Scientists analysing data from the UK Biobank have reported that hormone replacement therapy (HRT) is associated with a reduced risk of dementia among postmenopausal women. The study followed 183,450 women for an average of 13 years and identified almost 4,000 dementia cases, revealing that women who used HRT for at least one year were 10% less likely to develop any form of dementia and 16% less likely to be diagnosed with Alzheimer’s disease.
Key Findings Across Different Groups
The protective association was strongest among women who experienced surgical menopause. Those who had undergone surgical removal of the ovaries showed a 26% lower risk of any dementia compared with non‑users of HRT. Women with naturally lower lifetime estrogen exposure—such as those whose periods started later or who entered menopause early—also benefited, showing a 16% reduction in overall dementia risk.
Genetic factors appeared to influence the relationship as well. Participants carrying the ApoE4 allele, a known risk variant for Alzheimer’s, exhibited a more pronounced benefit from HRT use. Professor Anne‑Marie Minihane, director of the Norwich Institute for Healthy Ageing and lead author of the study, highlighted that ApoE4 carriers are typically considered high‑risk and have limited preventive options, making the observed association especially noteworthy.
Study Context and Limitations
The research, published in the journal Alzheimer’s & Dementia, relied on observational data rather than randomized controlled trials, meaning causality cannot be definitively established. The authors noted that HRT users tended to have higher average education levels, a socioeconomic factor that can also affect dementia risk. Although the analysis adjusted for such variables, residual differences between users and non‑users could still influence the outcomes.
Dr. Susan Kohlhaas, executive director of research and partnerships at Alzheimer’s Research UK, cautioned that the findings alone are insufficient to recommend HRT as a dementia‑prevention strategy. She emphasized the need for further research to determine whether HRT itself drives the risk reduction and to identify which formulations might be most effective.
Implications for Women and Clinicians
Historically, HRT has been prescribed primarily to alleviate menopausal symptoms such as hot flashes and night sweats. The new evidence suggests that timing of therapy and a woman’s hormonal history could also play a role in long‑term cognitive health. Minihane explained that the study aimed to explore how HRT might prevent dementia and whether specific subgroups respond differently.
Healthcare providers are advised to discuss both potential benefits and risks of HRT with patients considering initiation or discontinuation. As Dr. Kohlhaas noted, individualized assessment remains essential, and decisions should be made in consultation with a general practitioner.
Overall, the study adds to a growing body of literature linking hormonal factors to brain health in women, underscoring the importance of further investigation into therapeutic strategies that could mitigate the higher dementia burden observed in females, partly due to longer life expectancy and menopause‑related metabolic changes.
Helene Elliott is the senior reporter for News Raise. She covers Science news. She also has a keen interest in photojournalism. Helene holds a nomination for the prestigious Red Smith Award. She is married to author Dennis D’Agostino, a former publicist with the New York Mets.
