HOMA-IR and QUICKI: decide on a general standard instead of making further comparisons

TG: HDL-C Ratio as Insulin Resistance Marker for Metabolic Syndrome in Children With Obesity

Insulin resistance (IR) is an important variable in the diagnosis of metabolic syndrome (MetS). Currently, IR is not part of the existing pediatric definition of MetS, instead elevated fasting blood glucose (FBG) is measured as an indicator of hyperglycemia. Arguably, many obese children with severe IR are still able to regulate their FBG well. Hence, this study aimed to assess the utility of triglyceride-to-high-density lipoprotein cholesterol (TG : HDL-C) ratio as an IR marker in the modeling of pediatric MetS among children with obesity using structural equation modeling (SEM). A total of 524 blood samples from children with obesity (age 10-16 years old) were analyzed for FBG, lipids, insulin, leptin, and adiponectin. Both exploratory (EFA) and confirmatory factor analysis (CFA) were used to examine TG : HDL-C ratio as an IR marker in pediatric MetS. EFA shows that TG: HDL-C ratio (standardized factor loading = 0.904) groups together with homeostasis model assessment-estimated insulin resistance (HOMA-IR) (standardized factor loading = 0.664), indicating a strong correlation to the IR factor. Replacing FBG with TG: HDL-C ratio improved the modeling of MetS structure in children with obesity. Our MetS model of TG: HDL-C ratio as IR component shows comparable model fitness indices (goodness of fit, Akaike's information criterion, and Bayesian information criterion) with leptin:adiponectin ratio (platinum standard for adiposity:IR marker) model. The least model fit was seen when using FBG as an IR surrogate. TG : HDL-C ratio performed better as IR surrogate in MetS structures (standardized factor loading = 0.39) compared to FBG (standardized factor loading = 0.27). TG: HDL-C ratio may be considered as an IR component in pediatric MetS.

Ectopic pancreatic fat as a risk factor for hypertension in children and adolescents with nonalcoholic fatty liver disease

Although nonalcoholic fatty liver disease (NAFLD) is known to be a risk factor for cardiovascular diseases, few studies have reported an association between ectopic fat deposition and metabolic complications, including hypertension, in children with NAFLD. The present study evaluated the risk factors for hypertension in children with NAFLD from the aspect of ectopic fat. This cross-sectional retrospective study investigated 65 children with NAFLD (49 boys, mean age 13.0 ± 3.2 years, mean body mass index z-score [BMI-z] 2.5 ± 1.2), who underwent liver biopsy and magnetic resonance imaging-based fat fraction measurement for ectopic hepatic and pancreatic fats, as well as anthropometry, blood pressure, laboratory tests, and body composition analysis. A logistic regression model was used to identify the risk factors for hypertension. Through a simple logistic regression analysis, age (OR 1.392), BMI-z (OR 3.971), waist circumference-to-height ratio (OR 1.136), fat-free mass index (OR 1.444), γ-glutamyl transferase (OR 1.021), quantitative insulin sensitivity check index (OR 0.743), dyslipidemia (OR 5.357), and pancreatic fat fraction (PFF) (OR 1.205) were associated with hypertension. The optimal cut-off of PFF to divide children with NAFLD into two groups with and without hypertension was 4.39% (area under the curve 0.754, p = .001, sensitivity 82.4%, specificity 73.9%). Multiple logistic regression analysis in the fully adjusted model revealed both BMI-z (OR 4.912, 95% CI, 1.463-16.497) and PFF (OR 1.279, 95% CI, 1.007-1.624) were independent risk factors for hypertension. In conclusions, in addition to BMI-z, ectopic pancreatic fat is an important risk factor for hypertension in children with NAFLD.

Effects of probiotic and synbiotic supplementation on insulin resistance in women with polycystic ovary syndrome: a meta-analysis

Objective

This meta-analysis evaluated the effect of probiotics and synbiotics on insulin resistance in patients with polycystic ovary syndrome (PCOS).

Methods

A systematic search was performed to identify all relevant publications listed on the electronic databases (PubMed®, Web of Science, Embase® and China National Knowledge Infrastructure) between inception and 30 October 2020. All statistical analyses were performed on randomized controlled trials (RCTs) using RevMan version 5.3 software provided by the Cochrane Collaboration.

