New Irish findings connect lifetime oestrogen exposure and dementia risk
A new study from Ireland suggests that women who maintain higher exposure to oestrogen across their lives—and those who use hormone replacement therapy (HRT) after menopause—may face a lower risk of developing dementia. Led by Dr Emer McGrath, an associate professor of medicine at the University of Galway, the research adds to a growing body of work examining how female hormones influence brain ageing.
The researchers examined how reproductive and hormonal factors across a woman’s life may relate to brain health in later years. The study, carried out with 1,329 women who did not have dementia, drew on data from the Framingham Heart Study in Boston, the world’s longest-running longitudinal cohort. The aim was to identify links between factors such as age at menarche, age at menopause, number of pregnancies, and postmenopausal HRT use—and their potential impact on cognitive ageing.
Key findings: menopause timing and cognitive protection
One of the main results showed that entering menopause at an earlier age (before 49) was associated with an increased dementia risk compared with women who reached menopause around ages 50 to 51. The authors emphasised that menopausal timing could play a role in brain ageing trajectories, although they cautioned that more research is needed to establish causation.
Crucially, the study found evidence suggesting that taking HRT after menopause is associated with a lower risk of dementia. This association was linked to greater lifetime oestrogen exposure, which the team described as potentially supporting cognitive performance and preserving brain structure.
Brain structure and cognitive performance linked to oestrogen
The researchers reported that higher blood oestrogen levels and an older age at menopause were connected to better cognitive test performance, particularly in visuospatial skills—the ability to interpret and manipulate visual information. The study noted a consistent theme in existing literature: women are more likely than men to develop dementia, which underscores the importance of understanding sex-specific factors in brain ageing.
Overall, the authors concluded that “greater exposure to oestrogen throughout a woman’s reproductive lifespan was associated with enhanced cognitive performance and larger brain volumes.” They added that while the findings point toward potential cognitive benefits from higher lifetime oestrogen exposure, they call for further validation through additional studies.
Bridging knowledge gaps in sex and dementia
Dr McGrath and her team highlighted that while attention to sex and gender differences in cardiovascular health has grown, dementia research has lagged in this regard. The study contributes to a broader effort to understand how hormonal histories may shape brain ageing and the risk of cognitive decline in later life.
The team noted some conflicting results in other studies about the impact of the number of children on dementia risk, suggesting that the relationship between reproductive factors and brain ageing is complex and may depend on multiple interacting variables. They advocate for more research to clarify these links and to explore how hormone therapies might be optimised for cognitive health across diverse populations.
What this means for women’s health strategies
For clinicians and researchers, the Galway study offers a framework for considering lifetime oestrogen exposure as a factor in brain ageing. It does not establish a definitive preventative strategy, but it does open avenues for exploring personalised approaches to menopause management and postmenopausal care that might support long-term cognitive health.
As science continues to probe the relationship between hormones, ageing, and dementia, women’s health decisions during menopause could gain new context from such findings, underscoring the importance of informed discussions between patients and healthcare providers.
