Serum gamma glutamyltransferase as a marker of metabolic syndrome and coronary disease likelihood in nondiabetic middle-aged and elderly adults

Association of mixed polycyclic aromatic hydrocarbons exposure with oxidative stress in Korean adults

Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants associated with several adverse health effects and PAH-induced oxidative stress has been proposed as a potential mechanism. This study evaluated the associations of single and multiple PAHs exposure with oxidative stress within the Korean adult population, using serum gamma glutamyltransferase (GGT) as an oxidative stress marker. Data from the Second Korean National Environmental Health Survey (2012-2014) were analyzed. For analysis, 5225 individuals were included. PAH exposure was assessed with four urinary PAH metabolites: 1-hydroxyphenanthrene, 1-hydroxypyrene, 2-hydroxyfluorene, and 2-naphthol. After adjusting for age, sex, body mass index, drinking, passive smoking, and current smoking (model 1), as well as the presence of diabetes and hepatobiliary diseases (model 2), complex samples general linear model regression analyses for each metabolite revealed a significant positive association between Ln(1-hydroxyphenanthrene) and Ln(GGT) (model 1: β = 0.040, p < 0.01 and model 2: β = 0.044, p < 0.05). For the complete dataset (n = 4378), a significant positive association was observed between mixture of four urinary PAH metabolites and serum GGT in both the quantile g-computation and the Bayesian kernel machine regression analysis. Our study provides evidence for the association between mixed PAH exposure and oxidative stress.

Blood and Urinary Biomarkers of Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Antipsychotic (AP)-induced MetS (AIMetS) is the most common adverse drug reaction (ADR) of psychiatric pharmacotherapy. Herein, we review the results of studies of blood (serum and plasma) and urinary biomarkers as predictors of AIMetS in patients with schizophrenia (Sch). We reviewed 1440 studies examining 38 blood and 19 urinary metabolic biomarkers, including urinary indicators involved in the development of AIMetS. Among the results, only positive associations were revealed. However, at present, it should be recognized that there is no consensus on the role of any particular urinary biomarker of AIMetS. Evaluation of urinary biomarkers of the development of MetS and AIMetS, as one of the most common concomitant pathological conditions in the treatment of patients with psychiatric disorders, may provide a key to the development of strategies for personalized prevention and treatment of the condition, which is considered a complication of AP therapy for Sch in clinical practice.

Serum gamma-glutamyltransferase is not associated with subclinical atherosclerosis in patients with type 2 diabetes

BACKGROUND

This study investigated the association between serum gamma-glutamyltransferase (GGT) level and subclinical atherosclerosis in patients with type 2 diabetes.

METHODS

This cross-sectional study involved 1024 patients with type 2 diabetes mellitus. Measurement of brachial-ankle pulse wave velocity (baPWV; as a marker of arterial stiffness) and an ultrasound assessment of carotid atherosclerosis were performed. Subclinical atherosclerosis was defined by the presence of a high baPWV (≥1720 cm/s), carotid atherosclerosis (intima-media thickness >0.8 mm or the presence of plaques), and carotid stenosis (≥50 % of luminal narrowing). The subjects were stratified into quartiles according to GGT level, and the relationship between GGT level and subclinical atherosclerosis was analysed.

RESULTS

Serum GGT levels were closely associated with obesity, atherogenic dyslipidemia, and metabolic syndrome. However, serum GGT levels did not show a linear association with baPWV, carotid intima-media thickness, or plaque grade. The prevalence of high baPWV, carotid atherosclerosis, and carotid stenosis did not differ between the quartiles in men and women. Multivariate logistic regression analyses revealed no association between GGT level and high baPWV, carotid atherosclerosis, and carotid stenosis, either as continuous variables or quartiles.

CONCLUSIONS

Serum GGT levels were significantly associated with obesity, atherogenic dyslipidaemia, and metabolic syndrome, but not with the early and late stages of atherosclerotic vascular changes, in patients with type 2 diabetes. Serum GGT level may not be a reliable marker of subclinical atherosclerosis in type 2 diabetes.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Factors influencing insulin resistance in relation to atherogenicity in mood disorders, the metabolic syndrome and tobacco use disorder

OBJECTIVE

This study examines the effects of malondialdehyde (MDA) and uric acid on insulin resistance and atherogenicity in subjects with and without mood disorders, the metabolic syndrome (MetS) and tobacco use disorder (TUD).

