KL and Alzheimer disease: A significant association was found for all 3 CSF AD biomarkers in the entire cohort; CSF Klotho levels had a significant positive association with CSF Aβ42 levels (β = 0.519; 95% CI, 0.201-0.836; P < .001), a significant negative association with CSF T-tau levels (β = −0.884; 95% CI, 0.223 to −0.395; P < .001), and a significant negative association with CSF P-tau levels (β = −0.672; 95% CI, −1.022 to −0.321; P < .001).