APOE and early-onset autosomal dominant Alzheimer disease: The strengths of our study include a well-characterized cohort with longitudinal follow-up over highly relevant timeframes for secondary prevention trials of Alzheimer’s disease.29 Our study also features the latest plasma Aβ42/Aβ40 assay which has been shown to be effective in estimating Alzheimer’s disease-related outcomes on its own and combined.30–36 This assay, along with APOE status and age, combines to make up a well-validated test which has been certified for use in predicting risk for amyloid pathology.