Liver enzymes as a predictor for incident diabetes in a Japanese population: the Hisayama study

The different associations of serum gamma-glutamyl transferase and alanine aminotransferase with insulin secretion, β-cell function, and insulin resistance in non-obese Japanese

The present study investigated the associations of serum gamma-glutamyl transferase (GGT), a marker of fatty liver and oxidative stress, and ALT/AST, a marker of fatty liver, with percentage trunk fat and postload glucose, insulin resistance, and β-cell function in middle-aged Japanese individuals, whose BMI averaged < 23.0 kg/m2. Pancreatic β-cell function was assessed using the disposition index calculated by a product of the insulinogenic index (IGI) and Matsuda insulin sensitivity index, a biomarker of early-phase glucose-stimulated insulin secretion and whole-body insulin sensitivity, respectively. Multivariate linear regression analyses revealed that the disposition index was associated inversely with GGT independently of percentage trunk fat, homeostasis model assessment insulin resistance (HOMA-IR), a marker of insulin resistance, and Matsuda index. When IGI was included instead of the disposition index, IGI (inversely) and HOMA-IR were associated with GGT independently of percentage trunk fat and Matsuda index. When the area under the glucose concentration curve (AUCg) during an oral glucose tolerance test was included instead of the disposition index, AUCg and HOMA-IR emerged as independent determinants of GGT. ALT/AST was associated with HOMA-IR alone. Results suggest a different pathophysiologic basis between GGT and ALT/AST in predicting diabetic risk in non-obese Japanese.

A case-control regression analysis of liver enzymes in obesity-induced metabolic disorders in South Asian females

Excessive body weight may disrupt hepatic enzymes that may be aggravated by obesity-related comorbidities. The current case-control study was designed to evaluate the extent of liver enzyme alteration in obesity-related metabolic disorders. Obese females with BMI ≥ 30 suffering from metabolic disorders were grouped according to existing co-morbidity and their hepatic enzymes were compared with non-obese healthy females. The resultant data was subjected to analysis of variance and mean difference in liver enzymes were calculated at P = 0.05. Analysis of variance indicated that obese diabetic and obese hypertensive females had almost 96% and 67% increase in the concentration of gamma-glutamyl transferase than control, respectively (P<0.0001). The obese females suffering from diabetes and hypertension exhibited nearly 54% enhancement in alanine transaminase level (P<0.0001) and a 17% increase in aspartate aminotransferase concentration (P = 0.0028). Obesity along with infertility decline liver enzyme production and a 31% significant decline in aspartate aminotransferase was observed while other enzyme concentrations were not significantly altered. Regression analysis was performed on the resultant data to understand the association between liver enzyme alteration and the development of metabolic diseases. Regression analysis indicated that obese diabetic and obese diabetic hypertensive women had 20% production of normal liver enzymes and 80% enzymes produced abnormally. Obese hypertensive and obese infertile females had only 5% and 6% normal production of liver enzymes, respectively. This research leads to the conclusion that the ability of the liver to function normally is reduced in obesity-related diabetes and hypertension. This may be due to inflamed and injured liver and poses a serious threat to developing fatty liver disease and ultimately liver cirrhosis.

Comparative effects of high-intensity interval training and moderate-intensity continuous training on weight and metabolic health in college students with obesity

The purpose of this study was to compare the effects of High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) on weight, body composition, blood lipid indicators, and metabolic status in college students living with obesity. The study focused on a sample of 40 college students living with obesity, including 20 males and 20 females, aged between 18 and 25. Participants were randomly assigned to either the HIIT group or the MICT group. Both groups underwent an 8-week intervention, consisting of three sessions per week with alternate-day training. The MICT group's training consisted of continuous aerobic exercise for 35 min at 60-70% of maximum heart rate. The HIIT group engaged in 28 min of alternating high-intensity and low-intensity exercise, where the high-intensity phase was at 85-90% of maximum heart rate for 4 min, followed by a 3-min recovery period at 50-60% of maximum heart rate, repeated four times. Both groups underwent heart rate monitoring before and after the training sessions to ensure the accuracy of the training intensity. Within each group, further distinctions were made based on gender, resulting in the following subgroups: Male HIIT group (n = 10), Female HIIT group (n = 10), Male MICT group (n = 10), and Female MICT group (n = 10). Differences in anthropometric and biochemical indicators among the groups were analyzed, and the different effects of the two intervention strategies on the obese college student population were comprehensively evaluated. Compared to the baseline assessment, the HIIT group showed a more favorable declining trend than the MICT group in terms of body morphology and body composition, particularly in the aspect of body fat percentage (BF%). The male HIIT group, female HIIT group, male MICT group, and female MICT group respectively reduced by - 23.71%, - 26.76%, - 9.81%, - 7.16%. Male and female HIIT group experienced a more pronounced decrease compared to the MICT group, with the female HIIT group reducing an additional 3.75% more than the male HIIT group. Regarding intergroup differences, BF% significant differences were shown between male MICT group and the HIIT group (P < 0.05), and female MICT group and the HIIT group (P < 0.01). In terms of biochemical indicators, the HIIT group also presented a more favorable declining trend compared to the MICT group, with male HIIT participants showing more reduction than female HIIT participants, especially in total cholesterol (TC) (10.64%), low-density lipoprotein cholesterol (LDL-C) (11.73%), alanine aminotransferase (ALT) (11.99%), and uric acid (UA) (11.76%). Regarding triglycerides (TG), significant intergroup differences were observed between male MICT and HIIT groups (P < 0.01) and female MICT and HIIT groups (P < 0.01). Concerning ALT, a significant difference was shown between female MICT and HIIT groups (P < 0.01), while no significant difference was observed among male participants. Overall, for college students living with obesity, both HIIT and MICT have shown positive effects. Among these, HIIT demonstrates greater effectiveness compared to MICT in BF% and biochemical markers.

Association between liver enzymes and type 2 diabetes: a real-world study

Aim

This study aimed to examine the association of liver enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl-transferase (GGT), with type 2 diabetes (T2D) risk, particularly their dose-response relationship.

Methods

This cross-sectional study enrolled participants aged >20 years old who underwent physical examination at our local hospital from November 2022 to May 2023. A generalized additive model (GAM) was fit to assess the dose-response relationship between liver enzymes and T2D risk. Furthermore, data from the UK Biobank (n=217,533) and National Health and Nutrition Examination Survey (NHANES 2011-2018; n= 15,528) were analyzed to evaluate whether the dose-response relationship between liver enzymes and T2D differed by population differences.

Results

A total of 14,100 participants were included (1,155 individuals with T2D and 12,945 individuals without diabetes) in the analysis. GAM revealed a non-linear relationship between liver enzymes and T2D risk (P non-linear < 0.001). Specifically, T2D risk increased with increasing ALT and GGT levels (range, <50 IU/L) and then plateaued when ALT and GGT levels were >50 IU/L. Elevated AST within a certain range (range, <35 IU/L) decreased the risk of T2D, whereas mildly elevated AST (>35 IU/L) became a risk factor for T2D. The UK Biobank and NHANES data analysis also showed a similar non-linear pattern between liver enzymes and T2D incidence.

Conclusion

Liver enzymes were non-linearly associated with T2D risk in different populations, including China, the UK, and the US. Elevated ALT and GGT levels, within a certain range, could increase T2D risk. More attention should be given to liver enzyme levels for early lifestyle intervention and early T2D prevention. Further studies are necessary to explore the mechanism of the non-linear association between liver enzymes and T2D risk.

Associating Liver Enzymes and Their Interactions with Metabolic Syndrome Prevalence in a Japanese Working Population

Background: Serum gamma-glutamyltransferase (γ-GT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels often increase in metabolic diseases. Objective: This study was conducted to determine which liver enzymes are strongly associated with metabolic syndrome (MetS), how they interact to produce different probability estimates, and what cutoff levels should be used to guide clinical decision-making. Methods: The researchers examined the insurance-based medical checkup data of 293,610 employees ≥35 years years of age, who underwent medical checkups between April 1, 2016, and March 31, 2017. Liver enzyme levels were grouped into quartiles. The association and interaction of liver enzymes with MetS were examined using logistic regression, and receiver operating characteristic (ROC) analyses were used to determine the optimal cutoff values for each liver enzyme in detecting the prevalence of MetS. Results: High levels of γ-GT and ALT were more strongly associated with MetS than AST. At various levels, the tested liver enzymes were found interactive, and associated with the likelihood of MetS prevalence. ROC analysis underscored the significance of all liver enzymes in predicting the development of MetS. The cutoff values for each liver enzyme were determined. Conclusion: This findings of this study directly support the identification of MetS risks within the population, prioritize prevention strategies, and potentially inform policy formulation.

Reductions in liver enzymes are associated with anti-hyperglycaemic and anti-obesity effects of tofogliflozin in people with type 2 diabetes: Post-hoc analyses

AIMS

How the pathology of type 2 diabetes (T2D), including hyperglycaemia and obesity, affects liver enzymes has not been clinically demonstrated. Thus, we compared time courses of gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) with those of fasting plasma glucose (FPG) and body weight (BW) during treatment with the SGLT2 inhibitor tofogliflozin for T2D.

