KL and diabetes mellitus: In vivo experiments and clinical studies show that low serum klotho levels accelerate senescence (Xiao et al., 2004; Dërmaku-Sopjani et al., 2013) and death (Kresovich and Bulka, 2022), and are also associated with an increased risk of age-related diseases such as atherosclerosis (Pan et al., 2018; Chen et al., 2021), chronic kidney disease (Manya et al., 2010; Drew et al., 2017), type 2 diabetes mellitus (T2DM) (Nie et al., 2017), metabolic syndrome (Kim et al., 2019), and pulmonary emphysema (Suga et al., 2000).