METHODS

We included 314 subjects with depression and bipolar depression, with and without the MetS and TUD and computed insulin resistance using the updated homeostasis model assessment (HOMA2IR) and atherogenicity using the atherogenic index of plasma (AIP), that is log10 (triglycerides/high density lipoprotein (HDL) cholesterol.

RESULTS

HOMA2IR is correlated with body mass index (BMI) and uric acid levels, but not with mood disorders and TUD, while the AIP is positively associated with BMI, mood disorders, TUD, uric acid, MDA and male sex. Uric acid is positively associated with insulin and triglycerides and negatively with HDL cholesterol. MDA is positively associated with triglyceride levels. Comorbid mood disorders and TUD further increase AIP but not insulin resistance. Glucose is positively associated with increasing age, male gender and BMI.

DISCUSSION

The results show that mood disorders, TUD and BMI together with elevated levels of uric acid and MDA independently contribute to increased atherogenic potential, while BMI and uric acid are risk factors for insulin resistance. The findings show that mood disorders and TUD are closely related to an increased atherogenic potential but not to insulin resistance or the MetS. Increased uric acid is a highly significant risk factor for insulin resistance and increased atherogenic potential. MDA, a marker of lipid peroxidation, further contributes to different aspects of the atherogenic potential. Mood disorders and TUD increase triglyceride levels, lower HDL cholesterol and are strongly associated with the atherogenic, but not insulin resistance, component of the MetS.

Serum gamma-glutamyl transferase is associated with the elevated uric acid levels in normotensive Chinese adults

BACKGROUND

Although both serum gamma-glutamyltransferase (GGT) and uric acid are correlated with hypertension, studies on the association between serum GGT and uric acid in normotensive individuals are rare. In this study, we tried to reveal this relationship in normotensive Chinese adults.

METHODS

Four hundred seven normotensive adults were recruited. The subjects were divided into 3 subgroups according to serum GGT tertiles. Anthropometric parameters as well as systolic blood pressure (SBP), diastolic blood pressure (DBP), uric acid, GGT, alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood glucose, blood lipids, and fasting insulin were measured. Insulin resistance was assessed using HOMA-IR index.

RESULTS

Uric acid was increased in parallel with increasing serum GGT (P<0.001). After correction for age, sex, smoking and alcohol consumption, serum GGT was positively associated with uric acid (r=0.42, P<0.001), SBP (r=0.22, P<0.001), and DBP (r=0.19, P<0.001). When compared with lowest GGT tertile, the odds ratio of the middle tertile for the increased serum uric acid was 3.43 (95% CI, 1.39-8.47) and 7.29 (95% CI, 1.57-33.82) for the highest tertile after adjustment for age, sex, BMI, smoking, alcohol consumption, SBP, DBP, creatinine and HOMA-IR.

CONCLUSIONS

Serum GGT is strongly associated with the increased uric acid concentrations in normotensive Chinese adults.

The complement system in human cardiometabolic disease

The complement system has been implicated in obesity, fatty liver, diabetes and cardiovascular disease (CVD). Complement factors are produced in adipose tissue and appear to be involved in adipose tissue metabolism and local inflammation. Thereby complement links adipose tissue inflammation to systemic metabolic derangements, such as low-grade inflammation, insulin resistance and dyslipidaemia. Furthermore, complement has been implicated in pathophysiological mechanisms of diet- and alcohol induced liver damage, hyperglycaemia, endothelial dysfunction, atherosclerosis and fibrinolysis. In this review, we summarize current evidence on the role of the complement system in several processes of human cardiometabolic disease. C3 is the central component in complement activation, and has most widely been studied in humans. C3 concentrations are associated with insulin resistance, liver dysfunction, risk of the metabolic syndrome, type 2 diabetes and CVD. C3 can be activated by the classical, the lectin and the alternative pathway of complement activation; and downstream activation of C3 activates the terminal pathway. Complement may also be activated via extrinsic proteases of the coagulation, fibrinolysis and the kinin systems. Studies on the different complement activation pathways in human cardiometabolic disease are limited, but available evidence suggests that they may have distinct roles in processes underlying cardiometabolic disease. The lectin pathway appeared beneficial in some studies on type 2 diabetes and CVD, while factors of the classical and the alternative pathway were related to unfavourable cardiometabolic traits. The terminal complement pathway was also implicated in insulin resistance and liver disease, and appears to have a prominent role in acute and advanced CVD. The available human data suggest a complex and potentially causal role for the complement system in human cardiometabolic disease. Further, preferably longitudinal studies are needed to disentangle which aspects of the complement system and complement activation affect the different processes in human cardiometabolic disease.

