Diagnosing insulin resistance in the general population

A WFS1 haplotype consisting of the minor alleles of rs752854, rs10010131, and rs734312 shows a protective role against type 2 diabetes in Russian patients

BACKGROUND

Rare variants of the WFS1 gene encoding wolframin cause Wolfram syndrome, a monogenic disease associated with diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. In contrast, common variants of WFS1 showed association with type 2 diabetes (T2D) in numerous Caucasian populations.

AIM

In this study, we tested whether the markers rs752854, rs10010131, and rs734312, located in the WFS1 gene, are related to the development of T2D in a Russian population.

METHODS

The polymorphic markers were genotyped in Russian diabetic (n = 1,112) and non-diabetic (n = 1,097) patients using a Taqman allele discrimination assay. The correlation between the carriage of disease-associated WFS1 variants and the patients' clinical and metabolic characteristics was studied using ANOVA and ANCOVA. Adjustment for confounding variables such as gender, age, body mass index, obesity, HbA1c, and hypertension was made.

RESULTS

Haplotype GAG, consisting of the minor alleles of rs752854, rs10010131, and rs734312, respectively, showed association with decreased risk of T2D (OR = 0.44, 95% CI = 0.32-0.61, p = 4.3 x 10(-7)). Compared to other WFS1 variants, non-diabetic individuals homozygous for GAG/CAG had significantly increased fasting insulin (p(adjusted) = 0.047) and homeostasis model assessment of β-cell function (HOMA-β) index (p(adjusted) = 0.006). Diabetic patients homozygous for GAG/GAG showed significantly elevated levels of 2-h insulin (p(adjusted) = 0.029) and HOMA-β = 0.011.

CONCLUSIONS

Disease-associated variants of WFS1 contribute to the pathogenesis of T2D through impaired insulin response to glucose stimulation and altered β-cell function.

Comparison between surrogate indexes of insulin sensitivity/resistance and hyperinsulinemic euglycemic glucose clamps in rhesus monkeys

The euglycemic glucose clamp is the reference method for assessing insulin sensitivity in humans and animals. However, clamps are ill-suited for large studies because of extensive requirements for cost, time, labor, and technical expertise. Simple surrogate indexes of insulin sensitivity/resistance including quantitative insulin-sensitivity check index (QUICKI) and homeostasis model assessment (HOMA) have been developed and validated in humans. However, validation studies of QUICKI and HOMA in both rats and mice suggest that differences in metabolic physiology between rodents and humans limit their value in rodents. Rhesus monkeys are a species more similar to humans than rodents. Therefore, in the present study, we evaluated data from 199 glucose clamp studies obtained from a large cohort of 86 monkeys with a broad range of insulin sensitivity. Data were used to evaluate simple surrogate indexes of insulin sensitivity/resistance (QUICKI, HOMA, Log HOMA, 1/HOMA, and 1/Fasting insulin) with respect to linear regression, predictive accuracy using a calibration model, and diagnostic performance using receiver operating characteristic. Most surrogates had modest linear correlations with SI(Clamp) (r ≈ 0.4-0.64) with comparable correlation coefficients. Predictive accuracy determined by calibration model analysis demonstrated better predictive accuracy of QUICKI than HOMA and Log HOMA. Receiver operating characteristic analysis showed equivalent sensitivity and specificity of most surrogate indexes to detect insulin resistance. Thus, unlike in rodents but similar to humans, surrogate indexes of insulin sensitivity/resistance including QUICKI and log HOMA may be reasonable to use in large studies of rhesus monkeys where it may be impractical to conduct glucose clamp studies.

Metabolic syndrome in liver transplant recipients: prevalence, risk factors, and association with cardiovascular events

Features of metabolic syndrome are not uncommon in patients after liver transplantation. To examine the prevalence and risk factors of posttransplantation metabolic syndrome (PTMS), the files of 252 transplant recipients (mean age, 54.5 ± 2.8 years, 57.9% male) were reviewed for pretransplant and posttransplant clinical and laboratory parameters (mean follow-up, 6.2 ± 4.4 years). Rates of obesity (body mass index >30 kg/m(2) ), hypertriglyceridemia (>150 mg/dL), high-density lipoprotein cholesterol <40 mg/dL (men) or <50 mg/dL (women), hypertension, and diabetes were significantly higher after transplantation than before. Metabolic syndrome was diagnosed in 5.4% of patients before transplantation and 51.9% after. Besides significantly higher rates of the typical metabolic derangements (P < 0.0001), the patients with PTMS were older and heavier than those without PTMS, and they had a higher rate of pretransplant hepatitis C virus infection (P < 0.03) and more posttransplant major vascular and cardiac events (20 events in 15.2% of patients with PTMS versus 6 events in 4.9% of patients without PTMS; P < 0.007). There was no between-group difference in mortality or causes of death (mainly related to recurrent disease, graft failure, and sepsis). Significant independent predictors of PTMS on logistic regression analysis were age (odds ratio [OR] = 1.04), pretransplant nonalcoholic fatty liver disease (OR = 3.4), body mass index (OR = 1.13), diabetes (OR = 5.95), and triglycerides (OR = 1.01). The rate of metabolic syndrome in liver transplant recipients is more than twice that reported for the general population. PTMS is associated with cardiovascular morbidity but not mortality, and it may be predicted by pretransplantation conditions. Prospective studies are required to determine the significance and management of PTMS.

Prevalence and association between obesity and metabolic syndrome among Chinese elementary school children: a school-based survey

Background

China has experienced an increase in the prevalence of childhood overweight/obesity over the last decades. The purpose of this study was to examine the prevalence of obesity and metabolic syndrome among Chinese school children and determine if there is a significant association between childhood obesity and metabolic syndrome.

Methods

A cross-sectional study was conducted among 1844 children (938 males and 906 females) in six elementary schools at Guangzhou city from April to June 2009. The body mass index (BMI), waist circumference, blood pressure, Tanner stage, lipids, insulin and glucose levels were determined. Criteria analogous to ATPIII were used for diagnosis of metabolic syndrome in children.

Results

Among 1844 children aged 7-14 years, 205 (11.1%) were overweight, and 133 (7.2%) were obese. The prevalence of metabolic syndrome was 6.6% overall, 33.1% in obese, 20.5% in overweight and 2.3% in normal weight children. Multiple logistic regression analysis showed that BMI (3rd quartile)(OR 3.28; 95%CI 0.35-30.56), BMI (4th quartile)(OR 17.98; 95%CI 1.75-184.34), homeostasis model assessment (HOMA-IR) (2nd quartile) (OR2.36; 95% CI 0.46-12.09), HOMA-IR (3rd quartile) (OR 2.46; 95% CI 0.48-12.66), HOMA-IR (4th quartile) (OR3.87; 95% CI 0.72-20.71) were significantly associated with metabolic syndrome.

Conclusions

The current epidemic of obesity with subsequent increasing cardiovascular risk factors has constituted a threat to the health of school children in China. HOMA-IR and BMI were strong predictors of metabolic syndrome in children. Therefore, rigorous obesity prevention programs should be implemented among them.

Overweight, obesity, and their associations with insulin resistance and β-cell function among Chinese: a cross-sectional study in China

The aim of this study was to evaluate the associations of body mass index (BMI) with insulin resistance and β-cell function in subjects with normal glucose tolerance. A cross-sectional study was carried out in Fujian province by multistratified sampling from July 2007 to May 2008. The sample consisted of 2931 subjects aged from 20 to 79 years. The questionnaires, physical examinations, and laboratory tests were obtained from all the participants. The homeostasis model assessment of insulin resistance (HOMA-IR) index was used to estimate insulin sensitivity, insulin secretion was assessed using the HOMA-β index, and β-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 minutes during the oral glucose tolerance test (ΔI30/ΔG30). Another measure was adjusted for insulin sensitivity as it modulates β-cell function ([ΔI30/ΔG30]/HOMA-IR). Associations of BMI with morbidities were estimated using multiple logistic regression analysis. Relationships of BMI to insulin resistance and β-cell function were assessed using multiple linear regression analysis and analysis of covariance. The age- and sex-adjusted prevalence of overweight and obesity was 23.04% (27.44% in men and 18.40% in women) and 2.65% (2.75% in men and 2.55% in women), respectively. After adjustment for covariables, BMI was independently associated with morbidity conditions; and there were increasing trend for odds ratios of morbidities across the BMI categories. There were independent differences for HOMA-IR, HOMA-β, and ΔI30/ΔG30 between the normal-weight, overweight, and obese groups except for (ΔI30/ΔG30)/HOMA-IR. Body mass index was significantly and independently associated with HOMA-IR, HOMA-β, and ΔI30/ΔG30 in the multiple linear regression analysis. Body mass index was an independent risk factor for hypertension, type 2 diabetes mellitus, dyslipidemia, metabolic syndrome, as well as the indexes of insulin resistance and β-cell function. It is imperative that the whole society pay more attention to the identification and intervention of overweight and obesity to prevent obesity-related diseases at the very early stage.

