Increase in gamma-glutamyltransferase level and development of established cardiovascular risk factors and diabetes in Japanese adults

Relationship between traditional risk factors for hypertension and systolic blood pressure in the Tohoku Medical Megabank Community-based Cohort Study

Risk factors for hypertension have been emphasized in the Japanese Society of Hypertension Guidelines for the Management of Hypertension. However, large-scale studies on the association of smoking, potassium excretion, and gamma-glutamyl transferase level with BP in the Japanese population are limited. We conducted a cross-sectional study to examine the association between hypertension risk factors and systolic blood pressure in the Tohoku Medical Megabank Community-based Cohort Study (23,446 men and 38,921 women aged ≥20 years). A model adjusted for age, body mass index, smoking status, drinking status, estimated daily salt intake, potassium excretion, (or urinary sodium-to-potassium ratio), gamma-glutamyl transferase, physical activity, education level, status of damage to homes during the Great East Japan Earthquake, and residential areas was used. The average age and systolic blood pressure were 62.5 (10.3) years for men and 59.6 (11.3) years for women, 128.9 (16.7) mmHg for men and 124.7 (17.5) mmHg for women, respectively. Body mass index estimated daily salt intake, urinary sodium-to-potassium ratio and gamma-glutamyl transferase levels were positively associated with systolic blood pressure. Compared with never-drinkers, current drinkers who consumed 23-45 g/day and ≥46.0 g/day had significantly increased systolic blood pressure. Conversely, current smokers (1-10 cigarettes/day and 11-20 cigarettes/day) were inversely associated with systolic blood pressure compared to never-smokers. Overall, systolic blood pressure was associated with gamma-glutamyl transferase and hypertension risk factors, including body mass index, alcohol consumption, estimated daily salt intake, urinary sodium-to-potassium ratio, and potassium excretion. Our findings support the notion that lifestyle modifications should be attempted to prevent hypertension.

Fatty liver index is independently associated with deterioration of renal function during a 10-year period in healthy subjects

A potential link between chronic kidney disease (CKD) and non-alcoholic fatty liver disease (NAFLD) has been suggested. We investigated the relationship between fatty liver index (FLI), a noninvasive and simple predictor of NAFLD, and the development of CKD defined as estimated glomerular filtration rate < 60 mL/min/1.73 m² or positive for urinary protein during a 10-year follow-up period in subjects who received annual health examinations (n = 28,890). After exclusion of CKD at baseline, a total of 14,163 subjects (male/female: 9077/5086) were recruited. During the 10-year period, 1458 males (16.1%) and 737 females (14.5%) had new onset of CKD. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard ratios (HRs) of CKD development increased with a higher FLI at baseline in both males and females after adjustment of confounders. When divided by tertiles of FLI level at baseline (T1 ~ T3), the adjusted risk of CKD development in the T3 group (HR [95% confidence interval], male/female: 1.33 [1.16–1.54]/1.33 [1.08–1.63]) was significantly higher than that in both sexes in the T1 group as the reference. The addition of FLI into traditional risk factors significantly improved the discriminatory capability for predicting CKD. In conclusion, a high level of FLI predicts the development of CKD in both sexes in a general population.

Association Between Sex-Specific Serum Gamma-Glutamyltransferase and Incidence of Hypertension in a Chinese Population Without Metabolic Syndrome: A Prospective Observational Study

