THE EFFECT OF ESTROGEN REPLACEMENT THERAPY ON COGNITIVE FUNCTION IN WOMEN - A CRITICAL-REVIEW OF THE LITERATURE

Objective: To conduct a review of the available clinical trials to det ermine whether sufficient evidence exists to support the conclusion th at estrogen replacement therapy has a beneficial effect on cognitive p erformance in post-menopausal women and in women with Alzheimer's dise ase. Studies were identified through a MEDLINE search of all English-l anguage publications between 1970 and 1996 in which the words estrogen and cognition or estrogen and memory appeared. Data Extraction: Data were extracted for each study, including features of subjects and elig ibility criteria, duration of follow-up, and treatment regimen. Baseli ne characteristics were evaluated, including age; menopausal status; f ollicle-stimulating hormone, luteinizing hormone, and estradiol levels ; mood; and measures of cognitive function. Psychological tests were e valuated for construct validity. Results: Nineteen studies were review ed, including 10 randomized trials of estrogen replacement therapy ver sus placebo. Extreme heterogeneity among subjects and variability in t he use of cognitive measures across the studies precluded performing a quantitative summary. Of the 10 randomized trials, eight claimed ther apeutic benefits for estrogen therapy, three of which reported signifi cant improvements in memory and two of which showed improvements in at tention. These studies did not control for potential confounds such as depression and vasomotor symptoms. Of the nine observational studies, five found a significant association between estrogen use and cogniti ve function. Conclusion: Although several observational studies provid e encouraging evidence for the beneficial effect of estrogen on cognit ive function, there is currently inadequate evidence available from ra ndomized, controlled trials to support the conclusion that estrogen re placement therapy improves cognitive function in post-menopausal women or women with Alzheimer's dementia. (C) 1997 Elsevier Science Inc.