Insulin resistance is independently associated with liver aminotransferases in diabetic patients without ultrasound signs of nonalcoholic fatty liver disease

BACKGROUND

It has been shown that elevated levels of alanine and aspartate aminotransferases (ALT and AST) are associated with insulin resistance and type 2 diabetes mellitus; however, the pattern of this association in diabetic patients with negative or mild steatosis is not well understood. The aim of this study was to assess the association between elevated liver enzymes and insulin resistance in diabetic subjects without ultrasound signs of nonalcoholic fatty liver disease (NAFLD) (i.e., with less than 30% steatosis).

METHODS

In a cross-sectional study, a total of 670 diabetic subjects without established causes of liver injury were included. Patients with evidence of NAFLD in ultrasonography were not included. Fasting blood samples were obtained and plasma glucose, insulin, glycosylated hemoglobin (HbA1c), C-peptide, alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lipid profile were measured. Three indices of insulin sensitivity/insensitivity: Homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and McAuley were also calculated.

RESULTS

Elevated ALT was significantly (p < 0.001) correlated with fasting insulin, C-peptide, HOMA-IR, QUICKI, McAuley, and waist circumference. The same correlations were also observed for AST, which in all cases were weaker than ALT. Multivariate regression analysis showed that, among the above-mentioned variables, only HOMA-IR and fasting insulin were independently correlated with both ALT and AST. This correlation was independent of body mass index (BMI) or waist circumference.

CONCLUSION

In type 2 diabetes, in the absence of a detectable steatosis by ultrasonography, ALT and AST are associated with hyperinsulinemia and insulin resistance, independent of obesity. This finding possibly indicates that in diabetes a mild stage of steatosis is sufficient to mediate the association between insulin resistance and aminotransferases.

Effects of a nutraceutical combination (berberine, red yeast rice and policosanols) on lipid levels and endothelial function randomized, double-blind, placebo-controlled study

BACKGROUND AND AIMS

Some nutraceuticals are prescribed as lipid-lowering substances. However, doubts remain about their efficacy. We evaluated the effects of a nutraceutical combination (NC), consisting of 500 mg berberine, 200mg red yeast rice and 10mg policosanols, on cholesterol levels and endothelial function in patients with hypercholesterolemia.

METHODS AND RESULTS

In this single centre, randomized, double-blind, placebo-controlled study, 50 hypercholesterolemic patients (26 males and 24 females, mean age 55±7 years, total cholesterol 6.55±0.75 mmol/l, BMI 28±3.5) were randomized to 6 weeks of treatment with a daily oral dose of NC (25 patients) or placebo (25 patients). In a subsequent open-label extension of 4 weeks, the whole sample received NC. The main outcome measure was decrease total cholesterol (C) levels in the NC arm. Secondary outcome measures were decreased low-density lipoprotein cholesterol (LDL-C) and triglyceride levels, and improved endothelial-dependent flow-mediated dilation (FMD) and insulin sensitivity in relation to NC. Evaluation of absolute changes from baseline showed significant reductions in NC versus placebo for C and LDL-C (C: -1.14±0.88 and -0.03±0.78 mmol/l, p<0.001; LDL-C: -1.06±0.75 and -00.4±0.54 mmol/l, p<0.001), and a significant improvement of FMD (3±4% and 0±3% respectively, p<0.05). After the extension phase, triglyceride levels decreased significantly from 1.57±0.77 to 1.26±0.63 mmol/l, p<0.05 and insulin sensitivity improved in a patient subgroup with insulin resistance at baseline (HOMA: from 3.3±0.4 to 2.5±1.3, p<0.05). No adverse effect was reported.

CONCLUSIONS

This NC reduces cholesterol levels. The reduction is associated with improved endothelial function and insulin sensitivity.

Insulin resistance and risk of incident hypertension among men

J Clin Hypertens (Greenwich). 2009;11:483-490. (c) 2009 Wiley Periodicals, Inc.The independent association between insulin resistance and the development of hypertension remains in doubt because insulin resistance correlates with other metabolic factors also proposed to be associated with hypertension. The authors examined the association between the insulin sensitivity index and incident hypertension in a prospective nested case-control study among 1453 men (mean age, 61 years) who participated in the Health Professionals' Follow-up Study. The authors computed the insulin sensitivity index for each man in the study based on fasting insulin and triglyceride levels. Logistic regression was performed conditioned on age and adjusted for standard hypertension risk factors as well as renal function, cholesterol, and uric acid. The insulin sensitivity index was 6% lower in the cases compared with the controls (P<.001). The multivariable odds ratio for hypertension comparing the lowest with highest quartile of insulin sensitivity index was 1.09 (0.71-1.65) among the entire sample. However, the association between the insulin sensitivity index and incident hypertension differed significantly by age (P interaction <.001). Among men younger than 60 years, the multivariable odds ratio for the lowest compared with highest quartile was 1.93 (1.01-3.71) but was 0.67 (0.37-1.24) among older men. Insulin resistance is independently associated with incident hypertension among younger men.

Chronic ethanol feeding impairs AMPK and MEF2 expression and is associated with GLUT4 decrease in rat myocardium

Chronic and heavy alcohol consumption is one of the causes of heart diseases. However, the effects of ethanol on insulin sensitivity in myocardium has been unclear. To investigate the effects of ethanol on the expression of AMP-activated protein kinase (AMPK), myocyte enhancer factor 2 (MEF2) and glucose transporter 4 (GLUT4), all of which are involved in the regulation of insulin sensitivity, in the myocardium, we performed three parts of experiments in vivo and in vitro. I: Rats were injected with 5-amino-4-imidazolecarboxamide ribonucleotide (AICAR, 0.8 mg.kg(-l)) for 2 h. II: Rats received different dose (0.5, 2.5 or 5 g.kg(-l).d(-l)) of ethanol for 22-week. III: Primary neonatal rat cardiomyocytes were isolated and treated with or without 100 mM ethanol or 1 mM AICAR for 4 h. The cardiac protein and mRNA expression of AMPKalpha subunits, MEF2 and GLUT4 were observed by western-blotting and RT-PCR, respectively. Serum TNFalpha levels were assessed by ELISA. The results showed chronic ethanol exposure induced insulin resistance. Ethanol decreased the mRNA levels of AMPKalpha1 and alpha2, the protein levels of total- and phospho-AMPKalpha in cardiomyocytes. Similarly, ethanol showed inhibitory effects on both the mRNA and protein levels of MEF2A and 2D, and GLUT4 in a dose-response-like fashion. Correlation analysis implied an association between phospho-AMPKalpha and MEF2A or MEF2D, and between the levels of MEF2 protein and GLUT4 transcription. In addition, ethanol elevated serum TNFalpha level. Taken together, chronic ethanol exposure decreases the expression of AMPKalpha and MEF2, and is associated with GLUT4 decline in rat myocardium.

Adiponectin-leptin ratio: a useful estimate of insulin resistance in patients with Type 2 diabetes

AIMS

Adiponectin and leptin are adipocytokines associated with insulin resistance. The objective of this study was to evaluate the performance of the adiponectin-leptin ratio as a measure of insulin resistance in comparison with other surrogate measures of insulin resistance based on fasting insulin and glucose levels [homeostasis model assessment (HOMA), quantitative insulin sensitivity check index (QUICKI), fasting glucose/insulin ratio] and with measures based on fasting insulin and triglyceride levels (McAuley index) in Caucasian patients with Type 2 diabetes (T2D).

METHODS

In 70 patients included in DEMAND (delapril and manidipine for nephroprotection in diabetes) study, fasting samples of plasma insulin and adiponectin were determined by a radioimmunoassay, whereas plasma leptin was determined by an enzyme-linked immunosorbent assay. Insulin resistance estimates were derived by the established equations and compared with the direct measurement of insulin resistance obtained with the euglycemic hyperinsulinemic clamp. Insulin resistance estimates and the clamp derived sensitivity index were compared by correlation analysis.

