NEFL and Alzheimer disease: Five constructs emerged: "Brain & Vascular Health" (greater hippocampal volume, basal ganglia enlarged perivascular spaces (ePVS), cerebral blood flow, and HDL cholesterol; lower ventricle volume and BMI), "Structural Integrity" (greater cortical thickness, fractional anisotropy, and basal ganglia ePVS), "White Matter (WM) Fluid Dysregulation" (greater WM ePVS and Free Water), "AD Biomarkers" (higher phosphorylated tau [pTau]181 and pTau217; lower amyloid-beta 42/40 ratio), and "Neuronal Injury" (higher glial fibrillary acidic protein and neurofilament light chain).