Postmenopausal hormone therapy and cognitive function in healthy older women

OBJECTIVE: Accumulating biologic evidence suggests that estrogen is related to cognitive function. Several epidemiologic investigations have reported that hormone therapy may reduce the risk of Alzheimer's disease. However, f ewer studies have examined the relation of postmenopausal hormone use to ge neral cognitive function in nondemented older women. Thus, we examined the association of hormone therapy to performance on four cognitive tests among healthy participants of the Nurses' Health Study. DESIGN: Cohort study. SETTING: The Nurses' Health Study, an ongoing prospective cohort study begu n in 1976. PARTICIPANTS: From the Nurses' Health Study, 2138 women aged 70-78 years. MEASUREMENTS: From 1995-1999 we administered four cognitive tests (Telephon e Interview for Cognitive Status (TICS), immediate and delayed recall of th e East Boston Memory Test (EBMT), and verbal fluency) by telephone. Hormone use was ascertained from biennial questionnaires beginning in 1976. Linear and logistic regression models were used to calculate multivariate-adjuste d differences in scores and relative risks of a low score for never users c ompared to current and past hormone users. RESULTS: After adjustment for confounders, neither current nor long-term ho rmone users demonstrated better performance on an overall measure of cognit ion (TICS), or on three tests of verbal memory (immediate and delayed recal l of the EBMT, immediate recall of the TICS 10-word list) than never users. On the test of verbal fluency, current hormone users scored significantly better than never users (linear regression estimate of the difference in sc ore = 0.78 points, 95% confidence interval (CI) 0.19-0.38, P =.01 for any c urrent use; and 0.91 points, 95% CI 0.28-1.54, P =.005 for greater than or equal to 5 years current use). Current hormone users also had a 30% decreas e (RR = 0.70, 95% CI 0.45-1.09) in their risk of a low score on the test of verbal fluency. These results were similar for women taking estrogen alone and estrogen combined with a progestin. CONCLUSIONS: Verbal fluency may be enhanced among women taking postmenopaus al hormones, however, there is little support for better overall cognitive function in hormone users than nonusers.