APOE and Alzheimer disease: In the testing set, the C‐index of AD protein risk score predicting AD risk was 0.867 (95% CI, 0.828, 0.906), which was comparable to that of CogDrisk‐AD risk factors (C‐index, 0.856; 95% CI, 0.823, 0.889), but significantly superior to that of APOE genotypes (C‐index, 0.705; 95% CI, 0.660, 0.750).