What does serum -glutamyltransferase tell us as a cardiometabolic risk marker?

gamma-glutamyltransferase plays a key role in the synthesis and metabolism of extracellular glutathione, a major antioxidant in several defence mechanisms in the body. -glutamyltransferase is affected by environmental and genetic factors, and is raised when there is depletion of glutathione. Hence, it is a marker of oxidative stress. There is robust evidence that -glutamyltransferase even when values are within the reference interval is associated with increased cardiovascular and all-cause mortality in both sexes, in normal subjects and subjects with coronary artery disease, in the middle-aged and the elderly after adjusting for confounding factors. -glutamyltransferase even within the reference interval is associated with future presentation of type 2 diabetes, and the longitudinal increase in -glutamyltransferase activity is associated with increased risk of type 2 diabetes and cardiovascular mortality. -glutamyltransferase is associated with cardiovascular risk factors and metabolic syndrome. It has a prognostic value after a previous acute myocardial infarction and may be an indicator of adverse outcome in acute coronary syndromes and other chronic cardiac disorders. There is limited data about -glutamyltransferase and any association with peripheral arterial disease and also whether knowing -glutamyltransferase activity improves cardiovascular risk prediction beyond conventional risk factors. -glutamyltransferase is present in atherosclerotic lesions in the coronary and carotid arteries, and has a prooxidant role leading to the production of reactive oxygen species and atherosclerosis. Current reference intervals for -glutamyltransferase are inappropriate and need to be addressed. Some laboratories still use non- International Federation of Clinical Chemistry methods for estimation of -glutamyltransferase which are associated with lower results. Such laboratories should review their method and consider changing to the International Federation of Clinical Chemistry method.