Plasma gamma-glutamyltransferase is strongly determined by acylation stimulating protein levels independent of insulin resistance in patients with acute coronary syndrome

Background. Steatosis is a manifestation of the metabolic syndrome often associated with release of liver enzymes and inflammatory adipocytokines linked to cardiovascular risk. Gamma-glutamyltransferase (GGT) is one sensitive liver marker recently identified as an independent cardiovascular risk factor. Mechanisms involved in enhanced hepatic lipogenesis causing steatosis are not yet identified and are usually linked to insulin resistance (IR). Acylation stimulating protein (ASP), a potent lipogenic factor, was recently shown to increase in patients with steatosis and was implicated in its pathogenesis. Aim. To investigate the association of plasma ASP levels with liver and metabolic risk markers in acute coronary syndrome (ACS) patients. Methods. 28 patients and 30 healthy controls were recruited. Their anthropometrics, lipid profile, liver markers, insulin, and ASP levels were measured. Results. In the patients, ASP, liver, and metabolic risk markers were markedly higher than in the controls. ASP strongly predicted GGT levels (B = 0.75, P < 0.0001), followed by triglycerides (B = 0.403, P = 0.017), together determining 57.6% variation in GGT levels. Insulin and IR correlated with metabolic risk components but not with liver enzymes. Conclusion. The strong association of ASP with GGT in ACS patients suggests that ASP, independent of IR, may contribute to a vicious cycle of hepatic lipogenic stimulation and GGT release promoting atherogenesis.

Serum γ-glutamyltransferase: independent predictor of risk of diabetes, hypertension, metabolic syndrome, and coronary disease

Serum γ-glutamyltransferase (GGT) is associated with oxidative stress and hepatic steatosis. The extent to which its value in determining incident cardiometabolic risk (coronary heart disease (CHD), metabolic syndrome (MetS), hypertension and type 2 diabetes) is independent of obesity needs to be further explored in ethnicities. After appropriate exclusions, a cohort of 1,667 adults of a general population (age 52 ±11 years) was evaluated prospectively at 4 year's follow-up using partly Cox proportional hazard regressions. GGT activity was measured kinetically, and values were log-transformed for analyses. MetS was identified by Adult Treatment Panel-III criteria modified for male abdominal obesity. Median (interquartile range) GGT activity was 24.9 (17.0; 35.05) U/l in men, 17.0 (12.3; 24.0) U/l in women. In linear regression analysis, while smoking status was not associated, (male) sex, sex-dependent age, alcohol usage, BMI, fasting triglycerides and C-reactive protein (CRP) were significant independent determinants of circulating GGT. Each 1-s.d. increment in (= 0.53 ln GGT) GGT activity significantly predicted in each sex incident hypertension (hazard ratio (HR) 1.20 (95% confidence interval (CI) 1.10; 1.31)), and similarly MetS, after adjustment for age, alcohol usage, smoking status, BMI and menopause. Strongest independent association existed with diabetes (HR 1.3 (95% CI 1.1; 1.5)) whereas GGT activity tended to marginally predict CHD independent of total bilirubin but not of BMI. Higher serum total bilirubin levels were protective against CHD risk in women. We conclude that elevated serum GGT confers, additively to BMI, risk of hypertension, MetS, and type 2 diabetes but only mediates adiposity against CHD risk.

