CX3CL1 and Alzheimer disease: Urinary CX3CL1 levels were negatively correlated with age in AD patients (r = −0.264, p = 0.007) (Figures 3B, 4C) and in the male AD subgroup (r = −0.299, p = 0.031) (Supplementary Figure S2B), while no such correlation was observed in the female AD subgroup (Supplementary Figure S2B).