Prevalence of insulin resistance and associated cardiovascular disease risk factors among normal weight, overweight, and obese individuals

LDL Cholesterol Rises With BMI Only in Lean Individuals: Cross-sectional U.S. and Spanish Representative Data

OBJECTIVE

Elevated LDL cholesterol (LDLc) is not strongly associated with obesity or metabolic syndrome (MS), but this relationship repeatedly has been examined assuming a linear association. This study aimed to assess the dose-response relationship between body mass index (BMI) or waist circumference (WC) and LDLc and to evaluate its link to metabolic impairment.

RESEARCH DESIGN AND METHODS

Participants in the continuous National Health and Nutrition Examination Survey (NHANES, 1999-2010) (n = 12,383) and the Study on Nutrition and Cardiovascular Risk (ENRICA, 2008-2010) (n = 11,765), representative samples of U.S. and Spanish noninstitutionalized populations, were cross-sectionally investigated. LDLc was modeled with age- and sex-adjusted regressions, with BMI and/or WC as explanatory variables included in models as two-segment linear and natural cubic splines.

RESULTS

In NHANES and ENRICA, slopes of the BMI-LDLc association changed (P < 0.001) at BMI 27.1 and 26.5 kg/m², respectively, forming an inverted U shape. Below these BMI inflection points, LDLc rose 2.30 and 2.41 mg/dL per kg/m² (both P < 0.001). However, above said points, LDLc declined -0.37 and -0.38 mg/dL per kg/m² (both P < 0.001). The WC-LDLc relationship was similar to the BMI-LDLc relationship. Accumulation of MS traits was associated with a weakening of the positive BMI-LDLc association among lean participants (below the BMI inflection point). Aging shifted the inflection point of the BMI-LDLc relationship to lower BMI values.

CONCLUSIONS

The BMI- and WC-LDLc relationships have inverted U shapes. Diminishing associations between BMI and LDLc might indicate metabolic impairment as a result of aging or other metabolic diseases. In lean individuals, small weight losses might help to lower LDLc for cardiovascular prevention.

A Synergistic Formulation of Plant Extracts Decreases Postprandial Glucose and Insulin Peaks: Results from Two Randomized, Controlled, Cross-Over Studies Using Real-World Meals

This study investigated the efficacy of a plant-derived dietary supplement with respect to decreasing postprandial glucose and insulin peaks after the intake of real-world meals. Two randomized, double-blind, placebo-controlled, cross-over experiments were conducted on healthy subjects who received a supplement containing extracts of white mulberry, white bean, and green coffee or one containing the three extracts with added fibre before consuming high-GI/GL (glycaemic index/glycaemic load) meals. In study one, 32 subjects received an investigational product/placebo before a standardized meal at two visits. In study two, 150 subjects received an investigational product/placebo before five different standardized meals. Postprandial glucose and insulin concentrations were lower 20–35 min after meal intake among subjects taking the investigational product, and fewer episodes of postprandial reactive hypoglycaemia were noted. For example, after consuming breakfast cereal with milk, lower glucose peaks were observed for the investigational product (vs. placebo) after 20 min (100.2 ± 1.97 vs. 112.5 ± 3.12 mg/dL, respectively; p < 0.01); lower insulin peaks were noted at the same time point (45.9 ± 4.02 IU/mL vs. 68.2 ± 5.53 IU/mL, respectively, p < 0.01). The combined formulation decreases the adverse consequences of high-GI/GL meal consumption. It can be an effective dietary supplement for the management of metabolic syndrome and type 2 diabetes mellitus.

Objectively-Measured Physical Activity and Sedentary Time are Differentially Related to Dietary Fat and Carbohydrate Intake in Children

Background: Research on the clustering of physical activity, sedentary, and dietary intake behaviors in children has relied on retrospective and parent-report measures, which may obscure true associations. The current study combined objectively-measured moderate-to-vigorous intensity physical activity (MVPA) and sedentary time (ST) data from waist-worn accelerometers, with multiple child-report 24-h dietary recalls to assess specific components of dietary intake (i.e., dietary fat, carbohydrates, protein; glycemic load, fruits and vegetables) in children.

Methods: Participants (n = 136, ages 8–12 years) wore an accelerometer for 7 days. On two of those days, children completed 24-h recall phone interviews to assess dietary intake.

Results: After adjusting for child age, sex, ethnicity, annual household income, and body mass index (BMI) percentile; ST was positively associated with percent dietary fat intake, and negatively associated with percent dietary carbohydrate intake and glycemic load (p's < 0.01). MVPA was positively associated with percent dietary carbohydrate intake and daily glycemic load, and negatively associated with percent dietary fat intake (p's < 0.05).

Conclusion: Despite its direct health benefits, physical activity may be associated with consuming greater proportion of total intake from carbohydrates, especially those with a higher glycemic index. Further research is needed to understand the differential implications of these unique behavioral interrelations for diabetes, cardiovascular, and obesity risk.

