Disparities in Age-Associated Cognitive Decline Between African-American and Caucasian Populations: The Roles of Health Literacy and Education.

Abstract

To examine health literacy as a mediator of racial disparities in cognitive decline as measured by executive function in elderly adults. Prospective cohort study. Secondary analysis of ElderWalk trial in Boston, Massachusetts. English-speaking African-American and Caucasian individuals in a walking intervention for community-dwelling adults aged 65 and older without dementia at baseline who completed baseline and 12-month evaluations (N = 198). Health literacy was measured using the Short Test of Functional Health Literacy in Adults. Fluid and crystallized cognitive functions were measured at baseline and 12 months using the Trail-Making Test Part B minus Part B (TMT B-A) and the Controlled Oral Word Association Test (COWAT). Associations between health literacy and 12-month cognitive decline were modeled using multivariate linear regression. Participants with higher health literacy and education experienced less cognitive decline than those with limited health literacy according to the TMT B-A (P = .01). After adjusting for covariates, Caucasian participants (n = 63) experienced less decline than African-American participants (n = 135) on TMT B-A (P = .001) and COWAT (P = .001). Adjusting for health literacy led to a 25.3% decrease in the point estimate for racial difference in TMT B-A and a 19.5% decrease in COWAT. Although independently related to cognitive decline, educational attainment did not mediate racial differences. Health literacy is a partial mediator of racial disparities in cognitive decline. These results indicate the need to develop interventions to mitigate cognitive decline that individuals with low heath literacy can use and to modify the healthcare environment to better accommodate this population.