Results

A total of 486 patients from seven RCTs were included in the meta-analysis. Probiotic and synbiotic supplementation appeared to improve levels of homeostatic model assessment of insulin resistance (mean difference = –0.37; 95% confidence interval –0.69, –0.05) and serum insulin (standardized mean difference = –0.66; 95% confidence interval –1.19, –0.12). The results failed to show any influence of probiotic and synbiotic supplementation on body mass index, waist circumference, hip circumference and fasting blood sugar.

Conclusions

Probiotics and synbiotics appear to have a partially beneficial effect on indices of insulin resistance in patients with PCOS.

Insulin resistance and type 2 diabetes in children

Type 2 diabetes (T2D) is an emerging health risk in obese children and adolescents. Both environmental (lack of physical activity, excess nutritional intake, sedentary lifestyle) and genetic factors contribute to this global epidemic. The growing prevalence of T2D in youth is also associated with a consistently increased incidence of metabolic and cardiovascular complications. Insulin resistance (IR), i.e., whole-body decreased glucose uptake in response to physiological insulin levels, determines impaired glucose homeostasis and it is recognized as cardinal trigger of T2D and cardiovascular disease in both adults and children. In particular, IR and beta-cell dysfunction lead to the persistent hyperglycemia which characterizes T2D. Indeed, both pathological states influence each other and presumably play a crucial, synergistic role in the pathogenesis of T2D, although the precise mechanisms are not completely understood. However, beta-cell dysfunction and IR induce impaired glucose metabolism, thus leading to the progression to T2D. Therefore, understanding the mechanisms correlated with the decline of beta-cell function and IR is crucial in order to control, prevent, and treat T2D in youth. This review focuses on the current knowledge regarding IR and T2D in children and adolescents and showcases interesting opportunities and stimulating challenges for the development of new preventative approaches and therapeutic strategies for young patients with T2D.

Effect of vitamin D supplementation on polycystic ovary syndrome: A meta-analysis

The aim of the present meta-analysis was to evaluate the effect of vitamin D supplementation on patients with polycystic ovary syndrome (PCOS). A literature search was performed to identify all of the relevant studies comparing the effect of vitamin D supplementation with placebo in PCOS patients, in the PubMed, Embase and Web of Science databases. All statistical analyses were performed on case-control studies using Review Manager 5.3 software, provided by the Cochrane Collaboration. A total of 11 studies involving 483 participants were included in the current meta-analysis. Vitamin D supplementation appeared to lead to an improvement in the levels of total testosterone [weighted mean differences (WMD) = -0.10, 95% CI (-0.18, -0.02)], homeostasis model assessment of insulin resistance [WMD = -0.44, 95% CI (-0.86, -0.03)], homeostasis model assessment of β-cell function [WMD = -16.65, 95% CI (-19.49, -13.80)], total cholesterol [WMD = -11.90, 95% CI (-15.67, -8.13)] and low-density lipoprotein-cholesterol [WMD = -4.54; 95% CI (-7.29, -1.80)]. The results failed to show a positive effect of vitamin D supplementation on the body mass index, dehydroepiandrosterone sulfate, triglyceride levels or high-density lipoprotein-cholesterol. In conclusion, the data from the available randomized controlled trials (RCTs) suggested vitamin D supplementation reduced insulin resistance and hyperandrogenism, as well improving the lipid metabolism of patients with PCOS to an extent. Further high-quality RCTs from a variety of regions in the world are required to determine the effectiveness of vitamin D supplementation in PCOS patients, and to determine a suitable dose and unit of vitamin D.

Endocrine causes of recurrent pregnancy loss

OBJECTIVE

To review the available data on endocrine disorders and recurrent pregnancy loss.

FINDINGS

Our group found that most endocrine disorders do not seem to be correlated with a diagnosis of recurrent pregnancy loss (RPL). The exception to this is testing for thyroid stimulating hormone and thyroid antibodies, which is recommended due to a strong correlation with recurrent pregnancy loss and positive anti-thyroid peroxidase antibodies.

CONCLUSION

The available literature supports testing thyroid function and antibodies in women with RPL. Testing for other endocrine disorders is only warranted if otherwise clinically indicated, independent from a history of recurrent pregnancy loss.

