APOE and Alzheimer disease: In addition to CERAD-DR and ApoE4, presence of MC (i.e. belonging to the MC+ group) was also associated with an increased risk of future AD (HR = 2.55, 95% CI: 1.33–4.89) and significantly increased model fit (Δ-Chi2 = 9.5, df = 1, p = 0.002, change in Nagelkerke's R2 = 2.1%).