Fig. 1. Differences in the proportions of the subjects with (A) prediabetes and (B) diabetes among the five groups classified according to serum cystatin C levels. Serum cystatin C groups: first (<0.8 mg/L), second (0.8 mg/L), third (0.9 mg/L), fourth (1.0 mg/L), and fifth (>1.0 mg/L). ^aP values were calculated using the chi-square test.