Fatty acid transport receptor soluble CD36 and dietary fatty acid pattern in type 2 diabetic patients: a comparative study

Recently, it has been remarked that dietary fatty acids and fatty acid receptors might be involved in the aetiology of diabetes. Therefore, this study was conducted to determine the relationship between dietary fatty acid pattern, fatty food preferences and soluble CD36 (sCD36) and insulin resistance in type 2 diabetes mellitus (DM). The study was carried out with thirty-eight newly diagnosed type 2 DM patients and thirty-seven healthy volunteers, aged 30-65 years. In the study, socio-demographic characteristics, dietary fat type and fatty acid pattern of individuals were recorded. After anthropometric measurements were taken, blood CD36, glucose, TAG and insulin levels were analysed. The results showed that although the type of fatty acid intake did not differ between the groups (P>0·05), the consumption of olive oil in the type 2 DM group was lower than the control group (P0·05). Crucially, elevated sCD36 levels increased the type 2 DM risk (OR 1·21, P<0·05). In conclusion, sCD36 level may be a possible biomarker, independent from the dietary fatty acid pattern, for type 2 DM owing to its higher levels in these patients. Therefore, the new insights make CD36 attractive as a therapeutic target for diabetes.

TG : HDL-C Ratio Is a Good Marker to Identify Children Affected by Obesity with Increased Cardiometabolic Risk and Insulin Resistance

Metabolic syndrome (MetS) is an important predictor of cardiovascular diseases in adulthood. This study aims to examine the clinical utility of triglyceride to high-density lipoprotein ratio (TG : HDL-C) in identifying cardiometabolic risk and insulin resistance (IR) among children with obesity, in comparison with MetS as defined by the International Diabetes Federation (IDF). Data of 232 children with obesity aged 10-16 years were obtained from our study, MyBFF@school study, conducted between January and December 2014. Children were divided into tertiles of TG : HDL-C ratio. The minimum value of the highest tertile was 1.11. Thus, elevated TG : HDL-C ratio was defined as TG : HDL-C ≥1.11. Children with MetS were categorized based on the definition established by the IDF. Out of 232 children, 23 (9.9%) had MetS, out of which 5.6% were boys. Almost twofold of boys and girls had elevated TG : HDL-C ratio compared to MetS: 13.8% vs. 5.6% and 13.8% vs. 4.3%, respectively. Children with elevated TG : HDL-C ratio had lower fasting glucose compared to children with MetS (boys = 5.15 ± 0.4 vs. 6.34 ± 2.85 mmol/l, p=0.02; girls = 5.17 ± 0.28 vs. 6.8 ± 4.3 mmol/l, p=0.03). Additionally, boys with elevated TG : HDL-C ratio had a higher HDL-C level compared to those with MetS (1.08 ± 0.18 vs. 0.96 ± 0.1 mmol/l, p=0.03). There was no significant difference across other MetS-associated risk factors. Overall, TG : HDL-C ratio demonstrated higher sensitivity (42.7% vs. 12.9%) but lower specificity (74.8% vs. 93.2%) than MetS in identifying IR, either in HOMA-IR ≥2.6 for prepubertal children or HOMA-IR ≥4 for pubertal children. TG : HDL-C ratio in children with obesity is thus as useful as the diagnosis of MetS. It should be considered an additional component to MetS, especially as a surrogate marker for IR.

Inappropriate Use of Homeostasis Model Assessment Cutoff Values for Diagnosing Insulin Resistance in Pediatric Studies

Background

Assessing pediatric patients for insulin resistance is one way to identify those who are at a high risk of developing type 2 diabetes mellitus. The homoeostasis model assessment (HOMA) is a measure of insulin resistance based on fasting blood glucose and insulin levels. Although this measure is widely used in research, cutoff values for pediatric populations have not been established.

Objective

To assess the validity of HOMA cutoff values used in pediatric studies published in peer-reviewed journals.

Methods

Studies published from January 2010 to December 2015 were identified through MEDLINE. Initial screening of abstracts was done to select studies that were conducted in pediatric populations and used HOMA to assess insulin resistance. Subsequent full-text review narrowed the list to only those studies that used a specific HOMA score to diagnose insulin resistance. Each study was classified as using a predetermined fixed HOMA cutoff value or a cutoff that was a percentile specific to that population. For studies that used a predetermined cutoff value, the references cited to provide evidence in support of that cutoff were evaluated.

