GPT and diabetes mellitus: Metabolic syndrome (MetS) includes multifaceted metabolic disorders in the whole body, which is closely related to cardiovascular and cerebrovascular diseases as well as diabetes mellitus.[1–10] The diagnostic factors include abdominal obesity and abnormal metabolic indexes such as blood pressure, blood glucose, blood lipid, and so on.[11–15] Alanine aminotransferase (ALT) is a sensitive indicator of liver injury, which is commonly used to screen and detect the abnormal liver function and evaluate its abnormal degree.[16] In China, the normal upper limit of ALT is usually 40 U/L.