Hepatic fat content-independent association of the serum level of gamma-glutamyltransferase with visceral adiposity, but not subcutaneous adiposity

We investigated the association between the serum level of gamma-glutamyltransferase (GGT) and parameters of adiposity and lipid profile, including the serum triglyceride (TG), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) levels in Japanese patients with type 2 diabetes mellitus and non-diabetic subjects. A total of 257 Japanese subjects (169 patients with type 2 diabetes and 88 non-diabetic subjects) were enrolled in the study. To assess the hepatic fat content, the ratio of the CT attenuation value of the liver to that of the spleen (L/S ratio) was calculated. Serum GGT was significantly correlated with the waist circumference, BMI, visceral fat area (VFA), L/S ratio and TG, but not with the subcutaneous fat area (SFA). The serum GGT was still correlated with the VFA and TG, but not with the SFA, after adjustment for the four variables of age, gender, serum HbA1c and the L/S ratio. Our finding that the serum GGT is specifically associated with the VFA, but not with the SFA, suggests that the serum GGT may be useful as a convenient indicator of VFA in the clinical treatment of obesity.