Serum γ-glutamyltransferase level and metabolic syndrome in children and adolescents: Korean National Health and Nutrition Examination Survey

Serum Gamma Glutamyltransferase: A Biomarker for Identifying Postprandial Hypertriglyceridemia

Purpose

Elevated serum gamma-glutamyltranspeptidase (GGT) is an independent marker of the activation of systemic inflammation, while conditions associated with elevated triglyceride (TG) levels, such as type 2 diabetes, non-alcoholic fatty liver disease, obesity, and metabolic syndrome, are associated with an increased inflammatory burden. Moreover, serum liver enzymes (GGT, alanine aminotransferase [ALT], aspartate aminotransferase [AST], and alkaline phosphatase [ALP]) are associated with metabolic syndrome and its components, including hypertriglyceridemia. However, the relationship between liver enzymes and postprandial hypertriglyceridemia (PHTG) remains unclear. Therefore, in this study we conducted oral fat tolerance tests (OFTTs) to understand the differences in serum liver enzyme levels among individuals with different lipid tolerance levels and their correlation with PHTG.

Patients and Methods

 For the OFTT, we enrolled 202 non-diabetic volunteers whose fasting triglyceride (TG) levels were less than 1.7 mmol/L in this case-control study. The participants were categorized into two groups according to the TG levels at the 0- and 4-h OFTT: a postprandial normal TG (PNTG) group and a PHTG group. Routine fasting serum biochemical indices, liver enzyme (GGT, ALT, AST, and ALP) levels, and 0- and 4-h OFTT lipid levels were assessed.

Results

The PHTG group had significantly higher serum GGT and ALT levels and a lower AST/ALT ratio than those in the PNTG group. However, no significant difference was observed in AST and ALP levels compared with the PNTG group. After adjusting for major confounders, logistic regression analysis indicated a significant correlation between serum GGT and PHTG (odds ratio = 1.168, P < 0.001), but not with ALT level, AST level, AST/ALT ratio, and ALP level. The receiver operating characteristic curve analysis demonstrated that the serum GGT level was an effective predictor of PHTG.

Conclusion

Serum GGT levels are significantly associated with PHTG risk and serve as an effective biomarker for early identification.

Association of gamma-glutamyl transferase and alanine aminotransferase with type 2 diabetes mellitus incidence in middle-aged Japanese men: 12-year follow up

AIMS/INTRODUCTION

To prospectively investigate whether simultaneous elevation of gamma-glutamyl transferase (GGT) and alanine aminotransferase (ALT) is associated with the increase of type 2 diabetes mellitus incidence independent of alcohol drinking, body mass index and triglycerides.

METHODS

A total of 2,775 Japanese male workers who had no history of type 2 diabetes mellitus were followed. High GGT and ALT were defined as the top tertiles (GGT cutpoint: 49 IU/L, ALT cutpoint: 28 IU/L). Three groups were created using these dichotomized GGT and ALT cutpoints: both low, either high or both high. Multivariable Cox proportional hazards models were carried out adjusted for potential confounding factors.

RESULTS

A total of 276 type 2 diabetes mellitus cases were identified during 12 years (27,040 person-years) of follow up. Participants with simultaneously elevated GGT and ALT had a significantly higher incidence of type 2 diabetes mellitus, even after adjustment for fasting insulin and fasting blood glucose compared with the group without GGT or ALT elevation. Similar associations were observed in non- or light-to-moderate alcohol drinkers, as well as in participants with normal weight. However, the association was weaker in participants with triglycerides <150 mg/dL. We then evaluated whether the addition of GGT and ALT would improve the prediction of type 2 diabetes mellitus incidence, and found that their inclusion significantly increased the C-statistic, net reclassification improvement and integrated discrimination improvement.

CONCLUSIONS

Simultaneous elevation of GGT and ALT was significantly associated with type 2 diabetes mellitus incidence, independent of potential confounding factors, including alcohol drinking and obesity, although the association might require concomitant elevation of triglycerides. Inclusion of GGT and ALT improved type 2 diabetes mellitus risk prediction.

Plasma cholinesterase is associated with Chinese adolescent overweight or obesity and metabolic syndrome prediction

Purpose: To determine the plasma concentrations of butyrylcholinesterase (BChE), also known as pseudocholinesterase, in different weight categories of adolescents, and to explore the possible association between plasma BChE and overweight (OW), obesity, and metabolic syndrome (MetS) in Chinese adolescents. Patients and methods: This cross-sectional study included 1,236 Chinese adolescents (194 obese [OB], 188 OW, 732 normal weight [NW], and 122 underweight [UW]). The biochemical variables and anthropometric variables of the study participants were evaluated. Plasma BChE level was measured by DGKC method. Results: OB was associated with a higher prevalence of upper strata plasma BChE levels when compared with the BChE levels in UW, NW, and OW group. A logistic regression analysis showed that plasma BChE was positively associated with the OB group when compared with the NW group. Boys in the OW group, but not the OB group, had a significantly higher prevalence of upper stratum of BChE levels. Plasma triglyceride, total cholesterol, low-density lipoprotein-cholesterol, and ApoB levels were positively associated with the upper stratum of BChE levels when compared with lower stratum. MetS and most of its components were more prevalent among subjects with upper stratum rather than lower stratum BChE levels. Receiver operating characteristic curves for plasma BChE in subjects with MetS indicated that the AUC was 0.80 (95%CI:0.70-0.90,P<0.001) and 0.89 (95%CI:0.82-0.95,P<0.001) in girls and boys, respectively. After adjusting for age, the multivariate-adjusted odds ratio for MetS in the upper stratum of BChE levels was 8.73 (95%CI: 3.49-21.84) in the boys cohorts and also in the girls cohorts (OR=1.71, 95%CI: 1.35-21.70). Conclusion: This study confirmed an association between BChE levels and weight status in Chinese adolescents, and demonstrated that the upper strata of plasma BChE levels were associated with being OW, and even more highly associated with obesity. Plasma BChE levels were positively associated with MetS and its components and could be useful for identifying adolescents with MetS.