Association between γ-glutamyl transpeptidase activity and status of disorders constituting insulin resistance syndrome

Background: Serum γ-glutamyl transferase (γGTP) activity is a well-established marker of alcohol consumption. However, recently, a correlation between serum γGTP activity and insulin resistance status has been demonstrated. Methods: To determine whether serum γGTP activity could be associated with the status of various disorders caused by increased insulin resistance levels, namely, insulin resistance syndrome, a cross-sectional study for 11,884 Japanese men was performed. They were divided into three groups by their age, and associations between γGTP and various indexes of insulin resistance syndrome were studied by multiple logistic regression analysis in which subjects' drinking styles were corrected for in each age bracket. Results: Consuming ethanol more than 40 g/day, body mass index more than 25.9 kg/m², and triglyceride levels more than 150 mg/dl were significant risk factors accounting for increased γGTP activity (more than 78 IU/liters) irrespective of age. In addition, when subjects of 40 to 59 years old were selectively studied, hypertension, hypercholesteremia, hyperuricemia, and increased glycohemoglobin A1C levels were also significant risk factors for increased γGTP activity. Conclusions: There are significant associations between γGTP and the status of insulin resistance syndrome. In addition to excessive alcohol consumption, the status of insulin resistance syndrome could affect subjects' γGTP activities.