Socioeconomic, health, and psychosocial mediators of racial disparities in cognition in early, middle, and late adulthood

Abstract

Racial disparities in cognitive performance exist across the life course, but it is not known whether mediators of disparities differ by age. Understanding sources of cognitive disparities at different ages can inform policies and interventions. Data were obtained for non-Hispanic Black and White respondents to The National Survey of Midlife Development in the United States from 3 age groups: 28-44 (N = 1210; 20% Black); 45-64 (N = 2693; 15% Black); and 65-85 (N = 1298; 11% Black). Moderated mediation models characterized direct and indirect effects of race on episodic memory and executive function composite scores through economic, health, and psychosocial variables as a function of age group. Education, income, chronic health conditions, and external locus of control mediated cognitive disparities across the life course, although income was a stronger mediator at younger ages. Perceived discrimination was a weaker mediator among young adults due to an absence of racial differences in perceived discrimination in that group. Despite multiple indirect effects, there were still significant unexplained effects of race on cognition that were not moderated by age group. Interventional work is needed to determine whether increasing educational attainment and income, and reducing chronic health conditions and perceived constraints among Blacks, reduce cognitive disparities. Targeting income inequality and discrimination (or buffering the impact of those variables) may be differently effective at reducing cognitive disparities at different stages of the adult life course. (PsycINFO Database Record

Figure 1

Moderated mediation model. Path “a” reflects racial differences in the levels of the six potential mediating variables: education, income, body mass index, chronic conditions, daily discrimination, and external locus of control. Path “b” reflects associations between the six potential mediating variables and cognition. The indirect path is the product of the “a” and “b” paths. The direct path (path “c”) reflects the association between race and cognition independent of the mediators. The exogenous, three-category variable of age group (i.e., young adulthood, midlife, late life) was allowed to moderate the indirect path via interactions with the exposure (path “mod(a)”) and all mediators (path “mod(b)”), as well as the direct path via interactions with the exposure (path “mod(c)”). Separate models were run for episodic memory and executive functioning. All six potential mediating variables were included in each model.

Figure 2

Pure natural indirect effects of African American race on (a) episodic memory or (b) executive functioning as a function of age group. Dotted lines correspond to 95% confidence intervals around the indirect effect. Absence of overlap between the confidence interval and 0 indicates a significant indirect effect. Slopes reflect significant age group moderation of each indirect effect.