Increased γ-glutamyl transferase levels predict early mortality in patients with acute pulmonary embolism

BACKGROUND

Increased γ-glutamyl transferase (GGT) level is associated with increased oxidative stress, all-cause mortality, the development of cardiovascular disease, and metabolic syndrome. However, its role in acute pulmonary embolism (PE) is unknown. In this study, we aimed to investigate the relationship between GGT and early mortality in patients with acute PE.

METHODS

A total of 127 consecutive patients with confirmed PE were evaluated. The optimal cutoff value of GGT to predict early mortality was measured as more than 55 IU/L with 94.4% sensitivity and 66.1% specificity. Patients with acute PE were categorized prospectively as having no increased (group I) or increased (group II) GGT based on a cutoff value.

RESULTS

Of these 127 patients, 18 patients (14.2%) died during follow-up. Among these 18 patients, 1 (1.4%) patient was in group I, and 17 (30.9%) patients were in group II (P < .001). γ-Glutamyl transferase level on admission, presence of shock, heart rate, oxygen saturation, right ventricular dilatation/hypokinesia, main pulmonary artery involvement, troponin I, alanine aminotransferase, alkaline phosphatase, and creatinine levels were found to have prognostic significance in univariate analysis. In the multivariate Cox proportional hazards model, GGT level on admission (hazard ratio [HR], 1.015; P = .017), presence of shock (HR, 15.124; P = .005), age (HR, 1.107; P = .010), and heart rate (HR, 1.101; P = .032) remained associated with an increased risk of acute PE-related early mortality after the adjustment of other potential confounders.

CONCLUSIONS

We have shown that a high GGT level is associated with worse hemodynamic parameters, and it seems that GGT helps risk stratification in patients with acute PE.

Metabolic syndrome: nature, therapeutic solutions and options

INTRODUCTION

Metabolic syndrome (MetS) defines the clustering in an individual of multiple metabolic abnormalities, based on central obesity and insulin resistance. In addition to its five components, prothrombotic and proinflammatory states are essential features. The significance of MetS lies in its close association with the risk of type 2 diabetes and cardiovascular disease (CVD). This field being an evolving one necessitated the current review.

AREAS COVERED

The areas covered in this review include the so far unproven concept that enhanced low-grade inflammation often leads to dysfunction of the anti-inflammatory and atheroprotective properties of apolipoprotein A-I (apoA-I) and HDL particles, which further increases the risk of diabetes and CVD. It was emphasized that lifestyle modification is essential in the prevention and management of MetS, which includes maintenance of optimal weight by caloric restriction, adherence to a diet that minimizes postprandial glucose and triglyceride fluctuations, restricting alcohol consumption, smoking cessation and engaging in regular exercise. Drug therapy should target the dyslipoproteinemia and the often associated hypertension or dysglycemia.Statins are the drugs of first choice, to be initiated in patients with MetS at high 10-year cardiovascular risk. Such treatment is inadequate if fasting serum triglycerides remain at > 150 mg/dl, when niacin should be combined. Fibrates, omega 3 fatty acids, metformin, angiotensin-converting enzyme inhibitors and pioglitazone are additional options in drug therapy.

EXPERT OPINION

Research on MetS in subpopulations prone to impaired glucose tolerance and insulin resistance has indicated that proinflammatory state and oxidative stress are often prominently involved in MetS, to the extent that evidence of impaired function of HDL and apo A-I particles is discernible by biological evidence of functional defectiveness via outcomes studies and/or correlations with inflammatory and anti-inflammatory biomarkers. A sex difference has been clear in this development.

Metabolic syndrome: definitions and controversies

Metabolic syndrome (MetS) is a complex disorder defined by a cluster of interconnected factors that increase the risk of cardiovascular atherosclerotic diseases and diabetes mellitus type 2. Currently, several different definitions of MetS exist, causing substantial confusion as to whether they identify the same individuals or represent a surrogate of risk factors. Recently, a number of other factors besides those traditionally used to define MetS that are also linked to the syndrome have been identified. In this review, we critically consider existing definitions and evolving information, and conclude that there is still a need to develop uniform criteria to define MetS, so as to enable comparisons between different studies and to better identify patients at risk. As the application of the MetS model has not been fully validated in children and adolescents as yet, and because of its alarmingly increasing prevalence in this population, we suggest that diagnosis, prevention and treatment in this age group should better focus on established risk factors rather than the diagnosis of MetS.

