The Aβ42/Aβ40 ratio measured either in plasma or NDEVs was lower in MCI-DEM than NRM-NRM group at baseline, whereas NDEV-associated proBDNF was lower in MCI-DEM and DEM-DEM groups compared to NRM-NRM, with its levels decreasing longitudinally as dementia was advancing. Here, BDNF is linked to dementia.