy over extended periods

Senior author Professor Aimee Spector emphasized the practical implications: "Currently, the World Health Organization provides no guidance on menopause hormone therapy and cognitive outcomes, leaving a critical gap for clinicians and policymakers. To cut through the noise, we reviewed the most rigorous research there is on the subject and found that menopause hormone therapy does not appear to impact dementia risk either positively or negatively."

This comprehensive review will help inform upcoming WHO guidelines on reducing the risk of cognitive decline and dementia, expected to be released in 2026. For now, the research reinforces current clinical guidance that hormone therapy decisions should be based on perceived benefits and risks for managing menopausal symptoms, not for dementia prevention.