KL and Alzheimer disease: Analysis showed significantly lower median CSF Klotho levels in the AD-dementia group compared with the control group among participants younger than 65 years (AD-dementia, 1057 pg/mL [range, 698.18-1411.9 pg/mL]; controls, 1313.1 pg/mL [range 846.5-1726.3 pg/mL]; P = .003).