Background: Serum gamma-glutamyltransferase (GGT) is commonly measured as a marker of hepatobiliary disorders in clinical practice, but little is known about its distribution and prognostic value for all-cause mortality.
Methods: Distribution and determinants of serum GGT levels were assessed among 8,043 construction workers ages 25-64 who underwent occupational health examinations in six centers in Southern Germany from 1986 to 1988. Study participants were followed for all-cause mortality until 1994.
Results: Serum GGT levels were considerably higher in this cohort than among male employees examined in a national survey conducted during the same period. The factors most strongly related to serum GGT were self-reported alcohol consumption, body mass index, diabetes, and hypertension, but relations of GGT levels were also found with nationality, occupation, and smoking. There was a strong dose-response relation between serum GGT levels and all-cause mortality (P value for trend < 0.001). Compared with men with GGT levels below 15 U/liter (measured at 25 degrees C), relative risks (95% CI) were 1.46 (0.86-2.49), 1.78 (1.08-2.94), 2.09 (1.26-3.45), and 3.44 (2.20-5.38) for men with GGT levels of 15-19, 20-29, 30-49, and > or = 50 U/liter, respectively. This relation was reduced but not eliminated by control for body mass index, diabetes, hypertension, alcohol consumption, and other covariates in multivariable analysis.
Conclusion: Serum GGT is a strong risk indicator of all-cause mortality.