RESULTS

The adiponectin-leptin ratio correlated best with the clamp derived sensitivity index (r=0.553, p<0.001) compared to other surrogate measures of insulin resistance. In multiple linear regression models including different surrogate measures of insulin resistance as independent predictors of the sensitivity index, the model with the adiponectin-leptin ratio accounted for the highest variability of the sensitivity index (r2=0.336, p<0.001).

CONCLUSIONS

The adiponectin-leptin ratio is associated with insulin resistance, measured with the euglycemic hyperinsulinemic clamp, in Caucasians with T2D. The association with clamp derived sensitivity index is even stronger than that of HOMA, QUICKI, fasting glucose/insulin ratio or McAuley index and is independent of body mass index or glycemic control. The adiponectin-leptin ratio promises to become a new laboratory marker of insulin resistance in T2D.

Body mass index and waist circumference cutoffs to define obesity in indigenous New Zealanders

BACKGROUND

The suggestion that body mass index (BMI) cutoffs to define obesity should differ in persons of Polynesian descent compared with Europeans is based principally on the observation that persons of Polynesian descent have a relatively higher proportion of lean body mass for a given BMI.

OBJECTIVES

The objectives were to determine whether the relation between BMI, waist circumference, and metabolic comorbidity differs in the 2 major ethnic groups in New Zealand and to ascertain whether ethnicity-specific BMI and waist circumference cutoffs for obesity are justified for Māori (indigenous New Zealanders).

DESIGN

Subjects included a convenience sample of 1539 men and women aged 17-82 y (47% Māori, 53% white) with measures of BMI, waist circumference, blood pressure, fasting insulin, glucose, and lipids. The sensitivity and specificity of BMI (in kg/m(2); 30 and 32), waist circumference (80 and 88 cm in women, 94 and 102 cm in men), and waist-to-height ratio (WHtR; > or =0.6) in relation to insulin sensitivity, insulin resistance, and the metabolic syndrome were determined. Receiver operating characteristic curves and areas under the curve (AUCs) were also calculated.

RESULTS

No ethnic or sex differences between AUCs were observed for BMI, waist circumference, or WHtR, which showed that these anthropometric measures perform similarly in Māori and European men and women and correctly discriminate between those with and without insulin resistance or the metabolic syndrome 79-87% of the time. Any increase in specificity from a higher BMI cutoff of 32 in Māori was offset by appreciable reductions in sensitivity.

CONCLUSION

These findings argue against having different BMI or waist circumference cutoffs for people of Polynesian descent.

Nutritional intervention in patients with type 2 diabetes who are hyperglycaemic despite optimised drug treatment--Lifestyle Over and Above Drugs in Diabetes (LOADD) study: randomised controlled trial

OBJECTIVE

To determine the extent to which intensive dietary intervention can influence glycaemic control and risk factors for cardiovascular disease in patients with type 2 diabetes who are hyperglycaemic despite optimised drug treatment.

DESIGN

Randomised controlled trial.

SETTING

Dunedin, New Zealand.

PARTICIPANTS

93 participants aged less than 70 years with type 2 diabetes and a glycated haemoglobin (HbA(1c)) of more than 7% despite optimised drug treatments plus at least two of overweight or obesity, hypertension, and dyslipidaemia.

INTERVENTION

Intensive individualised dietary advice (according to the nutritional recommendations of the European Association for the Study of Diabetes) for six months; both the intervention and control participants continued with their usual medical surveillance.

MAIN OUTCOME MEASURES

HbA(1c) was the primary outcome. Secondary outcomes included measures of adiposity, blood pressure, and lipid profile.

RESULTS

After adjustment for age, sex, and baseline measurements, the difference in HbA(1c) between the intervention and control groups at six months (-0.4%, 95% confidence interval -0.7% to -0.1%) was highly statistically significant (P=0.007), as were the decreases in weight (-1.3 kg, -2.4 to -0.1 kg; P=0.032), body mass index (-0.5, -0.9 to -0.1; P=0.026), and waist circumference (-1.6 cm, -2.7 to -0.5 cm; P=0.005). A decrease in saturated fat (-1.9% total energy, -3.3% to -0.6%; P=0.006) and an increase in protein (1.6% total energy, 0.04% to 3.1%; P=0.045) in the intervention group were the most striking differences in nutritional intake between the two groups.

CONCLUSIONS

Intensive dietary advice has the potential to appreciably improve glycaemic control and anthropometric measures in patients with type 2 diabetes and unsatisfactory HbA(1c) despite optimised hypoglycaemic drug treatment.

TRIAL REGISTRATION

Clinical trials NCT00124553.

Impending hyperglycemia in normoglycemic renal transplant recipients--an experimental predictive surrogate

BACKGROUND

beta-Cell dysfunction and insulin resistance combine to cause new-onset diabetes after transplantation. The product of these two parameters, quantitatively measured as disposition index (DI), is a mathematical constant in normoglycemia and declines in advance of impending hyperglycemia. The aim of this study was to derive a simple surrogate for the DI to expose predysglycemic abnormalities posttransplantation.

METHODS

First-phase insulin secretion and sensitivity were determined by mathematical minimal model analysis of 58 frequently sampled, intravenous glucose tolerance tests in 58 non-diabetic renal transplant recipients and correlated against surrogate indexes based on fasting blood samples. Products of insulin secretion/resistance indexes were correlated against calculated DI, regression analysis performed for hyperbolic compatibility, autocorrelation studies conducted, and surrogates tested in various subgroups of renal transplant recipients to ensure robustness in a heterogeneous group.

RESULTS

The best correlation was achieved with "HOMA(sec) (first-phase insulin secretion)xMcAuley's index (insulin resistance)" (r=0.594, P<0.001). Regression analysis was consistent with a mathematical hyperbola (ln HOMA(sec) vs. ln McAuley's index, r=-0.639 [95% confidence interval, -1.772 to -0.950]), statistical autocorrelation was excluded (in a subset of 20 patients with repeat metabolic investigations), and the surrogate remained valid in different subgroups of transplant recipients.

CONCLUSIONS

Our surrogate "HOMA(sec)xMcAuley's index," requiring only fasting glucose, insulin, and triglycerides, is a simple and noninvasive surrogate for the DI. Its predictive utility for identifying impending hyperglycemia posttransplantation should be investigated further to ascertain whether its experimental nature can translate to clinical validity.

Prevalence, associated factors and relationship between prehypertension and hypertension: a study of two ethnic African populations in Northern Nigeria

To determine the prevalence and relationship between prehypertension and hypertension, we studied 782 ethnic Hausa and Fulanis (men, 409; women, 373) aged 38.9±13.9 years recruited by multistage cluster sampling. Demographic, anthropometry, metabolic and JNC VII-based blood pressure categories were obtained and analysed using univariate and multivariate models. The prevalence rates of prehypertension and hypertension were 58.7% (men 59.2%, women 58.2%) and 24.8% (men 25.9%, women 23.6%), respectively. Only 16.5% of the population had JNC VII defined optimum blood pressure. Compared to hypertension, prehypertension had earlier onset (second versus third decade) and peak (fourth versus fifth decade) of life. The peak and trough prevalence of hypertension and prehypertension, respectively were observed in the 5th decade of life. Obesity, abnormalities of glucose metabolism and insulin resistance were the major factors associated with prehypertension and hypertension. Multivariate analysis identified obesity and impaired glucose tolerance as independent predictors of hypertension. Of those with hypertension, 13.9% were aware of their high blood pressure status of which 85.7% were commenced on treatment and 12.5% achieved blood pressure control. Overall, 1.5% of the study population had blood pressure <140/90 mm Hg. It is concluded that less than 20% of people of Hausa and Fulani ethnicities had optimum blood pressure. These are predominantly in their second decade of life suggesting that rise in blood pressure begins early in this population. The fifth decade of life may represent a period of transition from prehypertension to hypertension.

