Assessing Early-Life Contributions to Racial Disparities in Cognition for Older Americans: The Importance of Educational Quality and Experience

ImportanceStudies on racial disparities in cognition have primarily focused on mid-life to late-life risk factors. Given the critical role of neurocognitive development in early life, understanding contributions of early-life circumstances has important implications for preventive strategies. ObjectiveTo assess the extent to which racial differences in early-life circumstances, particularly educational quality and experience, can individually and collectively contribute to racial disparities in late-life cognition. Design, Setting, and Participants9,015 participants (7,381 non-Hispanic White (White) and 1,634 non-Hispanic Black (Black) with comprehensive life-history data were assembled from the Health and Retirement Study (HRS) (1995-2018), a nationally representative longitudinal survey of Americans 50 years or older. Main Outcomes and MeasuresBlinder-Oaxaca Decomposition (BOD) was used to quantify disparities in cognitive outcomes between White and Black participants attributable to racial differences in early-life circumstances. Cognitive score and cognitive impairment were assessed using the Telephone Interview for Cognitive Status (TICS). Early-life educational quality and experience were included as key explanatory variables, and traditional early-life factors including cohort, regional, financial, health, trauma, relationship factors, and educational attainment were included as additional explanatory variables. Demographic and genetic factors were included as covariates. ResultsAmong White and Black participants, the mean (SD) ages were 73.2 (10.1) and 69.2 (9.2) years, respectively, and 4,410 (59.7%) and 1,094 (67.0%) were female. Cognitive scores (range: 0-27 points) were significantly lower in Black (13.5, 95% CI, 13.3-13.7) than White participants (15.8, 95% CI, 15.7-15.9), while the prevalence of cognitive impairment was significantly higher in Black (33.6, 95% CI, 31.3-35.9) than White participants (16.4, 95% CI, 15.6-17.2). Substantial racial differences were observed in early-life circumstances. Overall, racial differences in early-life circumstances accounted for 65.9% and 85.1% of the gaps in cognitive score and impairment, respectively. Educational quality and experience played a prominent role, independently explaining 34.1% of the gap in cognitive score and 51.3% in cognitive impairment. Notably, school racial segregation (attending all minority schools before college) explained 26.7%-40.6% of the gaps in cognition. These findings remained consistent after adjusting for genetic risks. Conclusions and RelevanceLess favorable early-life circumstances contribute to clinically meaningful and statistically significant racial gaps in late-life cognition. Policies that improve educational equity may have long-lasting impacts on reducing racial disparities in cognition into older ages. Key PointsO_ST_ABSQuestionsC_ST_ABSHow much do differences in early-life circumstances, including educational quality and experience, individually and collectively explain late-life disparities in cognitive outcomes between non-Hispanic Black (Black) and non-Hispanic White (White) older adults? FindingsEarly-life circumstances contribute substantially to racial disparities in cognitive outcomes over age 50. Educational quality and experience are the most important early-life contributors, independent of a rich set of sociodemographic and genetic factors. MeaningExposure to less favorable early-life circumstances for Black than White adults is associated with large racial gaps in cognitive outcomes.