MATERIALS AND METHODS

We post-hoc analysed preexisting data on 1046 people with T2D administered tofogliflozin or placebo for 24 weeks in four tofogliflozin studies. First, time courses of percent changes in variables during the intervention were analysed using a mixed effect model to explore the similarity of the time courses and to evaluate time-treatment interactions. Second, clinical factors related to the percent changes in GGT and ALT were clarified using multivariate analyses.

RESULTS

GGT levels and FPG values rapidly and significantly decreased via tofogliflozin as early as week 4, with decreases maintained until week 24. Conversely, BW and ALT decreased progressively until week 24. Time courses of FPG (p = .365, time-treatment interaction) and GGT (p = .510) reductions were parallel between tofogliflozin and placebo from weeks 4 to 24, while BW and ALT reductions (p < .001, respectively) were not. Reductions in GGT at week 24 were associated with reductions in FPG and BW at week 24, whereas ALT reductions were only associated with reductions in BW.

CONCLUSIONS

Reductions in GGT and ALT were associated with the anti-hyperglycaemic and anti-obesity effects of tofogliflozin, respectively, in people with T2D. Therefore, GGT and ALT may be surrogate markers for hyperglycaemia and obesity in T2D.

Association between serum ALT levels and incidence of new-onset diabetes in general population of Japanese: a longitudinal observational study (ISSA-CKD)

OBJECTIVE

We aimed to clarify the relationship between serum alanine transaminase (ALT) levels and incidence of new-onset diabetes in a Japanese general population.

SETTING

Population-based retrospective cohort study using annual health check-up data for residents of Iki City, Nagasaki Prefecture, Japan.

PARTICIPANTS

A total of 5330 Japanese individuals (≥30 years old) without diabetes at baseline were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Serum ALT levels were determined using an enzymatic method and were classified into gender-specific quartile groups as follows: group 1 (3-16 U/L in men and 3-13 U/L in women), group 2 (17-21 U/L in men and 14-16 U/L in women), group 3 (22-29 U/L in men and 17-22 U/L in women) and group 4 (30-428 U/L in men and 23-268 U/L in women). The study outcome was the incidence of diabetes (fasting glucose ≥7.0 mmol/L, non-fasting glucose ≥11.1 mmol/L, glycated haemoglobin ≥6.5% or use of glucose-lowering therapies).

RESULTS

After an average follow-up period of 5.0 years, 279 individuals developed diabetes. The incidence rate of diabetes increased with elevation of serum ALT levels (0.7% per 100 person-years in group 1, 0.9% in group 2, 0.9% in group 3 and 1.7% in group 4) (p<0.001 for trend). This association was significant after adjustment for other risk factors including age, sex, obesity, hypertension, dyslipidaemia, smoking, current daily alcohol intake and regular exercise (p<0.001 for trend). Comparable associations were observed between men and women (p=0.459 for interaction).

CONCLUSION

Serum ALT levels were associated with future development of diabetes in the general Japanese population.

Association of gamma-glutamyl transferase concentrations with all-cause and cause-specific mortality in Chinese adults with type 2 diabetes

BACKGROUND

Evidence links gamma-glutamyl transferase (GGT) to mortality in the general population. However, the relationship of GGT with all-cause and cause-specific mortality risk has been little explored in type 2 diabetes mellitus (T2DM) patients.

METHODS

We recruited 20 340 community-dwelling T2DM patients between 2013 and 2014 in Jiangsu, China. Cox regression models were used to assess associations of GGT with all-cause and specific-cause mortality. Restricted cubic splines were used to analyze dose-response relationships between GGT and mortality. Stratified analysis was conducted to examine potential interaction effects by age, sex, smoking status, body mass index (BMI), diabetes duration, and dyslipidemia.

RESULTS

During a median follow-up period of 7.04 years (interquartile range: 6.98-7.08), 2728 deaths occurred, including 902 (33.09%) due to cardiovascular disease (CVD), and 754 (27.58%) due to cancer. GGT concentrations were positively associated with all-cause, CVD, and cancer mortality. Multivariable hazard ratios (HRs) for the highest (Q5) vs. the lowest quintile (Q1) were 1.63 (95% confidence intervals [CI]: 1.44-1.84) for all-cause mortality, 1.87 (95% CI: 1.49-2.35) for CVD mortality, and 1.43 (95% CI: 1.13-1.81) for cancer mortality. Effect modification by BMI and dyslipidemia was observed for all-cause mortality (both p for interaction <.05), and HRs were stronger in the BMI <25 kg/m2 group and those without dyslipidemia.

CONCLUSIONS

Our findings suggest that, in Chinese T2DM patients, elevated serum GGT concentrations were associated with mortality for all-cause, CVD, and cancer, and further research is needed to elucidate the role of obesity, nonalcoholic fatty liver disease, and lipids in this association.

Serum Mac-2 Binding Protein Glycosylation Isomer Concentrations Are Associated With Incidence of Type 2 Diabetes

CONTEXT

Serum Mac-2 binding protein glycosylation isomer (M2BPGi) concentrations are known to be an indicator of chronic liver injury and fibrosis.

OBJECTIVE

This study aimed to investigate the association between serum M2BPGi concentrations and the development of type 2 diabetes in a Japanese community.

METHODS

A total of 2143 community-dwelling Japanese individuals aged 40-79 years without diabetes at baseline were followed up for 7 years. Serum M2BPGi concentrations were divided into quintiles: Q1, ≤0.37 cutoff index (COI); Q2, 0.38-0.49 COI; Q3, 0.50-0.62 COI; Q4, 0.62-0.80 COI; and Q5, ≥0.81 COI. Cox proportional hazards models were used to estimate hazard ratios and 95% CIs for the development of type 2 diabetes.

RESULTS

During the follow-up period, 219 individuals developed type 2 diabetes. The age- and sex-adjusted cumulative incidence of type 2 diabetes significantly increased with elevating serum M2BPGi levels (P for trend < .01). This association remained significant after adjustment for potential confounders (P for trend = .04). This significant association attenuated to a nonsignificant level after additionally adjusting for serum high-sensitivity C-reactive protein or homeostasis model assessment of insulin resistance.

CONCLUSION

The present study demonstrated that higher serum M2BPGi concentrations were significantly associated with higher risk of diabetes in a Japanese community. Moreover, inflammation and insulin resistance were suggested to contribute to the excess risk of diabetes in individuals with higher serum M2BPGi levels. These findings shed light on the importance of inflammation and insulin resistance when considering the pathogenesis of diabetes.

Associations of alanine aminotransferase/aspartate aminotransferase with insulin resistance and β-cell function in women

We tested whether alanine aminotransferase/aspartate aminotransferase (ALT/AST), a marker of hepatosteatosis, associates with insulin resistance, β-cell function and postglucose glycemia. We studied 311 young and 148 middle-aged Japanese women, whose BMI averaged < 23.0 kg/m². Insulinogenic index and Matsuda index were evaluated in 110 young and 65 middle-aged women. In two groups of women, ALT/AST was associated positively with homeostasis model assessment insulin resistance (HOMA-IR) and inversely with Matsuda index. In middle-aged women only, the ratio was also associated positively with fasting and postload glycemia and HbA1c. The ratio showed negative association with disposition index (a product of insulinogenic index and Matsuda index). On multivariate linear regression analysis, HOMA-IR emerged as a single determinant of ALT/AST in young and middle-aged women (standardized β: 0.209, p = 0.003 and 0.372, p = 0.002, respectively). ALT/AST was associated with insulin resistance and β-cell function even in non-obese Japanese women, suggesting a pathophysiologic basis in its prediction of diabetic risk.

Gut microbiome is associated with metabolic syndrome accompanied by elevated gamma-glutamyl transpeptidase in men

It is predicted that by 2035, metabolic syndrome (MS) will be found in nearly more than half of our adult population, seriously affecting the health of our body. MS is usually accompanied by the occurrence of abnormal liver enzymes, such as elevated gamma-glutamyl transpeptidase (GGT). More and more studies have shown that the gut microbiota is involved in MS; however, the correlation between gut microbiota and MS with elevated GGT has not been studied comprehensively. Especially, there are few reports about its role in the physical examination of the population of men with MS and elevated GGT. By using the whole-genome shotgun sequencing technology, we conducted a genome-wide association study of the gut microbiome in 66 participants diagnosed as having MS accompanied by high levels of GGT (case group) and 66 participants with only MS and normal GGT level (control group). We found that the number of gut microbial species was reduced in participants in the case group compared to that of the control group. The overall microbial composition between the two groups is of significant difference. The gut microbiota in the case group is characterized by increased levels of “harmful bacteria” such as Megamonas hypermegale, Megamonas funiformis, Megamonas unclassified, Klebsiella pneumoniae, and Fusobacterium mortiferum and decreased levels of “beneficial bacteria” such as Faecalibacterium prausnitzii, Eubacterium eligens, Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bacteroides dorei, and Alistipes putredinis. Moreover, the pathways of POLYAMSYN-PWY, ARG+POLYAMINE-SYN, PWY-6305, and GOLPDLCAT-PWY were also increased in the case group, which may play a role in the elevation of GGT by producing amine, polyamine, putrescine, and endogenous alcohol. Taken together, there are apparent changes in the composition of the gut microbiome in men with MS and abnormal GGT levels, and it is high time to discover specific gut microbiome as a potential therapeutic target in that population. More in-depth studies of relevant mechanism could offer some new methods for the treatment of MS with elevated GGT.