Serum calcium levels are associated with novel cardiometabolic risk factors in the population-based CoLaus study

BACKGROUND

Associations of serum calcium levels with the metabolic syndrome and other novel cardio-metabolic risk factors not classically included in the metabolic syndrome, such as those involved in oxidative stress, are largely unexplored. We analyzed the association of albumin-corrected serum calcium levels with conventional and non-conventional cardio-metabolic risk factors in a general adult population.

METHODOLOGY/PRINCIPAL FINDINGS

The CoLaus study is a population-based study including Caucasians from Lausanne, Switzerland. The metabolic syndrome was defined using the Adult Treatment Panel III criteria. Non-conventional cardio-metabolic risk factors considered included: fat mass, leptin, LDL particle size, apolipoprotein B, fasting insulin, adiponectin, ultrasensitive CRP, serum uric acid, homocysteine, and gamma-glutamyltransferase. We used adjusted standardized multivariable regression to compare the association of each cardio-metabolic risk factor with albumin-corrected serum calcium. We assessed associations of albumin-corrected serum calcium with the cumulative number of non-conventional cardio-metabolic risk factors. We analyzed 4,231 subjects aged 35 to 75 years. Corrected serum calcium increased with both the number of the metabolic syndrome components and the number of non-conventional cardio-metabolic risk factors, independently of the metabolic syndrome and BMI. Among conventional and non-conventional cardio-metabolic risk factors, the strongest positive associations were found for factors related to oxidative stress (uric acid, homocysteine and gamma-glutamyltransferase). Adiponectin had the strongest negative association with corrected serum calcium.

CONCLUSIONS/SIGNIFICANCE

Serum calcium was associated with the metabolic syndrome and with non-conventional cardio-metabolic risk factors independently of the metabolic syndrome. Associations with uric acid, homocysteine and gamma-glutamyltransferase were the strongest. These novel findings suggest that serum calcium levels may be associated with cardiovascular risk via oxidative stress.

Gamma-glutamyl transferase level predicts the development of hypertension in Hong Kong Chinese

BACKGROUND

Plasma activities of alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase, and γ-glutamyl transferase (GGT) are often increased in cardiometabolic diseases. We investigated if hypertension is associated with increased activities of these plasma markers.

METHODS

We included 235 hypertensive and 708 normotensive subjects (mean age 47.3±9.6 and 58.0±10.2 years respectively) from the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS-2) in 2000-2004 who had drank <1/week. In the follow-up study in 2005-2008 (CRISPS-3), 126 out of the 708 subjects had developed hypertension.

RESULTS

Raised plasma ALT (OR=1.22 per SD of log-transformed level, P=0.045) and GGT (OR=1.38 per SD of log-transformed level, P=0.001) levels were associated with hypertension at baseline in CRISPS-2 after adjusting for covariates. Among subjects not on anti-hypertensive medications, plasma ALP, ALT and GGT were related to blood pressure (P<0.01). In subjects normotensive at CRISPS-2, plasma GGT, but not ALP, ALT and AST, was an independent predictor of new-onset hypertension at CRISPS-3 (OR=1.38 per SD of log-transformed level, P=0.020 and OR=2.68 for 3rd tertile vs. 1st tertile, P=0.004) after adjusting for covariates.

CONCLUSIONS

Among the 4 plasma markers, increased GGT activity is the strongest predictor for existing and new-onset hypertension in Hong Kong Chinese.

