Deleterious Impact of “High Normal” Glucose Levels and Other Metabolic Syndrome Components on Arterial Endothelial Function and Intima-Media Thickness in Apparently Healthy Chinese Subjects: The CATHAY Study

Hypothyroidism is associated with signs of endothelial dysfunction despite 1-year replacement therapy with levothyroxine

OBJECTIVE

Hypothyroidism is associated with elevated cardiovascular risk, not fully explained by classical risk factors. Instead, endothelial dysfunction may link hypothyroidism to atherosclerosis. The effect of levothyroxine substitution on endothelial function has been sparsely studied and the results are unclear. This study tested endothelial function as estimated by concomitant measurements of endothelial dependent vascular dilatory capacity and plasma concentration of von Willebrand factor antigen in patients with hypothyroidism and further examined the impact of subsequent levothyroxine substitution.

DESIGN AND PATIENTS

Sixteen consecutive patients (13 women, 3 men, aged 46 +/- 11 years) with hypothyroidism were included and compared to 16 matched healthy controls (13 women, 3 men, aged 49 +/- 11 years). Patients with hypothyroidism were reexamined after 3, 6 and 12 months of levothyroxine substitution.

MEASUREMENTS

Dilatory responses of the brachial artery to post-ischaemic increased blood flow (endothelium-dependent flow-associated dilatation) and to nitroglycerin (endothelium-independent nitroglycerin induced dilatation) were measured by ultrasound. Plasma concentrations of von Willebrand factor antigen were measured by ELISA.

RESULTS

Flow-associated dilatation was impaired in patients with hypothyroidism as compared to controls (102.7 +/- 3.6 vs. 105.6 +/- 3.8%, P = 0.04) whereas no differences in plasma concentration of von Willebrand factor antigen were found. One year levothyroxine substitution did not improve flow-associated dilatation and was associated with an increase of the plasma von Willebrand factor antigen concentration.

CONCLUSIONS

Hypothyroid patients are characterized by endothelial dysfunction sustained despite long-term levothyroxine substitution and potentially increasing the risk of atherosclerosis. Different estimates of endothelial dysfunction seem unequally influenced by hypothyroidism.

Endothelial Dysfunction in Patients With Obstructive Sleep Apnoea Independent of Metabolic Syndrome

Introduction: Obstructive sleep apnoea syndrome (OSAS), characterised by intermittent hypoxia/re-oxygenation, has been identified as an independent risk factor for cardiovascular diseases and endothelial dysfunction. Our aim was to investigate flow-mediated dilatation (FMD) in patients with obstructive sleep apnoea with and without metabolic syndrome. Materials and Methods: Fifty-two subjects with OSAS diagnosed by polysomnography were classified into 2 groups according to the presence and absence of the metabolic syndrome and also according to the severity: mild to moderate OSAS group and severe OSAS group. Endothelial function of the brachial artery was evaluated by using high-resolution vascular ultrasound. Endothelial- dependent dilatation (EDD) was assessed by establishing reactive hyperaemia and endothelial- independent dilatation (EID) was determined by using sublingual isosorbide dinitrate. Spearman correlation and regression analysis were performed. Results: EDD was not significantly different in patients with OSAS and metabolic syndrome as compared with OSAS without metabolic syndrome (4.62 ± 0.69 versus 4.49 ± 0.93, P >0.05). Conclusions: Endothelial dysfunction in OSA may be independent of metabolic syndrome. Key words: Endothelial function, Metabolic syndrome, Obstructive sleep apnoea syndrome

Both aerobic endurance and strength training programmes improve cardiovascular health in obese adults

Regular exercise training is recognized as a powerful tool to improve work capacity, endothelial function and the cardiovascular risk profile in obesity, but it is unknown which of high-intensity aerobic exercise, moderate-intensity aerobic exercise or strength training is the optimal mode of exercise. In the present study, a total of 40 subjects were randomized to high-intensity interval aerobic training, continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks, three times/week. The high-intensity group performed aerobic interval walking/running at 85-95% of maximal heart rate, whereas the moderate-intensity group exercised continuously at 60-70% of maximal heart rate; protocols were isocaloric. The strength training group performed 'high-intensity' leg press, abdominal and back strength training. Maximal oxygen uptake and endothelial function improved in all groups; the greatest improvement was observed after high-intensity training, and an equal improvement was observed after moderate-intensity aerobic training and strength training. High-intensity aerobic training and strength training were associated with increased PGC-1alpha (peroxisome-proliferator-activated receptor gamma co-activator 1alpha) levels and improved Ca(2+) transport in the skeletal muscle, whereas only strength training improved antioxidant status. Both strength training and moderate-intensity aerobic training decreased oxidized LDL (low-density lipoprotein) levels. Only aerobic training decreased body weight and diastolic blood pressure. In conclusion, high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function. An important contribution towards improved aerobic work capacity, endothelial function and cardiovascular health originates from strength training, which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform.

High-normal fasting glucose levels are associated with increased prevalence of impaired glucose tolerance in obese children

The natural history of impaired glucose tolerance (IGT) and Type 2 diabetes among obese children is not clear. Although the cut-off for impaired fasting glucose (IFG) has recently been changed from 110 (6.1 mmol/l) to 100 mg/dl (5.6 mmol/l), it does not seem a reliable way to find all subjects with impaired glucose homeostasis. The aim of our study was to determine whether high-normal fasting glucose level could predict the occurrence of IGT and metabolic syndrome. Three hundred and twenty-three Italian obese children and adolescents were included in the study (176 females, mean age 11+/-2.9 yr; mean body mass index z-score: 3+/-0.6). Waist circumference, serum glucose, insulin, triglyceride, cholesterol HDL, blood pressure were evaluated and an oral glucose tolerance test (OGTT) was performed. The prevalence of IFG and IGT were respectively 1.5% (5 subjects) and 5% (18 patients); no diabetic patients were found. Metabolic syndrome was diagnosed in 20% of patients. Fasting glycemia values <100 mg/dl (5.6 mmol/l) have been divided in quintiles. Metabolic syndrome prevalence increased across quintiles, although not in a statistically significantly manner, but it could depend on the selected diagnostic criteria as no univocal definition exists for metabolic syndrome in youths. Interestingly high-normal fasting plasma glucose levels constitute an independent risk factor for IGT among obese children and adolescents; therefore, this very easy-to-use parameter may help to identify obese patients at increased risk of diabetes or at least could suggest in which subjects to perform an OGTT.

Blood lipid levels in relation to glucose status in European men and women without a prior history of diabetes: the DECODE Study

OBJECTIVE

Dyslipidaemia is present not only in diabetic but also in prediabetic subjects. The purpose of this study is to investigate the relationship between lipid and glucose levels in a large European population without a prior history of diabetes.

RESEARCH DESIGN AND METHODS

Data from the population-based studies of 8960 men and 10,516 women aged 35-74 years representing 15 cohorts in 8 European countries were jointly analyzed. Multivariate adjusted linear regression analyses with standardized coefficients (beta) were performed to estimate the relationship between lipid and plasma glucose.