Association Between Serum Aminotransferases and Risk of New-Onset Cardiometabolic Disease in a Healthy Chinese Population: A Cohort Study

Purpose

This study aimed to investigate the association between serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and incident metabolic disease in a cohort of community-based older Chinese people.

Patients and Methods

Five thousand healthy Gaohang residents who attended community health checks at the Shanghai East Hospital in 2013 were recruited. Biological, biochemical, and lifestyle variables were collected. The cohort was followed for new-onset metabolic disease in 2014 and 2017, with a final study population of 3,123 (63%) after follow-up. The study outcome included type-2 diabetes mellitus and metabolic syndrome.

Results

Baseline AST and ALT were associated with incident type-2 diabetes mellitus (HR 1.019, 95% CI 1.006-1.032, p = 0.003 and HR 1.016, 95% CI 1.008-1.025, p < 0.001 respectively). These associations persisted after adjusting for traditional risk factors including age, sex, income, waist circumference, systolic blood pressure, diastolic blood pressure, HbA1c, triglyceride, cholesterol, HDL and eGFR. Baseline AST and ALT were associated with incident metabolic syndrome in the crude analysis (HR 0.980, 95% CI 0.965-0.996, p = 0.012 and HR 0.992, 95% CI 0.988-0.997, p = 0.001, respectively). However, the association between AST and ALT with metabolic syndrome was non-significant after adjusting for biochemical parameters such as the lipid profile.

Conclusion

This study demonstrated that serum AST and ALT are associated with new-onset type-2 diabetes mellitus, independent of traditional risk factors, in a cohort of older Chinese people. These findings may contribute to disease risk stratification and management in type-2 diabetes.

Serum liver enzymes and diabetes from the Rafsanjan cohort study

BACKGROUND

We evaluated the relation between ALT, AST, GGT and ALP with diabetes in the Rafsanjan Cohort Study.

MATERIALS AND METHODS

The present study is a cross-sectional research including 9991 adults participated via sampling. We used data obtained from the Rafsanjan Cohort Study (RCS), as a part of the prospective epidemiological research studies in IrAN (PERSIAN). Elevated serum levels of ALT, AST, GGT and ALP were defined according to the reference range of the laboratory in the cohort center. Serum liver enzymes levels within the normal range were categorized into quartiles, and their relationship with diabetes was evaluated by logistic regressions.

FINDINGS

In present study, elevated serum levels of ALT, AST, GGT, and ALP were associated with increased odds of diabetes (adjusted ORs: 1.81, 95%CI 1.51-2.17; 1.75, 95%CI 1.32-2.32; 1.77, 95%CI 1.50-2.08; 1.60, 95%CI 1.35-1.90 respectively). Also, in subjects with normal levels of ALT, GGT and ALP, a dose-response increase was shown for diabetes.

CONCLUSION

Elevated levels of ALT, AST, GGT and ALP are related to a higher odds of diabetes. Also, increased levels of ALT, GGT and ALP even within normal range were independently related with the increased odds of diabetes. These results indicated the potential of elevated liver enzymes as biomarkers for the possible presence of diabetes.

A problem of proportions: estimates of metabolic associated fatty liver disease and liver fibrosis in Australian adults in the nationwide 2012 AusDiab Study

Metabolic Associated Fatty Liver Disease (MAFLD) is the most common cause of liver disease in Australia, but prevalence data are limited. We aimed to describe the frequency of alanine aminotransferase (ALT) elevation, and MAFLD within a large prospective Australian cohort. Cross-sectional analysis of the 2012 survey of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study which included 4747 Australian adults (aged 34–97 yrs) was performed. Frequency of ALT elevation (men ≥ 40 IU/L, women ≥ 30 IU/L) and MAFLD (Fatty Liver Index (FLI) > 60 alongside metabolic risk factors) was determined and risk of advanced fibrosis stratified using the BARD score. Elevated ALT was found in 13% of the cohort, including 22% of people with diabetes, 18% with obesity, and 17% with the metabolic syndrome. 37% of the cohort had MAFLD, and those with MAFLD were more likely to be older (OR 1.01 per 1 year (95% CI 1.00–1.02)), male (OR 1.37 (95% CI 1.17–1.59)), have ALT elevation (OR 3.21 (95% CI 2.59–3.99)), diabetes (OR 3.39 (95% CI 2.61–4.39)), lower HDL-C (OR 0.15 per 1 mmol/L (95% CI 0.12–0.19)), higher diastolic blood pressure (OR 1.05 per 10 mmHg (95% CI 1.05–1.06)), a sedentary lifestyle (OR 1.99 (95% CI 1.59–2.50)) and less likely to have tertiary education (OR 0.81 (95% CI 0.7–0.94) compared to those without MAFLD. Of those with MAFLD, 61% had a BARD score suggesting risk of advanced fibrosis and 22% had an elevated ALT. Over 10% of this Australian cohort had elevated ALT, and 37% had MAFLD, with many at risk for advanced fibrosis.

The Risk Factors for Development of Type 2 Diabetes: Panasonic Cohort Study 4

(1) Background: As no study has evaluated the risk factors contributing to the development of type 2 diabetes according to body weight mass (BMI) categories in a large cohort and over a long period in a Japanese population, we aimed to assess them in 46,001 Japanese individuals; (2) Methods: This long-term retrospective cohort study included individuals who participated in a medical health checkup program at Panasonic Corporation from 2008 to 2018. In total, 3,208 participants developed type 2 diabetes. The BMI at 2008 were divided into 3 groups: BMI < 22 kg/m², 22 ≤ BMI < 25 kg/m², and BMI ≥ 25 kg/m² to evaluate the risk factors for type 2 diabetes; (3) Results: Cox regression analyses revealed that the significant risk factors were age, BMI, systolic blood pressure, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting plasma glucose, current smoking status, and alcohol consumption in populations with BMI ≥ 25.0 kg/m². The risk factors in the population with 22 ≤ BMI < 25 kg/m² were identical to that of BMI ≥ 25.0 kg/m² excluding systolic blood pressure, low-density lipoprotein cholesterol, and skipping breakfast. However, in the population with BMI < 22.0 kg/m², no association was found as to BMI, SBP, LDL cholesterol level, and triglycerides; (4) Conclusions: The risk factors for developing diabetes were quite different between the population with BMI < 22 kg/m² and the population with 22 ≤ BMI < 25 kg/m² or BMI ≥ 25 kg/m² in a Japanese population.

To explore association between gamma-glutamyl transferase and type 2 diabetes using a real-world study and mendelian randomization analysis

AIM

The association between gamma-glutamyl transferase (GGT) and type 2 diabetes mellitus (T2DM) is controversial. In this study, we investigated the association between GGT and the risk of T2DM using real-world data, Mendelian randomization (MR) analysis, and literature mining.

METHODS

A cross-sectional study enrolled 3,048 participants (>40 years) from a community in Northeastern China was conducted. A generalized additive model was used to examine the relation between GGT and T2DM. A two-sample MR was performed to investigate the causal effect of GGT (61,089 individuals, mostly of European ancestry) on T2DM (29,193 cases and 182,573 controls of European ancestry).

RESULTS

GGT was related to glucose metabolism indicators, such as fasting plasma glucose and glycosylated hemoglobin (P < 0.05). The odds ratios (ORs) [95% confidence interval (95% CI), P] for T2DM across the GGT categories (14-16, 17-20, 21-25, 26-35, ≥36) were 1.14 [(0.88-1.47), P = 0.330], 1.55 [(1.22-1.98), P < 0.001], 1.87 [(1.47-2.28), P < 0.001], 1.97 [(1.55-2.52), P < 0.001], and 2.29 [(1.78-2.94), P < 0.001] versus GGT ≤ 13 category after adjusting for potential confounding factors. A generalized additive model identified a non-linear correlation between GGT and T2DM and indicated that the risk of T2DM almost levelled out when GGT exceeded 34 IU/L. The MR analysis showed that the odds of having T2DM for a one-time increase in genetically determined GGT was 0.998 [(0.995-1.002), P = 0.34].

CONCLUSIONS

Our analysis of observational study suggested that GGT, its increment, within a certain range, is indicative of the development of T2DM. However, MR analysis provided no evidence that GGT is a linear causal factor of T2DM. Further investigation is required to determine if GGT exerts a non-linear causal effect on T2DM.

The association of liver enzymes with diabetes mellitus risk in different obesity subgroups: A population-based study

BACKGROUND

Numerous observational studies have shown that liver enzymes correlated with diabetes mellitus (DM) risk significantly, but limited studies showed whether different obesity subgroups present the same correlation. Our objective was to evaluate the association of liver enzymes with DM risk in different obesity subgroups based on a middle-aged Chinese population.

METHODS

We conducted a population-based cross-sectional study and surveyed 9,916 people aged 40 years and above. A two-slope linear regression model was used to analyze the cutoff points of obesity in DM risk. Restricted cubic splines were used to analyze the correlation between liver enzymes and DM risk in different obesity categories. The odds ratios and 95% confidence intervals (CIs) were calculated using the logistic regression model.

RESULTS

The cutoff points of body mass index (BMI) and waist circumference were 30.55 kg/m² and 98.99 cm for DM risk, respectively. The serum gamma-glutamyl transferase (GGT) concentration was positively correlated with DM risk in the subgroups with waist circumference <98.99 cm [OR = 1.04, 95% CI (1.03-1.05)], BMI <30.55 kg/m² [OR = 1.04, 95% CI (1.03-1.05)], and BMI ≥30.55 kg/m² [OR = 1.18, 95% CI (1.04-1.39)], but not in the subgroup with waist circumference ≥98.99 cm. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations have no significant correlation with the risk of diabetes in all groups.

