Estrogen therapy linked to fewer signs of Alzheimer’s disease in brain tissue

Research published in Neurology suggests that women who use estrogen-only hormone therapy during menopause may have a reduced risk of developing Alzheimer's disease. The analysis, which examined patient data from two large databases, found that women who used estrogen-only hormone therapy had less physical evidence of the disease in their brains and better memory test scores.

Alzheimer's affects more than two-thirds of all patients worldwide, and researchers have explored whether estrogen's decline during menopause contributes to this disparity. Estrogen regulates brain health, including inflammation and the blood-brain barrier's integrity. Past studies on hormone therapy's dementia protection have produced mixed results.

To investigate further, Stanford University researchers Jennifer L. Bruno and colleagues analyzed records of thousands of older women. They compared 2,959 deceased women who had used estrogen-only hormone therapy to a group of 17,561 non-users, finding that the former had a lower chance of advanced Alzheimer's pathology at death and fewer signs of cerebrovascular disease.

The findings were specific to a formulation called conjugated estrogens, not another formulation called estradiol. The researchers also studied living patients from the same database, discovering that hormone therapy users had lower odds of receiving a clinical dementia diagnosis and better performance on memory tests. When examining biological markers in blood plasma and cerebrospinal fluid, hormone therapy users had higher levels of a specific amyloid protein, indicating less amyloid buildup in the brain.

While this study cannot prove causation, it suggests that estrogen-only hormone therapy may be associated with lower levels of early-stage amyloid buildup and improved brain health in women.