Association between mild anemia and executive function impairment in community-dwelling older women: The Women's Health and Aging Study II

OBJECTIVES: To evaluate the relationship between mild anemia and executive function in community-dwelling older women. DESIGN: Cross-sectional. SETTING: Community-based. PARTICIPANTS: High-functioning subjects participating in the baseline assessment of the Women's Health and Aging Study (WHAS) II, Baltimore, Maryland, 1994 to 1996. WHAS II eligibility criteria included aged 70 to 80, a Mini-Mental State Examination score of 24 or greater, and absence of advanced disability (difficulty in no more than 1 domain of physical function). Included in this study were 364 subjects with a hemoglobin concentration 10 g/dL or greater and known executive function status. MEASUREMENTS: Trail Making Test (TMT) Parts B and A. Tertiles of time to complete each test were used to define best (bottom), intermediate, and worst (top) performance. Tertiles of the difference TMT-B minus TMT-A were calculated. Anemia defined as hemoglobin concentration less than 12 g/dL. RESULTS: The percentage of subjects in the worst TMT-B, TMT-A, and TMT-B minus TMT-A performance tertile was highest for those with anemia. Prevalent anemia substantially increased the likelihood of performing worst (as opposed to best) on the TMT-B (odds ratio (OR) = 5.2, 95% confidence interval (CI) = 1.3-20.5), TMT-A (OR = 4.8, 95% CI = 1.5-15.6), and TMT-B minus TMT-A (OR = 4.2, 95% CI = 1.0-17.2), even after controlling for age, education, race, prevalent diseases, and relevant physiological and functional parameters. CONCLUSION: This study provides preliminary evidence in support of the hypothesis that mild anemia might be an independent risk factor for executive function impairment in community-dwelling older adults. Whether such an association is causal or noncausal remains to be determined.