Major study finds hormone therapy doesn’t increase dementia risk

The major review of prior research has been undertaken by University College London researchers and supported by the University of Exeter.

The findings, commissioned by the World Health Organization (WHO), have been published in The Lancet Healthy Longevity.

The findings show no evidence to suggest that hormone replacement therapy (HRT) either increases or decreases dementia risk in post-menopausal women.

The topic has been hotly debated with some studies previously suggesting there may be a link to increased dementia rates.

But the new study reinforces the current medical guidance that use of HRT should be guided by perceived benefits and risks and not for dementia prevention.

This follows a recent announcement by the U.S. Food and Drug Administration (FDA) that they will be removing ‘black box’ warnings - disproven claims about potential long-term health risks including dementia - from HRT products.

Professor Chris Fox from the University of Exeter Medical School said: “The role of menopause hormone treatment and relationship to dementia is a worry for many women.

"But our state-of-the-art review indicates there is no evidence that menopause hormone treatment reduces or increases the risk of dementia.

"When deciding whether to take menopause hormone treatment, reducing one's risk of dementia should not be part of that decision "

The new systematic review and meta-analysis is the most comprehensive and rigorous synthesis of evidence on menopause hormone therapy and dementia risk completed to date.

It includes data from 1,016,055 participants.

The study publication follows a November announcement by the U.S. Food and Drug Administration (FDA) that it would remove the ‘black box’ warnings on menopause hormone therapy products.

These warnings had previously included disproven claims about potential long-term health risks, including a claim of potential increased dementia risk.

The FDA announcement further suggested that menopause hormone therapy might reduce the risk of Alzheimer’s disease, however, the findings of this latest review indicate that this claim is also not supported by the available evidence.

Lead author, PhD student Melissa Melville, said: “Across the globe, dementia disproportionately affects women, even after accounting for women’s longer lifespans, so there’s a pressing need to understand what might be driving that risk, and to identify ways to reduce women’s risk of dementia.

"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.

"Conflicting research and concerns about potential harms have fuelled public and clinical debate, leaving women and clinicians unsure whether menopause hormone therapy might raise or reduce their risk of dementia.”

The international research team, based in the UK, Ireland, Switzerland, Australia and China, pulled together the best evidence on any potential links between menopause hormone therapy and dementia risk, including Alzheimer’s disease and other types of dementia.

This included one randomized controlled trial and nine observational studies, with a total of

They found no significant association between menopause hormone therapy and the risk of dementia or mild cognitive impairment.

Additional analysis of subgroups within the study participant pools, based on timing, duration and type of menopause hormone therapy, still did not reveal any significant effects.

They found no evidence that menopause hormone therapy affected dementia risk after early menopause.

Senior author Professor Aimee Spector (UCL Psychology & Language Sciences) said: “This review will help to inform the upcoming WHO guidelines on reducing the risk of cognitive decline and dementia, which are expected to be released in 2026.

“More high-quality, long-term research is still needed to fully understand the long-term impacts of menopausal hormone therapy.”