GFAP and Alzheimer disease: Our main findings are: 1) In both cohorts, we observed that the synaptic biomarker CSF neurogranin is higher in women, while the neurodegeneration marker CSF NfL and astrocytic markers CSF GFAP and S100B are increased in men; 2) The discrimination accuracy of core AD CSF biomarkers to identify CU Aβ PET-positive participants did not differ by sex; 3) Higher baseline levels of several CSF biomarkers, including core AD biomarkers, NfL and glial biomarkers, showed a stronger association with higher Aβ PET uptake in women than in men.