Background: Higher serum gamma-glutamyltransferase (GGT) is associated with high risk of hypertension. We aimed to examine the association between sex-specific serum GGT levels and incident of hypertension in a Chinese population without metabolic syndrome. Methods: Participants who were free of hypertension and metabolic syndrome from the First Affiliated Hospital of Wenzhou Medical University between 2009 and 2014 were included. Participants were grouped into sex-specific quartiles of GGT levels (Q1-Q4) defined as: ≤19, 20-26, 27-38, and ≥39 U/L for male; ≤12, 13-15, 16-19, and ≥20 U/L for female. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of hypertension according to sex-specific quartiles of GGT levels. Kaplan-Meier analysis and interaction analysis were conducted. Results: Among 38,806 participants included (average age 36.0 years, 54.0% men), 4,505 of them developed hypertension. In the overall study population, using Q1 as the reference group, participants in Q2, Q3, and Q4 showed a higher risk of developing hypertension, with HRs (95% CIs) of 1.126 (1.029-1.232), 1.187 (1.083-1.302), and 1.300 (1.182-1.431), respectively (P < 0.001), after adjusting for known confounders. Sex-specific analysis showed that the adjusted HRs for participants in Q4 (reference: Q1) were greater in females [1.321 (1.100-1.586, P < 0.001)] than in males [1.268 (1.133-1.420, P < 0.001)] (P for interaction = 0.047). Moreover, interaction analysis showed that this association was consistently observed when the participants were stratified by age, body mass index, and fatty liver status. Conclusion: Among Chinese adults without metabolic syndrome, serum GGT level was positively associated with incidence of hypertension, and the association was stronger in females than in males.

Prognostic Value of Gamma-Glutamyltransferase in Male Patients With Idiopathic Pulmonary Arterial Hypertension

Background: The elevated gamma-glutamyltransferase (GGT) activity is regarded as an indicator of cardiovascular disease, with males having higher values than females. The greater incidence of idiopathic pulmonary arterial hypertension (IPAH) is observed in women, whereas prognosis is poor in men. The present study aims to investigate the potential association of GGT on male patients.

Methods: Serum GGT levels were measured in 338 consecutive adult IPAH patients, who underwent bone morphogenetic protein receptor type 2 (BMPR2) genetic counseling, and matched with healthy subjects by sex and age. The followed interval was 48 ± 34 months.

Results: Increased serum GGT levels were more common in patients with IPAH than controls (p < 0.001). GGT values were significantly higher in male patients than those of females (p < 0.001). Compared with female patients with BMPR2 mutation, GGT level in male patients with BMPR2 mutation was further increased (p = 0.002). Higher GGT levels were associated with worse hemodynamics and Nterminal pro B-type natriuretic peptide in all patients. However, males with a GGT concentration ≥ 53 U/L had a worse survival than those of females. Contrarily, if GGT concentration <53 U/L, there was no survival difference between male and female patients. After adjustment for relevant variables of clinical features and hemodynamics, baseline higher GGT levels remained increased risks of all-cause mortality in males rather than females. During rehospitalization follow-up, male patients still had significantly higher values of GGT than females.

Conclusions: Increased GGT levels were correlated with BMPR2 mutation, hemodynamic dysfunction, and poor outcomes in male patients with IPAH. Further studies are needed to explain the origin of abnormal GGT and its potential pathogenesis in men.

Heavy Exposure of Waste Collectors to Polycyclic Aromatic Hydrocarbons in a Poor Rural Area of Middle China

Manual collection and open-air incineration of waste materials is a common practice in rural regions of China and beyond. Low-temperature combustion of rubber and plastic waste generates high levels of airborne polycyclic aromatic hydrocarbons (PAHs). We investigated ten urinary hydroxylated PAH metabolites (OH-PAHs), the oxidative damage biomarker (8-hydroxy-deoxyguanosine, 8-OHdG), and four serum biomarkers including gamma-glutamyl transferase (GGT) and alanine aminotransferase (ALT) in 41 waste collectors and 122 control subjects residing in the same or a distant rural village in Henan Province. The level of PAH metabolites in urine (median: 17.24 μg/g Cre) was twice that of controls living in the same area without an occupational history involving waste collection (median: 8.16 μg/g Cre) and thrice that of controls living 30 km away (median: 6.07 μg/g Cre). The concentrations of OH-PAHs were positively associated with urinary 8-OHdG levels (β = 0.283, p < 0.05). Serum GGT and ALT were slightly increased in waste collectors. Urinary 8-OHdG levels were similar in one-year and longer-term workers, suggesting that rubber and plastic waste collection/incineration carries a high PAH exposure risk. These data provide solid baseline information, emphasizing the importance of monitoring the long-term health outcomes of waste collectors and changes in exposure patterns associated with rural development and regulation of waste disposal.

