GPT and Insulin resistance: The association between ln-GGT and ln-PFOA reached a significant level in the fully adjusted model (model 3; coefficient, 0.015; 95% CI: 0.010, 0.019) mainly due to the contribution of insulin resistance and BMI, which appeared to be highly associated with ln-GGT (Table 2); fitted values of GGT by deciles of PFOA showed an apparent positive association (Figure 1C), although it was less clear than that shown for ALT.