The Effects of Exercise and Physical Activity on Weight Loss and Maintenance

Obesity represents a major health problem in the United States and is associated with increased prevalence of cardiovascular (CV) disease risk factors. Physical activity (PA) and exercise training (ET) are associated with reduced CV risk, improved cardiometabolic risk factors, and facilitated weight loss through creating a negative energy balance. Clinicians need to counsel overweight and obese patients on how much PA/ET is needed to promote weight loss and weight loss maintenance. This will help establish realistic expectations and maximize improvements in CV risk factors. Although the minimum guidelines for aerobic PA (150 min of moderate or 75 min of vigorous physical activity per week) can improve CV health, these levels are generally inadequate for clinically significant weight loss or weight maintenance without caloric restriction. The purpose of this review is to evaluate the role of ET to promote clinically significant weight loss and promote weight maintenance. In particular, we will evaluate the likelihood of weight loss from ET programs composed of aerobic training only, resistance training only and programs that combine diet and ET. We will also explore the role of PA in promoting short-term and long-term weight maintenance.

The Relation of Light-to-Moderate Alcohol Consumption to Glucose Metabolism and Insulin Resistance in Nondiabetic Adults: the Moderating Effects of Depressive Symptom Severity, Adiposity, and Sex

PURPOSE

We examined the relation of alcohol consumption to glucose metabolism and insulin resistance (IR) as a function of depressive symptoms, adiposity, and sex.

METHOD

Healthy adults (aged 18-65 years) provided fasting blood samples and information on lifestyle factors. Alcohol intake was categorized as never, infrequent (1-3 drinks/month), occasional (1-7 drinks/week), and regular (≥2 drinks/day) drinkers. The Beck Depression Inventory (BDI) was used to assess symptom severity. Primary outcomes were fasting insulin, glucose, and IR assessed by the homeostasis model assessment (HOMA).

RESULTS

In univariate analysis, alcohol consumption was negatively associated with HOMA-IR (p = 0.03), insulin (p = 0.007), and body mass index (BMI) (p = 0.04), but not with glucose or BDI. Adjusting for potential confounders including BMI, alcohol consumption was associated with HOMA-IR (p = 0.01) and insulin (p = 0.009) as a function of BDI and sex. For women with minimal depressive symptoms, light-to-moderate alcohol consumption was associated with lower HOMA-IR and insulin. Alcohol consumption was not associated with metabolic markers in women with higher depressive symptoms and in men. In analysis using BMI as a continuous moderator, alcohol consumption was only associated with insulin (p = 0.004). Post-hoc comparisons between BMI groups (<25 vs ≥25 kg/m²⁾ revealed that light-to-moderate alcohol consumption was associated with lower insulin but only in subjects with BMI ≥ 25 kg/m².

CONCLUSIONS

The benefits of light-to-moderate alcohol consumption on fasting insulin and IR are sex dimorphic and appear to be independently moderated by adiposity and depressive symptom severity.

Adipose morphology and metabolic disease

Adipose morphology is defined as the number and size distribution of adipocytes (fat cells) within adipose tissue. Adipose tissue with fewer but larger adipocytes is said to have a 'hypertrophic' morphology, whereas adipose with many adipocytes of a smaller size is said to have a 'hyperplastic' morphology. Hypertrophic adipose morphology is positively associated with insulin resistance, diabetes and cardiovascular disease. By contrast, hyperplastic morphology is associated with improved metabolic parameters. These phenotypic associations suggest that adipose morphology influences risk of cardiometabolic disease. Intriguingly, monozygotic twin studies have determined that adipose morphology is in part determined genetically. Therefore, identifying the genetic regulation of adipose morphology may help us to predict, prevent and ameliorate insulin resistance and associated metabolic diseases. Here, we review the current literature regarding adipose morphology in relation to: (1) metabolic and medical implications; (2) the methods used to assess adipose morphology; and (3) transcriptional differences between morphologies. We further highlight three mechanisms that have been hypothesized to promote adipocyte hypertrophy and thus to regulate adipose morphology.

Wrist circumference is associated with increased systolic blood pressure in children with overweight/obesity

Wrist circumference is a clinical marker for insulin-resistance in overweight/obese children and adolescents. Insulin resistance is considered a major determinant of increased vascular resistance and hypertension. The aim of the study was to investigate the association between wrist circumference and systolic (S) and diastolic (D) blood pressure (BP) in a population of overweight/obese children and adolescents. A population of 1133 overweight/obese children and adolescents (n = 1133) were consecutively enrolled. Multivariate regression analyses were used to investigate the influence of independent variables on the variance of BP. The prevalence of hypertension was 21.74% in males and 28.95% in females (p = 0.048). The results showed that SBP was significantly associated with wrist circumference in both genders (p < 0.0001 for both comparisons). We found no association between DBP and wrist circumference in either gender. Wrist circumference accounted for 17% of the total variance of SBP in males and 14% in females. Wrist circumference, a marker of insulin resistance, is associated with increased SBP in overweight/obese children and adolescents, suggesting a role of insulin resistance in the pathogenesis and development of hypertension.