Urinary polycyclic aromatic hydrocarbons and measures of oxidative stress, inflammation and renal function in adolescents: NHANES 2003-2008

OBJECTIVE

Recent evidence has suggested that polycyclic aromatic hydrocarbons (PAHs) may contribute to cardiometabolic and kidney dysfunction by increasing oxidative stress, but little is known about impacts in childhood.

STUDY DESIGN

We performed cross-sectional analyses of 660 adolescents aged 12-19 years in the 2003-2008 National Health and Nutrition Examination Survey (NHANES), using levels of 10 monohydroxylated urinary PAH metabolites as our exposure. Our primary outcomes of interest were biomarkers of oxidative stress and renal function, including estimated glomerular filtration rate (eGFR), urinary albumin to creatinine ratio (ACR), insulin resistance, and serum uric acid, gamma glutamyl transferase (GGT) and C-reactive protein (CRP).

RESULTS

We observed statistically significant associations between PAH metabolites and levels of serum GGT, CRP, uric acid and eGFR. Each 100% increase in 2-hydroxyphenanthrene was related to a 3.36% increase in uric acid (95% CI: 0.338-6.372; p=0.032), a 3.86% increase in GGT (95% CI: 1.361-6.362; p=0.005) and a 16.78% increase in CRP (95% CI: 1.848-31.689; p=0.029). Each 100% increase in 4-hydroxyphenanthrene was associated with a 6.18% increase in GGT (95% CI: 4.064-8.301; p<0.001) and a 13.66% increase in CRP (95% CI: 2.764-24.564; p=0.017). Each 100% increase in 9-hydroxyfluorene was associated with a 2.58% increase in GGT (95% CI: 0.389-4776; p=0.024). Each 100% increase in 3-hydroxyphenanthrene was associated with a 2.66% decrease in eGFR (95% CI: -4.979 to -0.331; p=0.028).

CONCLUSIONS

Urinary PAH metabolites were associated with serum uric acid, GGT and CRP, suggesting possible impacts on cardiometabolic and kidney function in adolescents. Prospective work is needed to investigate the potential long-term health consequences of these findings.

Gender differences in the association of hypertension with gamma-glutamyltransferase and alanine aminotransferase levels in Chinese adults in Qingdao, China

The aim of the study was to study the associations of hypertension with gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) levels. Data of 3575 men and 5504 women were analyzed. Multivariate logistic regression analysis was performed to estimate the odds ratio (OR) for hypertension with GGT and ALT. Compared with the lowest quartile, the multivariate adjusted ORs for hypertension were 0.97 (0.79, 1.19) in men and 0.88 (0.74, 1.04) in women for ALT and 2.29 (1.68, 3.14) and 1.52 (1.27, 1.83) for GGT in the highest quartile group. The ORs for hypertension in the low waist circumference category were 2.61 (1.56, 4.36) in men and 1.41 (0.94, 2.12) in women and in the high waist circumference category 4.01 (2.21, 7.29) and 2.26 (1.54, 3.32) for GGT. The elevated GGT, but not ALT, was associated with the presence of the hypertension in men and women. The association is stronger in obese men and women than in their lean counterparts.

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.

Relationship between serum γ-glutamyltransferase level and leukocyte count in Korean children and adolescents

BACKGROUND

Elevated γ-glutamyltransferase (GGT) is an important risk factor for cardiometabolic diseases, which may result from chronic low-grade inflammation. Leukocyte count is widely considered a marker of inflammation and is also an independent predictor of cardiometabolic diseases. This study aimed to determine the relationship between GGT and leukocyte count in a representative sample of Korean children and adolescents.

