KL and Alzheimer disease: Individuals in the AD-dementia group carrying APOE4 had significantly lower median concentrations of Klotho than noncarriers (APOE4 carriers, 1050.8 pg/mL [range, 698.1-1661.4 pg/mL]; noncarriers, 1378.6 pg/mL [range, 1357.7-1411.0]; P < .001).