Sexual Dimorphism for the Association between Vitamin D and Insulin Resistance in Chinese People

BACKGROUND

The relationship between vitamin D and insulin resistance is still controversial. Many factors could influence this relationship. In addition, this relationship in different genders was still unclear.

METHODS

A total of 6597 subjects, including 2813 males and 3784 females, were analyzed. The serum levels of 25(OH)D, fasting blood glucose (FBG), fasting insulin, HbA1c, and other metabolic parameters were tested. The waist circumference (WC), weight, and height were also measured. Questionnaires regarding smoking and drinking were collected from these subjects.

RESULTS

Serum 25(OH)D was categorized into quartiles. Increasing 25(OH)D levels were associated with reduced trend of homeostasis model assessment of insulin resistance (HOMA-IR) in both males and females. Pearson's correlation indicated 25(OH)D level was inversely associated with the HOMA-IR for male subjects (r = -0.055, P = 0.028) but not for female subjects (r = -0.005, P = 0.798). Age, triglyceride (TG), and low-density lipoprotein (LDL) were associated with the vitamin D levels in males and females. In regression analysis, serum 25(OH)D concentration was significantly associated with HOMA-IR only in overweight males.

CONCLUSION

We found an inverse association between 25(OH)D and HOMA-IR in Chinese overweight males. Vitamin D supplementation might be beneficial in this population. However, further clinical trials are needed to confirm this association.

Obesogenic endocrine disruptors and obesity: myths and truths

Obesogenic endocrine disruptors, also known as obesogens, are chemicals potentially involved in weight gain by altering lipid homeostasis and promoting adipogenesis and lipid accumulation. They included compounds to which human population is exposed over daily life such as pesticides/herbicides, industrial and household products, plastics, detergents and personal care products. The window of life during which the exposure happens could lead to different effects. A critical window is during utero and/or neonatal period in which the obesogens could cause subtle changes in gene expression and tissue organization or blunt other levels of biological organization leading to increased susceptibility to diseases in the adulthood. Some of the reasons for this increased sensitivity include the lack of the protective mechanisms that are available in adult such as DNA repair mechanisms, a competent immune system, detoxifying enzymes, liver metabolism and the blood/brain barrier still not fully functional in the fetus or newborn. The mechanisms of action of obesogens lay on their ability to increase the number and/or the size of the adipocytes and to alter appetite, satiety and food preferences. The ability of obesogens to increase fat deposition results in an increased capacity for their own retention due to their lipophilic properties; thus prolonging the exposure and increasing the detrimental metabolic consequences.

Nutrition, microRNAs, and Human Health

MicroRNAs (miRs) hybridize with complementary sequences in mRNA and silence genes by destabilizing mRNA or preventing translation of mRNA. Over 60% of human protein-coding genes are regulated by miRs, and 1881 high-confidence miRs are encoded in the human genome. Evidence suggests that miRs not only are synthesized endogenously, but also might be obtained from dietary sources, and that food compounds alter the expression of endogenous miR genes. The main food matrices for studies of biological activity of dietary miRs include plant foods and cow milk. Encapsulation of miRs in exosomes and exosome-like particles confers protection against RNA degradation and creates a pathway for intestinal and vascular endothelial transport by endocytosis, as well as delivery to peripheral tissues. Evidence suggests that the amount of miRs absorbed from nutritionally relevant quantities of foods is sufficient to elicit biological effects, and that endogenous synthesis of miRs is insufficient to compensate for dietary miR depletion and rescue wild-type phenotypes. In addition, nutrition alters the expression of endogenous miR genes, thereby compounding the effects of nutrition-miR interactions in gene regulation and disease diagnosis in liquid biopsies. For example, food components and dietary preferences may modulate serum miR profiles that may influence biological processes. The complex crosstalk between nutrition, miRs, and gene targets poses a challenge to gene network analysis and studies of human disease. Novel pipelines and databases have been developed recently, including a dietary miR database for archiving reported miRs in 15 dietary resources. miRs derived from diet and endogenous synthesis have been implicated in physiologic and pathologic conditions, including those linked with nutrition and metabolism. In fact, several miRs are actively regulated in response to overnutrition and tissue inflammation, and are involved in facilitating the development of chronic inflammation by modulating tissue-infiltrated immune cell function.

Metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer outcomes: hypothesis and proposed pathways

BACKGROUND

Women with obesity and type 2 diabetes (T2D) are at greater risk of dying from breast cancer than women without these conditions. Obesity and T2D are associated with insulin resistance and endogenous hyperinsulinemia and are more common in Black women. There is increasing disparity in breast cancer mortality between Black and White women in the USA. We hypothesize that insulin resistance and endogenous hyperinsulinemia in Black women with breast cancer contribute to their greater breast cancer mortality and are associated with increased insulin receptor signalling in tumours.