METHODS

A nationwide cross-sectional study was conducted to examine the relationship between GGT and leukocyte count in 830 boys and 714 girls (aged 10-18 years), using data from the 2010-2012 Korean National Health and Nutrition Examination Survey. The odds ratios (ORs) and 95% confidence intervals (CIs) for high leukocyte count (≥ 75th percentile) were calculated across GGT quartiles using multiple logistic regression analyses.

RESULTS

Leukocyte count gradually increased in accordance with serum GGT quartiles in both boys and girls (all p-values < 0.001). The OR (95% CI) for high leukocyte of the highest GGT quartile was 2.19 (1.05-4.58) for boys and 2.36 (1.13-4.93) for girls after adjusting for age, BMI, blood pressure, total cholesterol, triglyceride, physical activity, household income, and residential area. Similarly, these positive associations were observed in multiple logistic regression analysis using log2-transformed serum GGT as a continuous variable.

CONCLUSIONS

The present study demonstrates a positive relationship between serum GGT and leukocyte count. These findings indicate that serum GGT may be closely related with subclinical low-grade inflammation in children and adolescents.

Combined effect of serum gamma-glutamyltransferase and uric acid on Framingham risk score

BACKGROUND AND AIMS

Gamma-glutamyltransferase (GGT) and uric acid (UA) are novel coronary heart disease (CHD) risk factors. In the present study we investigated the combined effects of GGT and UA on Framingham risk score (FRS) in a Korean population.

METHODS

A total of 10,096 subjects (5,124 females and 4,972 males) were enrolled in this study. A 10-year coronary heart disease (CHD) risk was calculated using the FRS modified by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III). Levels of circulating GGT and UA were measured using validated assays.

RESULTS

The 10-year CHD risk gradually augmented with increase in the circulating levels of GGT and UA. For the highest quartile of GGT and UA, odds ratio (OR) of intermediate-risk and beyond for CHD (10-year risk ≥10%) compared with the lowest quartile was 3.44 (95% CI: 2.60-4.55, p <0.001) and 1.97 (95% CI: 1.56-4.55, p <0.001) after adjusting for confounders, respectively. OR of intermediate-risk and beyond for CHD in both 3(rd) and 4(th) quartile of GGT and UA was 9.9 (95% CI: 5.2-18.6) compared with the first quartile of those.

CONCLUSIONS

GGT and UA levels are well associated with the 10-year CHD risk estimated using NCEP ATP III in Koreans after adjusting for confounders and combination of GGT and UA levels can have a strong synergy in predicting the development of CHD.

Identification of cardiovascular risk components in urban Chinese with metabolic syndrome and application to coronary heart disease prediction: a longitudinal study

Background

Metabolic syndrome (MetS) is proposed as a predictor for cardiovascular disease (CVD). It involves the mechanisms of insulin resistance, obesity, inflammation process of atherosclerosis, and their complex relationship in the metabolic network. Therefore, more cardiovascular risk-related biomarkers within this network should be considered as components of MetS in order to improve the prediction of CVD.

Methods

Factor analysis was performed in 5311 (4574 males and 737 females) Han Chinese subjects with MetS to extract CVD-related factors with specific clinical significance from 16 biomarkers tested in routine health check-up. Logistic regression model, based on an extreme case-control design with 445 coronary heart disease (CHD) patients and 890 controls, was performed to evaluate the extracted factors used to identify CHD. Then, Cox model, based on a cohort design with 1923 subjects followed up for 5 years, was conducted to validate their predictive effects. Finally, a synthetic predictor (SP) was created by weighting each factor with their risks for CHD to develop a risk matrix to predicting CHD.

Results

Eight factors were obtained from both males and females with a similar pattern. The AUC to classify CHD under the extreme case-control suggested that SP might serve as a useful tool in identifying CHD with 0.994 (95%CI 0.984-0.998) for males and 0.998 (95%CI 0.982-1.000) for females respectively. In the cohort study, the AUC to predict CHD was 0.871 (95%CI 0.851-0.889) for males and 0.899 (95%CI 0.873-0.921) for females, highlighting that SP was a powerful predictor for CHD. The SP-based 5-year CHD risk matrix provided as convenient tool for CHD risk appraisal.

