Racial Disparities in Cognitive Function Among Middle-Aged and Older Adults: The Roles of Cumulative Stress Exposures Across the Life Course.

Abstract

Racial disparities in cognitive function are well documented, but factors driving these disparities remain underexplored. This study aims to quantify the extent to which cumulative stress exposures across the life course explain Black-White disparities in executive function and episodic memory in middle-aged and older adults. Data were drawn from the 2004-2006 wave of the Midlife Development in the United States Study (MIDUS 2) and the MIDUS Refresher study (N = 5,947; 5,262 White and 685 Black). Cumulative stress exposures were assessed by 10 stressor domains (ie, childhood stress, stressful life events in adulthood, financial stress, work psychological stress, work physical stress, work-family conflicts, neighborhood disorder, relationship stress, perceived inequality, and perceived discrimination). Cognitive function was assessed using the Brief Test of Adult Cognition by Telephone. Marginal structural models were used to quantify the proportion of the effect of race/ethnicity status on cognitive function mediated through cumulative stress exposures. After adjusting for age, sex, and sample, on average, Black participants had lower levels of executive function (difference: -0.83 SD units, 95% CI: -0.91, -0.75) and episodic memory (difference: -0.53 SD units, 95% CI: -0.60, -0.45) scores than White participants. Cumulative stress exposures accounted for 8.4% of the disparity in executive function and 13.2% of the disparity in episodic memory. Cumulative stress exposures across the life course explained modest proportions of Black-White disparities in cognitive function in this large cross-sectional study.