NEFL and Alzheimer disease: Unadjusted for other covariates and compared with the control group of nondemented subjects (22.0 ± 12.4 pg/mL), average NfL concentrations were highly significantly higher in the MCI-AD group (38.1 ± 15.9 pg/mL, p < 0.005), and even further elevated in the ADD group (49.1 ± 28.4 pg/mL; p < 0.001).