In this large prospective primary care-based study, we evaluated the prognostic performance of plasma Aβ42/Aβ40 ratio and plasma levels of P-tau181, NfL, and GFAP, and confirmed that these biomarkers are associated with an increased risk of progressing to clinically-diagnosed DAT during ∼8 years of follow-up in individuals without dementia, aged 79–94 years, and regularly visiting the primary care system. Here, GFAP is linked to dementia.