NEFL and Mental deterioration: Although the association between plasma biomarkers and cognitive decline, as well as the risk of progressing to DAT, has been extensively examined in clinically-based cohorts,8,25,26 to our knowledge no studies had yet extensively studied Aβ42/Aβ40 ratio, P-tau181, NfL, and GFAP in the oldest old individuals without dementia in primary care.