Different associations between obesity and impaired fasting glucose depending on serum gamma-glutamyltransferase levels within normal range: a cross-sectional study

Long-Term Cumulative Exposure to High γ-Glutamyl Transferase Levels and the Risk of Cardiovascular Disease: A Nationwide Population-Based Cohort Study

BACKGRUOUND

Elevated γ-glutamyl transferase (γ-GTP) levels are associated with metabolic syndrome. We investigated the association of cumulative exposure to high γ-GTP with the risk of cardiovascular disease (CVD) in a large-scale population.

METHODS

Using nationally representative data from the Korean National Health Insurance system, 1,640,127 people with 4 years of consecutive γ-GTP measurements from 2009 to 2012 were included and followed up until the end of 2019. For each year of the study period, participants were grouped by the number of exposures to the highest γ-GTP quartile (0-4), and the sum of quartiles (0-12) was defined as cumulative γ-GTP exposure. The hazard ratio for CVD was evaluated using the Cox proportional hazards model.

RESULTS

During the 6.4 years of follow-up, there were 15,980 cases (0.97%) of myocardial infarction (MI), 14,563 (0.89%) of stroke, 29,717 (1.81%) of CVD, and 25,916 (1.58%) of death. Persistent exposure to high γ-GTP levels was associated with higher risks of MI, stroke, CVD, and death than those without such exposure. The risks of MI, stroke, CVD, and mortality increased in a dose-dependent manner according to total cumulative γ-GTP (all P for trend <0.0001). Subjects younger than 65 years, with a body mass index <25 kg/m2, and without hypertension or fatty liver showed a stronger relationship between cumulative γ-GTP and the incidence of MI, CVD, and death.

CONCLUSION

Cumulative γ-GTP elevation is associated with CVD. γ-GTP could be more widely used as an early marker of CVD risk, especially in individuals without traditional CVD risk factors.

Can Gamma-glutamyl Transferase Predict Unhealthy Metabolic Phenotypes Among Healthcare Workers in Azar Cohort Study?

Background: Although various studies have assessed the correlation between gamma-glutamyl transferase (GGT) and cardiometabolic risk factors in obesity, no research has differentiated among metabolically-healthy obese (MHO) and metabolically unhealthy obese (MUHO), metabolically-healthy lean (MHL), and metabolically-unhealthy lean (MUHL). Objectives: Accordingly, this study evaluated the correlation between GGT and cardiometabolic phenotypes among healthcare workers. Methods: 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 1458 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 four cardiometabolic phenotypes. Results: 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, MUHO, and MHL 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. However, the correlation between the GGT tertile and MUHL did not reveal a similar trend. 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. Conclusions: 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.

Gender Difference in Liver Enzymes in Newly Defined Subgroups of Diabetes Revealed by a Data-Driven Cluster Analysis

BACKGROUND

Recently, a newly proposed data-driven approach for classifying diabetes has challenged the status quo of the classification of adult-onset patients with diabetes. This study investigated the association between liver injury and diabetes, classified by data-driven cluster analysis, as liver injury is a significant risk factor for diabetes.

METHODS

We enrolled 822 adult patients with newly diagnosed diabetes. Two-step cluster analysis was performed using six parameters, including age at diagnosis, body mass index, hemoglobin A1C, homoeostatic assessment model 2 estimates about insulin resistance (HOAM2-IR) and beta-cell function (HOMA2-B), and glutamic acid decarboxylase antibodies (GADA) positivity. Patients were allocated into five clusters. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity were compared as indicators of liver injury among clusters.

RESULTS

Serum ALT and AST activities were significantly different among clusters (P=0.002), even among those without GADA positivity (P=0.004). Patients with severe insulin-resistant diabetes (SIRD) and mild obesity-related diabetes (MOD) had a more severe liver injury. Gender dimorphism was also found for serum ALT and AST activities among subgroups. Female patients had better liver function than males with SIRD and MOD.

CONCLUSIONS

We verified the feasibility of a newly proposed diabetes classification system and found robust and significant relationship and gender differences between serum ALT and AST activities and diabetes in some specific subgroups. Our findings indicate that more attention should be paid to diabetes subgroups when studying risk factors, indicators, or treatment in diabetic research.