Gamma-glutamyl transferase: a novel cardiovascular risk biomarker

Gamma-glutamyl transferase (GGT) is a second-generation enzymatic liver function test available for several decades, initially used as a sensitive indicator of alcohol ingestion, hepatic inflammation, fatty liver disease, and hepatitis. Longitudinal and cross-sectional investigational studies since 1990 have associated GGT with an increase in all-cause mortality, as well as chronic heart disease events such as congestive heart failure and components of the metabolic syndrome (abnormal body mass index and levels of high-density lipoprotein cholesterol, glucose, triglycerides, and systolic and diastolic blood pressure). In the upper reference range, GGT was found to be an independent biomarker of the metabolic syndrome, with a 20% per GGT quartile trend rise. Additionally, GGT was positively correlated with an 18% per quartile risk of cardiovascular events and a 26% per quartile increased risk of all-cause mortality. Furthermore, it may be considered a biomarker for "oxidative stress" associated with glutathione metabolism and possibly a "proatherogenic" marker because of its indirect relationship in the biochemical steps to low-density lipoprotein cholesterol oxidation. GGT is becoming an important addition to the multimarker approach to cardiovascular risk evaluation. It should be considered a valuable adjunct in stratifying patient risk and in assessing the aggressiveness of appropriate treatment, with hopes of preventing unnecessary cardiac events and deaths in future years.

The importance of gamma-glutamyltransferase activity in patients with coronary artery disease

BACKGROUND

In this study, we sought to investigate the relation of gamma-glutamyltransferase (GGT) levels with the significance of coronary artery disease (CAD), clinical presentation, left ventricular (LV) function, and inflammatory activity.

METHODS

A total of 235 patients (mean age: 60.1 +/- 10.5 years, 166 [70%] males) who had coronary angiography were included in the study. Patients who had CAD constituted the study group (Group 1, n=189) and patients who had insignificant coronary disease or normal coronary activity constituted the control group (Group 2, n=46).

RESULTS

GGT levels were higher in Group 1 than Group 2 (38.7 +/- 30.9 U/L versus 27.5 +/- 17.5 U/L, p =0.025). Left ventricular ejection fraction (LVEF) was lower in Group 1 than Group 2 (52.6% +/- 11.7% versus 58.8% +/- 11.3%, p < 0.002). GGT activity (40.2 +/- 32.5 U/L versus 29.1 +/- 18.3 U/L, p < 0.002) and c-reactive protein (CRP) levels (33.9 +/- 43.6 mg/dl versus 17.8 +/- 29.8 mg/dl, p < 0.002) were higher, LVEF (52.6% +/- 12.1% versus 56.5% +/- 11.0%, p =0.021) was lower in patients with acute coronary syndrome compared with stable CAD group. In regression analysis, CRP levels (p < 0.0001, odds ratio [OR]=3.77, 95% confidence interval [CI] 0.10 < OR < 0.32), LVEF (p =0.016, OR=- 2.44, 95% CI - 0.95 < OR < - 0.10) and LV end-diastolic pressure (p =0.015, OR=4.31, 95% CI - 1.19 < OR < - 0.13) were independent predictors of GGT activity.

CONCLUSIONS

The increased GGT activity is related to LV function, clinical stability, and inflammatory activity rather than the severity of CAD. Measurement of GGT activity may be useful in predicting cardiovascular risk.

Inflammation, hepatic enzymes and resistance training in individuals with metabolic risk factors

AIMS

Increases in inflammatory markers, hepatic enzymes and physical inactivity are associated with the development of the metabolic syndrome (MetS). We examined whether inflammatory markers and hepatic enzymes are correlated with traditional risk factors for MetS and studied the effects of resistance training (RT) on these emerging risk factors in individuals with a high number of metabolic risk factors (HiMF, 2.9 +/- 0.8) and those with a low number of metabolic risk factors (LoMF, 0.5 +/- 0.5).

METHODS

Twenty-eight men and 27 women aged 50.8 +/- 6.5 years (mean +/- sd) participated in the study. Participants were randomized to four groups, HiMF training (HiMFT), HiMF control (HiMFC), LoMF training (LoMFT) and LoMF control (LoMFC). Before and after 10 weeks of RT [3 days/week, seven exercises, three sets with intensity gradually increased from 40-50% of one repetition maximum (1RM) to 75-85% of 1RM], blood samples were obtained for the measurement of pro-inflammatory cytokines, C-reactive protein (CRP), gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT).