METHODS

We will recruit 350 Black women and 936 White women with newly diagnosed breast cancer. We will determine the presence or absence of the metabolic syndrome/pre-diabetes and insulin resistance by measuring body mass index, waist circumference, lipids, blood pressure, glucose, insulin-like growth factor binding protein 1 and insulin. Breast cancer prognosis will be determined by a Nottingham Prognostic Index (NPI), with poor prognosis being defined as NPI >4.4. Tumour insulin receptor signalling will be determined by immunohistochemistry. Insulin receptor subtype expression will be measured using Nanostring. Analysis of these factors will determine whether endogenous hyperinsulinemia is associated with a worse prognosis in Black women than White women and increased tumour insulin receptor signalling.

CONCLUSIONS

The results of this study will determine if the metabolic syndrome and pre-diabetes contribute to racial disparities in breast cancer mortality. It may provide the basis for targeting systemic insulin resistance and/or tumour insulin receptor signalling to reduce racial disparities in breast cancer mortality. Copyright © 2016 John Wiley & Sons, Ltd.

Review: Obesity and cardiometabolic syndrome in children

The cardiometabolic syndrome is highly prevalent among overweight youth. The risk of developing the cardiometabolic syndrome is likely triggered or exacerbated by concurrent obesity, unhealthy lifestyle/eating habits, and hormonal changes (puberty). Current screening recommendations include measurement of blood pressure, fasting insulin and glucose, and total cholesterol. However, limiting assessments to these measures underestimates cardiometabolic risk in overweight youth, particularly minorities. Early identification of cardiometabolic risk in its incipient stages may justify early and more aggressive intervention to prevent progression and complications. This review provides rationale for additional assessments to determine cardiometabolic risk in overweight youth and recommends treatment options.

Adipose Cell Size and Regional Fat Deposition as Predictors of Metabolic Response to Overfeeding in Insulin-Resistant and Insulin-Sensitive Humans

Obesity is associated with insulin resistance, but significant variability exists between similarly obese individuals, pointing to qualitative characteristics of body fat as potential mediators. To test the hypothesis that obese, insulin-sensitive (IS) individuals possess adaptive adipose cell/tissue responses, we measured subcutaneous adipose cell size, insulin suppression of lipolysis, and regional fat responses to short-term overfeeding in BMI-matched overweight/obese individuals classified as IS or insulin resistant (IR). At baseline, IR subjects exhibited significantly greater visceral adipose tissue (VAT), intrahepatic lipid (IHL), plasma free fatty acids, adipose cell diameter, and percentage of small adipose cells. With weight gain (3.1 ± 1.4 kg), IR subjects demonstrated no significant change in adipose cell size, VAT, or insulin suppression of lipolysis and only 8% worsening of insulin-mediated glucose uptake (IMGU). Alternatively, IS subjects demonstrated significant adipose cell enlargement; decrease in the percentage of small adipose cells; increase in VAT, IHL, and lipolysis; 45% worsening of IMGU; and decreased expression of lipid metabolism genes. Smaller baseline adipose cell size and greater enlargement with weight gain predicted decline in IMGU, as did increase in IHL and VAT and decrease in insulin suppression of lipolysis. Weight gain in IS humans causes maladaptive changes in adipose cells, regional fat distribution, and insulin resistance. The correlation between development of insulin resistance and changes in adipose cell size, VAT, IHL, and insulin suppression of lipolysis highlight these factors as potential mediators between obesity and insulin resistance.

High-fructose and high-fat feeding correspondingly lead to the development of lysoPC-associated apoptotic cardiomyopathy and adrenergic signaling-related cardiac hypertrophy

BACKGROUND

The heart is a highly adaptive organ that demonstrates remarkable structural, functional, and metabolic remodeling in response to physiological and pathological stimuli. We hypothesize that the heart undergoes differential adaptations in high-fat and high-fructose diet, resulting in a distinct phenotype.

METHODS

High-fat and high-fructose diet-induced obese and non-obese insulin resistance (IR) rat models were used to understand how the heart adapts to long-term (12-week) overnutrition.

RESULTS

Rats fed the high-fat diet developed obese IR, whereas high-fructose diet developed non-obese IR. Obese IR rats developed fibrotic hypertrophy with impairment of preload-independent contractility. The sympathetic and renin-angiotensin-aldosterone (RAA) systems and myocardial adrenergic signaling were activated in obese IR rats. Non-obese IR rats developed apoptotic cardiomyopathy with severe systolic dysfunction. Myocardial calcium cycling regulatory proteins (CCRPs) were dysregulated in non-obese IR rats; specifically, troponin I protein expression was downregulated. Moreover, compared with the controls, lipidomics analysis revealed substantial differences in lipid metabolites in non-obese IR and obese IR rats. The overproduction of lysophosphatidylcholine (lysoPC) and fatty acids was observed in non-obese IR rat hearts. A strong correlation was observed between the myocardial lysoPC and plasma troponin I levels. Treatment of cardiomyocytes with lysoPC resulted in cell death in a dose- and time-dependent manner. The overproduction of myocardial lysoPCs was associated with circulating sPLA2 levels.

