Squires et al.: HRT and Dementia Risk in UK Biobank Women (Alzheimer's & Dementia 2026)

Tier 1: Established: peer-reviewed research or government health authority
Publisher: Alzheimer's & Dementia (Alzheimer's Association journal); University of East Anglia / University of Exeter · Published: August 26, 2026 · Accessed: August 28, 2026

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Claims this source supports

In 183,450 postmenopausal women from the UK Biobank followed for an average of 13.3 years (~4,000 dementia cases), use of menopausal hormone therapy (HRT) for ≥1 year was associated with a 10% lower risk of all-cause dementia and a 16% lower risk of Alzheimer's disease compared with non-users (Squires et al., Alzheimer's & Dementia, Aug 2026; DOI 10.1002/alz.71679).
The overall association was driven by subgroups. For women with naturally timed menopause – the group most women will think of – there was no statistically significant benefit from HRT; this null finding was not stated in the abstract.
The strongest reduction was in women with early surgical menopause (ovaries removed): HRT use was associated with a 26% lower risk of any dementia, consistent with restoring estrogen after surgery-induced loss rather than broad neuroprotection.
Among APOE ε4 carriers, HRT use was associated with a 13% lower dementia risk; among women with lower lifetime endogenous estrogen exposure (<37 years from menarche to menopause), a 16% lower risk. In the highest-risk subgroup (APOE ε4 carriers with shortest estrogen exposure), the reduction was 14% but not statistically significant.
Observational only: cannot establish cause and effect. MHT exposure was a one-time self-reported snapshot at enrollment (2006-2010) with no dose, formulation, route, or full duration data; healthy-user effect, reverse causation, and the UK Biobank's healthier-than-average cohort are acknowledged limitations.
The authors conclude the findings 'suggest a potential differential response to HRT in female subgroups and rationalize the need for confirmation in an RCT setting to inform a more personalised approach to HRT prescribing.'