RESULTS

At baseline, HiMF had higher interleukin-6 (33.9%), CRP (57.1%), GGT (45.2%) and ALT (40.6%) levels, compared with LoMF (all P < 0.05). CRP, GGT and ALT correlated with the number of risk factors (r = 0.48, 0.51 and 0.57, respectively, all P < 0.01) and with other anthropometric and clinical measures (r range from 0.26 to 0.60, P < 0.05). RT did not significantly alter inflammatory markers or hepatic enzymes (all P > 0.05).

CONCLUSIONS

HiMF was associated with increased inflammatory markers and hepatic enzyme concentrations. RT did not reduce inflammatory markers and hepatic enzymes in individuals with HiMF.

Association of serum gamma-glutamyltransferase and alanine aminotransferase activities with risk of type 2 diabetes mellitus independent of fatty liver

BACKGROUND

Although elevated serum concentrations of gamma-glutamyltrans- ferase (GGT) or alanine aminotransferase (ALT) have been associated with type 2 diabetes mellitus, it is unclear whether each is an independent predictor of type 2 diabetes or merely a surrogate marker for fatty liver or hepatic injury.

METHODS

We assessed clinical and laboratory findings in 3556 non-diabetic subjects (2217 men, 1339 women; age, 45.7 +/- 8.1 (range 20-79) years) without fatty liver or clinically significant hepatic dysfunction who underwent voluntary medical check-ups at a 5-year interval.

RESULTS

The odds ratio of developing type 2 diabetes increased significantly with increasing GGT and ALT levels at baseline. In multiple logistic regression models adjusted for age, sex, alcohol consumption, smoking, body mass index (BMI), triglycerides, high-density lipoprotein (HDL)-cholesterol, fasting glucose, and ALT, the highest quartile of GGT remained significantly associated with type 2 diabetes. Compared with the first GGT quartile, the odds ratios of the second, third, and fourth GGT quartiles were 0.64 (95% CI, 0.25-1.65), 1.12 (0.45-2.78), and 3.07 (1.21-7.76), respectively. The adjusted odds ratios for the second, third, and fourth ALT quartiles in the same logistic regression model were 2.40 (0.83-6.94), 2.85 (1.03-7.90), and 4.31 (1.56-11.88), respectively. The risk of type 2 diabetes was additive with respect to GGT and ALT quartiles.

CONCLUSIONS

Increased serum GGT and ALT levels are independent, additive risk factors for the development of type 2 diabetes mellitus in subjects without fatty liver or hepatic dysfunction.

Lipoprotein(a) is associated with coronary heart disease independent of metabolic syndrome

AIM

To assess (i) the association between lipoprotein(a) [Lp(a)] with the likelihood of coronary heart disease and metabolic syndrome (MS) and (ii) its covariates in Turkish adults.

METHODS

Cross-sectional evaluation of 1309 adults, who had serum Lp(a) determinations by Behring nephelometry, and followed for a mean 1.0 year. MS was defined by ATPIII criteria modified for male abdominal obesity.

RESULTS

Mean age of the sample was 56.8+/-11.3 years. After adjustment for sex, age, and smoking status, log-transformed Lp(a) levels were associated significantly with coronary heart disease likelihood in both sexes combined [odds ratio: 1.53 (95% confidence interval: 1.06; 2.20)]. This association persisted after additional adjustment for MS [odds ratio: 1.57 (95% confidence interval: 1.09; 2.26)]. The Lp(a) mid-tertile (5-17 mg/dl), accompanied by significantly lower serum triglycerides than the two remaining tertiles, was inversely associated significantly with MS in either sex; in women, this association was independent of waist circumference. In a linear regression comprising seven variables, excepting total cholesterol, only gamma-glutamyltransferase in women (P=0.002) and waist circumference (P=0.057) in men were inverse covariates of modest magnitude of Lp(a).

CONCLUSION

Coronary heart disease likelihood, significantly associated with Lp(a) concentrations, is independent of MS and insulin resistance. Suggestive evidence was provided that intermediary Lp(a) concentrations, when accompanied by the presence of MS, could accelerate progression of vascular disease, especially in women.

