Increased levels of GGT were significantly associated with MetS by both definitions, harbouring about 30% higher risks after adjustment for age, sex, smoking, and T2DM family history (OR [95% CI] = 1.28 [1.12–1.46] and 1.30 [1.14–1.49] for a 5 U/L increase in GGT according to IDF and Cook's criteria, respectively in model II, with both p‐values < 0.001); these relationships significantly reduced after further adjustment for ALT (Model III). The gene discussed is GPT; the disease is type 2 diabetes mellitus.