Stanford study links estrogen-only hormone therapy to lower dementia risk

Researchers at Stanford University have identified a potential link between estrogen-only menopausal hormone therapy and a reduced risk of dementia and Alzheimer’s disease in older women. An analysis of medical records and autopsy data from over 21,000 women suggests that those using estrogen-only treatment had a 39 percent lower chance of a clinical dementia diagnosis and a 33 percent lower risk of memory and functional decline.

Crucially, the study utilized brain autopsies to examine biological markers, finding that women on estrogen-only therapy exhibited 35 percent fewer Alzheimer’s-related changes, such as amyloid plaque accumulation, compared to those who did not use the therapy.

Experts emphasize that these findings show a correlation rather than direct causation and do not prove that hormone therapy prevents dementia. The study focused specifically on estrogen-only users—typically women who have undergone a hysterectomy—as previous research suggested that combined estrogen and progestin therapy might increase dementia risk. Medical professionals advise against individuals starting or stopping hormone treatments based on this study alone, noting that further research is required to establish definitive preventative roles.