Serum elevated gamma glutamyltransferase levels may be a marker for oxidative stress in Alzheimer's disease

BACKGROUND

Gamma glutamyltransferase (GGT) plays a role in cellular glutathione uptake, which is an important element of antioxidant mechanisms. An increase in serum GGT is thought to be an early and sensitive marker of oxidative stress. Oxidative stress has a role in the pathogenesis of Alzheimer's disease (AD). The aim of this study was to investigate the GGT levels in AD.

METHOD

In this cross-sectional study, 132 patients with AD (mean age: 74.1 +/- 7.4, female 62.9%) and 158 age- and gender-matched normal controls (mean age: 74.5 +/- 6.3, female 67.1%) were evaluated. For cognitive assessment, MMSE and clock drawing tests were performed; DSM-IV and NINCDS-ADRDA criteria were used. Serum GGT, aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase concentrations were determined.

RESULTS

Median (min-max) GGT levels were 18 (9-70) in AD group and 17 (5-32) in normal controls. Mann-Whitney U test showed that GGT levels were significantly higher in AD patients (p = 0.012). Linear regression analysis revealed AD was an independent correlate of elevated GGT levels. Hypertension, diabetes mellitus, total cholesterol, and low density lipoprotein cholesterol were not associated with GGT levels.

CONCLUSION

GGT levels were increased significantly in AD patients. To evaluate the role of GGT as a marker of oxidative stress in AD, further studies are needed.

Seasonal changes in mood and behavior are linked to metabolic syndrome

BACKGROUND

Obesity is a major public health problem worldwide. Metabolic syndrome is a risk factor to the cardiovascular diseases. It has been reported that disruptions of the circadian clockwork are associated with and may predispose to metabolic syndrome.

METHODOLOGY AND PRINCIPAL FINDINGS

8028 individuals attended a nationwide health examination survey in Finland. Data were collected with a face-to-face interview at home and during an individual health status examination. The waist circumference, height, weight and blood pressure were measured and samples were taken for laboratory tests. Participants were assessed using the ATP-III criteria for metabolic syndrome and with the Seasonal Pattern Assessment Questionnaire for their seasonal changes in mood and behavior. Seasonal changes in weight in particular were a risk factor of metabolic syndrome, after controlling for a number of known risk and potential confounding factors.

CONCLUSIONS AND SIGNIFICANCE

Metabolic syndrome is associated with high global scores on the seasonal changes in mood and behavior, and with those in weight in particular. Assessment of these changes may serve as a useful indicator of metabolic syndrome, because of easy assessment. Abnormalities in the circadian clockwork which links seasonal fluctuations to metabolic cycles may predispose to seasonal changes in weight and to metabolic syndrome.

Obstructive sleep apnea syndrome is associated with metabolic syndrome rather than insulin resistance

The aim of this study was to investigate cross-sectionally the prevalence and covariates of obstructive sleep apnea syndrome (OSAS) and its relationship to metabolic syndrome (MS), insulin resistance (IR), and coronary heart disease (CHD) in a population sample of 1,946 men and women representative of Turkish adults. OSAS was identified when habitual snoring and episodes of apnea were combined with another relevant symptom. MS was diagnosed based on modified criteria of the Adult Treatment Panel III and IR by homeostatic model assessment (HOMA). OSAS was identified in 61 men (6.4%) and 58 women (5.8%), at a similar prevalence, after adjusting for covariates. Among individuals with OSAS, significantly higher odds ratios (ORs), adjusted for age, body mass index (BMI), and waist girth, were observed for MS, hypertension, and prevalent CHD, but not for HOMA or menopause. Significantly higher C-reactive protein existed only in women with OSAS who were also more frequent smokers. In logistic regression models, waist circumference, but not BMI nor hypertension, was significantly associated with OSAS among men. In women, by contrast, current cigarette smoking and hypertension were the significant independent covariates. Regression models controlling for sex, age, and smoking revealed that MS (and not IR per se) was associated significantly with OSAS (OR 1.94) in nondiabetic individuals. To conclude, abdominal rather than overall obesity in men and smoking among women are significant independent determinants of OSAS in Turkish adults. OSAS is associated with MS rather than IR per se. Relatively high prevalence of OSAS is observed in Turkish women in whom it is significantly associated with CHD.