Purpose: To explore the impact of varying hemoglobin levels on mortality, function, and cognition in a representative population of older persons.
Methods: Participants in this prospective cohort study included 1 744 men and women, aged 71 years or older, from a random household sample living in Durham and surrounding counties in North Carolina. Hemoglobin levels were obtained from participants at baseline in 1992. Functional status was measured at the 4-year follow-up interview using Katz and instrumental activities of daily living. Cognition was measured using the Short Portable Mental Status Questionnaire (SPMSQ). Death was determined by search of the National Death Index, and all deaths through 2000 are included.
Results: Using World Health Organization (WHO) criteria, the prevalence of anemia was 24%. There was a strong racial difference with an odds ratio, adjusted for age, education, estimated glomerular filtration rate and comorbidity of 3.0 (95% CI, 2.3-3.9) in African Americans compared with Caucasians. The risk ratio for 8-year mortality was 1.7 (95% CI, 1.5-2.0) for anemic subjects (P = .0001) and did not differ by sex or race. Anemia was strongly associated with poorer physical function (P = .0001) and cognitive function (P = .0001), and predicted decreases in both over a 4-year period.
Conclusions: In an elderly community-based population, anemia is more prevalent in African Americans and is independently associated with increased mortality over 8 years for both races and sexes. Anemia also is a risk factor for functional and cognitive decrease.