Overview
A new Irish study suggests that women who take hormone replacement therapy (HRT) after menopause may have a reduced risk of developing dementia. The research, led by University of Galway associate professor Dr. Emer McGrath, examined how lifetime exposure to oestrogen from various sources could influence brain aging and cognitive function.
What the study looked at
The study analyzed reproductive and hormonal factors across a woman’s life — from age at first period to the age of menopause, pregnancy, and usage of HRT after menopause — to understand potential links to dementia risk. The researchers emphasised that while cardiovascular sex and gender differences are increasingly studied, dementia research has often lagged behind in this area.
Key findings
Several findings emerged from the analysis of 1,329 women without dementia, drawn from the Framingham Heart Study, the world’s longest-running longitudinal cohort. The main results included:
- Entering menopause earlier (before age 49) was associated with a higher risk of dementia compared with menopause around ages 50–51.
- Postmenopausal use of HRT was linked to a lower risk of dementia, suggesting a possible protective effect of oestrogen after menopause.
- Greater lifetime exposure to oestrogen correlated with better cognitive performance and larger brain volumes, particularly in visuospatial skills, which involve analyzing and mentally manipulating visual-spatial information.
- Having one to two or more than three children was associated with better cognitive test scores compared with having no children, though the researchers noted conflicting findings in other studies and acknowledged the need for further validation.
The team cautioned that while higher oestrogen exposure across a reproductive lifespan showed potential cognitive benefits, the results require validation through additional research. They also noted that social and lifestyle factors connected to parenting could play a role in observed cognitive advantages.
Interpretation and context
Dr. McGrath’s team highlighted that dementia affects women more often than men and that understanding sex-specific factors could be crucial for prevention. The study does not claim that HRT is a universal solution for dementia but points to a potential avenue for reducing risk through hormonal exposure. The authors call for more research to confirm these associations and to clarify how different HRT regimens, timing, and duration might influence cognitive aging.
Caveats and next steps
Despite its strengths — notably leveraging data from a long-running, established cohort — the study is observational. This means it can reveal associations but not prove causation. The researchers advocate for further studies to dissect how oestrogen affects brain structure and function, including randomized trials and investigations into how individual factors such as genetics, comorbidities, and lifestyle interact with hormone exposure.
Practical implications
For clinicians and patients, the findings add to a growing conversation about personalized approaches to menopause management and dementia prevention. If future research corroborates these results, postmenopausal HRT could become a consideration in strategies aimed at supporting cognitive health in older women. Any decisions about HRT should involve a careful discussion of risks and benefits with a qualified healthcare professional, taking into account individual health history and preferences.
About the study
The Galway-led study analyzed data from 1,329 women in the Framingham Heart Study and was conducted in collaboration with Boston University. It explored how reproductive and hormonal factors across a woman’s life relate to brain aging markers and cognitive performance. The researchers emphasized the need for ongoing research to validate their observations and to better understand sex-specific factors in dementia.