RESULTS

In subjects without a prior history of diabetes, positive relationships were shown between fasting plasma glucose (FPG) and total cholesterol (TC) (beta=0.06 and 0.03, respectively for men and women, p<0.01), triglycerides (TG) (beta=0.14 and 0.12, p<0.001), non-high-density lipoprotein cholesterol (non-HDL-C) (beta=0.06 and 0.03, p<0.01) and TC to HDL ratio (beta=0.06 and 0.05, p<0.001) but a negative trend between FPG and HDL-C (beta=-0.02, p>0.05 in men and beta=-0.03, p<0.05 in women). The relationship between lipid and 2-h plasma glucose (2hPG) followed a similar pattern as that for FPG, except that TC was not increased and HDL-C was reduced in both sexes in subjects with impaired glucose tolerance (IGT).

CONCLUSIONS

For cardiovascular prevention, the different lipid patterns between impaired fasting glucose (IFG) and IGT may deserve further attention to evaluate the combined risks of dyslipidaemia and elevated glucose levels below the diagnostic threshold of diabetes.

The association between glycemia and endothelial function in nondiabetic individuals: the importance of body weight

The aim of this study was to examine the association between glycemia and markers of early atherosclerosis in healthy nondiabetic individuals. In 309 individuals without diabetes or symptomatic cardiovascular disease, we assessed long-term glycemia by glycosylated hemoglobin (HbA1c) and endothelial function by flow-mediated dilatation (FMD) in the brachial artery. HbA1c was negatively associated with FMD (r = -0.162, P = 0.004). Multivariate linear regression analysis after adjusting for common risk factors of cardiovascular disease showed that BMI was an effect modifier of the association between HbA1c and FMD (P = 0.034 for the HbA1c x BMI interaction). We stratified the FMD outcome data into two groups separated by the median BMI (group 1: BMI < or = 26.1 kg/m(2) and group 2: BMI > 26.1 kg/m(2)). In the lower BMI group, HbA1c was an independent predictor of FMD even when adjusted for confounding factors associated with impaired glucose metabolism (r = -0.215, P = 0.009), but in the higher BMI group HbA1c was not associated with FMD (r = -0.051, P = 0.5). In a nondiabetic population, long-term glycemia was associated with endothelial dysfunction only in lean individuals. In the overweight individuals, this association was not apparent, possibly because some of the mechanisms that mediate the effect of glycemia on vascular function are shared by obesity.

Effects of oral glucose load on endothelial function and on insulin and glucose fluctuations in healthy individuals

Background/aims. Postprandial hyperglycemia, an independent risk factor for cardiovascular disease, is accompanied by endothelial dysfunction. We studied the effect of oral glucose load on insulin and glucose fluctuations, and on postprandial endothelial function in healthy individuals in order to better understand and cope with the postprandial state in insulin resistant individuals. Methods. We assessed post-oral glucose load endothelial function (flow mediated dilation), plasma insulin, and blood glucose in 9 healthy subjects. Results. The largest increases in delta FMD values (fasting FMD value subtracted from postprandial FMD value) occurred at 3 hours after both glucose or placebo load, respectively: 4.80 ± 1.41 (P = .009) and 2.34 ± 1.47 (P = .15). Glucose and insulin concentrations achieved maximum peaks at one hour post-glucose load. Conclusion. Oral glucose load does not induce endothelial dysfunction in healthy individuals with mean insulin and glucose values of 5.6 mmol/L and 27.2 mmol/L, respectively, 2 hours after glucose load.

Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity

BACKGROUND

The effects of a very-low-carbohydrate, high-saturated-fat weight-loss diet (LC) on brachial artery flow-mediated dilatation (FMD) and markers of endothelial function are unknown.

OBJECTIVE

The effect of an LC on markers of endothelial function and cardiovascular disease (CVD) risk was compared with that of an isocaloric high-carbohydrate, low-saturated-fat diet (HC).

DESIGN

FMD and markers of endothelial function (n = 70) and CVD risk were measured before and after 8 wk of weight loss. Ninety-nine subjects aged 50.0 +/- 8.3 y with a body mass index (in kg/m2) of 33.7 +/- 4.1 completed the study.

RESULTS

Mean (+/-SD) FMD did not change significantly (P = 0.55) with either diet. Pulse wave velocity improved with both diets (P < 0.01). Endothelial markers, E- and P selectin, intracellular and cellular-adhesion molecule-1, tissue-type plasminogen activator, and plasminogen activator inhibitor-1 decreased (P < 0.001), with no diet effect. Adiponectin did not change significantly. More weight (P = 0.05 for diet x time interaction) and more abdominal fat mass (P = 0.05 for diet x time interaction) were lost with the LC than with the HC. LDL cholesterol decreased more with the HC than with the LC (P < 0.05, time x diet), and C-reactive protein decreased more with the HC than with the LC (P < 0.05 for diet x time interaction). Homocysteine increased more with the LC (P < 0.01 for diet x time interaction). Folate decreased with the LC and increased with the HC (P < 0.05, time; P < 0.001 for diet x time interaction).

CONCLUSION

An LC does not impair FMD. We observed beneficial effects of both diets on most of the CVD risk factors measured. This trial was registered with the Australian Clinical Trials Registry as ACTR N0 12606000203550.

Assessment of erectile dysfunction in diabetic patients

Erectile dysfunction (ED) aetiology is multifactorial, including endocrine, neurological, vascular, systemic disease, local penile disorders, nutrition, psychogenic factors, and drug-related. This study was performed to compare the relevant comprehensive biochemical parameters as well as the clinical characteristics in diabetic ED and healthy control subjects and to assess the occurrence of penile neuropathy in diabetic patients and thus the relationship between ED and diabetes. A total of 56 patients accepted to undergo assessment for penile vasculature using intracavernosal injection and colour Doppler ultrasonography. Of the 56 diabetic patients, 38 patients were found with normal blood flow and thus they were considered as the diabetic-ED group, whereas, ED diabetic patients with an arteriogenic component were excluded. These patients with an age range between 17 and 58 years, complaining of ED, with duration of diabetic illness ranging from 2 to 15 years. The Control group comprised of 30 healthy subject aged between 19 and 55 years. Peripheral venous levels of testosterone, prolactin, follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), malondialdehyde and glycosylated haemoglobin (HbA(1)c) were obtained in all subjects. Valsalva manoeuvre and neurophysiological tests were also determined. Testosterone, prolactine, FSH, LH, and TSH hormones of the diabetic patients were not significantly different from those of the control group. Diabetic patients with ED have higher HbA(1)c and oxidative stress levels while the R-R ratio was significantly decreased. Bulbocavernosus reflex latency was significantly prolonged, whereas its amplitude, the conduction velocity and amplitude of dorsal nerve of penis were significantly reduced in the diabetic patients. We concluded that although ED is a multifactorial disorder, yet, the present study revealed that in ED patients without arteriogenic ED a neurogenic component is present. Furthermore, the complex effect of the Valsalva manoeuvre on cardiovascular function is the basis of its usefulness as a measure of autonomic function. Thus, it can be of value in the diagnosis of ED although these hypotheses require follow-up in a large study cohort.