CONCLUSION

The results showed that serum GGT concentration was correlated with DM risk but not with AST or ALT in the middle-aged population. However, the correlation disappeared when waist circumference was over 98.99 cm, and serum GGT concentration had a limited value for DM risk in waist circumference over 98.99 cm.

The effects of Cynara scolymus L. supplementation on liver enzymes: A systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis was conducted to summarise studies conducted on the effects of artichoke supplementation on liver enzymes.

METHODS

Suitable studies were detected by searching online databases, including Medline, Embase, Cochrane Library, and Scopus databases, until 05 June 2021. As liver enzymes were reported in different units, standardised mean differences (SMD) were used and data were pooled using a random-effects model. Heterogeneity, publication bias, and sensitivity analysis were also assessed.

RESULTS

Pooled analysis, of eight clinical trials, revealed that artichoke supplementation significantly reduced the concentration of aspartate aminotransferase (AST) (P = .001) and alanine transaminase (ALT) (P = .016), in comparison with placebo. Subgroup analysis suggested that artichoke administration significantly reduces AST and ALT in patients with non-alcoholic fatty liver disease (P = .003 for AST and P < .001 for ALT), and ALT among overweight/obese subjects (P = .025).

CONCLUSIONS

Artichoke supplementation elicited significant reductions in liver enzymes, especially among patients with non-alcoholic fatty liver disease.

Influences of pregravid liver enzyme levels on the development of gestational diabetes mellitus

BACKGROUND & AIMS

Elevated liver enzymes are associated with later development of type 2 diabetes mellitus. The objective of this study was to assess the association between prepregnancy liver enzyme levels and subsequent risk of gestational diabetes mellitus.

METHODS

Data from a total of 236,109 women who participated in the National Health Screening Examination between 2011 and 2015 was analysed. Multivariate logistic regression analyses were performed to estimate the risk of developing gestational diabetes mellitus in relation to pregravid liver enzyme levels. Subgroup analyses were performed according to pregravid obesity and metabolic syndrome (MetS).

RESULTS

Approximately 5.7% and 1.1% of women developed gestational diabetes mellitus with and without insulin treatment requirement respectively. Pregravid gamma-glutamyl transferase and alanine aminotransferase levels with greater than or equal to the 4th quartile were associated with significantly increased risks of gestational diabetes mellitus requiring insulin treatment in women with obesity and with MetS, (odds ratios [ORs] with 6.228 and 9.505, respectively, P < .001 for both). In women without obesity and without MetS, the risks of gestational diabetes mellitus requiring insulin treatment were also significant (ORs with 2.837 and 3.029, respectively, P < .001 for both). The elevated pregravid liver enzymes were associated with gestational diabetes mellitus without insulin treatment requirement, but minimally.

CONCLUSIONS/INTERPRETATION

The elevated pregravid liver enzyme levels were significantly associated with the subsequent risk of gestational diabetes mellitus, especially gestational diabetes mellitus requiring insulin treatment, not only in women with obesity or MetS, but also in women without obesity or MetS.

Eating Fast and Until Full Is Associated with Elevated Alanine Aminotransferase Activity in Japanese Schoolchildren: A Cross-Sectional Study

Alanine aminotransferase (ALT) activity has been recognized as a marker for monitoring the risk of metabolic syndrome, diabetes and non-alcoholic fatty liver disease in children. Higher ALT activity was reported to be associated with eating fast in Japanese adults, but the association in children is unclear. Moreover, eating fast and eating until full are reported to be associated with being overweight. This study examined the association between elevated ALT and eating behaviors (eating fast and eating until full) among population-based schoolchildren (aged 9-10 years) in Ina Town, Saitama, Japan. Data for eating behaviors were obtained from a self-written questionnaire. Blood samples were drawn to measure ALT. Elevated ALT was defined as > 30 U/L in boys and > 19 U/L in girls. Logistic regression models and structural equation models were used to calculate the effect of eating behaviors on elevated ALT. Final data analysis was carried out for 1,870 boys and 1,739 girls. "Eating fast and eating until full" was significantly associated with elevated ALT in each sex. "Eating fast and not eating until full" was significantly associated with elevated ALT in boys, but after adjusting for exercise and body mass index, this association was not significant. In conclusion, "eating fast and eating until full" was associated with elevated ALT in schoolchildren. A sex difference in the association of "eating fast and not eating until full" with elevated ALT was observed. Modifying the behaviors of eating fast and eating until full is important for schoolchildren to prevent ALT elevation.

Combined associations of liver enzymes and obesity with diabetes mellitus prevalence: The Tohoku Medical Megabank Community-based Cohort Study

BACKGROUND

Alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) are enzymes associated with diabetes mellitus (DM) prevalence. However, limited information is available regarding the association of liver enzymes and DM consistently present in obese and non-obese individuals. We examined whether the combination of ALT and GGT enzymes is associated with the prevalence of DM regardless of obesity in a general Japanese population.

METHODS

We conducted a cross-sectional study of 62,786 participants aged ≥20 years who lived in Miyagi and Iwate, Japan. We divided all the participants into eight groups according to the ALT level (low: <30 IU/L and high: ≥30 IU/L), GGT level (low: <50 IU/L and high: ≥50 IU/L), and the presence of obesity. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression analysis, adjusting for potential confounders, to determine associations of the combination of ALT and GGT levels and obesity with DM prevalence.

RESULTS

Overall, 6,008 participants (9.6%) had DM. Compared to non-obese individuals with low ALT and GGT levels, the participants with high ALT and GGT levels had high ORs for DM in both obese (OR 4.06; 95% CI, 3.61-4.56) and non-obese groups (OR 2.19; 95% CI, 1.89-2.52). The obese group had high ORs for DM, even at low ALT and GGT levels.

CONCLUSION

High ALT and GGT levels are associated with DM prevalence in obese and non-obese participants. This finding suggests that correcting ALT and GGT levels and controlling obesity are important for the prevention of DM.

Positive Association of Serum Alkaline Phosphatase Level with Severe Knee Osteoarthritis: A Nationwide Population-Based Study

Serum alkaline phosphatase (ALP), a well-known marker of hepatobiliary and bone disorders, has recently been discovered to be a biochemical marker of cardiometabolic diseases and chronic low-grade inflammation. We aimed to evaluate the association of serum ALP level with knee osteoarthritis in the general population. The study included 3060 men and women aged ≥50 years who participated in the 2009–2011 Korea National Health and Nutrition Examination Survey. The participants were categorized into three groups based on log-transformed serum ALP level as follows: T1 (1.74–2.32), T2 (2.33–2.43), and T3 (2.44–3.01). Their radiographs were evaluated by two well-trained radiologists using the Kellgren–Lawrence (KL) grading system. After excluding those with KL Grade 0, we categorized the remaining participants into two groups, a severe osteoarthritis group (KL Grade 4) and a non-severe osteoarthritis group (KL Grades 1 to 3). The odds ratios (ORs) with 95% confidence intervals (CIs) of severe osteoarthritis according to the tertiles of log-transformed serum ALP levels of patients with osteoarthritis were calculated using a weighted multivariate logistic regression analysis. Compared with T1, the adjusted ORs (95% CIs) for severe osteoarthritis of the T3 serum ALP group was 1.613 (1.087–2.394; p = 0.018) after adjusting for the confounding variables. Conclusively, serum ALP activity was independently and positively associated with severe knee osteoarthritis in middle-aged and older adults.

Specificity of transaminase activities in the prediction of drug-induced hepatotoxicity

The activities of the transaminases (aminotransferases) alanine aminotransferase and aspartate aminotransferase in the blood (serum or plasma) are widely used as sensitive markers of possible tissue damage and, in particular for liver toxicity. On the other hand, an increase in transaminase activities is not always accompanied by findings suggestive of hepatotoxicity. Transaminases are some of the key enzymes in the gluconeogenesis and glycolysis pathways and exist in many organs and tissues which have high activities of the gluconeogenesis and glycolysis. The activities of transaminases are altered not only in the liver but also in other organs by modification of gluconeogenesis by nutritional or hormonal factors and this phenomenon leads to alteration of transaminase activity in the blood. Drugs, which are considered to directly or secondarily modify gluconeogenesis through lowering blood glucose levels or activating lipid metabolism, such as α-glucosidase inhibitors and fibrates, slightly increase transaminase activities in the blood but there is little evidence that the phenomenon is related to drug-induced liver injury (DILI). This type of elevations can be called pharmacology-related elevation. The pharmacology-related elevation of transaminase activities sometimes makes it difficult to assess precisely the potential hepatotoxicity of new investigational drugs. Considering the characteristic of transaminases, concomitant use of new biomarkers more specific to hepatic injury is needed in the assessment of DILI both in non-clinical and clinical studies. In this review, we will discuss the specificity of transaminases to DILI and future perspectives for transaminases in the estimation of risk of DILI.