Relationship between body mass index and insulin resistance in patients treated with second generation antipsychotic agents

Second generation antipsychotics (SGAs) can increase weight gain and weight-induced insulin resistance. Recent studies have suggested weight-independent effects of certain SGAs on insulin resistance; however the magnitude of these effects and the relationship between BMI and insulin resistance in patients on SGAs are not established. To evaluate, the relationship between body mass index (BMI) and insulin resistance in 54 patients being stably treated with olanzapine (n=19), risperidone (n=16), or aripiprazole (n=19) was compared with data from a large reference population (n=201) not on SGAs. Insulin resistance was directly quantified by measuring the steady-state plasma glucose (SSPG) concentration during the insulin suppression test. The relationship between BMI and SSPG was similar between the SGA (r=0.58) and the reference population (r=0.50). When SSPG was standardized based on expected values for the reference population, patients on olanzapine had a higher degree of insulin resistance (mean z-score+/-SD, 0.68+/-0.9) than expected for level of BMI compared with those on aripiprazole (-0.25+/-1) and risperidone (-0.3+/-0.9), F(2,51)=6.28 (p=0.004). Thus, olanzapine group was 0.76 SD above the reference population or in the 78 percentile for insulin resistance. SSPG was correlated with fasting plasma insulin concentration (0.78 (0.64-0.87), p<0.001) but not fasting glucose concentration (0.15 (-0.13-0.40), p=0.29). In conclusion, BMI contributes a quarter to a third of the variance in insulin resistance in the SGA population similar to the reference population. Olanzapine also appears to have an independent effect on insulin resistance that is above and beyond obesity.

Comparison of various maternal anthropometric indices of obesity for identifying metabolic syndrome in offspring

BACKGROUND

Several maternal anthropometric markers have been associated with the metabolic syndrome (MS) in offspring. The objectives of this study were (1) to determine the association between children's MS and maternal anthropometric markers such as body mass index (BMI), waist circumference (WC), WC/height, weight/sitting height squared, and WC/sitting height and (2) to compare the abilities of these five indices to identify children with MS.

METHODS

Data were collected cross-sectionally from five elementary schools between April 2007 and March 2008. BMI, WC, WC/height, weight/sitting height squared, and WC/sitting height were acquired in mothers and their children. Tanner stage, blood pressure, glucose, lipids, and insulin were measured in children. Criteria analogous to Adult Treatment Panel III for MS were used for children.

RESULTS

Of 624 children (307 boys) 8.96 +/- 1.86 years old, with their mothers being 36.25 +/- 7.14 years old, examined, 107 (17.1%) of children were obese (BMI >95th percentile per Centers for Disease Control and Prevention norms), and 95 (15.2%) were overweight (OW) (85th percentile < or =BMI < 95th percentile). Of the mothers, 109 (30.4%) were obese (BMI > 30 kg/m(2)), and 206 (33.0%) were OW (25 kg/m(2) < BMI < 30 kg/m(2)). Approximately 68% of the children were prepubertal. The prevalence of MS was 3.5% overall: 6.7% in OW and 13.9% in obese children. To determine which marker was a better predictor for MS, a receiver operating characteristics (ROC) curve was generated for the five maternal anthropometric measures, with children's MS as the dichotomous variable. The areas under the ROC curves were 0.697 +/- 0.07 for BMI, 0.698 +/- 0.07 for WC, 0.717 +/- 0.07 for WC/height, 0.725 +/- 0.07 for WC/sitting height, and 0.704 +/- 0.07 for weight/sitting height squared. There was no significant difference between the areas of the five maternal anthropometric markers as predictors of children's MS.

CONCLUSIONS

Measurement of maternal sitting height had no advantages over total height in the prediction of children's MS. All maternal anthropometric measures identified the MS in their children consistent with known familial associations of obesity and type 2 diabetes.

Dietary salt loading impairs arterial vascular reactivity

BACKGROUND

Studies of sodium have shown improvements in vascular function and blood pressure (BP). The effect of chronic sodium loading from a low-sodium diet to a Western diet on vascular function and BP has been less well studied.

OBJECTIVE

The objective was to examine the effects of dietary salt intake on vascular function and BP.

DESIGN

Thirty-five hypertensive volunteers met the inclusion criteria. After a 2-wk run-in with a low-sodium diet (60 mmol/d), the participants maintained their diets and were randomly assigned to receive sequentially 1 of 3 interventions for 4 wk, with a 2-wk washout between interventions: sodium-free tomato juice (A), tomato juice containing 90 mmol Na (B), and tomato juice containing 140 mmol Na (C). The outcomes were changes in pulse wave velocity (PWV), systolic BP (SBP), and diastolic BP (DBP).

RESULTS

The difference in PWV between interventions B and A was 0.39 m/s (95% CI: 0.18, 0.60 m/s; P < or = 0.001) and between C and A was 0.35 m/s (95% CI: 0.13, 0.57 m/s; P < or = 0.01). Differences in SBP and DBP between interventions B and A were 4.4 mm Hg (95% CI: 1.2, 7.8 mm Hg; P < or = 0.01) and 2.4 mm Hg (95% CI: 0.8, 4.1 mm Hg; P < or = 0.001), respectively, and between interventions C and A were 5.6 mm Hg (95% CI: 2.7, 8.4 mm Hg; P < or = 0.01) and 3.3 mm Hg (95% CI: 1.5, 5.0 mm Hg; P < or = 0.001), respectively. Changes in PWV correlated with changes in SBP (r = 0.52) and DBP (r = 0.58).

CONCLUSIONS

Dietary salt loading produced significant increases in PWV and BP in hypertensive volunteers. Correlations between BP and PWV suggest that salt loading may have a BP-independent effect on vascular wall function. This further supports the importance of dietary sodium restriction in the management of hypertension. This trial was registered with the Australian and New Zealand Clinical Trials Registry as ACTRN12609000161224.

Impaired glucose metabolism and the exaggerated blood pressure response to exercise treadmill testing in normotensive patients

The authors aimed to investigate the association between glucose metabolism measures and the exaggerated blood pressure response (EXBPR) to exercise testing in normotensive nondiabetic patients. One hundred and forty-two consecutive patients underwent office blood pressure (BP) measurements, 24-hour BP monitoring, echocardiography, and treadmill exercise test according to the Bruce protocol. The population was divided into 2 groups according to EXBPR at a submaximal workload level. Furthermore, blood samples were obtained for fasting glucose (FG), fasting insulin (FI), and lipid profile assessment. Measures of insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], and McAuley index) were also estimated, and a standardized oral glucose tolerance test was performed to evaluate glucose levels at 120 minutes (G120). Patients with EXBPR (n=40; 27 men) compared with those without EXBPR (n=102; 66 men) were older by 4+/-6 years (P<.001). FG, FI, G120, HOMA-IR, QUICKI, and McAuley index differed in patients with EXBPR compared with those without EXBPR (P<.001 for all). Logistic multivariable regression models revealed that the studied glucose metabolism measures, duration of exercise, and 24-hour systolic BP remained determinants of EXBPR (P<.05 for all) after adjustment. Impaired glucose measures are significant determinants of EXBPR to exercise testing in normotensive nondiabetic patients, suggesting that impaired glucose metabolism may contribute to adverse cardiovascular prognosis including new-onset hypertension.

Associação entre acrocórdons e resistência à insulina

FUNDAMENTOS: Acrocórdons são lesões dermatológicas comuns na população e estão associados ao diabetes mellitus, à obesidade, à resistência insulínica e à aterosclerose. A identificação precoce de pacientes com resistência insulínica pode ter papel preventivo primário. OBJETIVO: Avaliar a associação entre presença de acrocórdons cervicais ou axilares e resistência insulínica. MÉTODOS: Estudo transversal com pacientes dermatológicos adultos atendidos em hospital universitário. Casos foram definidos como portadores de mais de cinco acrocórdons cervicais e/ou axilares. A resistência insulínica foi estimada pelo índice HOMA-IR. Resultados foram ajustados pelas demais covariáveis de risco para resistência insulínica conhecidos, a partir de regressão logística múltipla. RESULTADOS: Avaliaram-se 98 casos e 103 controles, que não diferiram entre si quanto à idade ou ao gênero. Acrocórdons se associaram diretamente aos valores de HOMA-IR (Odds Ratio = 1,4), hipertrigliceridemia e índice de massa corpórea, independentemente do ajuste por diabetes mellitus, idade, fototipo, gênero, história de diabetes mellitus familiar e relação cintura/quadril. Níveis qualitativamente elevados de HOMA-IR (> 3,8) também evidenciaram associação significativa (Índice de probabilidade = 7,5). CONCLUSÕES: Presença de múltiplos acrocórdons se associou à resistência insulínica, independentemente dos demais fatores de risco.