Determinants of endothelial function in a cohort of patients with peripheral artery disease

OBJECTIVES

Endothelial dysfunction assessed by brachial artery flow-mediated dilatation (FMD) has been associated with cardiovascular events. There have been relatively few studies examining FMD or other measures of endothelial function in patients with peripheral artery disease (PAD). The aim of this study was to examine determinants of FMD in a homogenous cohort of patients with PAD.

METHODS

We prospectively assessed patients presenting with life style-limiting intermittent claudication to establish the presence of cardiovascular risk factors, obesity and metabolic syndrome. Fasting serum was assayed for lipids, C-reactive protein, adiponectin, leptin, resistin and osteoprotegerin (OPG). FMD was measured by high-resolution ultrasound.

RESULTS

Serum concentrations of OPG were elevated in patients with obesity and metabolic syndrome. FMD was impaired in patients with obesity and metabolic syndrome and negatively correlated with serum concentrations of OPG. By multiple regression analysis, metabolic syndrome was independently associated with impaired FMD after adjustment for age, smoking, ischaemic heart disease, cerebrovascular disease and severity of PAD.

CONCLUSIONS

Our findings suggest that metabolic syndrome is an important determinant of endothelial function in patients with PAD, and OPG may be a useful biomarker of this effect.

Fasting but not postprandial (postmeal) glycemia predicts the risk of death in subjects with coronary artery disease

BACKGROUND

Chronic hyperglycemia plays a role in the pathogenesis of coronary artery disease (CAD); however, the cut-off level beyond which glycemia becomes detrimental is still controversial. Postprandial glycemia may be a stronger CAD risk factor than fasting glycemia in patients without documented heart disease.

OBJECTIVES

To identify the contributions of fasting and postprandial glycemia to cardiovascular risk in patients with documented coronary artery disease.

METHODS

The Coronary Artery Surgery Study (CASS) registry is a database of 24,958 patients with suspected or proven CAD who underwent cardiac catheterization between 1974 and 1979. Median long-term follow up was 14.7 years (interquartile range 9.8 to 16.2 years). Clinical outcomes were evaluated according to fasting glucose levels and 2 h postprandial (postmeal) plasma glucose (2hPG) levels. A total of 13,176 patients with baseline fasting glucose levels and 1691 patients with 2hPG levels were identified.

RESULTS

Impaired fasting glycemia was associated with a 1.2-fold increase in both all-cause and cardiovascular mortality (adjusted hazard ratio 1.23; 95% CI 1.08 to 1.40 for cardiovascular mortality), while undiagnosed diabetes was associated with a 1.5-fold increased risk for the same end points. Postprandial hyperglycemia (2hPG of 7.8 mmol/L to 11.0 mmol/L following an average meal) was not associated with a significant risk of death after adjustment for traditional risk factors or in the presence of fasting glucose of less than 6.1 mmol/L.

CONCLUSIONS

In CAD patients, impaired fasting glucose is associated with increased all-cause and cardiovascular mortality, whereas postprandial hyperglycemia following an average meal does not appear to be a risk factor.

Prediction of all-cause mortality in a patient population with hypertension and type 2 DM by using traditional risk factors and serum-phosphate,-calcium and-magnesium

The aim of this study is to investigate whether the prediction of all-cause mortality from traditional risk factors is improved by adding electrolytes (serum-phosphate (S-P), serum-calcium (S-Ca) and serum-magnesium (S-Mg)) in a Cox regression. The study uses an 18-year follow-up of patients (n=2504) referred by physicians in primary health care and hospitals to the Vindeln Patient Education (VPE) Center, mainly with a diagnosis of hypertension (HT), type 2 diabetes mellitus (DM) and/or obesity. Cox regression, with the latest registered value and baseline values for risk factors, was used to study all-cause mortality in men and women. 221 out of 1096 men and 157 out of 1408 women died during the 18-year follow-up (20% and 11% respectively). The Cox regression analysis reveals that high blood glucose (B-Glu) and low S-Mg were significantly associated with increased all-cause mortality in the whole patient population as well as in men and women separately. Among women, type 2 DM and systolic blood pressure (SBP) and among men, high S-Ca, S-P, S-urate and body mass index (BMI) were the main predictors of all-cause mortality. There is significantly improved prediction of all-cause mortality with electrolytes added to the traditional risk factors. High B-Glu and low S-Mg in both men and women, and high S-Ca and S-P in men, are significantly associated with all-cause mortality. The metabolic disturbance in this high-risk group of patients can be more fully understood if ionic imbalance is included in the prediction of mortatlity.

Oxidative stress-mediated arterial dysfunction in patients with metabolic syndrome: Effect of ascorbic acid

Arterial dysfunction is a hallmark of early atherosclerosis; however, its behavior in patients with metabolic syndrome (MS) is still unclear. We investigated the role of oxidative stress on ischemia-induced flow-mediated dilatation (FMD) in patients with MS. FMD and oxidative stress, as assessed by serum levels of 8-hydroxy-2-deoxy-2-deoxyguanosine (8-OHdG), were studied in 18 MS and 30 control subjects. Thereafter, in the 18 MS patients, FMD was assessed after iv infusion of 1 g vitamin C or placebo in a randomized, double-blind, crossover design; serial blood samples were taken in peripheral circulation before and after FMD to analyze 8-OHdG. Compared to controls, MS patients had higher 8-OHdG (p<0.001) and lower FMD (p<0.001); 8-OHdG and FMD were inversely correlated (R=-0.74; p<0.01). In MS patients, placebo administration did not change FMD, whereas vitamin C significantly enhanced it (p<0.001). After placebo, ischemia-induced FMD was associated with a significant increase in 8-OHdG (p<0.001), an effect that was counteracted by vitamin C. Vitamin C infusion was associated with an inverse correlation between the changes in FMD and oxidative stress (R=-0.67; p<0.01). The present study shows that arterial dilatation is impaired and that enhanced oxidative stress may play a key role in patients with MS.

Endothelial dysfunction in Turkish patients with non-alcoholic fatty liver disease

BACKGROUND

The components of the metabolic syndrome are closely related with endothelial dysfunction, which is a pathophysiological issue of cardiovascular diseases. Non-alcoholic fatty liver disease (NAFLD) is considered as one of the components of the metabolic syndrome. The aim of this study was to evaluate the endothelial-dependent dilatation (EDD) and endothelial-independent dilatation (EID) of the brachial artery in NAFLD.

METHODS

Fifteen non-alcoholic steatohepatitis (NASH), 17 patients with simple steatosis and 16 healthy subjects formed the study group. Non-alcoholic fatty liver disease group was composed of patients admitted to the gastroenterology outpatient clinic because of increased liver enzymes. Endothelial functions of the brachial artery were evaluated by vascular ultrasound. EDD was assessed by establishing reactive hyperaemia, and EID was determined by using sublingual nitrate.