Serum Alanine Transaminase as a Predictor of Type 2 Diabetes Incidence: The Yuport Prospective Cohort Study

Prior studies have shown an association between the incidence of diabetes with liver enzymes, such as alanine transaminase (ALT). Liver fibrosis scores, such as the Fibrosis-4 index which indicates chronic liver damage, were also associated with diabetes development. However, no literature compared predictive accuracy between ALT and Fibrosis-4 index. Thus, we aimed to determine it, and to assess its association using inverse probability of treatment weighting. This was a non-concurrent prospective cohort study of 9,748 subjects without diabetes receiving Yuport Health Checkup in Japan between 1998 and 2006. ALT was categorized into three groups: the highest ALT group (men ≥ 30 U/L and women ≥ 20 U/L), the middle (men ≥ 20 and < 30 U/L, and women ≥ 14 and < 20 U/L), and the lowest (men < 20 U/L and women < 14 U/L). The primary outcome was the new onset of diabetes. The area under the receiver operating characteristic curves (AUC) of ALT for predicting the diabetes development was higher than that of any other markers of liver damage. The AUC for ALT was 0.71, while that for the Fibrosis-4 index was 0.51 (p < 0.001 for the difference between the AUCs). The highest and middle ALT groups had a significantly higher incidence of diabetes than the lowest group: adjusted relative risk 1.79 [95% confidence interval (CI): 1.29, 2.58], and 1.64 [95% CI: 1.17, 2.38] respectively. Of the various indicators of liver function, ALT is likely to be the most accurate and associated predictor of diabetes development.

The association of plasma levels of liver enzymes and risk of gestational diabetes mellitus: a systematic review and dose-response meta-analysis of observational studies

AIMS

Relationship between liver enzymes such as gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), aspartate transaminase (AST) and alkaline phosphatase and risk of gestational diabetes mellitus (GDM) is a controversial issue. The aim of this systematic review and dose-response meta-analysis was to investigate the association between liver enzymes and risk of GDM in observational studies.

METHODS

A comprehensive systematic literature search was conducted in MEDLINE/PubMed, SCOPUS and Web of Science databases up to September 2019. Combined odds ratios (ORs) with 95% confidence intervals (CIs) were evaluated by DerSimonian and Laird random-effects models. Dose-response analyses of these relationships were also carried out.

RESULTS

Eight studies with 25,451 participants containing 2549 cases were included in this study. Pooled results showed a significant association between GGT levels and risk of GDM (OR 2.10, 95% CI 1.14-3.86, I² 84%). In addition, random-effects model indicated a dramatic and direct significant association between GGT and risk of GDM in nonlinear (p < 0.001) and linear (p < 0.001) dose-response analysis. Associations between ALT and AST with risk of GDM were found to be non-significant (OR 1.32, 95% CI 0.91-1.90, I² 65% and OR 0.76, 95% CI 0.52-1.10, I² 16%, respectively).

CONCLUSION

This systematic review and dose-response meta-analysis highlights GGT as a significant and robust predictor of the incidence of GDM in pregnant women.

Prevalence of elevated liver enzymes and its association with type 2 diabetes: A cross-sectional study in Bangladeshi adults

BACKGROUND

Type 2 diabetes (T2D) is a major public health concern affecting millions of people worldwide. The relationship between liver enzymes and T2D has been reported in limited studies; however, there is still a lack of evidence for the Bangladeshi population. This study aimed to evaluate the prevalence of elevated liver enzymes and examine its association with the prevalence of T2D in Bangladeshi adults.

METHODS

A total of 270 individuals (110 diabetic and 160 nondiabetic) were enrolled in the study. Alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP) and γ-glutamyltransferase (GGT) activities were measured in blood serum collected from them. T2D was defined as fasting blood glucose (FBG) ≥126 mg/dL or self-reported recent use of insulin or antidiabetic medications. Association between liver enzymes and T2D was evaluated by multinomial logistic regression analysis.

RESULTS

Overall, 61.2% of participants in T2D and 37.1% of participants in the nondiabetes group had at least one or more elevated liver enzymes. The mean concentrations of serum ALT, AST, ALP and GGT were significantly higher in the T2D group compared to the nondiabetes group. The prevalence of elevated liver enzymes was significantly higher in the diabetes group compared to the nondiabetes group (P < .01). In regression analysis, serum GGT activity showed an independent association with the prevalence of T2D.

CONCLUSIONS

A high prevalence of elevated liver enzymes was observed in subjects having diabetes. Increased serum GGT activity was independently associated with the prevalence of T2D among Bangladeshi adults. More studies of this nature should be carried out in developing countries to get proper insights into the involvement of liver enzymes in T2D.

Incidence and causes of mildly to moderately elevated aminotransferase in Japanese patients with type 2 diabetes

Objectives

To identify the association of type 2 diabetes (T2DM) and liver disease with elevated ALT and factors associated with increased ALT in patients with and without T2DM.

Design and setting

We performed a retrospective study in adults with ≥ 2 claims for blood tests recorded in the Medical Data Vision claims database between 2010 and 2016.

Participants

Patients were entered into T2DM and non-DM groups based on diagnosis and medication claim codes.

Primary outcome measure

The primary endpoint was the first follow-up ALT elevation over three times the normal value, and etiologies were categorized by subsequent diagnoses. We estimated the ALT elevation incidence and association with T2DM using Poisson regression and Cox proportional hazard models.

Results

We identified 3161 cases of elevated ALT in 104,903 patients (follow-up, 280,659 patient-years). The age- and sex-adjusted incidence of elevated ALT in the T2DM group (13.47 per 1000 patient-years; 95% confidence interval (CI) 12.53-14.48) was significantly higher than that in the non-DM group (8.43 per 1000 patient-years; 95% CI 7.72-9.20, p < 0.0001). Compared to the non-DM group, the T2DM group had an approximately 3.5 times higher risk of fatty liver-related ALT elevation (adjusted hazard ratio (HR), 3.54; 95% CI 1.90-6.58). T2DM was not associated with an increased incidence of jointly elevated ALT and total bilirubin (adjusted HR, 0.94; 95% CI 0.77-1.15).

Conclusion

T2DM is strongly associated with increased liver enzymes secondary to fatty liver. The causes of liver enzyme abnormalities were not fully characterized due to a high proportion of unexplained ALT elevation.

Estimation of potential risk of allyl alcohol induced liver injury in diabetic patients using type 2 diabetes spontaneously diabetic Torii-Leprfa (SDT fatty) rats

In order to estimate the potential risk of chemicals including drug in patients with type 2 diabetes mellitus (T2DM), we investigated allyl alcohol induced liver injury using SD rats and Spontaneously Diabetic Torii-Lepr^fa (SDT fatty) rats as a model for human T2DM. The diabetic state is one of the risk factors for chemically induced liver injury because of lower levels of glutathione for detoxification by conjugation with chemicals and environmental pollutants and their reactive metabolites. Allyl alcohol is metabolized to a highly reactive unsaturated aldehyde, acrolein, which is detoxified by conjugation with glutathione. Therefore, we used allyl alcohol as a model compound. Our investigations showed that SDT fatty rats appropriately mimic the diabetic state in humans. The profiles of glucose metabolism, hepatic function tests and glutathione synthesis in the SDT fatty rats were similar to those in patients with T2DM. Five-week oral dosing with allyl alcohol to the SDT fatty rats revealed that the allyl alcohol induced liver injury was markedly enhanced in the SDT fatty rats when compared with the SD rats and the difference was considered to be due to lower hepatic detoxification of acrolein, the reactive metabolite of allyl alcohol, by depleted hepatic glutathione synthesis. Taking all the results of the present study into consideration, the potential for allyl alcohol to induce liver injury is considered to be higher in diabetic patients than in healthy humans.

Plasma Fetuin-A Levels and Risk of Type 2 Diabetes Mellitus in A Chinese Population: A Nested Case-Control Study

BACKGROUND

Fetuin-A is a hepatokine that involved in the pathogenesis of insulin resistance. Previous epidemiological studies have found a positive association between blood fetuin-A and type 2 diabetes mellitus (T2DM) risk among Caucasians and African Americans. We aimed to investigate the prospective relationship between fetuin-A and T2DM in an Asian population for the first time.

METHODS

A nested case-control study was established within a prospective cohort of Chinese living in Singapore. At blood collection (1999 to 2004), all participants were free of diagnosed T2DM and aged 50 to 79 years. At subsequent follow-up (2006 to 2010), 558 people reported to have T2DM and were classified as incident cases, and 558 controls were randomly chosen from the participants who did not develop T2DM to match with cases on age, sex, dialect group, and date of blood collection. Plasma fetuin-A levels were measured retrospectively in cases and controls using samples collected at baseline. Conditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence interval (CI). Restricted cubic spline analysis was used to examine a potential non-linear association between fetuin-A levels and T2DM risk.

RESULTS

Compared with those in the lowest fetuin-A quintile, participants in the highest quintile had a two-fold increased risk of developing T2DM (OR, 2.06; 95% CI, 1.21 to 3.51). A non-linear association was observed (P nonlinearity=0.005), where the association between fetuin-A levels and T2DM risk plateaued at plasma concentrations around 830 μg/mL.

CONCLUSION

There is a positive association between plasma fetuin-A levels and risk of developing T2DM in this Chinese population.

Serum lactate levels are associated with serum alanine aminotransferase and total bilirubin levels in patients with type 2 diabetes mellitus: A cross-sectional study

AIMS

It was recently reported that lactate acts as a metabolic mediator and rises in the diabetic state, but the physiological effects are as yet poorly understood. The objective of the current study was to evaluate the significance of serum lactate elevation in type 2 diabetes mellitus (T2DM) patients.