CONCLUSION

Obese IR rats developed severe fibrotic hypertrophy with the activation of adrenergic signaling and sympathetic and RAA systems. The sPLA2-lysoPC may play a crucial role in the induction of apoptotic cardiomyopathy in high fructose-induced non-obese IR rats.

A dose-response evaluation of freeze-dried strawberries independent of fiber content on metabolic indices in abdominally obese individuals with insulin resistance in a randomized, single-blinded, diet-controlled crossover trial

SCOPE

This study evaluated the dose-response relationship of strawberries, an anthocyanin-rich fruit, on postprandial glucose and insulin concentrations in individuals with insulin resistance (IR), including changes in plasma anthocyanins, markers of oxidative stress, and inflammation.

METHODS AND RESULTS

In a randomized controlled, four-arm, dose-response, crossover trial, 21 adults with IR consumed a high-carbohydrate, high-fat meal with one of four beverages containing 0 g freeze-dried whole strawberry powder (0g FDS, control), 10, 20, or 40 g FDS, controlled for fiber. Blood was collected at 0 min and at 30 min intervals postmeal until 2 h, then hourly until 6 h. Postmeal insulin concentrations (6 h) were significantly reduced after the 40-g FDS beverage compared to other beverages (p < 0.05). Postmeal 6 h glucose concentrations were not different, although mean insulin:glucose ratio was significantly different among beverages (p < 0.05). Pelargonidin-glucuronide was inversely associated with mean insulin concentrations after the 20 and 40 g FDS (p < 0.05). Oxidized low-density lipoprotein was reduced after 20 g FDS (p < 0.05) and IL-6 was not different among treatments. Strawberry intake reduced the insulin demand to manage postmeal glucose in obese individuals with IR, which was related to plasma anthocyanin/pelargonidin concentrations.

CONCLUSION

The data support a role of strawberries in improving insulin sensitivity in people with IR.

Aging and adipose tissue: potential interventions for diabetes and regenerative medicine

Adipose tissue dysfunction occurs with aging and has systemic effects, including peripheral insulin resistance, ectopic lipid deposition, and inflammation. Fundamental aging mechanisms, including cellular senescence and progenitor cell dysfunction, occur in adipose tissue with aging and may serve as potential therapeutic targets in age-related disease. In this review, we examine the role of adipose tissue in healthy individuals and explore how aging leads to adipose tissue dysfunction, redistribution, and changes in gene regulation. Adipose tissue plays a central role in longevity, and interventions restricted to adipose tissue may impact lifespan. Conversely, obesity may represent a state of accelerated aging. We discuss the potential therapeutic potential of targeting basic aging mechanisms, including cellular senescence, in adipose tissue, using type II diabetes and regenerative medicine as examples. We make the case that aging should not be neglected in the study of adipose-derived stem cells for regenerative medicine strategies, as elderly patients make up a large portion of individuals in need of such therapies.

The Associations Between Increasing Degrees of HOMA-IR and Measurements of Adiposity Among Euglycemic U.S. Adults

BACKGROUND

The purpose of this study was to examine the associations between increasing degrees of insulin resistance (using the homeostatic model assessment of insulin resistance [HOMA-IR]) and two measures of adiposity in a nationally representative sample of euglycemic U.S. adults.

MATERIALS AND METHODS

Sample included adult participants (≥ 20 years of age) [N = 1586 (body mass index, BMI model), N = 1577 (waist circumference, WC model)] from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). HOMA-IR was categorized into quartiles. BMI and WC were examined continuously as the dependent variables.

RESULTS

Following adjustment for covariates, those with HOMA-IR values in the second, third, and fourth quartiles had significantly higher BMIs (P < 0.001) compared with subjects in the first quartile. In the model using WC, significantly higher WCs were found in subjects in the second, third, and fourth quartiles of HOMA-IR (P < 0.001) compared with those in the first quartile. A significant moderate correlation was found between HOMA-IR and BMI (R(2) = 0.4171, P < 0.001), as well as HOMA-IR and WC (R(2) = 0.4826, P < 0.001).

CONCLUSIONS

Having a higher HOMA-IR value is associated with higher BMI and WC values in euglycemic subjects.

