Gamma-glutamyl transferase (GGT) is indirectly correlated with chronic inflammation and increased oxidative stress, which are closely connected to metabolic disorders. Moreover, the high ranges of GGT are correlated with cardiovascular diseases, atherosclerosis, type 2 diabetes, chronic kidney disease (CKD), and metabolic syndrome (MetS). Some evidence demonstrates that the normal ranges of GGT are connected with increased cardiovascular diseases and all-cause mortality. Although various studies have assessed the correlation between GGT and cardiometabolic risk factors in obesity, no research has differentiated among metabolically-healthy obese (MHO) and metabolically unhealthy obese. Accordingly, this study evaluated the correlation between GGT and cardiometabolic phenotypes among healthcare workers.

: In this study, there were anthropometric measurements as well as the measurements of fasting blood sugar (FBS), GGT, cholesterol, triglyceride (TG), high lipoprotein density (HDL), and blood pressure in 1403 healthcare workers enrolled in the Azar Cohort Study. Metabolic syndrome (MetS) was defined according to the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Accordingly, the participants were divided into two cardiometabolic phenotypes. Two groups of cardiometabolic phenotypes were determined based on the BMI cutoff point (25kg/m2) and the presence of MetS. Then the participants were classified into three groups of metabolically-healthy lean (MHL) (BMI<25 kg/m2 and no MetS), MHO ( BMI≥ 25 KG/M2 and no MetS) , and MUHO (BMI≥ 25 KG/M2 and MetS present). The participants were also divided into the following serum GGT tertiles: Tertile 1: ≤14 U/l; Tertile 2: 15–23 U/l; and Tertile 3: ≥24 U/l. The multinomial logistic regression analysis was used to estimate the relationship between the cardiometabolic phenotype and the serum GGT tertile

: In this cross-sectional study, there was a significant difference in the prevalence of cardiometabolic phenotypes regarding the GGT tertiles (P ≤ 0.001). The highest prevalence of MHO was observed in the third GGT tertile. The mean waist circumference, TG, FBS, HDL, and systolic and diastolic blood pressure levels increased in the MHO and MUHO groups in a dose dependent manner with an increase in the GGT tertiles (P < 0.05). In comparing the highest and lowest GGT tertile, the risk of MHO and MUHO increased by 2.84 (95%CI 2.01 - 4.01) and 9.12 (95%CI 5.54 - 15), respectively. The ROC curve shows the cutoff value of 18.5 U/L for GGT, which allowed us to distinguish between the MUHO and MHO individuals.

The findings revealed that GGT can indicate the risk of MetS as such, it can be used to detect at-risk MHO individuals and administer proper interventions.