The PPARgamma Pro12Ala variant is associated with insulin sensitivity in Russian normoglycaemic and type 2 diabetic subjects

The second isoform of the PPARgamma2 is specific for adipose tissue. In adipocytes, this isoform is involved in the regulation of adipogenesis and lipid storage, insulin and glucose metabolism. Pro12Ala, a missense mutation in exon 2 of PPARG, reduces transcriptional activity of PPARgamma2 and is shown to be associated with increased insulin sensitivity and protection from T2D. Previously, this polymorphism has never been assessed in a Russian population for its relationship to T2D, insulin resistance, and diabetes-related metabolic traits. In this study, we tested 588 Russian T2D patients and 597 normoglycaemic controls. Carriers of the Pro12 allele and subjects homozygous for Pro/Pro had significantly increased risk of developing T2D (OR 1.43 and 2.04, respectively). In Pro/Pro homozygotes, adjustment for potential confounding risk factors resulted in reducing the OR value from 2.04 to 1.69, but the association remained significant (p=0.046).The Pro/Pro genotype also showed association with increased levels of fasting insulin (p=0.019) in non-diabetic controls and elevated serum triglycerides (p=0.019) in T2D patients. Compared with other genotypes, non-diabetic and diabetic subjects homozygous for Pro/Pro had a significantly higher HOMA-IR score and reduced ISI value. This observation strongly supports the implication of the PPARG Pro12Ala in insulin resistance and T2D in a Russian population.

Relationship between obesity and metabolic syndrome among Argentinean elementary school children

BACKGROUND

Argentina has experienced marked increases in the prevalence of childhood overweight (OW)/obesity over the last few decades.

OBJECTIVES

We examined (1) the distribution of the mean values of lipids, glucose, and HOMA-IR according to the presence of OW/obesity, age, and sex and (2) the association between metabolic syndrome and OW/obesity, Tanner stage, gender, and HOMA-IR.

METHODS

Data were collected from 1009 children (508 males) in 10 elementary schools between April and September 2007. BMI, waist circumference, blood pressure, Tanner, lipids, insulin, and glucose were determined. Criteria analogous to ATPIII were used for metabolic syndrome in children.

RESULTS

Over 1009 children (508 males) aged 9.4 + or - 2.0 years were evaluated. One hundred and sixty-five (16.4%) were obese (>95th percentile), and 166 (16.5%) were OW (85-95th). Twenty-five (2.5%) were severely obese (BMI>99th). Most of the children (62%; 613/979) were at Tanner 1. Triglycerides, insulin, and HOMA-IR were higher (p<0.001) and HDL-C lower (p<0.001) in OW/obesity in both age groups and genders. The prevalence of metabolic syndrome was 5.8% overall, 32% in severely obese, 16.4% in OW/obese and 0.4% in normal weight children. Multiple logistic regression showed that BMI (OR 24.48; 95% CI 9.14-65.57), and HOMA-IR (OR 2.09; 95% CI 1.04-4.18) were associated with metabolic syndrome adjusted by gender and Tanner stage. Multiple linear regression also showed that BMI and HOMA-IR were independently associated with the number of metabolic syndrome components (R(2)=0.46).

CONCLUSIONS

A substantial number of OW/obese children have the metabolic syndrome. HOMA-IR and BMI were strong predictors of metabolic syndrome in children suggesting that OW/obese school children are at a higher risk for future cardiovascular disease.

Comparison of different anthropometric indices for identifying insulin resistance in schoolchildren

OBJECTIVES

Anthropometric indices have been associated with insulin resistance in children. This study (1) determined the association between insulin resistance and anthropometric indices, including body mass index (BMI), waist circumference (WC), WC/height, weight/(sitting height)(2), and WC/sitting height, and (2) compared the abilities of these five indices to identify children with insulin resistance.

METHODS

Data were collected from six elementary schools in Argentina between April and August 2007. Anthropometric data and Tanner staging were obtained. Fasting serum concentrations of glucose, lipids, and insulin were measured.

RESULTS

Six hundred twenty-five children (318 boys) between 6 and 14 years old were examined. The mean age of the children was 9.6 +/- 2.0 years. Ninety-six (15.4%) of the children were obese, 91 (14.6%) were overweight, and 438 (70.1%) were normal weight using Centers for Disease Control and Prevention norms. Sixty percent, 23.0%, 14.0%, and 3.0% were Tanner stage I, II, III, and IV, respectively. The areas under the receiver operator characteristic curves were as follows: WC = 0.78 +/- 0.021 (95% confidence interval [CI] 0.74-0.82), BMI = 0.77 +/- 0.022 (95% CI 0.73-0.82), weight/(sitting height)(2) = 0.76 +/- 0.022 (95% CI 0.72-0.81), WC/height = 0.67 +/- 0.027 (95% CI 0.62-0.72), and WC/sitting height = 0.67 +/- 0.27 (95% CI 0.62-0.72), indicating that BMI, WC, and weight/(sitting height)(2) were acceptable predictors for insulin resistance, whereas WC/height and WC/sitting height were fair predictors as the areas under the curve were <0.7.

CONCLUSIONS

This study suggests that WC and BMI are (and remain) the best correlates for insulin resistance. In contrast, the indices of the ratio between WC and height were fair predictors for insulin resistance. Additional longitudinal studies should be done to further confirm these findings.

Soluble CD40 ligand levels in essential hypertensive men: evidence of a possible role of insulin resistance

BACKGROUND

Elevated levels of the proinflammatory cytokine soluble CD40 ligand (sCD40L) were reported in subjects with diabetes, impaired glucose tolerance, metabolic syndrome (MS), obesity, and insulin resistance. Metabolic abnormalities might also account for increased sCD40L in subjects with essential hypertension.

METHODS

Several metabolic and vascular correlates of sCD40L levels have been investigated in 90 nondiabetic never-treated essential hypertensive men.

RESULTS

Median sCD40L level was 8.7 ng/ml (interquartile range: 4.9-11.7). On the basis of sCD40L, subjects were divided by tertiles (thresholds at 6.6 and 11.0 ng/ml). The three groups did not differ for age, body mass index (BMI), smokers, blood pressure (BP), prevalence of nondippers, lipids and lipoproteins, renal function, and albuminuria. Carotid intima-media thickness (IMT: 0.79 +/- 0.22, 0.83 +/- 0.29, and 0.85 +/- 0.30 mm) and percentage of subjects with wall thickening (IMT >0.9 to <1.3 mm: 23, 27, and 27%, respectively) were superimposable in the three groups. No differences were observed in high-sensitivity C-reactive protein (hs-CRP) and no correlation emerged between sCD40L and hs-CRP. An increase through sCD40L tertiles emerged for basal insulin (11.2 +/- 5.6, 14.7 +/- 7.7, and 16.8 +/- 13.5 microU/ml, P = 0.10) and fasting glucose (95 +/- 11, 103 +/- 16, and 105 +/- 14 mg/dl, P = 0.028). Consistently, along with the increase in sCD40L, a worsening in insulin sensitivity was observed, which was expressed as homeostasis model assessment for insulin sensitivity (HOMA%S: 99 +/- 52, 77 +/- 43, and 72 +/- 35, P < 0.05), composite insulin sensitivity index (ISIcomp; Matsuda index: 5.11 +/- 2.65, 3.61 +/- 1.98, and 3.28 +/- 1.87, P = 0.025), or oral glucose insulin sensitivity (OGIS) index (OGIS: 421 +/- 67, 386 +/- 90, and 362 +/- 72, P = 0.004).

CONCLUSIONS

In newly diagnosed hypertensive men, sCD40L levels are inversely related to insulin sensitivity, with no correlation with BP, other cardiovascular risk factors, or the degree of subclinical atherosclerosis.

Two-year results from a community-wide diabetes prevention intervention in a high risk indigenous community: the Ngati and Healthy project

We describe changes in markers and prevalence of glucose metabolism disorders following a 2-year community-wide intervention aimed at reducing insulin resistance (IR) prevalence in a high risk community. Surveys were undertaken before and 2 years after implementation of a community developed and led diabetes prevention program. Proportions and means were calculated and compared by sex and age groups: 25-49 years and 50+ years. A process evaluation contributed to interpretation of results. Response rates were around 50% and demographic characteristics similar in both surveys. Overall, IR prevalence decreased markedly from 35.5% to 25.4% (p=0.003). Most changes were observed amongst 25-49 years old women for whom there was a significant change in prevalences of IR and glucose metabolism disorders (p=0.015), largely due to reduced IR prevalence (38.2-25.6%). In 2006, 60.3% achieved minimum recommended exercise levels and 65.4% ate wholegrain bread compared with 45.1% (p=0.002) and 42.2% (p=0.044), respectively, in 2003. Participation in a community diabetes prevention intervention appeared to reduce IR prevalence after 2 years in those with the highest level of participation and most marked lifestyle changes.

