NfL is a nonspecific biomarker of large caliber axonal neurodegeneration.37 Cross-sectional studies of individuals with type 2 or type 1 diabetes have shown that higher blood NfL levels are associated with worse cognition, but longitudinal studies have been lacking.36,38 In the current study, we did not find associations of plasma NfL at baseline and cognition measured 8 to 12 years later. This evidence concerns the gene NEFL and type 1 diabetes mellitus.