METHODS

Fasting serum lactate levels, hematological and inflammatory serum markers and anthropometric parameters, obtained employing bioelectric impedance analysis, were measured in 103 patients with T2DM.

RESULTS

Statistically significant correlations of serum lactate levels with C-reactive peptide, insulin, aspartate aminotransferase, alanine aminotransferase (ALT), serum lipids, total bilirubin, adiponectin, homeostasis model assessment-insulin resistance, body weight, body mass index and body fat (weight or percentage of subcutaneous fat, visceral fat or total body fat), but neither fasting plasma glucose nor HbA1c, were detected. Stepwise regression analysis showed ALT to be independently positively associated with total bilirubin, while being negatively associated with serum lactate levels. Furthermore, serum lactate levels were significantly higher in patients with ALT-predominant liver dysfunction.

CONCLUSION

We found fasting serum lactate elevation in T2DM patients to be associated with the serum levels of ALT and total bilirubin independently of blood glucose control.

TRIAL REGISTRATION

UMIN clinical trials registry (UMIN000029178).

Direct-acting antiviral agents do not increase the incidence of hepatocellular carcinoma development: a prospective, multicenter study

BACKGROUND

While achieving sustained virological response (SVR) following interferon-based or direct-acting antiviral agent (DAA) treatments reduces the incidence of hepatocellular carcinoma (HCC), an increase in unexpected early occurrence or recurrence of HCC after hepatitis C virus elimination by DAA treatments has been reported. We prospectively investigated the incidence and risk factors of HCC after DAA treatment in a large multicenter cohort in Japan.

METHODS

Patients with chronic hepatitis C with or without cirrhosis who were treated with DAAs and obtained SVR were enrolled. DAAs were administered for 3 or 6 months. A total of 2552 patients were enrolled.

RESULTS

Of these, 70 patients (2.7%) developed HCC. The 12-, 24-, and 36-month cumulative HCC incidences were 1.3%, 2.9%, and 4.9% in all patients; 2.5%, 5.2%, and 10.0% in those with cirrhosis; and 0.9%, 2.1%, and 2.9% in those without cirrhosis, respectively. Multivariate analysis revealed age, sex, gamma-glutamyl transpeptidase level, and fibrosis-4 index to be independent factors associated with HCC. Patients with these four factors had an approximately six-to-sevenfold increased risk for HCC development. Five patients with large and early tumor occurrence did not receive contrast imaging examinations before treatment.

CONCLUSION

Although the results of our prospective study suggested that achieving SVR by DAA treatment reduces the incidence of HCC, HCC development still occurs. Careful follow-up is important in patients with risk factors.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG5.6, IFG6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG6.1 and IFG5.6. Limited data showed a higher T2DM incidence associated with HbA1c6.0 compared to HbA1c5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Higher level of GGT during mid-pregnancy is associated with increased risk of gestational diabetes mellitus

OBJECTIVE

This study was to explore the link between gamma-glutamyl transferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST) levels during early-middle pregnancy and subsequent risk of gestational diabetes mellitus (GDM).

METHODS

In a prospective cohort study, pregnant women enrolled prior to 16 weeks of gestation were followed up until delivery. GGT, AST and ALT levels were tested during weeks 14-18 of gestation and oral glucose tolerance test was conducted during 24-28 weeks to screen GDM.

RESULTS

The GDM rate was 8.1% (122/1512). Mean GGT level was higher in GDM than non-GDM women (18.7 ± 13.0 vs 14.5 ± 7.0, P < .001). The higher GGT level was 26.9~74.0 U/L, which was significantly associated with increased risk of GDM. The adjusted RR (95% CI) comparing higher GGT level versus lower was 5.40 (3.36-8.68). No significant correlation was found between ALT or AST levels and the risk of GDM.

CONCLUSIONS

The results suggest that pregnant women with higher serum GGT during early-middle pregnancy have higher risk of developing GDM. A GGT level >26.9 U/L may indicate an increased risk of developing GDM later and should be further concerned.

Sex-Specific Association between Metabolic Abnormalities and Elevated Alanine Aminotransferase Levels in a Military Cohort: The CHIEF Study

The association of metabolic syndrome (MetS) components with elevated serum alanine aminotransferase (ALT) levels, a marker of hepatic injury, may differ between men and women. However, the sex-specific association in a military young population which has a low prevalence of MetS was unclear. We conducted a cross-sectional examination in 6738 men and 766 women, aged 18-50 years, from the cardiorespiratory fitness study in armed forces (CHIEF) in eastern Taiwan. The components of MetS were defined according to the updated International Diabetes Federation (IDF) ethnic criteria for Asians. Elevated ALT levels were defined as ≥40 U/L for both sexes and ≥30 U/L for women alternatively. Multivariate logistic regression analysis was performed to determine the sex-specific association between MetS components and elevated ALT. The prevalence of MetS and elevated ALT in men were 11.9% and 12.7% respectively, and in women were 3.5%, and 3.8% respectively. In men, high-density lipoprotein < 40 mg/dL, blood pressures ≥ 130/85 mmHg, serum triglycerides ≥ 150 mg/dL, and waist size ≥ 90 cm were associated with elevated ALT (odds ratios (OR) and 95% confidence intervals: 1.59 (1.34-1.90), 1.40 (1.19-1.65), 2.00 (1.68-2.39), and 1.68 (1.38-2.04); all p < 0.001); whereas in women, only fasting plasma glucose ≥ 100 mg/dL was associated with elevated ALT ≥ 40 U/L (OR: 7.59 (2.35-24.51), p = 0.001) and ALT ≥ 30 U/L (2.67 (0.89-7.95), p = 0.08). Our findings suggest that the relationship between metabolic abnormalities and elevated ALT may differ by sex, possibly due to the MetS more prevalent in young adult men than in women.

Influence of non-pathological factors on ALT measurements

Alanine transaminase (ALT) is still the most sensitive marker for evaluating the damage of liver cells. ALT measurements may be affected by common non-pathological factors such as gender, age, pregnancy, different physiological conditions, circadian rhythm, diet, drinking, smoking, strenuous exercise, metabolic factors, drugs, blood collection methods, and specimen collection, transmission, and preservation. It is important to emphasize the definition of limits of normal ALT and the influence of the above-mentioned non-pathological factors on its test results.

Insulin-induced inhibition of gluconeogenesis genes, including glutamic pyruvic transaminase 2, is associated with reduced histone acetylation in a human liver cell line

OBJECTIVES

Hepatic glutamic pyruvic transaminase (GPT; also known as alanine aminotransferase) is a gluconeogenesis enzyme that catalyzes conversions between alanine and pyruvic acid. It is also used as a blood biomarker for hepatic damage. In this study, we investigated whether insulin regulates GPT expression, as it does for other gluconeogenesis genes, and if this involves the epigenetic modification of histone acetylation.

METHODS

Human liver-derived HepG2 cells were cultured with 0.5-100nM insulin for 8h, and the mRNA expression of GPT, glutamic-oxaloacetic transaminase (GOT), γ-glutamyltransferase (GGT), PCK1, G6PC and FBP1 was measured. We also investigated the extent of histone acetylation around these genes.

RESULTS

Insulin suppressed the mRNA expression of gluconeogenesis genes (GPT2, GOT1, GOT2, GGT1, GGT2, G6PC, and PCK1) in HepG2 cells in a dose-dependent manner. mRNA levels of GPT2, but not GPT1, were decreased by insulin. Histone acetylation was also reduced around GPT2, G6PC, and PCK1 in response to insulin.

CONCLUSION

The expression of GPT2 and other gluconeogenesis genes such as G6PC and PCK1 was suppressed by insulin, in association with decreases in histone H3 and H4 acetylation surrounding these genes.

A longitudinal assessment of miR-122 and GLDH as biomarkers of drug-induced liver injury in the rat

CONTEXT

There is an ongoing search for specific and translational biomarkers of drug-induced liver injury (DILI). MicroRNA-122 (miR-122) has previously shown potential as a sensitive, specific, and translational biomarker of DILI in both rodent, and human studies.

OBJECTIVE

To build on previous work within the field, we examined biomarker kinetics in a rat model of acetaminophen (APAP)-induced liver injury to confirm the sensitivity, and specificity of miR-122 and glutamate dehydrogenase (GLDH).

MATERIALS AND METHODS

qRT-PCR and a standard enzymatic assay were used for biomarker analysis.

RESULTS

Both miR-122 and GLDH were demonstrated to be more readily-detectable biomarkers of APAP-DILI than alanine aminotransferase (ALT). Peak levels for all biomarkers were detected at 2 days after APAP. At day 3, miR-122 had returned to baseline; however, other biomarkers remained elevated between 3 and 4 days. We were also able to demonstrate that, although miR-122 is present in greater quantities in exosome-free form, both exosome-bound and non-vesicle bound miR-122 are released in a similar profile throughout the course of DILI.

DISCUSSION AND CONCLUSIONS

Together, this study demonstrates that both GLDH and miR-122 could be used during preclinical drug-development as complementary biomarkers to ALT to increase the chance of early detection of hepatotoxicity.

