Study Suggests Hormone Therapy Linked to Lower Alzheimer’s Risk in Women

A comprehensive study published on August 12, 2026, in the journal Neurology indicates that women who utilized hormone therapy later in life may have a reduced risk of developing dementia. However, researchers caution that these findings indicate an association rather than causation, necessitating further research before any recommendations can be made regarding hormone therapies and brain health.

“While these findings help us better understand the relationship between hormone therapy use and various markers of dementia, more research needs to be done before we can make recommendations to women about their use of these therapies in relation to their brain health,” stated Dr. Jennifer Bruno of Stanford Medicine. She noted that the participants in the study had used hormone therapy decades ago, which may not align with today’s standards of medical practice.

Extensive Participant Analysis

The research drew from two large datasets encompassing 21,462 women who underwent clinical evaluations. Within this cohort, 728 participants received brain scans or biomarker testing, while 2,959 underwent autopsies at an average age of 82. The participants were monitored for approximately three to five years, starting around the age of 71.

Of all participants, 1,953 used hormone therapy while 19,509 did not, with hormone therapy initiation typically occurring after the age of 70. The study specifically focused on estrogen-only therapy, as previous studies suggested that combinations with progestin may increase dementia risk. Under current medical guidelines, estrogen-only therapy is primarily prescribed post-hysterectomy due to potential endometrial cancer risks.

Reduced Alzheimer’s Indicators

Notably, autopsy results revealed that women who had used hormone therapy were less likely to show signs of Alzheimer’s disease. The researchers evaluated key features associated with Alzheimer’s: amyloid-beta plaques, tau tangles, and neuritic plaques. Among the hormone therapy users, 18% exhibited no signs of Alzheimer’s at autopsy, compared to just 10% of non-users.

Additionally, 40% of hormone therapy users displayed all three Alzheimer’s indicators, contrasted with 51% among non-users. After adjusting for factors such as age, education, genetics, race, and hypertension, hormone therapy use correlated with a 35% lower likelihood of showing Alzheimer’s symptoms at autopsy.

Biomarkers Indicate Less Amyloid Accumulation

A separate analysis of biomarker tests taken during life suggested that women who used hormone therapy exhibited lower levels of amyloid-beta protein in their blood and spinal fluid, indicating lesser amyloid buildup in the brain. Furthermore, hormone therapy was associated with a 39% lower chance of receiving a clinical dementia diagnosis, with these women also experiencing fewer memory problems and less decline in everyday functioning.

Limitations of the Study

Dr. Bruno noted a significant limitation: the hormone therapy usage patterns of the study participants differ from current practices, with the average participant age at hormone therapy initiation being 70. In contrast, today’s guidelines typically recommend starting treatment in the late 40s to early 50s and discontinuing it before age 60.

Despite these limitations, the findings provide evidence supporting a potential link between estrogen-only hormone therapy in later life and improved outcomes related to dementia and overall brain health.

The study received support from the National Institute on Aging.