Recent studies have demonstrated that serum FGF23 and α-klotho levels were associated with vascular calcification and endothelial dysfunction, both of which were key factors involved in atherosclerosis [14–18], and elevated FGF23 and decreased α-klotho levels were found to be independently associated with unstable plaques, carotid intima-media thickness (CIMT) and epicardial fat thickness (EFT) in the general populations [19–24], yet few focused on these relationships in T2DM patients, and still researchers argued that such relationships actually did not exist [25–28]. Here, KL is linked to endothelial dysfunction.