GFAP and Alzheimer disease: In the present study, we aimed to measure plasma levels of Aβ40, Aβ42, neurofilament light (NfL), α-syn, p-tau181, p-tau217, p-tau231 and GFAP in two large Chinese cohorts comprising NIID (n = 87), AD (n = 147), preNIID individuals (n = 26), and healthy controls (HCs, n = 136).