B2M and prediabetes syndrome: This study observed a strong association between the reduced tubular degradation of β2M (FrTDβ2M) and tubular cell injury biomarkers (ENAG) in subjects with diabetes (R2 = 0.340) and those with FPG levels commensurate with prediabetes (R2 = 0.354) who were exposed to Cd and Pb.