APOE and Alzheimer disease: In order to investigate potential associations between plasma apoE levels and AD-associated pathological processes, we assessed potential links between plasma apoE levels; age; global cognition (MMSE scores); levels of CSF AD biomarkers Αβ40, Αβ42, t-tau, and p-tau; ratio of tau/Αβ42; and other relevant markers including CSF NfL, sTREM2, and plasma lipid levels.