Synergistic effect of gamma glutamyltransferase and obesity on metabolic syndrome, independent of hepatic steatosis

Purpose: Both obesity and gamma glutamyltransferase (GGT) are individually considered to be closely associated with metabolic syndrome (MetS). Whether the 2 factors synergistically associate with MetS is not yet confirmed. The purpose of this study was to investigate whether obesity and GGT are interactively associated with MetS. Methods: A cross-sectional study of 7390 adults (age 32-62 years old) was conducted from 2009 to 2010. Results: Our results showed that greater serum GGT quartiles were positively associated with all MetS components and fatty liver (P < .001). The odds ratio of MetS increased significantly along with quartiles of GGT and obesity. In comparison with subjects with normal body mass index and first quartile GGT, the odds ratio of MetS in obese groups with 1st, 2nd, 3rd, and 4th quartile GGT were 6.8, 14.5, 20.3, and 45.2, respectively, and it remained tenable after adjustment for fatty liver. The synergy index of GGT and obesity on MetS is 2.2 (95% confidence interval, 1.9-2.6). Conclusions: Serum GGT level in combination with obesity can be a simple but useful tool for risk stratification of developing MetS. Obese individuals with high normal GGT levels require close monitoring for high risk of MetS. (C) 2012 Elsevier Inc. All rights reserved.