Relationship Between Serum Gamma-Glutamyl Transferase Level and Impaired Fasting Glucose Among Chinese Community-Dwelling Adults: A Follow-Up Observation of 6 Years

Objective: We aimed to investigate the relationship between serum gamma-glutamyl transferase (GGT) and fasting blood glucose (FBG) levels, as well as the cumulative risk of impaired fasting glucose (IFG) regulation in the Chinese adult population after 6 years of follow-up. Methods: A total of 1360 apparently healthy Chinese men and women who completed a community-based health examination survey and did not have IFG in central China in 2010 and 2016 were included in this study. The patients were divided into four groups according to their baseline GGT (in quartiles). The relationship between GGT levels and FBG levels was examined using general linear regression models. The effect of the GGT level on the risk of IFG was analyzed using multivariate logistic regression. The first quartile group of GGT levels was set as the dummy variable in the model, and the odds ratios and 95% confidence intervals of the remaining quartile groups relative to the first quartile group were obtained. Results: After 6 years of follow-up, 16.4% (188/1148) of participants were diagnosed with IFG. The cumulative incidence of IFG in the four groups according to their baseline GGT levels (in quartiles) was 7.7%, 16.1%, 15.8%, and 26.8%, respectively. Based on the Cox multiple regression, the hazard ratio for IFG increased by 28.9% for each unit of increase in the baseline GGT level after adjusting for the confounding factors. The GGT levels of participants in the first quartile were used as the reference group. The relative risks of IFG in the second, third, and fourth quartiles of GGT were 1.70, 1.55, and 2.46, respectively (P = 0.005). Conclusions: GGT was positively associated with the risk of IFG and can be used as an indicator to assess whether a patient may develop prediabetes.

Aminotransferase levels, body mass index, and the risk of diabetes: a prospective cohort study

PURPOSE

To investigate whether the relationship between body mass index (BMI) and incident diabetes is modified by different alanine or aspartate aminotransferases (ALT or AST) levels.

METHODS

We carried out an analysis of 6484 participants aged 40 years or older using data from the Korean Genome Epidemiology Study. The serum aminotransferase levels were stratified into low and high groups according to the median values and classified into three groups: both low, either high, and both high. To assess the association between BMI and incident diabetes according to the serum aminotransferase levels, multiple logistic regression models were used.

RESULTS

In participants with high levels of both ALT and AST, compared with the first BMI quartile, the adjusted odds ratios for incident diabetes of the second, third, and fourth BMI quartiles were 1.72 (95% confidence interval, 0.84-3.55), 2.19 (1.11-4.33), and 3.08 (1.60-5.90), respectively (P trend < .001). In participants with either high ALT or AST, the adjusted odds ratios were 3.58 (1.23-10.41), 2.65 (0.90-7.76), and 5.28 (1.86-15.02), respectively (P trend = .005). However, in participants with both low ALT and AST levels, high BMI was not independently associated with the risk of incident diabetes.

CONCLUSIONS

There was a strong association between BMI and incident diabetes among individuals with high aminotransferase levels, whereas no association was observed among those with low aminotransferase levels.

Gender-related association between uric acid, homocysteine, γ-glutamyltransferase, inflammatory biomarkers and metabolic syndrome in subjects affected by obesity

AIM

Evaluation of gender-related differences in uric acid (UA), homocysteine and inflammatory biomarkers as metabolic syndrome (MetS) determinants.

PATIENTS & METHODS

Anthropometric and routine data were obtained from 825 obese subjects (591 F, mean age 54 ± 14 years).

RESULTS

Hyperuricemia was 24% in both genders. Waist circumference, creatinine, triglycerides, C-reactive protein and γ-glutamyltransferase were identified as UA-independent determinants in females and creatinine and insulin in males. Hyperuricemia increased MetS risk in both genders (2.8-fold and 1.5-fold in males and females).

CONCLUSION

UA and γ-glutamyltransferase positively relate to MetS in both genders, although inflammatory abnormalities are closer related to UA and MetS in females. These differences in gender physiology may account for epidemiologic gender disparities and help to develop gender-targeted clinical strategies.

Liver Enzymes and the Development of Posttransplantation Diabetes Mellitus in Renal Transplant Recipients

BACKGROUND

Posttransplantation diabetes mellitus (PTDM) is common in renal transplant recipients (RTR), increasing the risk of graft failure, cardiovascular disease, and mortality. Early detection of a high risk for PTDM is warranted. Because liver function and liver fat are involved, we investigated whether serum liver markers are associated with future PTDM in RTR.

METHODS

Between 2001 and 2003, 606 RTR with a functioning allograft beyond the first year after transplantation were included of which 500 participants (56% men; age, 50 ± 12 years) were free of diabetes at baseline and had liver enzyme values (1 missing) available. Serum concentrations of alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), alkaline phosphatase were measured at baseline at 6.0 (6.2-11.5) years posttransplantation. PTDM cases were recorded until April 2012.

RESULTS

During median follow-up for 9.6 years (interquartile range [IQR], 6.2-10.2) beyond baseline, 76 (15.2%) patients developed PTDM. Comparing the highest to the lower tertiles, higher liver enzyme activities were significantly related to incident PTDM for ALT (hazard ratio [HR], 2.22; IQR, 1.42-3.48), for GGT (HR, 2.93; IQR, 1.87-4.61), and for alkaline phosphatase (HR, 1.78; IQR, 1.13-2.80). The associations of ALT and GGT with development of PTDM were independent of potential confounders and risk factors, including age, sex, renal function, medication use, lifestyle factors, adiposity, presence of the metabolic syndrome, fasting glucose, HbA1c, proinsulin, and cytomegalovirus status.