Conclusions

Eight factors were extracted from sixteen biomarkers in subjects with MetS and the SP adds to new insights into studies of prediction of CHD risk using data from routine health check-up.

Gamma-glutamyltransferase level and risk of hypertension: a systematic review and meta-analysis

Background

Several prospective observational studies suggest that gamma-glutamyltransferase(GGT) level is positively associated with risk of hypertension. However, these studies draw inconsistent conclusions. Therefore, we conducted a systematic review and meta-analysis to evaluate the exact association between GGT level and subsequent development of hypertension.

Methods

We searched Pubmed, Embase, and Science Citation Index (ISI Web of Science) for prospective cohort studies examining the association between GGT level and hypertension. Then, pooled effect estimates (RRs) for the association between GGT level and hypertension were calculated.

Results

A total of 13 prospective cohort studies including 43314 participants and 5280 cases of hypertension were included. The pooled RR of hypertension was 1.94(95%CI: 1.55–2.43; P<0.001) when comparing the risk of hypertension between the highest versus lowest category of GGT levels. Moreover, the risk of hypertension increased by 23% (summary RR: 1.23; 95%CI: 1.13–1.32; P<0.001) per 1 SD logGGT increment. Subgroup analyses showed significant positive associations in each subgroup except in ≧160/95 subgroup (RR: 2.56, 95%CI: 0.87–7.54; P = 0.088) and nondrinkers subgroup (RR: 1.76, 95%CI: 0.88–3.53; P = 0.113). Sensitivity analyses showed no single study significantly affects the pooled RRs. No publication bias was found in our meta-analysis.

Conclusions

GGT level is positively associated with the development of hypertension. Further studies are needed to confirm our findings and elucidate the exact mechanisms between GGT level and the incidence of hypertension.

Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men

BACKGROUND

To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD).

METHODS

One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated.

RESULTS

Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old.

CONCLUSIONS

In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.

Serum gamma-glutamyl transferase within its normal concentration range is related to the presence of impaired fasting glucose and diabetes among Japanese community-dwelling persons

INTRODUCTION. Serum gamma-glutamyl transferase (GGT) activity changes in response to oxidative stress. Little data are available on the association between serum GGT and the prevalence of impaired fasting glucose (IFG) and diabetes among Japanese community-dwelling persons. METHODS. We recruited 871 men, aged 61 ± 14 (range, 20-89) years, and 1,139 women, aged 63 ± 12 (range, 21-88) years during their annual health examination from a single community. We performed a cross-sectional study to examine whether serum GGT was associated with IFG and diabetes. RESULTS AND CONCLUSIONS. The levels of most confounding characteristics varied with increasing GGT activity. The prevalence of IFG and diabetes was significantly and linearly associated with increasing quartiles of serum GGT. After adjustment for sex, age, smoking status, drinking status, low-density lipoprotein cholesterol, uric acid, estimated glomerular filtration rate, and alanine aminotransferase, the odds ratio (OR) [95% confidence interval (CI)] for IFG compared with the participants with lowest quartile of serum GGT was 1.91 (1.31-2.78) for second quartiles, 2.41 (1.63-3.57) for third quartiles, and 3.24 (2.03-5.17) for highest quartiles. The multivariate-adjusted OR (95% CI) for diabetes was 1.91 (1.18-3.09) for second quartiles, 2.15 (1.30-3.54) for third quartiles, and 3.79 (2.11-6.82) for highest quartiles. Furthermore, the multivariate-adjusted ORs for IFG were also associated with increasing levels of serum GGT within subgroups of age, body mass index, drinking status, serum high-molecular-weight adiponectin levels, insulin resistance, and the presence of antihypertensive/antilipidemic medication. These results suggested that higher serum GGT within normal concentration range was significantly associated with IFG and diabetes in the general population.