Relationship of Liver Enzymes to Insulin Sensitivity and Intra-Abdominal Fat

Relationship of Liver Enzymes to Insulin Sensitivity and Intra-Abdominal Fat Tara M. Wallace , MD 1 , Kristina M. Utzschneider , MD 1 , Jenny Tong , MD 1 , Darcy B. Carr , MD 2 , Sakeneh Zraika , PHD 1 , Daniel D. Bankson , MD 3 , Robert H. Knopp , MD 4 and Steven E. Kahn , MB, CHB 1 1 Department of Medicine, VA Puget Sound Health Care System, and University of Washington, Seattle, Washington 2 Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington 3 Department of Pathology and Laboratory Medicine, VA Puget Sound Health Care System, and University of Washington, Seattle, Washington 4 Harborview Medical Center, University of Washington, Seattle, Washington Address correspondence and reprint requests to Steven E. Kahn, MB, ChB, VA Puget Sound Health Care System (151), 1660 S. Columbian Way, Seattle, WA 98108. E-mail: skahn{at}u.washington.edu Abstract OBJECTIVE — The purpose of this study was to determine the relationship between plasma liver enzyme concentrations, insulin sensitivity, and intra-abdominal fat (IAF) distribution. RESEARCH DESIGN AND METHODS — Plasma γ-glutamyl transferase (GGT), aspartate transaminase (AST), alanine transaminase (ALT) levels, insulin sensitivity (insulin sensitivity index [ S I ]), IAF area, and subcutaneous fat (SCF) area were measured in 177 nondiabetic subjects (75 men and 102 women, aged 31–75 years) with no history of liver disease. On the basis of BMI (< or ≥27.5 kg/m 2 ) and S I (< or ≥7.0 × 10 −5 min/pmol) subjects were divided into lean insulin sensitive (LIS, n = 53), lean insulin resistant (LIR, n = 60), and obese insulin resistant (OIR, n = 56) groups. RESULTS — Levels of all three liver enzymes were higher in men than in women ( P < 0.0001 for each). In men, GGT levels were higher in insulin-resistant than in insulin-sensitive subjects ( P < 0.01). In women, GGT levels were higher in the OIR than in the LIS group ( P < 0.01) but no different in the LIR group. There was no difference in ALT and AST levels among the LIS, LIR, and OIR groups. GGT was associated with S I (r = −0.26, P < 0.0001), IAF area ( r = 0.22, P < 0.01), waist-to-hip ratio (WHR) ( r = 0.25, P = 0.001), BMI ( r = 0.17, P < 0.05), and SCF area ( r = 0.16, P < 0.05) after adjustments for age and sex. In men, only S I ( r = −0.29, P < 0.05) remained independently correlated with GGT in multiple regression analysis. In women, IAF area ( r = 0.29, P < 0.01) and WHR ( r = 0.29, P < 0.01) were independently associated wi