CONCLUSIONS

Markers for liver function and liver fat in the subclinical range are potential markers for future PTDM, independent of other known risk factors. This may allow for early detection and management of PTDM development.

Gamma-glutamyltransferase activity as a surrogate biomarker of metabolic health status in young nondiabetic obese women

Aim: We investigated the association of gamma-glutamyltransferase (GGT) activity with atherogenic risk factors and metabolic health status in young nondiabetic obese women. Methods & results: In 140 obese women GGT activity was independently associated with BMI, triglyceride to high-density cholesterol ratio and homeostasis model assessment. Metabolically healthy but obese women had significantly lower GGT activity, associated with a normal insulin sensitivity, favorable lipid profile and apolipoprotein B to apolipoprotein AI ratio. GGT activity showed good diagnostic accuracy to distinguish between metabolically healthy but obese and obese women at risk (77.8% sensitivity and 60% specificity). GGT activity >17 U/l can predict atherogenic risk and insulin resistance. Conclusion: GGT activity may serve as a potential surrogate biomarker of atherogenic risk and metabolic health status.

Fasting glycemia and glycated hemoglobin categories: Relationship to serum lipoprotein(a) level and disparity in 2 geographic regional groups of Turkey

OBJECTIVE

The goal of the present study was to determine covariates of serum lipoprotein (Lp) (a) within fasting glucose and glycated hemoglobin (HbA1c) categories, and to detect features that were different among covariates based on residence in Marmara and Central Anatolia (Marm-CA) regions or remaining 5 geographic regions of Turkey.

METHODS

Data of randomly-selected group of 1167 men and women (mean age 61 years) who participated in biennial surveys of 2013 and 2015 were cross-sectionally analyzed in 6 categories.

RESULTS

In multiple linear regression analysis of nondiabetic women, homeostatic model assessment (HOMA) index score was inversely associated with Lp(a) (ß coefficient 0.49; p=0.001); this was not true for men. In the whole sample, Lp(a) was significantly positively associated with female sex and with serum creatinine, and inversely in each sex with HOMA index (ß coefficient 0.63; p<0.001). Linear models within separate categories showed significant associations of Lp(a) only in individuals with no evidence of diabetes other than HbA1c >6.5%: in women, positive association with total cholesterol and inverse relationship with creatinine were found, and in men, positive association with apolipoprotein (apo) B was determined. Similar age, diastolic blood pressure, fasting glucose, triglyceride, uric acid, and C-reactive protein values were obtained from participants of 2 regional groups. Residents of the Marm-CA region who were nondiabetic exhibited significantly (by 23%) lower serum Lp(a) among individuals with HbA1c ≥5.7%, significantly higher HOMA index score, concentrations of apoB, and low-density lipoprotein cholesterol.

CONCLUSION

Hallmark of prediabetic and diabetic glycemia/HbA1c categories seems to be an independent inverse association between Lp(a) protein (yet not of apoB) and HOMA score, this being primarily so in residents of Marm-CA region.

Fatty liver disease: Disparate predictive ability for cardiometabolic risk and all-cause mortality

AIM: To assess the association of a surrogate of fatty liver disease (FLD) with incident type-2 diabetes, coronary heart disease, and all-cause mortality.

METHODS: In a prospective population-based study on 1822 middle-aged adults, stratified to gender, we used an algorithm of fatty liver index (FLI) to identify associations with outcomes. An index ≥ 60 indicated the presence of FLD. In Cox regression models, adjusted for age, smoking status, high-density lipoprotein cholesterol, and systolic blood pressure, we assessed the predictive value of FLI for incident diabetes, coronary heart disease (CHD), and all-cause mortality.

RESULTS: At a mean 8 year follow-up, 218 and 285 incident cases of diabetes and CHD, respectively, and 193 deaths were recorded. FLD was significantly associated in each gender with blood pressure, total cholesterol, apolipoprotein B, uric acid, and C-reactive protein; weakly with fasting glucose; and inversely with high-density lipoprotein-cholesterol and sex hormone-binding globulin. In adjusted Cox models, FLD was (with a 5-fold HR) the major determinant of diabetes development. Analyses further disclosed significant independent prediction of CHD by FLD in combined gender [hazard ratio (HR) = 1.72, 95% confidence interval (CI): 1.17-2.53] and men (HR = 2.35, 95%CI: 1.25-4.43). Similarly-adjusted models for all-cause mortality proved, however, not to confer risk, except for a tendency in prediabetics and diabetic women.

CONCLUSION: A surrogate of FLD conferred significant high risk of diabetes and coronary heart disease, independent of some metabolic syndrome traits. All-cause mortality was not associated with FLD, except likely in the prediabetic state. Such a FLI may reliably be used in epidemiologic studies.