Results

In the 298 articles analyzed, 51 different HOMA cutoff values were used to classify patients as having insulin resistance. Two hundred fifty-five studies (85.6%) used a predetermined fixed cutoff value, but only 72 (28.2%) of those studies provided a reference that supported its use. One hundred ten studies (43%) that used a fixed cutoff either cited a study that did not mention HOMA or provided no reference at all. Tracing of citation history indicated that the most commonly used cutoff values were ultimately based on studies that did not validate their use for defining insulin resistance.

Conclusion

Little evidence exists to support HOMA cutoff values commonly used to define insulin resistance in pediatric studies. These findings highlight the importance of validating study design elements when training medical students and novice investigators. Using available data to generate population ranges for HOMA would improve its clinical utility.

Evaluation of surrogate measures of insulin sensitivity - correlation with gold standard is not enough

Background

Impaired insulin sensitivity is a key abnormality underlying the development of type 2 diabetes. Measuring insulin sensitivity is therefore of importance in identifying individuals at risk of developing diabetes and for the evaluation of diabetes-focused interventions. A number of measures have been proposed for this purpose. Among these the hyperinsulinemic euglycemic clamp (HEC) is considered the gold standard. However, as the HEC is a costly, time consuming and invasive method requiring trained staff, there is a need for simpler so called surrogate measures.

Main message

A frequently used approach to evaluate surrogate measures is through correlation with the HEC. We discuss limitations with this method. We suggest other aspects to take into consideration, such as repeatability, reproducibility, systematic biases and discrimination ability. In addition, we focus on three frequently used surrogate measures. We argue that they are one-to-one transformations of each other, and therefore question the benefits of further comparison between them. They give the same results in all rank-based methods, for instance Spearman correlations, Mann-Whitney tests and receiver operating characteristic (ROC) analysis.

Conclusions

We suggest investigating further aspects than correlation alone when evaluating a surrogate measure of insulin sensitivity. We recommend choosing one of the three surrogate measures HOMA-IR, QUICKI and FIRI for analysis of a clinical study.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0521-y) contains supplementary material, which is available to authorized users.

Maternal dietary free or bound fructose diversely influence developmental programming of lipogenesis

Background

Maternal dietary choices throughout preconception, pregnancy, and lactation irreversibly affect the development of fetal tissues and organs, known as fetal programming. Recommendations tend to emphasize reducing added sugars. However, the impact of maternal dietary free or bound fructose in added sugars on developmental programming of lipogenesis is unknown.

Methods

Virgin Sprague-Dawley rats were randomly divided into five groups. Rats were given feed and plain water (control) or water containing maltodextrin (vehicle), fructose, high-fructose corn syrup (HFCS) containing 55% fructose, sucrose (20% w/v) for 12 weeks before mating and throughout the pregnancy and lactation periods. Body weight, water, and feed intake were measured throughout the study. At the end of the lactation period, blood was drawn to determine the fasting levels of glucose, insulin, triglycerides, and non-esterified fatty acids (NEFA) in blood. Triglycerides and acetyl Co-A Carboxylase-1 (ACC1) levels in livers were analyzed, and insulin resistance was calculated.

Results

The energy intake of dams in the HFCS group was higher than in the fructose group, while weight gain was less in the HFCS group than in the fructose group. HFCS resulted in greater insulin resistance in dams, whereas free fructose had a robust effect on the fetal programming of insulin resistance. Free fructose and HFCS in the maternal diet increased blood and liver triglycerides and NEFA content in pups. Furthermore, fructose and HFCS exposure increased phosphorylated ACC1 as compared to maltodextrin and control, indicating greater fatty acid synthesis in pups and dams.

Conclusion

Different types of added sugar in the maternal diet have different metabolic effects on the developmental programming of lipogenesis. Consequently, high fructose intake via processed foods may increase the risk for chronic diseases, and free fructose might contribute to developmental programming of chronic diseases more than bound fructose.

Pathologic Impact of Insulin Resistance and Sensitivity on the Severity of Liver Histopathology in Pediatric Non-Alcoholic Steatohepatitis

PURPOSE

Insulin resistance (IR) has an important role in the development of non-alcoholic steatohepatitis (NASH). We aimed to analyze the association between liver histopathology and IR in pediatric patients with NASH.

MATERIALS AND METHODS

In 24 children with non-alcoholic fatty liver disease (NAFLD), we investigated whether the hepatic pathologic characteristics have relations with following three biochemical indices; IR index including homeostasis model assessment of IR (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and insulin sensitivity indices-free fatty acid (ISI-FFA).

