Elevated serum gamma-glutamyltransferase activity is associated with increased risk of mortality, incident type 2 diabetes, cardiovascular events, chronic kidney disease and cancer. A narrative review.

In clinical practice, increased serum g-glutamyltransferase (GGT) activity is usually interpreted as a marker of alcohol abuse and liver dysfunction. The knowledge of the GGT's physiological functions has expanded and several important epidemiological associations have been reported. This review examines evidence for an association of high normal serum GGT enzyme activity, mostly within the reference range, with the risk of mortality and major vascular (i.e., cardiovascular morbidity and mortality) and non-vascular outcomes (i.e., incident type 2 diabetes, chronic kidney disease and cancer), independent of alcohol consumption and other prognostic factors.