APOE and Alzheimer disease: The ability of APOE ε4 to discriminate AD from controls differed as a function of age (Fig 5) and was greatest in the group aged 65–69 years (AUC = 0.78 [0.75–0.80], p < 0.001) and poorer before 55 years (AUC = 0.55 [0.47–0.62], p = 0.32) and after 85 years (AUC = 0.61 [0.56–0.67], p = 0.001).