Estrogen replacement therapy and cognitive decline in memory-impaired post-menopausal women.

Background: Estrogen replacement therapy (ERT) may delay dementia-related cognitive decline in post-menopausal women, but few studies have longitudinally examined this relationship and none has controlled for baseline functioning or concurrent medication.
Methods: We report the results of a 1-year retrospective longitudinal study examining cognitive functioning in female estrogen and nonestrogen users (n = 3128) who presented to the state of California memory disorder clinics in a naturalistic multisite study of senile dementia, Alzheimer's type (SDAT), and other cognitive impairments.
Results: At baseline, estrogen users had significantly lower rates of SDAT diagnoses (possible and probable) than nonestrogen users, and significantly higher rates of the lesser diagnoses of "cognitive impairment" and "no dementia." ERT was significantly associated with higher cognitive functioning at baseline and at 1 year follow-up (n = 358). Nonestrogen users deteriorated significantly from baseline to follow-up; estrogen users did not. Results were similar in groups matched on baseline Blessed-Roth Dementia Rating Scale (BRDRS) ratings (n = 32) and in a variety of subpopulations.
Conclusions: These findings are consistent with estrogen acting as a protective factor against cognitive deterioration in post-menopausal women with SDAT and other cognitive impairments, and may suggest an increased effect in earlier stages of cognitive impairment.