Dietary pattern, the metabolic syndrome, and left ventricular mass and systolic function: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Little is known about the relations between dietary patterns, metabolic dysfunction, and left ventricular (LV) function.

OBJECTIVE

The objective was to examine associations of dietary patterns with LV mass and function and to explore the potential role of metabolic dysfunction in the association between diet and LV function.

DESIGN

Dietary patterns that maximally explained the variation in metabolic syndrome (MetSyn) components were derived by using reduced rank regression (RRR). LV mass, stroke volume, and LV ejection fraction (LVEF) were measured by magnetic resonance imaging. Associations between dietary pattern and LV indexes were analyzed cross-sectionally.

RESULTS

A total of 4601 participants aged 45-84 y and free of clinical cardiovascular disease were studied. The primary RRR dietary pattern score was positively correlated with intake of foods with a high glycemic index, high-fat meats, cheeses, and processed foods and negatively correlated with low intakes of vegetables, soy, fruit, green and black tea, low-fat dairy desserts, seeds and nuts, and fish. Multivariate analyses showed that each 1-unit increase in the RRR dietary pattern score was associated with a 0.32-g/m(2) increase in LV mass/body surface area, a 0.43-mL/m(2) decrease in stroke volume/body surface area, and a 0.21% decrease in LVEF. The associations of the RRR dietary pattern score with LV mass and stroke indexes were attenuated and became nonsignificant after adjustment for all MetSyn components (P > 0.05).

CONCLUSIONS

The results suggest that the RRR dietary pattern is significantly associated with unfavorable LV function, and this association might be mediated by metabolic dysfunction. Given the cross-sectional nature of our study, these results must be confirmed with the use of longitudinal data.

Characterizing traditionally defined periodontal disease in HIV+ adults

BACKGROUND

Results have varied from previous studies examining the level and extent of periodontal disease (PD) in HIV-1 infected (HIV+) adults. These studies used different methodologies to measure and define PD and examined cohorts with divergent characteristics. Inconsistent methodological approaches may have resulted in the underestimation of traditionally-defined PD in HIV+ individuals.

OBJECTIVES

To characterize the level, extent and predictors (i.e. immunologic, microbiologic, metabolic and behavioral) of PD in an HIV+ cohort during the era of highly active antiretroviral therapy (HAART).

STUDY DESIGN

Cross-sectional study.

SETTING

HIV+ adults receiving outpatient care at three major medical clinics in Cleveland, OH. Subjects were seen from May, 2005 to January, 2008.

MEASUREMENTS

Full-mouth periodontal examinations included periodontal probing depth (PPD), recession (REC) and clinical attachment level (CAL). Subgingival plaque was assessed for DNA levels of Porphyromonas gingivalis (Pg), Tannerella forsythia, and Treponema denticola by real-time DNA PCR assays developed for each pathogen. Rather than using categories, we evaluated PD as three continuous variables based on the percent of teeth with >or=1 site per tooth with PPD >or= 5mm, REC > 0 mm and CAL >or= 4mm.

RESULTS

Participants included 112 HIV+ adults. Each subject had an average 38% (+/-24%) of their teeth with at least one site of PD >or= 5 mm, 55% (+/-31%) of their teeth with at least one site of REC > 0 mm, and 50% (+/-32%) of their teeth with at least one site of CAL >or= 4 mm. CD4+ T-cell count <200 cells/mm(3) was significantly associated with higher levels of REC and CAL, but not PPD. Greater levels of Pg DNA were associated with PPD, REC and CAL.By regression analysis, CD4+ T-cell count <200 cells /mm3 had approximately twice thedeleterious effect on CAL as did smoking (standardized beta coefficient 0.306 versus 0.164) [corrected]. Annual dental visit compliance remained an independent predictor for lower levels of PD.

CONCLUSIONS

The level and extent of PD were high in this cohort even though most patients were being treated with HAART. The definition of periodontal disease used and cohort characteristics examined can influence the level of periodontal disease reported in studies of persons with HIV. Traditional periodontal pathogens are associated with PD in this cohort. Those with CD4+ T-cell counts <200 cells/mm(3) are at greater risk for PD. Therefore, earlier HAART initiation may decrease exposure to immunosuppression and reduce PD morbidity. Continuity of dental care remains important for HIV+ patients even when they are being treated with HAART.

Determining optimal approaches for weight maintenance: a randomized controlled trial

BACKGROUND

Weight regain often occurs after weight loss in overweight individuals. We aimed to compare the effectiveness of 2 support programs and 2 diets of different macronutrient compositions intended to facilitate long-term weight maintenance.

METHODS

Using a 2 x 2 factorial design, we randomly assigned 200 women who had lost 5% or more of their initial body weight to an intensive support program (implemented by nutrition and activity specialists) or to an inexpensive nurse-led program (involving "weigh-ins" and encouragement) that included advice about high-carbohydrate diets or relatively high-monounsaturated-fat diets.

RESULTS

In total, 174 (87%) participants were followed-up for 2 years. The average weight loss (about 2 kg) did not differ between those in the support programs (0.1 kg, 95% confidence interval [CI] -1.8 to 1.9, p = 0.95) or diets (0.7 kg, 95% CI -1.1 to 2.4, p = 0.46). Total and low-density lipoprotein (LDL) cholesterol levels were significantly higher among those on the high-monounsaturated-fat diet (total cholesterol: 0.17 mmol/L, 95% CI 0.01 to 0.33; p = 0.040; LDL cholesterol: 0.16 mmol/L, 95% CI 0.01 to 0.31; p = 0.039) than among those on the high-carbohydrate diet. Those on the high-monounsaturated-fat diet also had significantly higher intakes of total fat (5% total energy, 95% CI 3% to 6%, p < 0.001) and saturated fat (2% total energy, 95% CI 1% to 2%, p < 0.001). All of the other clinical and laboratory measures were similar among those in the support programs and diets.

INTERPRETATION

A relatively inexpensive program involving nurse support is as effective as a more resource-intensive program for weight maintenance over a 2-year period. Diets of different macronutrient composition produced comparable beneficial effects in terms of weight loss maintenance.

Open-labeled pilot study of cysteine-rich whey protein isolate supplementation for nonalcoholic steatohepatitis patients

BACKGROUND AND AIMS

Glutathione (GSH) depletion contributes to liver injury and development of steatohepatitis. Undenatured cysteine-rich whey protein isolate has been clinically proven to raise GSH in several patient groups. The aim of this study was to evaluate the effect of oral supplementation with whey protein on patients with nonalcoholic steatohepatitis (NASH).

METHODS

In an open-labeled clinical trial, 38 patients (18 male, 20 female; mean age 48 +/- 14 years) with NASH confirmed by computed tomography measurements and liver biochemistries were given with a daily dose of 20 g whey protein isolate for 12 weeks.

RESULTS

A significant reduction in alanine aminotransferase (ALT) (64 +/- 72 vs 46 +/- 36, P = 0.016) and aspartate aminotransferase (AST) (45 +/- 49 vs 33 +/- 18, P = 0.047) were observed. Plasma glutathione and total antioxidant capacity increased significantly at the end of study (53 +/- 11 vs 68 +/- 11, P < 0.05 and 1.26 +/- 0.10 vs 2.03 +/- 0.10, P < 0.05). Liver attenuation index improved from -13.4 +/- 11.1 to -9.7 +/- 13.1 (P = 0.048). Hepatic macrovesicular steatosis decreased significantly after 12 weeks of supplementation (33.82 +/- 12.82 vs 30.66 +/- 15.96, P = 0.046). Whey protein isolate was well tolerated. No serious adverse events were observed.

CONCLUSIONS

The results indicate that oral supplementation of cysteine-rich whey protein isolate leads to improvements in liver biochemistries, increased plasma GSH, total antioxidant capacity and reduced hepatic macrovesicular steatosis in NASH patients. The results support the role of oxidative stress in the pathogenesis of this disease.

Is there a role for insulin resistance in nonobese patients with idiopathic hirsutism?

BACKGROUND

Hirsutism is the presence of terminal hairs in women in a male-like pattern. It may result from various causes of androgen excess or may be idiopathic. Controversies exist concerning the presence of insulin resistance in idiopathic hirsutism (IH) or if it is a manifestation of a high body mass index (BMI).

OBJECTIVES

To assess insulin resistance in nonobese patients with IH.

