Factors Related to Racial Differences in Late-Life Level of Cognitive Function

Objective: The study aim was to identify factors associated with racial differences in level of cognitive function in old age. Method: Older Black (n = 5,950) and White (n = 3,469) residents of a geographically defined urban community were randomly split into exploratory and confirmatory subgroups. A global measure of cognition was derived from 4 brief performance tests, and potential correlates of cognition (candidates) were selected from demographic, health-related, and experiential measures. In the exploratory subgroup, using a stepwise search algorithm, we examined the cognitive difference by race and then allowed candidate measures and Race ×Candidate Measure interactions to enter the model. Results: The cognitive score in the exploratory subgroup (M = 0.257, SD = 0.714) was a mean of 0.403 unit lower in Black persons than White persons (SE = 0.021, p < .001), and race accounted for 7% of cognitive variability. After the candidate selection process, 16 measures were retained, including 12 candidate measures and the 2-way interactions of race with education, age, reading/cognitive activity, and neuroticism. In this model, which accounted for 45% of the variability in global cognition, race was no longer associated with global cognition (coefficient = 0.012, SE = 0.110, p = .912). Findings were replicated in the confirmatory subgroup. Conclusion: These cross-sectional analyses suggest that consideration of demographic, health-related, and experiential factors greatly attenuates racial differences in late-life level of cognition.