Astaxanthin as a Potential Protector of Liver Function: A Review

Protecting against liver damage, such as non-alcoholic fatty liver disease, is currently considered to be important for the prevention of adverse conditions, such as cardiovascular and cancerous diseases. Liver damage often occurs in relation to oxidative stress with metabolic disorders, including cellular lipid accumulation. Astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'dione), a xanthophyll carotenoid, is a candidate for liver protection. Here, we briefly review astaxanthin as a potential protector against liver damage. In particular, studies have reported antioxidative effects of astaxanthin in liver tissues. Astaxanthin treatment is also reported to improve hyperlipidemia, which indirectly induces the antioxidative effects of astaxanthin on liver pathologies. Furthermore, astaxanthin may alleviate liver damage independent of its antioxidative effects. Of note, there are still insufficient human data to observe the effect of astaxanthin treatment on liver function in clinical conditions. More studies investigating the relevance of astaxanthin on liver protection are necessary.

Circulating Neutrophil Extracellular Trap Levels in Well-Controlled Type 2 Diabetes and Pathway Involved in Their Formation Induced by High-Dose Glucose

OBJECTIVES

Although intensive therapy for type 2 diabetes (T2D) prevents microvascular complications, 10% of well-controlled T2D patients develop microangiopathy. Therefore, the identification of risk markers for microvascular complications in well-controlled T2D patients is important. Recent studies have demonstrated that high-dose glucose induces neutrophil extracellular trap (NET) formation, which can be a risk for microvascular disorders. Thus, we attempted to determine the correlation of circulating NET levels with clinical/laboratory parameters in well-controlled T2D patients and to reveal the mechanism of NET formation induced by high-dose glucose.

METHODS

Circulating NET levels represented by myeloperoxidase (MPO)-DNA complexes in the serum of 11 well-controlled T2D patients and 13 healthy volunteers were determined by enzyme-linked immunosorbent assay. The pathway involved in the NET formation induced by high-dose glucose was determined using specific inhibitors.

RESULTS

Serum MPO-DNA complex levels were significantly higher in some well-controlled T2D patients in correlation with the clinical/laboratory parameters which have been regarded as risk markers for microvascular complications. The aldose reductase inhibitor, ranirestat, could inhibit the NET formation induced by high-dose glucose.

CONCLUSIONS

Elevated levels of circulating NETs can be a risk marker for microvascular complications in well-controlled T2D patients. The polyol pathway is involved in the NET formation induced by high-dose glucose.

Nonalcoholic fatty liver disease is associated with an almost twofold increased risk of incident type 2 diabetes and metabolic syndrome. Evidence from a systematic review and meta-analysis

BACKGROUND AND AIM

The magnitude of the risk of incident type 2 diabetes (T2D) and metabolic syndrome (MetS) among patients with nonalcoholic fatty liver disease (NAFLD) is poorly known. We gauged the risk of developing T2D and MetS in patients with NAFLD diagnosed by either serum liver enzymes (aminotransferases or gamma-glutamyltransferase [GGT]) or ultrasonography.

METHODS

Pertinent prospective studies were identified through extensive electronic database research, and studies fulfilling enrolment criteria were included in the meta-analysis.

RESULTS

Overall, in a pooled population of 117020 patients (from 20 studies), who were followed-up for a median period of 5 years (range: 3-14.7 years), NAFLD was associated with an increased risk of incident T2D with a pooled relative risk of 1.97 (95% confidence interval [CI], 1.80-2.15) for alanine aminotransferase, 1.58 (95% CI, 1.43-1.74) for aspartate aminotransferase, 1.86 (95% CI, 1.71-2.03) for GGT (last vs first quartile or quintile), and 1.86 (95% CI, 1.76-1.95) for ultrasonography, respectively. Overall, in a pooled population of 81411 patients (from eight studies) who were followed-up for a median period of 4.5 years (range: 3-11 years), NAFLD was associated with an increased risk of incident MetS with a pooled relative risk of 1.80 (95% CI, 1.72-1.89) for alanine aminotransferase (last vs first quartile or quintile), 1.98 (95% CI, 1.89-2.07) for GGT, and 3.22 (95% CI, 3.05-3.41) for ultrasonography, respectively.

CONCLUSIONS

Nonalcoholic fatty liver disease, as diagnosed by either liver enzymes or ultrasonography, significantly increases the risk of incident T2D and MetS over a median 5-year follow-up.

Association between liver enzymes and incident type 2 diabetes in Singapore Chinese men and women

AIMS

To assess the association between liver enzymes and the risk of type 2 diabetes (T2D) in a Chinese population.

METHODS

A nested case-control study comprising 571 T2D cases and 571 matched controls was conducted within the Singapore Chinese Health Study. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were quantified in baseline plasma collected from them, while γ-glutamyltransferase (GGT) was assayed among 255 T2D cases with baseline hemoglobin A1c <6.5% and 255 matched controls. Participants were free of diagnosed diabetes, cardiovascular disease, and cancer at blood collections (1999-2004). Incident self-reported T2D cases were identified at follow-up II interview (2006-2010). Controls were matched to cases on age, sex, dialect group, and date of blood collection.

RESULTS

Higher levels of ALT and GGT were significantly associated with increased risk of T2D (p for trend <0.001 for ALT, p for trend=0.03 for GGT), and the ORs (95% CIs) comparing highest versus lowest tertiles of ALT and GGT were 2.00 (1.01 to 3.96) and 2.38 (1.21 to 4.66), respectively. A null association was observed for AST, ALP, and LDH with T2D risk. Adding GGT (<23 vs ≥23 IU/L) or ALT (<21 vs ≥21 IU/L) to a prediction model resulted in significant gain in net reclassification improvement and integrated discrimination improvement of T2D prediction (all p<0.001).

CONCLUSIONS

Higher levels of GGT and ALT are associated with increased T2D risk. GGT ≥23 IU/L and ALT ≥21 IU/L may identify people at higher risk of developing T2D in this Chinese population.

Risk of Future Diabetes in Japanese People with High-normal Fasting Plasma Glucose Levels: A 4-Year Follow-up Study

Objective There is no definite consensus regarding the treatment and guidance for individuals with high-normal fasting plasma glucose levels (FPG;100-109 mg/dL). The present study aimed to determine the risk factors for future diabetes in Japanese people with high-normal FPG. Methods Retrospective cohort studies were conducted from 2008 to 2012, including 15,097 individuals who underwent medical examinations. First, the participants were divided into normal FPG (n=13,065) and high-normal FPG (n=2,032) groups to compare the diabetes incidence. Second, the high FPG group was divided into diabetes onset (n=133) and non-diabetes onset (n=1,899) groups to compare the baseline values. Third, to determine the risk factors for future diabetes in the high-normal FPG group, multivariate analyses were conducted. Results The cumulative incidence during the mean follow-up of 4 years was 94/13,065 (0.72%) and 133/2,032 (6.55%) in the normal FPG and high-normal FPG groups, respectively. Within the high-normal FPG group, the baseline body mass index, waist circumference, triglycerides, FPG, alanine aminotransferase (ALT), and gamma-glutamyl transferase were significantly higher and high-density lipoprotein cholesterol (HDL-C) was significantly lower in the diabetes onset group than in the non-diabetes onset group. Obesity, abdominal obesity, hypertriglyceridemia, low HDL-C, and high ALT were significant risk factors for diabetes according to a multivariate analysis. Conclusion The high-normal FPG group had a higher risk of diabetes than the normal FPG group, particularly when accompanied with obesity, abdominal obesity, hypertriglyceridemia, low HDL-C, and high ALT. Thus, this high risk group should receive appropriate guidance for lifestyle changes to avoid developing diabetes at an early stage.

Presence of Concurrent Derangements of Liver Function Tests in Type 2 Diabetes and Their Relationship with Glycemic Status: A Retrospective Observational Study from Meghalaya

BACKGROUND AND OBJECTIVES

The liver plays a pivotal role in carbohydrate metabolism. Therefore, functional state of the liver in patients with diabetes is of interest. The objectives of the current study were to (i) identify co-existent biochemical derangements of liver function tests (LFTs) in type 2 diabetes and (ii) determine the association between liver function parameters and glycemic status in type 2 diabetics from Shillong, Meghalaya.

MATERIALS AND METHODS

Data from 320 type 2 diabetes patients were screened retrospectively for abnormalities in LFTs. Relationship of fasting serum glucose was assessed with the following tests in the LFT panel: Total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and albumin. Correlation coefficient was computed between individual LFT and fasting glucose status. These bivariate analyses were supplemented by multivariate linear regression analyses.

RESULTS

71.25% subjects had an abnormality in at least one LFT. Elevated ALT (46.8%) and elevated ALP (48.5%) were the most common abnormality in males and females, respectively. ALP correlated positively with fasting glucose in both sexes. AST, ALT, and ALP were found to be independent determinants of glycemic status.

CONCLUSION

Derangements in liver function are widely co-existent in type 2 diabetics from Shillong. Deranged liver enzymes are associated with glycemic status. Screening for liver dysfunction in diabetics and subsequent workup may lead to the identification of hepatic co-morbidities and better management.

Association between elevated serum alanine aminotransferase and cardiometabolic risk factors in rural Chinese population: a cross-sectional study

Background

Elevated alanine aminotransferase (ALT) levels may be associated with metabolic syndrome and cardiovascular diseases. This study aimed to investigate the association between elevated ALT levels and cardiometabolic risk factors in a rural Chinese population.

