Figure 2 shows the serum α-klotho level by oral health status. α-Klotho levels were significantly lower in participants with poorer oral health, with the medians being 800.5, 804.7, and 790.4 pg/mL for moderate/severe periodontitis, poor-rated oral health, and tooth loss, respectively (all P<0.01). Here, KL is linked to periodontitis.