NEFL and nervous system disorder: Levels of NfL also mediated the associations between the residual measure and several other predictors (age, sex, WML volume, and AD and astrocytic biomarkers), which could be expected given that NfL is a sensitive, but non-specific marker of neurological disorders [57], is associated with older age and male sex in CU [58, 59], and is closely associated with global cognitive performance and future cognitive decline [20, 60].