Aims: The aim of this study was to calculate the cut-off values of liver enzymes to identify the risk of incident type 2 diabetes (DM) and to investigate the association between liver enzymes and incident DM in participants with or without obesity.
Materials and methods: The long-term cohort study included 70,688 subjects who underwent medical health checkups in 2008. The cut-off values of alanine aminotransferase (ALT) and the aminotransferase (AST)/ALT ratio for incident DM were evaluated using the time-dependent receiver operating characteristic curves. The risk of incident type 2 DM was examined according to cut-off values of liver enzymes and the group with body mass index (BMI) ≥25 kg/m2 using Cox regression analyses.
Results: In total, 4181 of 70,688 subjects developed DM within 10 years. The area under the curve and cut-off values for the ALT and the AST/ALT ratio for incident type 2 DM at 10 years were 0.707 and 23 IU/L and 0.694 and 0.875, respectively. The risk of incident DM was higher in subjects with ALT ≥23 or AST/ALT ≤0.875 and BMI <25 kg/m2 than in those with ALT <23 IU/L or AST/ALT >0.875 and BMI ≥25 kg/m2 , respectively.
Conclusions: The cut-off values of ALT and the AST/ALT ratio associated with the risk of incident type 2 DM were determined. Non-obese individuals with AST/ALT ≤0.875 had a higher risk of incident type 2 DM than obese individuals with AST/ALT >0.875.
Keywords: ALT; AST/ALT ratio; NAFLD; liver enzyme; obesity; type 2 diabetes.
© 2022 John Wiley & Sons Ltd.