Regression analysis revealed that the log α-klotho concentration was positively associated with the presence of subclinical carotid atherosclerosis both in T1D subjects (incidence rate ratio [IRR]: 1.41; 95% confidence interval [CI], 1.06–1.89; p < 0.05) and in non-T1D subjects (IRR: 1.65; 95% CI, 1.02–2.75; p < 0.05). This evidence concerns the gene KL and type 1 diabetes mellitus.