RESULTS

No statistical difference for the basal diameter of brachial artery was found between the groups (P = 0.49). The values for EDD and EID were significantly different across all three groups (P < 0.0001 and P < 0.0001, respectively). EDD and EID were significantly lower in NASH compared with simple steatosis (P = 0.01 and P < 0.01, respectively). However, there was no statistical significance for EDD and EID in simple steatosis groups compared with controls (P = 0.58 and P = 0.98, respectively).

CONCLUSIONS

Our study showed that patients with NASH had significantly worse endothelial dysfunction compared with patients with simple steatosis and healthy subjects. The treatment strategies with ameliorative effects for endothelial dysfunction might be effective for delaying the development of cardiovascular complications in NAFLD.

High-normal fasting blood glucose in non-diabetic range is associated with increased coronary artery calcium burden in asymptomatic men

OBJECTIVE

: The objective of the study is to evaluate whether high fasting blood glucose (FBG) in the non-diabetic range (<126 mg/dl) is associated with subclinical coronary atherosclerosis as determined by coronary artery calcium (CAC) independent of clustering of metabolic syndrome (MS) risk factors.

METHODS & RESULTS

: Previously non-diabetic, 458 asymptomatic non-diabetic Brazilian men (mean age: 46+/-7 years, range: 29-65) underwent clinical consultation including FBG measurements and electron-beam tomography (EBT). The mean FBG of the study population was 88+/-10mg/dl. Overall, 190 (42%) of men had CAC>0. The prevalence of CAC was significantly higher among men with high-normal FBG (4th quartile: 94-125 mg/dl) versus normal FBG group (lower three quartiles: 66-93 mg/dl) (62% versus 35%, p<0.0001). In age adjusted analyses the odds ratio (OR) for any CAC among men with high-normal FBG versus normal FBG was 2.19 (95% CI: 1.33-3.58). On further adjustment for risk factors the relationship was slightly attenuated, however remained statistically significant (OR=1.78, 95% CI 1.05-3.00, p=0.03). In sub-stratified analyses high-normal FBG was associated with CAC among men without MS (OR: 1.99, 95% CI: 1.04-3.78) and with MS (OR: 2.12, 95% CI: 0.95-4.80). Similar relations with high-normal FBG were observed among individuals classified low risk (OR: 2.34, 95% CI: 1.14-4.83) as well intermediate high-risk men (OR: 1.95, 95% CI: 0.99-3.86) by Framingham risk score (FRS), respectively.

CONCLUSIONS

: Fasting blood glucose in the upper normal range appears to be associated with the presence of CAC in apparently non-diabetic Brazilian men.

Flow-induced remodeling in resistance arteries from obese Zucker rats is associated with endothelial dysfunction

Chronic increases in blood flow increase arterial diameter and NO-dependent dilation in resistance arteries. Because endothelial dysfunction accompanies metabolic syndrome, we hypothesized that flow-mediated remodeling might be impaired in obese rat resistance arteries. Obese and lean Zucker rat mesenteric resistance arteries were exposed to chronic flow increases through arterial ligation in vivo: arteries exposed to high flow were compared with normal flow arteries. Diameter was measured in vitro in cannulated arteries using pressure arteriography. After 7 days, outward remodeling (diameter increased from 346+/-9 to 412+/-11 mum at 100 mm Hg) occurred in lean high-flow arteries. Endothelium-dependent tone was reduced in high-flow arteries from obese rats by contrast with lean animals. On the other hand, diameter enlargement occurred similarly in the 2 strains. The involvement of NO in endothelium-dependent dilation (evidenced by NO blockade) and endothelial NO synthase phosphorylation was smaller in obese than in lean rats. Superoxide anion and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunit expression (p67phox and gp91phox) increased in obese rats and were higher in high-flow than in control arteries. Acute Tempol (a catalase mimetic), catalase plus superoxide dismutase, and l-arginine plus tetrahydrobiopterin restored endothelium-dependent dilation in obese rat normal and high-flow arteries to the level found in lean control arteries. Thus, flow-induced remodeling in obese resistance arteries was associated with a reduced endothelium-mediated dilation because of a decreased NO bioavailability and an excessive superoxide production. This dysfunction might have negative consequences in ischemic diseases in patients with obesity or metabolic syndrome.

Nitric oxide in the pathogenesis of cardiac disease

Endothelial dysfunction is characterized by a vasoconstrictive and prothrombotic state in the vasculature; it plays a role in all stages of cardiac disease and is a significant independent predictor of cardiovascular outcomes. Nitric oxide (NO) performs multiple biologic activities in the endothelium, including vasodilation and antithrombotic actions. Reduced NO bioactivity is a major component of endothelial dysfunction. Impaired NO bioactivity is an important factor in the pathogenesis of atherosclerosis and in the metabolic syndrome. The functions of NO bioactivity in the heart go well beyond those in the endothelium, as all 3 NO synthase (NOS) isoforms-endothelial NOS, neuronal NOS, and inducible NOS-are expressed in cardiac myocytes and mediate systolic, diastolic, and chronotropic cardiac functions. Impairment of NO bioactivity is a pathogenic factor in various forms of cardiac disease. Although these findings support the potential use of NO-targeted therapies for treatment of cardiac disease, the complexities of the biologic actions of NO in the vasculature and heart are such that development of therapies is still largely in the preliminary stages.

Metabolic syndrome and preclinical atherosclerosis: focus on femoral arteries

Several evidences revealed the relationship between the earliest stages of atherosclerosis and the components of metabolic syndrome. The aim of this study was to disclose preclinical atherosclerotic lesions in a cross-sectional observational study involving 147 patients with metabolic syndrome by the assessment of brachial flow-mediated vasodilation (FMV) and intima-media thickening at both carotid and femoral sites. The purpose was to investigate the association of this metabolic disorder with prevalent atherosclerotic damage in different vascular sites. A control group of 87 healthy subjects was also investigated. Patients had lower values of FMV and a higher mean intima-media thickness (IMT) at both the carotid and femoral sites with respect to controls. Flow-mediated vasodilation had a positive correlation with high-density lipoprotein (HDL) cholesterol and a negative one with low-density lipoprotein (LDL) cholesterol, glycemia, and insulinemia. Carotid mean IMT was directly related to LDL cholesterol and age, and inversely with HDL cholesterol; femoral mean IMT had a direct association with LDL cholesterol, triglycerides, glycemia, and insulinemia and an inverse correlation with HDL cholesterol and LDL size. LDL cholesterol, HDL cholesterol, insulin, and brachial artery diameter were predictive of brachial FMV (beta=-0.17, 0.21, -0.27, and -0.29, respectively; P<.05), whereas age, LDL cholesterol, and HDL cholesterol were independent predictors of mean carotid IMT (beta=0.19, 0.37, and -0.27, respectively; P<.05); on the other hand, LDL cholesterol, triglycerides, and insulin were independent predictors of mean femoral IMT (beta=0.32, 0.26, and 0.25, respectively; P<.05). In conclusion, the present study documented an altered endothelial function and intima-media thickening in patients with metabolic syndrome without overt cardiovascular disease. Moreover, it focused on the strong influence of metabolic syndrome on preclinical atherosclerotic lesions at the femoral site.

