Timing and level of educational attainment and late-life cognition in the KHANDLE study.

Introduction: The timing of educational attainment may modify its effects on late-life cognition, yet most studies evaluate education only at a single time point.
Methods: Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study cohort participants (N = 554) reported educational attainment (dichotomized at any college education) at two time points, and we classified them as having low, high, or later-life high educational attainment. Linear mixed-effects models estimated associations between educational attainment change groups and domain-specific cognitive outcomes (z-standardized).
Results: Compared to low educational attainment, high (β= 0.59 SD units; 95% confidence interval [CI]: 0.39, 0.79) and later-life high educational attainment (β = 0.22; 95% CI: 0.00, 0.44) were associated with higher executive function. Only high educational attainment was associated with higher verbal episodic memory (β = 0.27; 95% CI: 0.06, 0.48).
Discussion: Level and timing of educational attainment are both associated with domain-specific cognition. A single assessment for educational attainment may inadequately characterize protective associations with late-life cognition.
Highlights: Few studies have examined both level and timing of educational attainment on cognition. Marginalized populations are more likely to attain higher education in adulthood. Higher educational attainment in late life is also associated with higher cognition.
(© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)