- Approximately 32 million people worldwide have Alzheimer’s disease.
- About two-thirds of all Alzheimer’s cases are in women.
- Researchers from the University of Western Ontario have found female sex hormones play a significant role in how Alzheimer’s disease manifests in the brain.
In a new study, researchers from the University of Western Ontario found that female sex hormones play a significant role in how Alzheimer’s disease manifests in the brain.
The study appears in
About
Although researchers have some theories about why women are more likely to have Alzheimer’s disease than men, the underlying biological reasons remain unknown.
There are a few reasons why researchers believe women are at a higher risk for Alzheimer’s disease than men.
The first is longevity, as women tend to live longer than men. In high-income countries, women tend to live
Another factor may be genetics. A study published in October 2022 identified a specific gene on the
And scientists also believe women may be more prone to developing Alzheimer’s disease because of different hormones. Research in mice published in March 2022 discovered the follicle-stimulating hormone (FSH) — levels that rise during perimenopause — are linked to
Research presented in 2023 found menopausal women who experience frequent hot flashes during sleep had a higher risk for Alzheimer’s disease.
Medical News Today spoke with Dr. Vania Prado, professor in the Departments of Physiology, Pharmacology, Anatomy, and Cell Biology at Schulich School of Medicine & Dentistry and scientist at Robarts Research Institute at the University of Western Ontario, and senior author of this study.
Dr Prado said the team decided to examine the possible role of female sex hormones in the development of Alzheimer’s disease because of the chemical changes in the brain that can affect and contribute to
“One of the important contributors for regulating early pathology are brain cells that secrete
“When we examined the relationship between acetylcholine and Alzheimer’s pathology, we found that male and female mice had different responses.
However[,] men and women with Alzheimer’s presented a similar profile. Thus the question became why there are these differences between mice and humans? Sex hormones, because of the age we normally use mice, became the prime suspect.”
– Dr. Vania Prado
For this study, Dr. Prado and her team focused on the female sex hormone estradiol, which helps maintain a woman’s reproductive system and plays a significant role in the maturation and release of eggs during the menstrual cycle.
According to the researchers, the
Through various tests and image analysis on a mouse model of male and female mice and brain scans of older humans, the researchers found that when estradiol was present, the relationship between acetylcholine and toxic amyloid was lost.
But when sex hormones were eliminated, the relationship was connected, potentially increasing Alzheimer’s pathology. This is especially of note, the researchers said, as levels of estradiol
“We were surprised that in female mice the response was very different than male mice and different than humans, both men and women. The difference was likely because of female hormones, which are likely low in women with Alzheimer’s.”
– Dr. Vania Prado
As for how estradiol may affect the build-up of beta-amyloid protein in the brain, Dr. Prado said that is still not fully understood.
“There is evidence that low levels of estradiol may affect how immune cells respond to amyloid in the brain,” she continued. “There is also evidence that loss of estradiol increases amyloid pathology.”
Medical News Today also spoke with Dr. Verna Porter, a neurologist and director of the Dementia, Alzheimer’s Disease, and Neurocognitive Disorders at Providence Saint John’s Health Center in Santa Monica, CA, about this study.
As a doctor treating female patients at high risk for Alzheimer’s disease, she said she found this study to be one of great interest.
“The findings presented in the study provide valuable insights into the role of sex-specific factors, particularly the impact of estradiol and cholinergic signaling, in Alzheimer’s disease.
Understanding these factors can significantly influence how I approach risk assessment and discussions with female patients, especially those in the perimenopausal age range. In future discussions with my female patients, I would use these findings to provide a more personalized and informative approach to Alzheimer’s risk assessment and management.”
– Dr. Verna Porter
Dr. Porter said these findings may also lead to a need to emphasize the importance of considering the patient’s hormonal status, including their menopausal stage and the role of estradiol, when assessing their Alzheimer’s risk.
“This would be particularly relevant for perimenopausal women, as the study suggests that estradiol may impact the relationship between cholinergic signaling and amyloid pathology,” she added.
“For those in the perimenopausal age range, we should continue to stress the importance of monitoring cognitive health and considering lifestyle modifications, such as maintaining