Educational Attainment and Dementia: Mediation by Mid-Life Vascular Risk Factors.

Introduction: Lower education is associated with higher burden of vascular risk factors in mid-life and higher risk of dementia in late life. We aim to understand the causal mechanism through which vascular risk factors potentially mediate the relationship between education and dementia.

Methods: In a cohort of 13,368 Black and White older adults in the Atherosclerosis Risk in Communities Study, we assessed the relationship between education (grade school, high school without graduation, high school graduate or equivalent, college, graduate/professional school) and dementia among all participants and among those with incident stroke. Cox models were adjusted for age, race-center (a variable stratified by race and field center), sex, apolipoprotein E (APOE) ε4 genotype, and family history of cardiovascular disease. Causal mediation models assessed mediation by mid-life systolic blood pressure, fasting blood glucose, body mass index, and smoking.

Results: More education was associated with 8 to 44% lower risk of dementia compared to grade school-level education in a dose-response pattern, while the relationship between education and post-stroke dementia was not statistically significant. Up to 25% of the association between education and dementia was mediated through mid-life vascular risk factors, with a smaller percentage mediated for lower levels of education.

Interpretation: A substantial proportion of the relationship between education and dementia was mediated through mid-life vascular risk factors. However, risk factor modification is unlikely to fully address the large educational disparities in dementia risk. Prevention efforts must also address disparities in socioeconomic resources leading to divergent early-life education and other structural determinants of mid-life vascular risk factors. ANN NEUROL 2023;94:13-26.