Similarly, compared with noncarriers and participants in the lower NfL tertile, APOE4 carriers with middle and upper tertiles of NfL levels experienced accelerated cognitive decline, with a β (SD) of −0.04 (0.02) (P = .006) and −0.03 (0.02) (P = .07), respectively, although the difference was not significant for upper tertiles. Here, APOE is linked to Mental deterioration.