Anemia and 9-year domain-specific cognitive decline in community-dwelling older women: The Women's Health and Aging Study II.

OBJECTIVES: To test the hypothesis that anemia (hemoglobin <12 g/dL) is associated with a faster rate of cognitive decline over 9 years in a community-dwelling sample of women aged 70 to 80 at baseline.
DESIGN: A population-based, prospective cohort study.
SETTING: East Baltimore, Maryland. PARTICIPANTS: Four hundred thirty-six women sampled to be representative of the two-thirds least-disabled women aged 70 to 80 at baseline (1994-1996). MEASUREMENTS: Nine-year trajectories of cognitive decline, analyzed using linear random effects models, in the domains of immediate verbal recall, delayed verbal recall, psychomotor speed, and executive function.
RESULTS: At baseline and after adjustment for demographic and disease covariates, women with anemia were slower to complete a test of executive function; the difference in baseline function between women with anemia and those without was -0.43 standard deviations (SDs) (95% confidence interval (CI)=-0.74 to -0.13) on the Trail Making Test Part B. During follow-up, anemia was associated with a faster rate of decline in memory. Between baseline and Year 3, the difference in the rates of decline between women with anemia and those without was -0.18 SDs per year (95% CI=-0.29 to -0.06) on the Hopkins Verbal Learning Test (HVLT) and -0.15 SDs per year (95% CI=-0.26 to -0.04) on the HVLT-Delayed.
CONCLUSION: Anemia was associated with poorer baseline performance on a test of executive function and with faster rates of decline on tests of immediate and delayed verbal recall. If this relationship is causal, it is possible that treatment of anemia could prevent or postpone cognitive decline.