RESULTS

Among 24 patients, 16 (66.6%) had a high NAFLD activity score (NAS), which is diagnostic of NASH. Higher serum triglyceride level was significantly correlated with a high NAS. Higher steatosis grades were significantly associated with low insulin sensitivity (p=0.023). In addition, severe lobular inflammation was associated with higher IR: HOMA-IR (p=0.014) and QUICKI (p=0.023). Severe fibrosis correlated with low insulin sensitivity and high IR indexes: ISI-FFA (p=0.049), HOMA-IR (p=0.028), and QUICKI (p=0.007).

CONCLUSION

Patients with high IR had more severe lobular inflammation and hepatic fibrosis. Analyses of biochemical and endocrine parameters can be applied to determine the severity of the hepatic pathologic status in patients with NASH, especially in children who cannot undergo a liver biopsy.

Definition of insulin resistance affects prevalence rate in pediatric patients: a systematic review and call for consensus

BACKGROUND

As a result of the rising prevalence of childhood obesity, there is an increasing interest in the type 2 diabetes mellitus precursor insulin resistance (IR). The aim of this study is to review definitions (methods and cutoff values) to define IR in children and to apply these definitions to a previously described obese pediatric population.

METHODS

A systematic literature review on prevalence and/or incidence rates in children was performed. The extracted definitions were applied to an obese pediatric population.

RESULTS

In the 103 identified articles, 146 IR definitions were reported based on 14 different methods. Fasted definitions were used 137 times, whereas oral/intravenous glucose tolerance test-derived methods were used nine times. The homeostasis model for the assessment of insulin resistance (HOMA-IR) and fasted plasma insulin (FPI) were the most frequently used fasted methods (83 and 37 times, respectively). A wide range in cutoff values to define IR was observed, resulting in prevalence rates in the predefined obese pediatric population between 5.5% (FPI>30 mU/L) and 72.3% (insulin sensitivity indexMatsuda≤7.2).

CONCLUSIONS

To compare IR incidence and prevalence rates in pediatric populations, a uniform definition of IR should be defined.

Metabolic syndrome in Turner syndrome and relation between body composition and clinical, genetic, and ultrasonographic characteristics

BACKGROUND

An increased relative risk of diabetes, ischemic heart disease, atherosclerosis, and hypertension have been reported in Turner syndrome (TS) patients. No data are currently available on the prevalence of metabolic syndrome in TS subjects. We evaluated the frequency of metabolic syndrome in obese and nonobese patients with TS.

PATIENTS AND METHODS

We evaluated 85 TS patients (27.05 ± 11.17 years). Obesity was defined as standard deviation score body mass index (SDS-BMI) ≥ 2 or BMI ≥ 30 kg/m(2) in adult patients. We classified metabolic syndrome according to the International Diabetes Federation (IDF). Hepatic ultrasound was performed in all girls.

RESULTS

The prevalence of metabolic syndrome was 4.7% (12.5% obese and 4.3% nonobese, P=0.16) and associated with visceral adiposity (P=0.008). Abnormalities in glucose metabolism and hypertension were not associated with genetic or therapeutic factors. The karyotype 45,X was associated with atherogenic profile. Pathological waist circumference was more frequent in girls treated with estro-progestin (P=0.03). Evidence of fatty liver was associated with metabolic syndrome (P=0.03) and insulin resistance (P=0.05). Elevated liver enzymes were found in 15 subjects and were not related to treatment or ultrasound abnormalities.

CONCLUSIONS

Prevalence of each component of metabolic syndrome in TS patients is partially influenced by genetic makeup and treatment. Hepatosteatosis was associated with metabolic syndrome and insulin resistance, but not to elevated liver enzymes.

Fatty Acid desaturase gene polymorphisms and metabolic measures in schizophrenia and bipolar patients taking antipsychotics

Atypical antipsychotics have become a common therapeutic option in both schizophrenia and bipolar disorder. However, these medications come with a high risk of metabolic side effects, particularly dyslipidemia and insulin resistance. Therefore, identification of patients who are at increased risk for metabolic side effects is of great importance. The genetics of fatty acid metabolism is one area of research that may help identify such patients. Therefore, in this present study, we aimed to determine the effect of one commonly studied genetic polymorphism from both fatty acid desaturase 1 (FADS1) and FADS2 gene on a surrogate measure of insulin resistance and lipid levels in a metabolically high-risk population of patients largely exposed to atypical antipsychotics. This study used a cross-sectional design, fasting blood draws, and genetic analysis to investigate associations between polymorphisms, haplotypes, and metabolic measures. A total of 320 subjects with schizophrenia (n = 226) or bipolar disorder (n = 94) were included in this study. The mean age of the population was 42.5 years and 45% were male. A significant association between FADS1 and FADS2 haplotypes was found with insulin resistance while controlling for confounders. Further investigation is required to replicate this finding.

