APOE and Alzheimer disease: A Cox hazards model with age at baseline (hazard ratio = 1.01, P = 0.59), gender (hazard ratio = 1.05, P = 0.84), t-tau/Aβ1–42 ratio (hazard ratio = 1.49, P = 0.002), APOE ε4 presence (hazard ratio = 1.13, P = 0.63) and education (hazard ratio = 1.02, P = 0.70) as covariates was used to test the association of the CSF complement biomarkers with conversion of MCI to AD.