Estrogen-only hormone therapy linked to 39% lower odds of dementia in study of 21,462 women
Women who used estrogen-only hormone therapy after menopause had 39% lower odds of dementia and 35% lower odds of Alzheimer's pathology at autopsy, per a study of 21,462 women published in Neurology. The benefit did not extend to combined estrogen-progestin therapy, which earlier
A study of 21,462 women published in Neurology, the journal of the American Academy of Neurology, found that those who used estrogen-only hormone therapy after menopause had 39% lower odds of developing dementia and 35% lower odds of Alzheimer's pathology found at autopsy. Researchers drew on two datasets: 728 participants completed brain scans or biomarker testing while alive, and 2,959 were autopsied at an average age of 82 to check for Alzheimer's signs, including reduced cerebral amyloid accumulation among hormone therapy users. The protective association applied only to estrogen-only therapy. Earlier research had linked the combined estrogen-progestin regimen to higher, not lower, dementia risk, which is why researchers isolated estrogen-only use in this analysis. The women in the study took hormone therapy decades ago, when dosing and timing differed from current medical guidance, so the findings describe a specific historical cohort rather than a green light for hormone therapy as practiced today. The result narrows a messy research history into a specific variable: it is the formulation, and possibly the timing, of hormone therapy, not hormone therapy as a blanket category, that appears to matter for long-term brain health.