A dose-response study of hormone replacement in young hypogonadal women: effects on intima media thickness and metabolism

OBJECTIVE

Young hypogonadal women appear to have an increased risk of cardiovascular disease. We studied the influence of increasing doses of hormone replacement therapy (HRT) on markers of metabolism and vascular physiology.

DESIGN

Nine-month sequential dose-ranging study.

PATIENTS

A total of 25 young hypogonadal women (Turner Syndrome, n = 14; 46,XX gonadal dysgenesis, n = 9), hypogonadotrophic hypogonadism (n = 2), mean age 31.9 years (range 18.5-42.2). All subjects sequentially received oral 17beta-oestradiol 1,2 and 4 mg daily in a cyclical formulation for 12 weeks each.

MEASUREMENTS

Metabolic markers and vascular physiology measurements to assess intima media thickness (IMT); arterial stiffness: pulse wave velocity (PWV) and augmentation index (AIx); endothelial function: flow-mediated dilatation (FMD). Results Increasing doses of oestrogen resulted in a reduction in IMT (0.63 +/- 0.06 vs. 0.58 +/- 0.06 vs. 0.56 +/- 0.06 mm at 1 mg, 2 mg and 4 mg 17beta-oestradiol, respectively, P = 0.001).

RESULTS

were similar in women with Turner Syndrome and normal karyotype. High-density lipoprotein (HDL) cholesterol concentrations increased (1.9 +/- 0.4 vs. 2.0 +/- 0.5 vs. 2.2 +/- 0.4 mmol/l, P = 0.001) and plasma glucose (4.8 +/- 0.4 vs. 4.7 +/- 0.3 vs. 4.6 +/- 0.6 mmol/l, P = 0.038) decreased slightly with the increasing dose of HRT. There was no correlation between the changes in IMT and HDL. Increasing HRT dose had no significant impact on blood pressure, weight, other lipid parameters, insulin, C-reactive protein, interleukin-6 and fibrinogen concentrations or FMD, PWV and AIx.

CONCLUSIONS

Increasing doses of HRT result in a reduction in carotid IMT in young hypogonadal women, along with increased serum HDL and decreased plasma glucose. This study raises the possibility that exogenous oestrogen may be cardioprotective in young women, but this observation needs to be balanced against a prothrombotic effect which is predominant in postmenopausal women.

Noninvasive assessment of preclinical atherosclerosis

Initially considered as a semipermeable barrier separating lumen from vessel wall, the endothelium is now recognised as a complex endocrine organ responsible for a variety of physiological processes vital for vascular homeostasis. These include the regulation of vascular tone, luminal diameter, and blood flow; hemostasis and thrombolysis; platelet and leucocyte vessel-wall interactions; the regulation of vascular permeability; and tissue growth and remodelling. The endothelium modulates arterial stiffness, which precedes overt atherosclerosis and is an independent predictor of cardiovascular events. Unsurprisingly, dysfunction of the endothelium may be considered as an early and potentially reversible step in the process of atherogenesis and numerous methods have been developed to assess endothelial status and large artery stiffness. Methodology includes flow-mediated dilatation of the brachial artery, assessment of coronary flow reserve, carotid intimamedia thickness, pulse wave analysis, pulse wave velocity, and plethysmography. This review outlines the various modalities, indications, and limitations of available methods to assess arterial dysfunction and vascular risk.

Increased carotid intima-media thickness in remote and urban Indigenous Australians: impact of diabetes and components of the metabolic syndrome

OBJECTIVE

Indigenous Australians have rates of cardiovascular (CVD) mortality some seven to 10-fold higher than non-Indigenous Australians aged 25-64 years. We aimed to evaluate the impact of type 2 diabetes and components of the metabolic syndrome on carotid intima-media thickness (CIMT) as a marker of cardiovascular risk in Indigenous Australians living in remote and urban environments and in Australians of European ancestry.

DESIGN, PATIENTS AND MEASUREMENTS

CIMT was measured by high-resolution B-mode ultrasound imaging of the common carotid artery in 119 remote Indigenous, 144 urban Indigenous and 122 urban European Australians with and without diabetes.

RESULTS

In nondiabetic participants, CIMT was lowest in Europeans (mean (SD) 0.64 mm (0.10)), higher in urban Indigenous Australians (0.67 mm (0.12)) and highest in remote Indigenous Australians (0.73 mm (0.15), P < 0.001). CIMT was higher with diabetes with the same pattern observed between populations: 0.73 mm, 0.79 mm and 0.82 mm, respectively (P < 0.001). Traditional risk factors (age, male gender, blood pressure and HbA1c) explained 35-45% of the variance of CIMT within each population group. However, differences in CIMT between population groups were maintained after adjustment for these cardiovascular risks plus cholesterol and smoking (P < 0.001). Factor analysis revealed that variables of the metabolic syndrome, together with smoking and elevated C-reactive protein (CRP) and urinary albumin-creatinine ratio (ACR), are likely to explain the higher CIMT in Indigenous Australians (and the urban-remote gradient). Unmeasured variables (genetic, psychosocial and socioeconomic) may also contribute to higher CIMT in these populations.

CONCLUSION

Glycaemic control and metabolic syndrome components contribute significantly to premature atherogenesis in Indigenous Australians and we recommend that therapy should be targeted accordingly.

Intimal media thickness, glucose intolerance and metabolic syndrome in Asian Indians--the Chennai Urban Rural Epidemiology Study (CURES -22)

AIMS

The aim of the present study was to assess carotid intimal media thickness (IMT) in different grades of glucose intolerance and the metabolic syndrome (MS) in Asian Indians, a high-risk group for diabetes and coronary artery disease.

METHODS

Subjects with normal glucose tolerance (NGT) (n = 1600), impaired glucose tolerance (IGT) (n = 330), newly diagnosed diabetes (NDD) (n = 330) and known diabetes (KD) (n = 1170) were recruited from the Chennai Urban Rural Epidemiology Study (CURES), an ongoing study on a representative population of Chennai (formerly Madras), in southern India. Assessment of carotid IMT was performed using high-resolution B-mode ultrasonography. MS was defined using modified adult treatment parel (ATP) III guidelines. Subjects with self-reported diabetes, hypertension and dyslipidaemia were excluded from the analysis on MS.

