In stratified analyses, FGF23 and FGF23/α-klotho ratio were both significantly related to T2DM combined with CIMT in the lowest- and highest-concentration groups of all strata, except for those < 54 y, and significant negative association between α-klotho and T2DM combined with CIMT was found only in males and those who ≥ 54 y (Table S5, Fig. 4), moreover, similar stratified results were observed among serum FGF23, α-klotho levels and FGF23/α-klotho ratio with T2DM combined with atherosclerosis (Table S6, Fig. 5). Here, KL is linked to type 2 diabetes mellitus.