Longitudinal electronic health records (EHRs), “dementia” diagnostic codes, and genetic data from All of Us were used to see if there is a higher risk of dementia and an attenuated impact of apolipoprotein ε4 (APOE4) on Alzheimer's disease (AD) risk in Black and Hispanic/Latino groups. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.