Postmenopausal estrogen and estrogen-progestin use and 2-year rate of cognitive change in a cohort of older Japanese American women - The Kame Project

Background: The relation between estrogen and cognition among postmenopausa l women remains controversial. Also uncertain is whether the proposed assoc iation varies between women taking unopposed estrogen and those taking estr ogen combined with progestin. Objective: To determine whether unopposed estrogen and combined estrogen-pr ogestin use were associated with the rate of cognitive change in a cohort o f older, Japanese American, postmenopausal women. Methods: A prospective observational study in a population-based cohort of older Japanese Americans (aged greater than or equal to 65 years) living in King County, Washington. Cognitive performance was measured in 837 women a t baseline (1992-1994) and 2-year follow-up (1994-1997) examinations using the 100-point Cognitive Abilities Screening Instrument (CASI). Least square s means general linear models were used to estimate the 2-year rate of cogn itive change according to categories of postmenopausal estrogen use. Results: Approximately half of this cohort (n = 455) had never used estroge n at any time since menopause, 186 were past users, 132 were current unoppo sed estrogen users, and 64 were current estrogen-progestin users. The major ity of current estrogen users were taking conjugated estrogens, and all wom en receiving combined therapy were taking medroxyprogesterone acetate. Afte r adjusting for age, education, language spoken at the interview, surgical menopause, and baseline CASI score, women who had never used postmenopausal estrogen improved slightly on the CASI scale (mean adjusted change, 0.79; SEM, 0.19). This change was significantly greater for current unopposed est rogen users (mean adjusted change, 1.68; SEM, 0.36; P=.04) and significantl y worse for current estrogen-progestin users (mean adjusted change, -0.41; SEM, 0.50; P=.02) compared with never users. The improvement observed in pa st users (mean adjusted change, 1.12; SEM, 0.29) was intermediate between t he changes for never users and current unopposed estrogen users and not sig nificantly greater than that for never users (P=.35). Conclusions: Our findings support a modest beneficial association between c urrent unopposed estrogen use and the rate of cognitive change. We also obs erved a modest detrimental association between current estrogen-progestin u se and the rate of cognitive change. The clinical significance of these mod est differences, however, is uncertain. Data from large, long-term randomiz ed trials are required before applying this information to the clinical set ting.