RESULTS

Subjects with glucose intolerance had significantly higher mean carotid IMT values compared with subjects with normal glucose tolerance (NGT 0.69 +/- 0.12 mm, IGT 0.75 +/- 0.16 mm, NDD 0.79 +/- 0.19 mm and KD 0.87 +/- 0.24 mm, P < 0.001). Regression analysis showed that there was a linear increase in mean IMT values with increasing severity of glucose intolerance, even after adjusting for age and gender. Mean IMT values were higher in those with MS and increased with increase in number of metabolic abnormalities (subjects without any metabolic abnormality 0.66 +/- 0.12 mm, one abnormality 0.67 +/- 0.13 mm, two 0.70 +/- 0.12 mm, three 0.72 +/- 0.12 mm, four 0.77 +/- 0.15 mm, five 0.76 +/- 0.13 mm). Regression models showed MS to be associated with IMT, even after adjusting for age, gender and presence of diabetes (P = 0.021).

CONCLUSIONS

In Asian Indians, carotid IMT increases progressively with increasing severity of glucose intolerance and is also associated with the metabolic syndrome, independent of age, gender and presence of diabetes.

Association of vascular risk factors with increasing glycemia even in normoglycemic subjects in an older Chinese population: the Guangzhou Biobank Cohort Study

Hyperglycemia increases cardiovascular disease risk, but the association between increasing glycemia and cardiovascular risk factors, angina, and coronary heart disease in normoglycemic subjects is less clear, particularly in Chinese. We report on possible associations in a large group of Mainland Chinese subjects. A total of 10,400 older subjects (> or = 50 years) were recruited, and vascular risk factors were measured, including anthropometry, blood pressure, and fasting plasma biochemical factors including glucose, lipid profile, and C-reactive protein (CRP). Subjects were categorized by glycemic status, and the relationship between glycemia and cardiovascular risk factors was investigated using analysis of variance and multiple linear regression analyses. Tertiles of fasting glucose levels showed a clear positive relationship with cardiovascular risk factors including age, obesity, blood pressure, lipid levels, and CRP (P < .001 for all). The overall prevalence of self-reported vascular disease was low, but significantly associated with increasing glycemia. Multiple regression showed that waist circumference (standardized regression coefficient beta = .10, P < .001), triglycerides (beta = 0.16, P < .001), CRP (beta = 0.06, P < .001), female sex (beta = .03, P = .007), high-density lipoprotein cholesterol (beta = -.02, P = .016), and mean arterial pressure (beta = .06, P < .001) were independently associated with fasting glucose levels. Among the normoglycemic subjects (n = 5190), increasing glycemia was still associated with increasing obesity indices, systolic blood pressure, triglyceride, and CRP levels (all P < .05). Increasing glycemia, even in the reference range, is associated with increasing prevalence of vascular risk factors. Control of these risk factors, particularly obesity, the most important avoidable independent determinant of glycemia in normoglycemic subjects, is critical to reduce the risk of the associated vascular disease.

Determinants of normoglycemia and contribution to cardiovascular risk factors in a Chinese population: the Hong Kong Cardiovascular Risk Factor Study

BACKGROUND

Glucose intolerance is clearly associated with increasing risk of cardiovascular disease, but the association among increasing glycemia and cardiovascular risk factors, angina and coronary heart disease in normoglycemic subjects is less clear, particularly in Chinese.

METHODS

A total of 2763 subjects were recruited and the prevalence of glucose intolerance investigated, using fasting or 2-h 75-g oral glucose tolerance test (OGTT), glucose levels. Subjects normoglycemic by both criteria were selected and the relationship between glycemia and cardiovascular risk factors investigated using analysis of variance and stepwise multiple linear regression analyses.

RESULTS

1931 (69.9%) subjects were normoglycemic by both tests. After adjustment for age and gender, quartiles of fasting and post-load glucose levels showed a clear positive relationship with cardiovascular risk factors, including obesity, blood pressure and lipid levels (p<0.001 for all). Additionally, other measures of glycemia and insulin resistance also dose-dependently increased with increasing fasting and post-load glucose levels (p<0.001 for all). Stepwise multiple regression showed that in females, age (standardised regression coefficient beta (beta)=0.23, p<0.001), insulin (beta=0.17, p<0.001), waist circumference (beta=0.11, p=0.007) were independently associated with fasting glucose levels; and body mass index (beta=0.17, p<0.001), age (beta=0.15, p<0.001) and triglycerides (beta=0.15, p<0.001) were independently associated with post-load glucose levels. In males, age (beta=0.19, p<0.001) and insulin (beta=0.18, p<0.001) were independently associated with fasting glucose levels; and waist circumference (beta=0.17, p<0.001), triglycerides (beta=0.16, p<0.001) and insulin (beta=0.12, p=0.001) were independently associated with post-load glucose levels.

Transient impairment of flow-mediated vasodilation in patients with metabolic syndrome at moderate altitude (1700 m)

BACKGROUND

The influence of moderate altitude on the cardiovascular system in patients with metabolic syndrome has not been investigated sufficiently, yet. The aim of this study was to assess the effect of acute and mid-term exposure to moderate altitude (1,700 m) on endothelial function in patients with metabolic syndrome.

METHODS

Flow-mediated (FMD) and nitroglycerin-mediated vasodilation (NMD) were assessed in 18 patients with coronary risk factors on 5 occasions: (1) at location A (576 m), (2) on the first day at moderate altitude (location B, 1,700 m), (3) after 3 weeks at moderate altitude, (4) and (5) again at location A (6 and 16 weeks after the stay at moderate altitude, respectively). In addition, markers of lipid metabolism, serum erythropoietin and endothelin were measured.

RESULTS

FMD on the first day at moderate altitude was similar compared to baseline FMD at location A (7.0 +/- 3.3 vs. 7.4 +/- 4.6%; NS). A 3-week stay at moderate altitude was associated with a significant reduction in FMD (7.4 +/- 4.6 vs. 3.8 +/- 2.5%; p < 0.05) despite a decrease in baseline diameter (4.5 +/- 0.3 vs. 4.3 +/- 0.4 mm; p < 0.05). Six weeks after returning to location A, FMD was still reduced compared to baseline (4.3 +/- 2.8%; p < 0.05) and after further 16 weeks, FMD returned to baseline values (5.5 +/- 3.5%). However, metabolic parameters improved significantly. In contrast, NMD and endothelin levels remained unchanged.

CONCLUSION

In patients with metabolic syndrome, a sojourn of 3 weeks at moderate altitude leads to a prolonged, but reversible impairment of FMD. The discrepancy to improvement of other cardiovascular and metabolic parameters requires further investigation.

Hyperglycaemia after glucose loading is a major predictor of preclinical atherosclerosis in nondiabetic subjects

OBJECTIVE

Carotid intima-media thickness (IMT) has proved to be an independent marker of preclinical atherosclerosis. The aim of this study was to determine whether carotid IMT is associated with the plasma glucose concentration in the fasting state, after loading with oral glucose, or with the insulin sensitivity index (ISI) in nondiabetic subjects with different levels of glucose intolerance and insulin resistance.

DESIGN

Cross-sectional study.

PATIENTS

A total of 160 nondiabetic subjects (147 from our obesity-overweight clinic and 13 healthy normal subjects) were included in the present study, among them 33 had normal glucose tolerance (NGT), 13 had impaired fasting glucose (IFG), 80 had impaired glucose tolerance (IGT) and 34 had both IFG and IGT.