Methods

This was a cross-sectional study conducted from July 2012 to August 2013, including 11,573 subjects (5,357 men and 6,216 women) aged ≥35 years in rural areas of Liaoning Province. A physical examination was performed and metabolic indicators were examined under standard protocols. Subjects were divided into those with elevated ALT levels (>40U/L) and those with normal ALT levels (≤40U/L).

Results

Participants with elevated ALT levels had higher levels of almost all cardiometabolic risk factors than those with normal ALT levels. In individuals with elevated ALT levels, weight, height, waist circumference, and body mass index (BMI), which are indicators for general and abdominal obesity, were significantly higher (p < 0.001) than those in individuals with normal ALT levels. There was no significant difference in race, current smoking, or physical activity between the two groups. Other cardiometabolic risk factors, such as systolic blood pressure, diastolic blood pressure, and fasting plasma glucose, TC, TG, low-density lipoprotein cholesterol, and serum uric acid levels, were higher in participants with elevated ALT levels than in those with normal ALT levels. Logistic regression analysis showed that male sex, younger age, and the presence of high TC, high TG, and low high-density lipoprotein cholesterol levels, current smoking status, BMI ≥25 kg/m², abdominal obesity, hyperuricemia, and HtgW phenotype were significantly (p < 0.05) associated with elevated ALT levels. Sex-related differences were also investigated. For men, hypertension (OR 1.33, 95 % CI 1.08–1.62), high TC levels (OR 1.63, 95 % CI 1.23–2.17), high TG levels (OR 1.62, 95 % CI 1.25–2.09), BMI ≥25 kg/m² (OR 1.52, 95 % CI 1.07–2.18), and hyperuricemia (OR 1.92, 95 % CI 1.52–2.40) were significantly (p < 0.05) related to elevated serum ALT levels, but this was not observed in women.

Conclusions

There are significant relationships of elevated ALT levels with cardiometabolic risk factors and several sex-related differences in rural Chinese. Elevated serum ALT levels are associated with a worse cardiac risk profile.

What does serum γ-glutamyltransferase tell us as a cardiometabolic risk marker?

γ-glutamyltransferase plays a key role in the synthesis and metabolism of extracellular glutathione, a major antioxidant in several defence mechanisms in the body. γ-glutamyltransferase is affected by environmental and genetic factors, and is raised when there is depletion of glutathione. Hence, it is a marker of oxidative stress. There is robust evidence that γ-glutamyltransferase even when values are within the reference interval is associated with increased cardiovascular and all-cause mortality in both sexes, in normal subjects and subjects with coronary artery disease, in the middle-aged and the elderly after adjusting for confounding factors. γ-glutamyltransferase even within the reference interval is associated with future presentation of type 2 diabetes, and the longitudinal increase in γ-glutamyltransferase activity is associated with increased risk of type 2 diabetes and cardiovascular mortality. γ-glutamyltransferase is associated with cardiovascular risk factors and metabolic syndrome. It has a prognostic value after a previous acute myocardial infarction and may be an indicator of adverse outcome in acute coronary syndromes and other chronic cardiac disorders. There is limited data about γ-glutamyltransferase and any association with peripheral arterial disease and also whether knowing γ-glutamyltransferase activity improves cardiovascular risk prediction beyond conventional risk factors. γ-glutamyltransferase is present in atherosclerotic lesions in the coronary and carotid arteries, and has a prooxidant role leading to the production of reactive oxygen species and atherosclerosis. Current reference intervals for γ-glutamyltransferase are inappropriate and need to be addressed. Some laboratories still use non- International Federation of Clinical Chemistry methods for estimation of γ-glutamyltransferase which are associated with lower results. Such laboratories should review their method and consider changing to the International Federation of Clinical Chemistry method.

Liver enzymes and incident diabetes in China: a prospective analysis of 10 764 participants in the Guangzhou Biobank Cohort Study

BACKGROUND

Impaired liver function has been shown to be associated with incident diabetes. The independent role of the different liver enzymes, including γ-glutamyltransferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST), has not been addressed properly, taking into account their high collinearity. We used partial least squares (PLS) regression to identify the contribution of ALT, AST and GGT, which appears causally associated with diabetes as a validation factor, to incident diabetes in a South China population where liver impairment and diabetes are common.

METHODS

Participants were from the Guangzhou Biobank Cohort Study recruited in 2003-2008, with follow-up re-examination up to the end of 2012. Multivariable generalised linear models and PLS were used to examine the adjusted associations of ALT, AST and GGT with diabetes. Incident diabetes was defined as self-reported diabetes, and/or initiation of hypoglycaemia medication or insulin during follow-up, or fasting glucose ≥7.0 mmol/L, or 2 h oral glucose tolerance test, glucose ≥11.1 mmol/L at follow-up examination.

RESULTS

In 10 764 Chinese participants aged ≥50 years with no diabetes at baseline, 1228 (11.4%) developed diabetes during the median 4 years of follow-up. Using PLS, the risk for incident diabetes was higher by 18% (95% CI 8% to 27%) per 1 SD increment in log-ALT, and expectedly higher by 36% (95% CI 26% to 52%) for log-GGT, adjusted for age, sex, education, smoking, alcohol, physical activity, waist circumference and body mass index. Similarly adjusted, no association for log-AST (relative risk 0.92, 95% CI 0.85 to 1.01) was found.

CONCLUSIONS

ALT but not AST was associated with incident diabetes. Further experimental studies are needed to confirm the causal association and clarify the underlying mechanisms.

Sex influenced association of directly measured insulin sensitivity and serum transaminase levels: Why alanine aminotransferase only predicts cardiovascular risk in men?

Background

Non alcoholic fatty liver disease (NAFLD) is an independent cardiovascular (CV) risk factor which is closely associated with insulin resistance measured by both direct or indirect methods. Gender specific findings in the relationship between alanine aminotransferase (ALT) and CV disease, the prevalence of NAFLD and type 2 diabetes (T2DM) have been published recently.

The aim of the present study was to explore the gender aspects of the association between insulin sensitivity, liver markers and other metabolic biomarkers in order to elucidate the background behind the sex influenced difference in both NAFLD, T2DM and their association with CV risk.

Patients and methods

158 female (47 normal and 111 impaired glucose intolerant) and 148 male (74 normal and 74 impaired glucose tolerant) subjects were included (mean age: 46.5 ± 8.31 vs. 41.6 ± 11.3, average Hba1c < 6.1 %, i.e. prediabetic population, drug naive at the time of the study). Subjects underwent a hyperinsulinemic normoglycemic clamp to determine muscle glucose uptake (M₃), besides liver function tests and other fasting metabolic and anthropometric parameters were determined.

Results

Significant bivariate correlations were found between clamp measured M₃ and all three liver enzymes (ALT, aspartate aminotransferase and gamma-glutamyl transferase) in both sexes. When data were adjusted for possible metabolic confounding factors correlations ceased in the male population but stayed significant in the female group. Feature selection analysis showed that ALT is an important attribute for M₃ in the female but not in male group (mean Z: 3.85 vs. 0.107). Multiple regression analysis confirmed that BMI (p < 0.0001) and ALT (p = 0.00991) significantly and independently predicted clamp measured muscle glucose uptake in women (R² = 0.5259), while in men serum fasting insulin (p = 0.0210) and leptin levels (p = 0.0294) but none of the liver enzymes were confirmed as significant independent predictors of M₃ (R² = 0.4989).

Conclusion

There is a gender specific association between insulin sensitivity, metabolic risk factors and liver transaminase levels. This might explain the sex difference in the predictive role of ALT elevation for CV disease. Moreover, ALT may be used as a simple diagnostic tool to identify insulin resistant subjects only in the female population according to our results.

Physical Activity- and Alcohol-dependent Association Between Air Pollution Exposure and Elevated Liver Enzyme Levels: An Elderly Panel Study

OBJECTIVES

The deleterious effects of air pollution on various health outcomes have been demonstrated. However, few studies have examined the effects of air pollution on liver enzyme levels.

METHODS

Blood samples were drawn up to three times between 2008 and 2010 from 545 elderly individuals who regularly visited a community welfare center in Seoul, Korea. Data regarding ambient air pollutants (particulate matter ≤2.5 μm [PM2.5], nitrogen dioxide [NO2], ozone [O3], carbon monoxide, and sulfur dioxide) from monitoring stations were used to estimate air pollution exposure. The effects of the air pollutants on the concentrations of three liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and γ-glutamyltranspeptidase [γ-GTP)]) were evaluated using generalized additive and linear mixed models.

RESULTS

Interquartile range increases in the concentrations of the pollutants showed significant associations of PM2.5 with AST (3.0% increase, p=0.0052), ALT (3.2% increase, p=0.0313), and γ-GTP (5.0% increase, p=0.0051) levels; NO2 with AST (3.5% increase, p=0.0060) and ALT (3.8% increase, p=0.0179) levels; and O3 with γ-GTP (5.3% increase, p=0.0324) levels. Significant modification of these effects by exercise and alcohol consumption was found (p for interaction <0.05). The effects of air pollutants were greater in non-exercisers and heavy drinkers.

CONCLUSIONS

Short-term exposure to air pollutants such as PM2.5, NO2, and O3 is associated with increased liver enzyme levels in the elderly. These adverse effects can be reduced by exercising regularly and abstinence from alcohol.