Telomere length as a predictor of response to Pioglitazone in patients with unremitted depression: a preliminary study

We studied peripheral leukocyte telomere length (LTL) as a predictor of antidepressant response to PPAR-γ agonist in patients with unremitted depression. In addition we examined correlation between LTL and the insulin resistance (IR) status in these subjects. Forty-two medically stable men and women ages 23-71 with non-remitted depression participated in double-blind placebo-controlled add-on of Pioglitazone to treatment-as-usual. Oral glucose tolerance tests were administered at baseline and at 12 weeks. Diagnostic evaluation of psychiatric disorders was performed at baseline and mood severity was followed weekly throughout the duration of the trial. At baseline, no differences in LTL were detected by depression severity, duration or chronicity. LTL was also not significantly different between insulin-resistant and insulin-sensitive subjects at baseline. Subjects with longer telomeres exhibited greater declines in depression severity in the active arm, but not in a placebo arm, P=0.005, r=-0.63, 95% confidence interval (95% CI)=(-0.84,-0.21). In addition, LTL predicted improvement in insulin sensitivity in the group overall and did not differ between intervention arms, P=0.036, r=-0.44, 95% CI=(-0.74,0.02) for the active arm, and P=0.026, r=-0.50, 95% CI=(-0.78,-0.03) for the placebo arm. LTL may emerge as a viable predictor of antidepressant response. An association between insulin sensitization and LTL regardless of the baseline IR status points to potential role of LTL as a non-specific moderator of metabolic improvement in these patients.

Early Biomarkers of Subclinical Atherosclerosis in Obese Adolescent Girls with Polycystic Ovary Syndrome

OBJECTIVES

Because in obese youth, pulse wave velocity (PWV), an early cardiovascular disease marker, is elevated, we tested if obese girls with polycystic ovary syndrome (OB-PCOS) have higher PWV and carotid intima-media thickness (cIMT) compared with obese girls without PCOS (OB-non-PCOS) and normal-weight girls without PCOS (NW-non-PCOS) and whether PWV and cIMT correlate with inflammatory and circulating endothelial function biomarkers.

STUDY DESIGN

Cross-sectional study of PWV and cIMT in 91 OB-PCOS, 30 obese controls (OB-non-PCOS), and 19 normal-weight controls (NW-non-PCOS). Body composition, blood pressure, fasting glucose, insulin, lipid concentrations, and endothelial function biomarkers were measured. OB-non-PCOS and OB-PCOS underwent 2-hour oral glucose tolerance testing.

RESULTS

PWV was higher in OB-PCOS (664 ± 24 cm/s) and OB-non-PCOS (624 ± 37 cm/s) compared with NW-non-PCOS (468 ± 13 cm/s, P < .001), with no differences in cIMT. Systolic blood pressure, low-density lipoprotein, and non-high-density lipoprotein cholesterol were higher, and high-density lipoprotein cholesterol and indices of insulin sensitivity were lower in OB-PCOS and OB-non-PCOS compared with NW-non-PCOS. Vascular cell adhesion molecule-1 and high-sensitivity C-reactive protein were higher in OB-PCOS compared with NW-non-PCOS. PWV correlated with adiposity (rs = .46), insulin sensitivity index (homeostatic model assessment-insulin resistance rs = .31), systolic blood pressure (rs = .24; P ≤ .003 for all), and free testosterone (rs = .24; P = .03). In multiple regression analysis with PWV as the dependent variable and age, race, body mass index, PCOS, and dysglycemia as independent variables, only body mass index was an independent contributor to the model (r(2) = 0.068, P = .003).

CONCLUSIONS

In adolescent girls, obesity and not PCOS appears to be associated with heightened cardiovascular disease risk. Increased PWV, vascular cell adhesion molecule-1, and high-sensitivity C-reactive protein may be the earliest subclinical atherosclerosis biomarkers in OB-PCOS.

The effect of vitamin D supplementation on insulin and glucose metabolism in overweight and obese individuals: systematic review with meta-analysis

The aim of this systematic review was to assess the effect of vitamin D supplementation on glucose and insulin metabolism in overweight and obese subjects. The search process was based on the selection of publications listed in the databases: PubMed, Scopus, Web of Knowledge, Embase and the Cochrane library that met the inclusion criteria. Twelve randomized controlled trials were included. The analysed population consisted of 1181 individuals with BMIs >23 kg/m2. Changes in the concentration of 25(OH)D, fasting glucose, insulin and the HOMA-IR index were assessed. In the meta-regression analysis, a restricted maximum likelihood method was applied. To combine individual study results, a meta-analysis was performed. Vitamin D supplementation did not have an effect on glucose concentrations, insulin level and HOMA-IR values when the supplemented dose, time of supplementation and baseline of 25(OH)D concentration were taken under consideration in subgroup-analysis. This meta-analysis provides evidence that vitamin D supplementation has no significant effect on glucose and insulin metabolism in overweight and obese individuals.

The associations between increasing degrees of homeostatic model assessment for insulin resistance and muscular strengthening activities among euglycaemic US adults

PURPOSE

To examine the associations between the homeostatic model assessment for insulin resistance and self-reported muscular strengthening activity in a nationally representative sample of euglycaemic US adults.

METHODS

Sample included euglycaemic adults (⩾20 years of age (n = 2009)) from the 1999 to 2004 National Health and Nutrition Examination Survey. Homeostatic model assessment for insulin resistance was categorized into quartiles and was the primary independent variable of interest. No reported muscular strengthening activity was the dependent variable.