MEASUREMENTS

Carotid IMT was assessed in the common carotid artery by a high-resolution B-mode ultrasound system. Plasma glucose was measured after fasting and at 30 min, 1, 2 and 3 h after a standard 75-g load of glucose. The ISI was calculated from the frequent sampling intravenous glucose tolerance test (FSIGT). Results The IMT values in the NGT group were lower than those in the IFG, IGT and IFG + IGT groups (P < 0.03). No statistical difference in IMT values was found among the latter three groups. Univariate correlation analyses showed that the IMT was positively associated with age, plasma glucose concentrations 1 and 2 h after glucose loading, and serum concentration of low density lipoprotein (LDL) cholesterol (r=0.39, 0.22, 0.25 and 0.18, respectively, P<0.05). Multiple regression analysis showed that only age, plasma glucose concentration 2 h after glucose loading, and LDL cholesterol appeared to be significant correlates of the IMT (P<0.0001), whereas the ISI was not.

CONCLUSIONS

In nondiabetic subjects with various degrees of glucose intolerance, there was a significant increase in IMT in those with IFG and IGT. Significant determinants of IMT, an indicator of preclinical atherosclerosis, include hyperglycaemia 2 h after a glucose load, age and LDL cholesterol, whereas fasting glucose concentration and the ISI were not significantly associated with IMT.

Hypercholesterolemia, not metabolic syndrome, related to adhesion of monocytes to cultured endothelium in nondiabetic subjects

The interaction of leukocytes and endothelium plays an important role in the development of atherosclerosis. Previous studies found that adhesion of leukocytes to endothelium is greater in subjects with hypercholesterolemia. It is not clear if metabolic syndrome, a contributing risk factor of cardiovascular disease, is related to this adhesion. Therefore, we conducted a study, in which 48 nondiabetic subjects were enrolled, to determine the relationship between leukocyte adhesion and the components of metabolic syndrome. After a 12-hour overnight fast, subjects' fasting blood was obtained for measurement of lipoprotein concentrations and glucose and insulin levels. Results of the number of monocyte adhesion to human umbilical vein endothelial cells were divided into high monocyte adhesion group and low monocyte adhesion group (n=24 in each group). Plasma concentrations of total cholesterol (245 +/- 5 vs 229+/- 4 mg/dL, P=.021) and low-density lipoprotein cholesterol (LDL-C) (162+/- 4 vs 146+/- 3 mg/dL, P=.003) were both higher in the high monocyte adhesion group than in the low monocyte adhesion group. Monocyte adhesion was significantly correlated to plasma concentrations of LDL-C (r=0.407, P=.002) but not to the total cholesterol (r=0.202, P=.085). However, there was no difference in monocyte adhesion to endothelium between subjects with or without metabolic syndrome, based on the modified criteria from the Adult Treatment Panel III of the National Cholesterol Education Program. Insulin resistance index, presented as homeostasis model assessment insulin resistance, and glucose or insulin responses to oral glucose tolerance test were similar between groups. Our study demonstrated that monocyte adhesion to endothelium has a stronger relationship with the plasma concentration LDL-C than with characteristics of metabolic syndrome.

Relation of plasma glucose and endothelial function in a population-based multiethnic sample of subjects without diabetes mellitus

To determine whether endothelial dysfunction precedes the clinical diagnosis of diabetes mellitus, we investigated the relation of endothelial flow-mediated dilation (FMD) with fasting plasma glucose among a multiethnic population-based cohort of 579 nondiabetic subjects without previous myocardial infarction or stroke enrolled in the Northern Manhattan Study (age 66 +/- 9 years; 41% men, 16% white, 15% black, and 68% Hispanic). Impaired fasting glucose or prediabetic status, defined as a fasting glucose level of 100 to 125 mg/dl, was present in 95 subjects (16%). Endothelial function was determined using FMD during reactive hyperemia. Multiple linear regression analyses were used to assess the relation between plasma glucose and endothelial function after adjustment for potential confounders. FMD was significantly lower (4.9 +/- 3.8% vs 6.1 +/- 3.7%, p = 0.003) in those with impaired fasting glucose than in subjects with normal fasting glucose. Prediabetic status was significantly associated with impaired FMD (odds ratio 1.9, 95% confidence interval 1.1 to 3.1, p = 0.02). After adjustment for age, gender, body mass index, and hypertensive status, a higher fasting glucose was significantly associated with a lower FMD (beta = -0.024 +/- 0.012, p = 0.04) in a continuous linear relation. Thus, for each 10-mg/dl increase in plasma glucose, a 0.24% decrease occurred in FMD. Impaired FMD was present among prediabetics. An elevated fasting plasma glucose level is associated with impaired endothelial function among nondiabetics. These results further support the role of hyperglycemia in the pathogenesis of vascular dysfunction at different stages of diabetes development and the role of impaired fasting glucose as a risk factor for macrovascular disease.

Normal fasting plasma glucose levels and type 2 diabetes in young men

BACKGROUND

The normal fasting plasma glucose level was recently defined as less than 100 mg per deciliter (5.55 mmol per liter). Whether higher fasting plasma glucose levels within this range independently predict type 2 diabetes in young adults is unclear.

METHODS

We obtained blood measurements, data from physical examinations, and medical and lifestyle information from men in the Israel Defense Forces who were 26 to 45 years of age.

RESULTS

A total of 208 incident cases of type 2 diabetes occurred during 74,309 person-years of follow-up (from 1992 through 2004) among 13,163 subjects who had baseline fasting plasma glucose levels of less than 100 mg per deciliter. A multivariate model, adjusted for age, family history of diabetes, body-mass index, physical-activity level, smoking status, and serum triglyceride levels, revealed a progressively increased risk of type 2 diabetes in men with fasting plasma glucose levels of 87 mg per deciliter (4.83 mmol per liter) or more, as compared with those whose levels were in the bottom quintile (less than 81 mg per deciliter [4.5 mmol per liter], P for trend <0.001). In multivariate models, men with serum triglyceride levels of 150 mg per deciliter (1.69 mmol per liter) or more, combined with fasting plasma glucose levels of 91 to 99 mg per deciliter (5.05 to 5.50 mmol per liter), had a hazard ratio of 8.23 (95 percent confidence interval, 3.6 to 19.0) for diabetes, as compared with men with a combined triglyceride level of less than 150 mg per deciliter and fasting glucose levels of less than 86 mg per deciliter (4.77 mmol per liter). The joint effect of a body-mass index (the weight in kilograms divided by the square of the height in meters) of 30 or more and a fasting plasma glucose level of 91 to 99 mg per deciliter resulted in a hazard ratio of 8.29 (95 percent confidence interval, 3.8 to 17.8), as compared with a body-mass index of less than 25 and a fasting plasma glucose level of less than 86 mg per deciliter.

