NEFL and Alzheimer disease: Our cross-sectional findings are in line with previous population-based studies, where AD blood biomarkers—particularly NfL—were shown to be altered in the presence of impaired kidney function.7-9,11,12,18,29-31 In fact, 1 previous study from our group9 and 2 studies from the Mayo Clinic Study of Aging7,11 found that CKD was one of the strongest conditions associated with altered levels of p-tau,9,11 t-tau,7,9 NfL,7,9 and GFAP9 in blood.