Oestrogen therapy can reduce Alzheimer's risk

Research show that Oestrogen therapy may ward off Alzheimer’s and dementia in elderly women.

This observational study does not show that hormone therapy prevents dementia, but found that women using oestrogen-only hormone therapy had a lower risk of developing dementia and fewer biological signs associated with Alzheimer’s disease.

For the study, researchers examined medical records from 21,462 female participants from two large American studies. The researchers looked only at participants who took oestrogen-only therapy, since previous studies had indicated that oestrogen plus progestin combination therapy may increase the risk of dementia. In current standard practice, oestrogen-only therapy is prescribed only for those who have undergone a hysterectomy due to the risk of endometrial cancer.

The research combined clinical data with biomarkers and evidence from brain tissue collected after death, providing a detailed picture of the relationship between hormone therapy and changes linked to Alzheimer’s disease than studies relying solely on dementia diagnoses. After adjusting for age, education, genetics, race and hypertension, researchers found that participants who took hormone therapy had 35% lower odds of signs of Alzheimer’s disease at autopsy when compared to those who did not take hormone therapy.
Use of hormone therapy was also associated with 39% lower odds of receiving a clinical diagnosis of dementia and less risk of showing symptoms of memory problems or decline in functional abilities.

Dr Tom Blackmore, Research Programmes Manager at Alzheimer’s Research UK, said:
“Dementia has been the leading cause of death for women in the UK for over a decade, yet we still don’t fully understand why women are more likely to be affected by the condition than men. Understanding how hormones, menopause and ageing influence brain health is an important area of dementia research.

“This study found that women who reported using oestrogen-only hormone therapy at an average age of around 70 were less likely to develop dementia and showed fewer biological signs associated with Alzheimer’s disease.

“While these findings are interesting, this study can only show an association and cannot tell us whether hormone therapy itself reduced dementia risk. Many factors influence a person’s likelihood of developing dementia, and women who received hormone therapy may differ from those who did not in ways that also affect their long-term brain health. It’s also important to note that women in this study reported using oestrogen-only hormone therapy at an average age of around 70, which differs substantially from how hormone replacement therapy is typically used today.

“This research also focused on oestrogen-only hormone therapy, which is typically prescribed to women who have had a hysterectomy. This means the findings cannot necessarily be applied to all women considering hormone replacement therapy today.

“These findings are not a reason for women to start or stop hormone replacement therapy with the aim of reducing dementia risk. Instead, the study provides valuable clues about the biology underlying dementia and highlights the need for more research into women’s brain health. Larger and more diverse studies will be needed to determine whether hormone-based treatments could play any role in reducing dementia risk.”