Women who used hormone therapy later in life had a lower risk of developing dementia, according to a large study published August 12, 2026, in Neurology, the medical journal of the American Academy of Neurology. The researchers were quick to add the essential caveat: what they found is an association, not evidence that hormone therapy prevents dementia.
The analysis drew on two large data sets covering 21,462 women who had undergone clinical testing while alive. Within that group, 728 participants also had brain scans or biomarker testing during their lifetimes, and 2,959 underwent autopsy after death at an average age of 82, allowing researchers to look directly for the physical hallmarks of Alzheimer's disease in brain tissue rather than relying on diagnosis records alone.
That combination of living biomarker data and postmortem examination is what gives the work its weight. Cognitive testing and clinical diagnoses can be imprecise, so being able to compare hormone therapy use against actual brain pathology helps clarify whether the link reflects something happening in the brain itself or simply differences in who gets diagnosed.
Study author Jennifer Bruno, PhD, of Stanford Medicine, cautioned that the women in this analysis were using hormone therapy decades ago, and both the timing and the formulations differ from what most women receive today. She said more research is needed before anyone can make recommendations to women about hormone therapy and brain health, describing the findings as informative but possibly not applicable to current practice.