METHODS

The study included three groups of age- and BMI-matched nonobese women: 30 patients with IH (group 1), 20 patients with hirsutism associated with polycystic ovary syndrome (PCOS) (group 2) and 20 healthy controls (group 3). The pattern of obesity based on waist to hip ratio (WHR), and insulin resistance based on fasting insulin levels and the homeostasis model assessment of insulin resistance (HOMA-IR) were assessed in all the groups.

RESULTS

Sixteen patients with IH and 17 with PCOS had insulin resistance with statistically significant differences in fasting insulin levels and HOMA-IR between the three groups, between patients with IH and healthy controls and between patients with PCOS and healthy controls; there were no significant differences between patients with IH and patients with PCOS. When classified according to the pattern of obesity, 23 patients in group 1, 17 in group 2 and two in group 3 had a WHR >or= 0.85 (android obesity) with highly significant higher values of fasting insulin levels and HOMA-IR in patients with a WHR >or= 0.85 when compared with those with a WHR < 0.85.

CONCLUSIONS

Insulin resistance occurs in nonobese patients with IH and appears to be related to android obesity.

Uric acid and insulin sensitivity and risk of incident hypertension

BACKGROUND

Uric acid, insulin sensitivity, and endothelial dysfunction may be important in the development of hypertension. Corresponding circulating biomarkers are associated with risk of hypertension, but because these factors may be interrelated, whether they independently affect risk is unknown.

METHODS

In 1496 women aged 32 to 52 years without hypertension at baseline, we prospectively analyzed the associations between fasting plasma levels of uric acid, insulin, triglycerides, the insulin sensitivity index, and 2 biomarkers associated with endothelial dysfunction (homocysteine and soluble intercellular adhesion molecule-1) and the odds of incident hypertension. Odds ratios were adjusted for standard risk factors and then for all biomarkers plus estimated glomerular filtration rate and total cholesterol level. Population-attributable risk was estimated for biomarkers significantly associated with hypertension.

RESULTS

All the biomarkers were associated with incident hypertension after adjustment for standard hypertension risk factors. However, after simultaneously controlling for all the biomarkers, estimated glomerular filtration rate, and total cholesterol level, only uric acid and insulin levels were independently associated with incident hypertension. Comparing the highest and lowest quartiles of uric acid levels, the odds ratio was 1.89 (95% confidence interval, 1.26-2.82). A similar comparison yielded an odds ratio of 2.03 (95% confidence interval, 1.35-3.05) for insulin levels. Using an estimated basal incidence rate of 14.6 per 1000 annually, 30.8% of all hypertension occurring in young women annually is associated with uric acid levels of 3.4 mg/dL or greater (to convert to micromoles per liter, multiply by 59.485). For insulin levels of 2.9 microIU/mL or greater (to convert to picomoles per liter, multiply by 6.945), this proportion is 24.2%.

CONCLUSIONS

Differences in uric acid and insulin levels robustly and substantially affect the risk of hypertension in young women. Measuring these biomarkers in clinical practice may identify higher-risk individuals.

Glucose and insulin responses to whole grain breakfasts varying in soluble fiber, beta-glucan: a dose response study in obese women with increased risk for insulin resistance

BACKGROUND

A high intake of whole grains containing soluble fiber has been shown to lower glucose and insulin responses in overweight humans and humans with type 2 diabetes.

AIM OF THE STUDY

We investigated the linearity of this response after consumption of 5 breakfast cereal test meals containing wheat and/or barley to provide varying amounts of soluble fiber, beta-glucan (0, 2.5, 5, 7.5 and 10 g).

METHODS

Seventeen normoglycemic, obese women at increased risk for insulin resistance consumed 5 test meals within a randomized cross-over design after consuming controlled diets for 2 days. Blood samples for glucose and insulin response were obtained prior to and 30, 60, 120 and 180 min after consuming the test meals.

RESULTS

Consumption of 10 g of beta-glucan significantly reduced peak glucose response at 30 min and delayed the rate of glucose response. Area under the curve for 2 h-postprandial glycemic response was not affected by beta-glucan content. However, peak and area under the curve of insulin responses were significantly affected by the beta-glucan amount in an inverse linear relationship.

CONCLUSION

These data suggest that acute consumption of 10 g of beta-glucan is able to induce physiologically beneficial effects on postprandial insulin responses in obese women at risk for insulin resistance.

The GGN and CAG repeat polymorphisms in the exon-1 of the androgen receptor gene are, respectively, associated with insulin resistance in men and with dyslipidemia in women

The human androgen receptor (AR) gene possesses two trinucleotide repeats of CAG and GGN in exon-1. The GGN repeat affects the amount of AR protein translated, while the CAG repeat affects the efficiency of AR transcriptionaly. In this study, we have genotyped these polymorphic tracts in a representative sample of 557 Caucasian adult individuals (314 women and 243 men) from the Canary Islands, Spain (the ENCA Study), and investigated their association with fasting serum levels of lipids, glucose and insulin. The number of CAG repeats in women (expressed as the average length of the two alleles) was inversely correlated with serum levels of LDL-cholesterol (Spearman rho=-0.179; P<0.01). Women with an average number of CAG repeats in the upper tertile showed significantly lower levels of LDL-cholesterol than those grouped in the lower and middle tertile, after adjusting for age, body mass index, waist-to-hip ratio, smoking and alcohol drinking. The number of GGN repeats in men was correlated with fasting insulin levels (Spearman rho=-0.206; P<0.01), the homeostasis model assessment of insulin resistance (HOMA-IR; Spearman rho=-0.230; P<0.01) and the McAuley index of insulin sensitivity (Spearman rho=0.194; P<0.01). Men with a number of GGN repeats in the upper tertile showed lower levels of insulin and HOMA and a higher level of the McAuley index than those grouped in the lower and middle tertile, after adjusting for the variables listed above. These results support the hypothesis that the longer alleles of the CAG and GGN polymorphisms in the exon-1 of the AR gene, indicative of lower androgenic signaling, respectively protect women from developing dyslipemia and men from developing insulin resistance.

Androgens in relationship to cardiovascular risk factors in the menopausal transition

OBJECTIVE

To establish the relationship between androgens and cardiovascular disease (CVD) risk factors in the menopausal transition.

METHODS

A total of 124 women were divided into four groups: 29 premenopausal (PreM), 35 women in the menopausal transition still menstruating (MTM), 29 women in the menopausal transition with 3-6 months amenorrhea (MTA), and 31 postmenopausal women (PostM). Levels of triglycerides, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, glucose and insulin were assayed in all samples and waist circumference was measured. In a subgroup of 83 women (19 PreM, 21 MTM, 28 MTA and 15 PostM), levels of total testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS) and estradiol were determined. The free androgen index, Homeostasis Model Assessment (HOMA) index, Quantitative Insulin Sensitivity Check Index (QUICKI) and McAuley index, estradiol/total testosterone and triglyceride/HDL cholesterol ratios were calculated.

RESULTS

Androstenedione was higher in MTA vs. PostM women (p < 0.05); DHEAS was higher in PreM women vs. the other three groups (p < 0.05). Sex hormone binding globulin (SHBG) in MTM women was higher than in MTA women (p < 0.05); the free androgen index was lower in MTM women than in MTA and PostM women. SHBG and the free androgen index showed negative and positive correlations, respectively with waist circumference, insulin resistance and lipids. In a multiple regression analysis, considering waist circumference, neither free androgen index nor SHBG showed significant differences between groups. The waist circumference correlated only with SHBG (p = 0.022) and correlations between SHBG and insulin resistance markers continued to be significant, but relationships between SHBG and lipoproteins and all correlations found with free androgen index were lost.

CONCLUSIONS

An increment in the androgenic milieu that correlates with abdominal fat, insulin resistance and atherogenic lipoproteins becomes evident after the menopausal transition and suggests that evaluation of cardiovascular disease risk in these women should include androgens, considering that abdominal obesity is one of the main determinants of the relationship between androgenic parameters and cardiovascular risk factors.

[Insulin resistance and secretion assessment across a range of glucose tolerance from normal individuals through diabetes]

AIM AND METHODS

Our main aim was to determine the association between clinical, demographical parameters and different insulin resistance and secretion indices in apparently healthy subjects, without previous knowledge of their own level of glucose tolerance. For that purpose, we evaluated 105 individuals from February to August 2003 by means of OGTT, aged 33.4+/-1.4 years old, 57.1% female. We allocated them in four groups: group 0 (normal): individuals with BMI < 25 Kg/m(2) and normal glucose metabolism, group 1 (obese): BMI >or= 25 Kg/m(2) and normal glucose metabolism, group 2 (IFG): impaired fasting glucose and group 3 (IGT): impaired glucose tolerance.