RESULTS

Following adjustment for covariates, those with homeostatic model assessment for insulin resistance values in fourth (odds ratio: 2.04, 95% confidence interval: 1.35-3.06, p < 0.001) quartile were found to have significantly greater odds of reporting no muscular strengthening activity. Following further adjustment for non-muscular strengthening activity specific aerobic leisure-time physical activity, results remained significant for the fourth (odds ratio: 2.30, 95% confidence interval: 1.50-3.52, p < 0.001) quartile. A significant trend was seen across quartiles of homeostatic model assessment for insulin resistance for increasing prevalence of no muscular strengthening activity (p < 0.001).

CONCLUSION

Having a higher homeostatic model assessment for insulin resistance value is associated with greater odds of reporting no muscular strengthening activity among euglycaemic US adults. This implies that subjects with an increasing degree of insulin resistance are more likely to not engage in muscular strengthening activity, an exercise modality that has been shown to reduce the risk of several cardiometabolic diseases and improve glycaemic status.

Effects of high-sugar and high-fiber meals on physical activity behaviors in Latino and African American adolescents

OBJECTIVE

This crossover experimental study examined the acute effects of high-sugar/low-fiber (HSLF) vs. low-sugar/high-fiber (LSHF) meals on sedentary behavior (SB) and light-plus activity (L+) in minority adolescents with overweight and obesity.

METHODS

87 Latino and African American adolescents (mean age = 16.3 ± 1.2 years, mean BMI z-score = 2.02 ± 0.52, 56.8% Latino, 51.1% male) underwent two experimental meal conditions during which they consumed HSLF or LSHF meals. Physical activity and SB were measured using accelerometers, and blood glucose and insulin were collected every 30 minutes over 5 hours. Mixed models were used to examine the temporal trends of SB and L+, whether the temporal trends of SB and L+ differed by meal condition, and the influence of blood glucose and insulin on the activity behaviors.

RESULTS

SB and L+ fluctuated over time during the HSLF condition but were stable during the LSHF condition. SB and L+ were influenced by the blood glucose response to the HSLF meals. Insulin did not influence SB or L+ in either meal condition.

CONCLUSIONS

Sugar and fiber content of meals can have differing acute impacts on activity behaviors in minority adolescents with overweight and obesity, possibly due to differing metabolic responses.

Association between metabolically unhealthy overweight/obesity and chronic kidney disease: the role of inflammation

AIM

Our study explored the association between subtypes of increased fat mass (with or without associated metabolic alterations) and the presence of chronic kidney disease (CKD).

METHODS

In this cross-sectional survey in China, body mass index (BMI) was used to assess fat mass. Metabolically healthy was defined as no insulin resistance or any metabolic syndrome components except abdominal obesity. We also used two previous definitions of metabolically healthy. Multiple logistic regression models were used. Normal weight with metabolic health was designated the reference group. Three other subgroups included normal weight with metabolic unhealthiness, overweight/obesity with metabolic health and overweight/obesity with metabolic unhealthiness.

RESULTS

Of the 2324 subjects, 11.77% overweight/obese subjects were metabolically healthy. Compared with normal-weight subjects who were metabolically healthy, overweight/obese subjects who were metabolically healthy did not have an increased risk of CKD (OR: 0.79, 95% CI: 0.29–2.14; P = 0.64), whereas overweight/obese subjects who were metabolically unhealthy had a significantly higher risk of CKD (OR: 2.47, 95% CI: 1.5–3.95; P < 0.001). Normal-weight subjects who were metabolically unhealthy also had a higher risk of CKD, but the P value was of borderline significance. On further adjusting for C-reactive protein (CRP) levels, ORs were much attenuated, but did not alter the associations observed. Using two other definitions of metabolically healthy resulted in similar results.

CONCLUSION

Metabolically unhealthy overweight/obesity, but not metabolically healthy overweight/obesity, is associated with an increased risk of CKD. Inflammation might mediate at least part of the association between metabolic changes and CKD prevalence.

Molecular mechanisms of fatty liver in obesity

Nonalcoholic fatty liver disease (NAFLD) covers a spectrum of liver disorders ranging from simple steatosis to advanced pathologies, including nonalcoholic steatohepatitis and cirrhosis. NAFLD significantly contributes to morbidity and mortality in developed societies. Insulin resistance associated with central obesity is the major cause of hepatic steatosis, which is characterized by excessive accumulation of triglyceride-rich lipid droplets in the liver. Accumulating evidence supports that dysregulation of adipose lipolysis and liver de novo lipogenesis (DNL) plays a key role in driving hepatic steatosis. In this work, we reviewed the molecular mechanisms responsible for enhanced adipose lipolysis and increased hepatic DNL that lead to hepatic lipid accumulation in the context of obesity. Delineation of these mechanisms holds promise for developing novel avenues against NAFLD.

Increased body mass index negatively impacts blastocyst formation rate in normal responders undergoing in vitro fertilization

PURPOSE

The aim of this study is to investigate the effect of female BMI and metabolic dysfunction on blastocyst formation rate.

