GPT and type 1 diabetes mellitus: T1DM: type 1 diabetes mellitus; T2DM: type 2 diabetes mellitus; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; ALT: alanine transaminase; HbA1C: glycosylated hemoglobin; RYGB: Roux-en-Y gastric bypass; LAGB: laparoscopic adjustable gastric banding