The incidence of metabolic syndrome in obese Czech children: the importance of early detection of insulin resistance using homeostatic indexes HOMA-IR and QUICKI

Common alimentary obesity frequently occurs on a polygenic basis as a typical lifestyle disorder in the developed countries. It is associated with characteristic complex metabolic changes, which are the cornerstones for future metabolic syndrome development. The aims of our study were 1) to determine the incidence of metabolic syndrome (based on the diagnostic criteria defined by the International Diabetes Federation for children and adolescents) in Czech obese children, 2) to evaluate the incidence of insulin resistance according to HOMA-IR and QUICKI homeostatic indexes in obese children with and without metabolic syndrome, and 3) to consider the diagnostic value of these indexes for the early detection of metabolic syndrome in obese children. We therefore performed anthropometric and laboratory examinations to determine the incidence of metabolic syndrome and insulin resistance in the group of 274 children with obesity (128 boys and 146 girls) aged 9-17 years. Metabolic syndrome was found in 102 subjects (37 %). On the other hand, the presence of insulin resistance according to QUICKI <0.357 was identified in 86 % and according to HOMA-IR >3.16 in 53 % of obese subjects. This HOMA-IR limit was exceeded by 70 % children in the MS(+) group, but only by 43 % children in the MS(-) group (p<0.0001). However, a relatively high incidence of insulin resistance in obese children without metabolic syndrome raises a question whether the existing diagnostic criteria do not falsely exclude some cases of metabolic syndrome. On the basis of our results we suggest to pay a preventive attention also to obese children with insulin resistance even if they do not fulfill the actual diagnostic criteria for metabolic syndrome.

Obesity, metabolic syndrome, and insulin resistance in urban high school students of minority race/ethnicity

OBJECTIVES

To determine the point prevalences of metabolic syndrome (MetS) and its components among healthy weight, overweight, and obese inner-city public high school students, to compare the prevalences of MetS when using 2 different definitions (one with the impaired fasting glucose [IFG] level and the other with a homeostasis model assessment of insulin resistance [HOMA-IR] of 3.99 or higher to define the glucose regulation component), and to compare the degree to which HOMA-IR and fasting glucose level are associated with the other MetS components.

DESIGN

Cross-sectional analysis.

SETTING

Two New York City public high schools, from April 2008 through August 2011.

PARTICIPANTS

Convenience sample of 1185 high school youth, comprising predominantly Hispanic and African American students from low-income households, participating in The Banishing Obesity and Diabetes in Youth Project, a medical screening and education program.

MAIN OUTCOME MEASURES

Prevalences of the following individual MetS components: IFG threshold, HOMA-IR, hypertension, central adiposity, hypertriglyceridemia, and low high-density lipoprotein cholesterol. Rates of MetSIFG and MetSHOMA-IR were also assessed.

RESULTS

MetSIFG and MetSHOMA-IR point prevalences were both 0.3% in the healthy weight group; they were 2.6% and 5.9%, respectively, in the overweight group and were 22.9% and 35.1%, respectively, in the obese group (P < .05 for both). An IFG threshold of 100 mg/dL or higher was found in 1.0% of participants, whereas a HOMA-IR of 3.99 or higher was found in 19.5% of participants.

CONCLUSIONS

An elevated HOMA-IR is much more sensitive than an IFG threshold in identifying adolescents with metabolic dysregulation. Using a HOMA-IR threshold of 3.99 identifies more youth with MetS than using an IFG threshold of 100 mg/dL. In addition to increasing the sensitivity of MetS detection, HOMA-IR has a much higher association with the other MetS components than the IFG threshold and may better reflect a unified underlying pathologic process useful to identify youth at risk for disease.

