Estrogen may delay Alzheimer's disease

For this longitudinal study of aging and health in New York City, 1124 elderly women were evaluated regarding their use of estrogen during the postmenopausal period. These individuals were, at the time of their enrollment, free of Alzheimer's disease. Because estrogen promotes the growth and survival of cholinergic neurons and could decrease cerebral amyloid deposition, the authors theorized that postmenopausal estrogen might delay the onset of or prevent Alzheimer's disease. They found that the age of onset of Alzheimer's disease was significantly higher among the 156 (12.5%) women who reported taking estrogen after the onset of menopause than in those who did not. The relative risk of disease was significantly reduced (nine in 156 [5.8%] estrogen users versus 158 in 968 [16.3%] nonusers). This difference held true after adjustment for differences in education, ethnic origin, and apolipoprotein-E genotype. Duration of estrogen use was found to be predictive. Women who had used estrogen for longer than 1 year had a greater reduction in risk. Of the 23 women who were taking estrogen at the time of study enrollment, none had developed Alzheimer's disease when the article was written.