Reply to Alanine Aminotransferase as an Independent Predictor of Incident Nonalcoholic Fatty Liver Disease

Abstract

First, the relationship between alanine aminotransferase (ALT) and nonalcoholic fatty liver disease (NAFLD) has not yet been clearly established, although increased liver enzymes are usually used as a surrogate marker of NAFLD. Tagher et al. have also noted that liver enzymes may be within the reference interval in up to 70% of patients diagnosed with NAFLD and that the full histological spectrum of NAFLD may be present in patients with normal liver enzymes. Our observations were therefore novel and have potential importance in understanding the relationship between ALT and NAFLD. Furthermore, several issues need to be clarified about ALT, including the isoforms of ALT and the role of different ALT isoforms in humans (1). Second, regarding the adjustment of confounders, such as insulin resistance, we did not perform this study using the euglycemic clamp and cannot comment on Tagher’s concerns about the interrelation between ALT, NAFLD, and insulin resistance as assessed by the euglycemic clamp …