The influence of the brain-derived neurotropic factor Val66Met genotype and HMG-CoA reductase inhibitors on insulin resistance in the schizophrenia and bipolar populations

INTRODUCTION

The brain-derived neurotrophic factor (BDNF) Val66Met variant and HMG-COA reductase inhibitors (statins) have been implicated in insulin resistance with a possible increased risk of diabetes. We sought to determine the effect of the BDNF Met variant and statin medication use on insulin resistance in schizophrenia and bipolar disorder using the homeostasis model assessment of insulin resistance (HOMA-IR).

METHODS

A cross-sectional design was used and patients with diabetes or on any medications affecting glucose regulation were -excluded. Associations between insulin resistance and genotype were then analyzed by ANOVA and regression analysis. Subjects were grouped by BDNF genotype as well as presence of statin.

RESULTS

Two hundred fifty-two subjects with a mean age of 44 years were included. The group was 53% male and 41% had a diagnosis of bipolar disorder; 78% and 19% were receiving atypical antipsychotics (AAPs) and statin medications, respectively. Analysis showed schizophrenia subjects with the BDNF met allele as well as schizophrenia subjects with both the BDNF met allele and were receiving a statin had significantly higher HOMA-IR values compared to the other groups (p= 0.046 and p= 0.016, respectively).

CONCLUSIONS

Our results suggest that in the metabolically high-risk population of schizophrenia the BDNF met allele alone and in combination with statin medications is associated with higher insulin resistance values. This was not seen in the bipolar population. Further validation of these associations remains necessary.

Surrogate estimates of insulin sensitivity in obese youth along the spectrum of glucose tolerance from normal to prediabetes to diabetes

CONTEXT

In epidemiological studies of childhood obesity, simple and reliable surrogate estimates of insulin sensitivity are needed because the gold standard, the hyperinsulinemic-euglycemic clamp, is not feasible on a large scale.

OBJECTIVE

To examine the correlation of fasting and oral glucose tolerance test (OGTT)-derived surrogate indices of insulin sensitivity with the hyperinsulinemic-euglycemic clamp in obese adolescents with normal glucose tolerance, prediabetes, and diabetes.

PATIENTS AND DESIGN

A total of 188 overweight/obese adolescents (10 to <20 yr old) who completed a standard 2-h OGTT and 3-h hyperinsulinemic-euglycemic clamp were included. Fasting-derived surrogates [fasting glucose (G(F)), fasting insulin (I(F)), 1/I(F), G(F)/I(F), homeostasis model assessment and quantitative insulin sensitivity check index] and OGTT-derived surrogates [whole-body insulin sensitivity index and the ratio of glucose and insulin areas under the curve (Gluc(AUC)/Ins(AUC))] were calculated.

MAIN OUTCOME MEASURES

We evaluated the correlations between the clamp-measured insulin sensitivity and the surrogate estimates and area under the receiver operating characteristic curves.

RESULTS

Fasting indices (1/I(F), G(F)/I(F), homeostasis model assessment of insulin sensitivity, and quantitative insulin sensitivity check index) correlated significantly with clamp insulin sensitivity (r = 0.82, 0.78, 0.81, and 0.80, respectively), with lower correlations between the OGTT surrogates and clamp (whole-body insulin sensitivity index, r = 0.77; Gluc(AUC)/Ins(AUC), r = 0.62). The area under the receiver operating characteristic curves was more than or equal to 0.94 for all surrogates except Gluc(AUC)/Ins(AUC.) Across quartiles of clamp-measured insulin sensitivity, there was a significant overlap in individual values of I(F), 1/I(F), and G(F)/I(F).

CONCLUSION

In obese adolescents with normal or impaired glucose tolerance or diabetes, OGTT-derived surrogates do not offer any advantage over the simpler fasting indices, which correlate strongly with clamp insulin sensitivity. Surrogate indices of insulin sensitivity could be used in epidemiological studies but not to define insulin resistance in individual patients or research subjects.

Prevention and current onset delay approaches of type 2 diabetes mellitus (T2DM)

The urgent need to treat type 2 diabetes mellitus (T2DM), which is currently reaching epidemic proportions, has been a major focus of healthcare systems and policy makers worldwide. Pharmacological treatment and lifestyle interventions together with the control of cardiovascular risk factors are the main strategies to prevent or delay the onset of T2DM. The present review discusses the state of the art knowledge of effective therapeutic approaches (metformin, thiazolidinediones, nateglinides, α-glucosidase inhibitors, incretin-based and angiotensin-based therapies, weight reducers, statins, fibric acid derivatives), including surgery, and identifies the major lifestyle changes for specific target groups.