CONCLUSIONS

Higher fasting plasma glucose levels within the normoglycemic range constitute an independent risk factor for type 2 diabetes among young men, and such levels may help, along with body-mass index and triglyceride levels, to identify apparently healthy men at increased risk for diabetes.

Glycosylated hemoglobin and mortality in patients with nondiabetic chronic kidney disease

In the general population, hyperglycemia in the absence of diabetes may be associated with increased risk for mortality. Hyperglycemia is prevalent in chronic kidney disease; however, the relationship between glycosylated hemoglobin (HbA(1c)) as a marker of chronic hyperglycemia and outcomes has not been studied in nondiabetic chronic kidney disease. HbA(1c) was measured at baseline in the randomized cohort of the Modification of Diet in Renal Disease Study (n = 840). Participants with diabetes (n = 43), fasting glucose levels >126 mg/dl (n = 20), or missing HbA(1c) levels (n = 9) were excluded. Survival status until December 2000 was obtained from the National Death Index. Death was classified as cardiovascular (CVD) when the primary cause was International Classification of Disease, Ninth Revision codes 390 to 459. Cox models were performed to assess the relationship of HbA(1c) with all-cause and CVD mortality. Mean (SD) age was 52 (12) years, and mean (SD) GFR was 32 (12) ml/min per 1.73 m(2). Eighty-six percent of participants were white, and 61% were male. Mean (SD) HbA(1c) was 5.6% (0.5). A total of 169 (22%) patients died, 96 (13%) from CVD. After adjustment for randomization assignments and demographic, CVD, and kidney disease factors, HbA(1c) was a predictor of all-cause mortality (hazard ratio per 1% increase 1.73; 95% confidence interval 1.24 to 2.41; P = 0.001). There was a trend toward statistical significance in the relationship between HbA(1c) and CVD mortality (hazard ratio per 1% increase 1.53; 95% confidence interval 0.96 to 2.43; P = 0.07). HbA(1c) is associated with increased mortality in nondiabetic kidney disease. Hyperglycemia may be a potential therapeutic target and HbA(1c) may be important as a risk stratification tool in this high-risk population.

Endothelial dysfunction and cardiovascular risk profile in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is consistently associated with features of the metabolic syndrome, a condition carrying a high risk of cardiovascular events. We measured the vasodilatory response of the brachial artery in response to ischemia (a test of endothelial function) (FMV) as well as cardiovascular risk profile in 52 NAFLD cases and 28 age- and sex-matched controls. The 10-year risk of coronary events was calculated according to the Framingham equation and the scores derived from the PROCAM study and NCEP-ATPIII proposals. FMV was 6.33% +/- 5.93% in NAFLD versus 12.22% +/- 5.05% in controls (P < .0001), and higher in pure fatty liver (9.93%) compared with nonalcoholic steatohepatitis (4.94%) (P = .010). No differences were observed in flow-independent vasodilation (response to sublingual nitroglycerin). Percent FMV was negatively associated with insulin resistance (homeostasis model assessment) in the whole population (r = -0.243; P = .030). In logistic regression analysis, NAFLD was associated with a percent FMV in the lower tertile (OR, 6.7; 95% CI, 1.26-36.1), after adjustment for age, sex, body mass index, and insulin resistance. Among NAFLD patients, low FMV was associated with nonalcoholic steatohepatitis (adjusted OR, 6.8; 95% CI, 1.2-40.2). The 10-year probability of cardiovascular events was moderately increased in NAFLD, and particularly in nonalcoholic steatohepatitis. In conclusion, our study provides evidence of endothelial dysfunction and increased risk of cardiovascular events in NAFLD. The risk of advanced liver disease is well recognized in NAFLD patients, but the large majority of cases might experience cardiovascular disease in the long term, indirectly limiting the burden of liver failure.

The metabolic syndrome in middle-aged men according to different definitions and related changes in carotid artery intima-media thickness (IMT) during 3 years of follow-up

OBJECTIVES

To examine the occurrence over time of the metabolic syndrome (MetS) according to different definitions and the relation to change during follow-up in carotid artery intima-media thickness (IMT), measured by ultrasound.

DESIGN

A cohort of 316, originally 58-year-old men, initially free of diabetes and cardiovascular disease, was followed for 3.2 +/- 0.2 years. IMT was measured bilaterally by high-resolution B-mode ultrasound at baseline and follow-up. The MetS was classified according to slightly modified World Health Organization (WHO) and National Cholesterol Education Program (NCEP) criteria.

RESULTS

In 88% WHO and NCEP definitions resulted in identical classifications. IMT was larger both at baseline and after 3 years in men fulfilling the criteria for the MetS, according to either of the definitions, compared to those without factors in the syndrome. Men who fulfilled the WHO criteria for the MetS, at the initial and final examination showed a statistically significant increase in carotid artery IMT during the study [76 (95% CI: 14-130) microm, n = 37]. Men fulfilling the WHO criteria for the MetS at baseline tended to have a larger annual increase in IMT than those not fulfilling the criteria or having no risk factors in the syndrome.

CONCLUSIONS

More than 10% of the men had the MetS both at baseline and after 3 years, and this was associated with an increase in IMT using the WHO definition. Several of the components included in the MetS deteriorated during follow-up, i.e. body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, blood glucose and blood pressure.

Renal Insulin Resistance Syndrome, Adiponectin and Cardiovascular Events in Patients with Kidney Disease: The Mild and Moderate Kidney Disease Study

The relationship among insulin resistance, adiponectin, and cardiovascular (CV) morbidity in patients with mild and moderate kidney disease was investigated. Insulin sensitivity (Homeostasis Model Assessment of Insulin Resistance [HOMA-IR]) and adiponectin plasma levels were assessed in 227 nondiabetic renal patients at different degrees of renal dysfunction and in 76 healthy subjects of similar age and gender distribution and body mass index. In renal patients, association with prevalent CV events was evaluated, and incident CV events were evaluated in a prospective study. HOMA-IR was markedly higher in patients than in healthy subjects (3.59 +/- 3.55 versus 1.39 +/- 0.51; P < 0.01). In renal patients, HOMA-IR was significantly correlated with body mass index (r = 0.477; P < 0.01), triglycerides (r = 0.384; P < 0.01), adiponectin plasma levels (r = -0.253; P < 0.01), and age (r = 0.164; P < 0.05), but not with renal function (GFR by iod-thalamate clearance). Patients with previous CV events were significantly older, had higher HOMA-IR and serum triglycerides, and had lower adiponectin plasma levels (all P < 0.05). Logistic regression analysis revealed age (P < 0.001) and adiponectin (P < 0.002) as independent variables related to prevalent CV events. In the prospective study, median follow-up was 54 mo. Patients who experienced CV events had significantly higher serum glucose and lower adiponectin plasma levels (both P < 0.05). In patients with chronic kidney diseases, a syndrome of insulin resistance is present even in the earliest stage of renal dysfunction, and several components of this syndrome are associated with CV events. Moreover, hypoadiponectinemia is a novel putative CV risk factor in patients with mild and moderate renal failure.