RESULTS

We have found statistical difference on all variables during OGTT between all groups: fasting glucose (p < 0.05), 2-hour glucose (p < 0.05), glucose peak value (p < 0.05), glucose delta (p = 0.02), glucose incremental percentage (p = 0.047), area under curve (p < 0.05), and glucose peak time (p = 0.022). We have not found difference on any variable in insulin curves or on glucose incremental velocity. Regarding insulin secretion indices there were no statistical significance in insulinogenic or delta indices, but they became significant after being corrected by insulin resistance (p = 0.008). When we evaluated insulin resistance alone, by using HOMA and QUICKI indices and the fasting glucose to insulin index, we have found statistical significance (p = 0.005; p = 0.005; p = 0.053).

CONCLUSION

Although studying a small sample, we could suggest that individuals with impaired fasting glucose and impaired glucose tolerance are in different stages of diabetes natural history disease. We found out that the best indices of insulin resistance are both HOMA and QUICKI. We also suggest that pancreatic secretion indices should be corrected by the insulin resistance, which could best reflect type 2 diabetes natural history.

[Metabolic syndrome, its phenotypes, and insulin resistance by HOMA-IR]

The diagnosis of the metabolic syndrome (MS) according to the National Cholesterol Education Program Adult Treatment Panel III does not reflect necessarily the presence of insulin resistance (IR), a potential therapeutical target for type 2 diabetes and cardiovascular disease prevention. Based on previous prevalence data, a cross-sectional study was conducted to determine the HOMA-IR relationship to the MS and some associated abnormalities. HOMA-IR > was higher in individuals with the MS (2.8+/-1.6 vs. 1.8+/-1.4) (p < 0.001). HOMA-IR >or= 2.5 allied good specificity and sensitivity levels for the association of MS and IR. Hyperglycemia, hypertrigliceridemia, and abdominal obesity, the MS components best related to IR, were statistically associated with HOMA-IR > 2.5, but not hypertension neither low HDL-c. The demonstration that some of MS phenotypes or associated abnormalities were more predictive for IR could point out to the possibility of the use of the index as a marker of the presence of IR associated to MS.

Mathematical models of diabetes progression

Few attempts have been made to model mathematically the progression of type 2 diabetes. A realistic representation of the long-term physiological adaptation to developing insulin resistance is necessary for effectively designing clinical trials and evaluating diabetes prevention or disease modification therapies. Writing a good model for diabetes progression is difficult because the long time span of the disease makes experimental verification of modeling hypotheses extremely awkward. In this context, it is of primary importance that the assumptions underlying the model equations properly reflect established physiology and that the mathematical formulation of the model give rise only to physically plausible behavior of the solutions. In the present work, a model of the pancreatic islet compensation is formulated, its physiological assumptions are presented, some fundamental qualitative characteristics of its solutions are established, the numerical values assigned to its parameters are extensively discussed (also with reference to available cross-sectional epidemiologic data), and its performance over the span of a lifetime is simulated under various conditions, including worsening insulin resistance and primary replication defects. The differences with respect to two previously proposed models of diabetes progression are highlighted, and therefore, the model is proposed as a realistic, robust description of the evolution of the compensation of the glucose-insulin system in healthy and diabetic individuals. Model simulations can be run from the authors' web page.

A lipid-parameter-based index for estimating insulin sensitivity and identifying insulin resistance in a healthy population

AIM

Insulin resistance needs to be identified as early as possible in its development to allow targeted prevention programmes. Therefore, we compared various fasting surrogate indices for insulin sensitivity using the euglycaemic insulin clamp in an attempt to develop the most appropriate method for assessing insulin resistance in a healthy population.

METHODS

Glucose, insulin, proinsulin, glucagon, glucose tolerance, fasting lipids, liver enzymes, blood pressure, anthropometric parameters and insulin sensitivity (Mffm/I) using the euglycaemic insulin clamp were obtained for 70 normoglycaemic non-obese individuals. Spearman's rank correlations were used to examine the association between Mffm/I and various fasting surrogate indices of insulin sensitivity. A regression model was used to determine the weighting for each variable and to derive a formula for estimating insulin resistance. The clinical value of the surrogate indices and the new formula for identifying insulin-resistant individuals was evaluated by the use of receiver operating characteristic (ROC) curves.

RESULTS

The variables that best predicted insulin sensitivity were the HDL-to-total cholesterol ratio, the fasting NEFA and fasting insulin. The use of the lipid-parameter-based formula Mffm/I=12x[2.5x(HDL-c/total cholesterol)-NEFA] - fasting insulin appeared to have high clinical value in predicting insulin resistance. The correlation coefficient between Mffm/I and the new fasting index was higher than those with the most commonly used fasting surrogate indices for insulin sensitivity.

CONCLUSION

A lipid-parameter-based index using fasting samples provides a simple means of screening for insulin resistance in the healthy population.

Comparison of short insulin tolerance test with HOMA Method for assessment of insulin sensitivity in Asian Indians in north India

BACKGROUND

Cost-effective method to assess insulin resistance is needed for Asian Indians.

METHODS

We compared HOMA with SITT methods in 40 subjects.

RESULTS

Values obtained from both methods did not show any correlation.

CONCLUSIONS

Both methods should be evaluated against hyperinsulinemic clamp to determine suitability in Asian Indians.

Correlation between serum lipid profile and carotid intima-media thickness in Polycystic Ovarian Syndrome

Abnormal lipid profile is often found in women with Polycystic Ovary Syndrome. To assess the impact of abnormal lipid profile on atherosclerosis in young Polycystic Ovary Syndrome women, carotid intima-media thickness as judged by B-mode ultrasonography were done in 30 young (18-35 yrs) Polycystic Ovary Syndrome women and in similarly age-matched 30 apparently healthy controls. Compared to controls, young Polycystic Ovary Syndrome women had significantly elevated serum total cholesterol, triglyceride and LDL-C levels and carotid intima-media thickness. HDL-C level did not differ significantly between two groups of women. In Polycystic Ovary Syndrome women carotid intima-media thickness was positively correlated with serum total cholesterol, triglyceride and LDL-C and negatively correlated with serum HDL-C. Our study suggests that even young Polycystic Ovary Syndrome women are prone to atherosclerosis from early age.

GLP-1 and adiponectin: effect of weight loss after dietary restriction and gastric bypass in morbidly obese patients with normal and abnormal glucose metabolism

BACKGROUND

It has been proposed that there is improvement in glucose and insulin metabolism after weight loss in patients who underwent diet restriction and bariatric surgery.

METHODS

Eleven normal glucose tolerant (NGT) morbidly obese patients [body mass index (BMI), 46.1+/-2.27 g/m2] and eight abnormal glucose metabolism (AGM) obese patients (BMI, 51.20 kg/m2) were submitted to diet-restriction and bariatric surgery. Prospective study on weight loss changes, over the glucose, insulin metabolism, glucagon-like peptide-1 (GLP-1), and adiponectin levels were evaluated by oral glucose tolerance test during three periods: T1 (first evaluation), T2 (pre-surgery), and T3 (9 months after surgery).

RESULTS

Insulin levels improved after surgery. T1 was 131.1+/-17.60 pmol/l in the NGT group and 197.57+/-57.94 pmol/l in the AGM group, and T3 was 72.48+/-3.67 pmol/l in the NGT group and 61.2+/-9.33 pmol/l in the AGM group. The major reduction was at the first hour of the glucose load as well as fasting levels. At 9 months after surgery (T3), GLP-1 levels at 30 and 60 min had significantly increased in both groups. It was observed that the AGM group had higher levels of GLP-1 at 30 min (34.06+/-6.18 pmol/l) when compared to the NGT group (22.69+/-4.04 pmol/l). Homeostasis model assessment of insulin resistance from the NGT and AGM groups had a significant reduction at periods T3 in relation to T1 and T2. Adiponectin levels had increased concentration in both groups before and after surgical weight loss. However, it did not have any statistical difference between periods T1 vs. T2.

CONCLUSIONS

Weight loss by surgery leads to improvement in the metabolism of carbohydrates in relation to sensitivity to the insulin, contributing to the reduction of type 2 diabetes incidence. This improvement also was expressed by the improvement of the levels of adiponectin and GLP-1.