The test measures gamma-glutamyl transferase (GGT) an enzyme produced primarily by the liver and catalyzes glutathione, the main antioxidant in the body. The enzyme is elevated in some forms of liver disease, so physicians use GGT levels to detect liver damage and alcohol abuse.
In analyzing data from a long-term study involving more than 160,000 Austrian adults, the researchers found that the higher a person's blood level of GGT, the greater the risk of cardiovascular death. The levels are given in units per liter (U/l) of blood. Normal low is less than 9 U/l for women and less than 14 U/l for men. A moderately high value for GGT is 18 U/I for women and 28 U/I for men. High levels (twofold elevated) are more than 36 U/I for women and 56 U/I for men.
"People with high GGT had more than a 1.5-fold risk of dying from cardiovascular diseases in comparison to people with normal low levels of GGT," said senior author Hanno Ulmer, Ph.D. "For people under 60 years of age, this risk is even higher, amounting to more than two-fold. "Over the past decade, some small studies have suggested a link between high GGT and cardiovascular disease," said Ulmer, associate professor of medical statistics at the Innsbruck Medical University in Austria.
Several years ago, Italian researchers reported that elevated GGT could indicate early atherosclerosis. Ulmer and his colleagues investigated the researchers' findings. They examined medical data collected from 19852001 from 163,944 (98.4 percent) of the then-enrolled volunteers in the Vorarlberg Health Monitoring and Promotion Program. This is an ongoing study in Austria's westernmost province that examines risk factors for chronic diseases.