Relationship between gamma-glutamyl transferase and glucose intolerance in first degree relatives of type 2 diabetics patients

BACKGROUND Considering that serum gamma-glutamyl transferase (GGT) activity could reflect several different processes relevant to diabetes pathogenesis and the increasing rate of type 2 diabetes worldwide, the aim of this study was to assess the association between serum GGT concentrations and glucose intolerance, in the first-degree relatives (FDR) of type 2 diabetic patients. METHODS In this descriptive study, 30-80 years old, non diabetic FDRs of type 2 diabetic patients were studied. Serum GGT was measured by enzymatic photometry method in all studied population. The relationship between GGT and glucose intolerance status (normal, prediabetic and diabetics) was evaluated. RESULTS During this study 551 non-diabetic FDRs of type 2 diabetic patients were studied. Mean of GGT was 25.3 ± 12.1 IU/L. According to glucose tolerance test, 153 were normal and 217 and 181 were diabetic and prediabetic respectively. Mean of GGT in normal, prediabetic and diabetic patients was 23.5 ± 15.9 IU/L, 29.1 ± 28.1 IU/L and 30.9 ± 24.8 IU/L respectively (p = 0.000). The proportion of prediabetic and diabetic patients was higher in higher quartile of GGT and there was a significant correlation between GGT and BMI, HbA1c, FPG, cholesterol, LDL-C, and triglyceride (p < 0.05). There was a significant relation between GGT and area under the curve (AUC) of oral glucose tolerance test (p = 0.00). CONCLUSIONS Measurement of GGT in FDRs of type 2 diabetic patients may be useful in assessing the risk of diabetes; those with chronically high levels of GGT should be considered as high risk group for diabetes.