METHODS

This was a retrospective cohort study that was performed in an academic center for reproductive medicine. Patients who were normal weight, overweight with metabolic dysfunction, or obese who had ≥6 oocytes retrieved in a fresh IVF cycle were included in the study. The blastocyst formation rate was calculated from the number of ≥5 cell embryos on day 3 observed in culture until day 5 or day 6. Only good quality blastocysts were included in the calculation as defined by a morphologic grade of 3BB or better.

RESULTS

The blastocyst formation rate was significantly better in the normal-weight controls versus overweight/obese patients (57.2 versus 43.6 %, p < 0.007). There was no difference in blastocyst formation between the patients with a BMI 25-29.9 kg/m(2) with metabolic dysfunction and those with a BMI ≥30 kg/m(2).

CONCLUSION

The maternal metabolic environment has a significant impact on embryo quality as measured by blastocyst formation. A decreased blastocyst formation rate is likely a significant contributor to poorer reproductive outcomes in overweight and obese women with infertility.

Comparison of the effect of 'metabolically healthy but obese' and 'metabolically abnormal but not obese' phenotypes on development of diabetes and cardiovascular disease in Chinese

The present study was designed to determine the prevalence of 'metabolically healthy but obese' (MHO) and 'metabolically abnormal but not obese' (MANO) phenotypes in Chinese population, and to investigate the association of these two phenotypes with the risk of diabetes and cardiovascular disease (CVD). A total of 2,764 subjects aged 30-90 were followed up over a mean period of 43.80 ± 11.25 months. The metabolic syndrome was defined according to the joint committee for developing Chinese guidelines on prevention and treatment of dyslipidemia in adults. Subjects with body fat percentage (BF %) >25 % for men or BF % >35 % for women were defined as being obese. The proportion of MHO and MANO phenotypes were 22.9, 7.6 % in men, and 26.2, 6.0 % in women, respectively. The MANO phenotype was associated with increased risk for diabetes both in men [hazard ratios (HR): 4.44 (1.21-16.26)] and women [HR: 8.68 (2.87-24.96)] after adjustment of age, serum total cholesterol (TC), triglycerides (TG), and family history of diabetes. This association held for CVD in women [HR: 2.87 (1.44-5.73)], but not in men after adjustment of age, serum TC, TG, and family history of CVD. No association was observed between the MHO phenotype and incident diabetes or CVD. MHO and MANO phenotypes are common in Chinese population. Metabolic risk factors appeared to play a more important role in the development of diabetes and CVD than body fat alone.

A novel criterion for identifying metabolically obese but normal weight individuals using the product of triglycerides and glucose

OBJECTIVES

Metabolically obese but normal weight (MONW) individuals constitute a subgroup of normal weight individuals that display impaired insulin sensitivity with a higher risk of developing diabetes, cardiovascular disease and mortality. We aimed to propose a novel criterion for defining MONW by examining the usefulness and the cutoff value of the TyG index, a product of the levels of triglycerides and glucose, in identifying MONW individuals. In addition, the performance of this criterion in predicting the future incidence of diabetes was assessed.

SUBJECTS/METHODS

A total of 7541 non-diabetic, normal weight (body mass index ⩾18.5 and <25 kg m(-)(2)) subjects were selected from the Korea National Health and Nutrition Examination Survey conducted in 2009-2010. Another 3185 participants with follow-up studies were selected from a prospective community-based cohort study. The TyG index was calculated as ln(fasting triglycerides (mg dl(-1)) × fasting glucose (mg dl(-1))/2).

RESULTS

The levels of the TyG index paralleled the prevalence of metabolic syndrome and its components. The cutoff value of the TyG index that reflected MONW based on the receiver operating characteristics analysis was 8.82 for men and 8.73 for women, with the area under the curve values being 0.855 and 0.868, respectively. The sensitivity and the specificity were 84.2 and 77.6% in men and 69.1 and 89.4% in women, respectively. Individuals designated as MONW, who have a normal weight and TyG levels higher than cutoff, displayed a metabolically unhealthy phenotype and an approximately twofold higher risk of developing diabetes compared with metabolically healthy normal weight subjects.

CONCLUSIONS

We propose a simple diagnostic criterion of MONW, which might be used to discriminate subjects with a higher risk of metabolic diseases.

In vivo 2H2O administration reveals impaired triglyceride storage in adipose tissue of insulin-resistant humans

Indirect evidence suggests that impaired triglyceride storage in the subcutaneous fat depot contributes to the development of insulin resistance via lipotoxicity. We directly tested this hypothesis by measuring, in vivo, TG synthesis, de novo lipogenesis (DNL), adipocyte proliferation, and insulin suppression of lipolysis in subcutaneous adipose tissue of BMI-matched individuals classified as insulin resistant (IR) or insulin sensitive (IS). Nondiabetic, moderately obese subjects with BMI 25-35 kg/m(2), classified as IR or IS by the modified insulin suppression test, consumed deuterated water ((2)H2O) for 4 weeks. Deuterium incorporation into glycerol, palmitate, and DNA indicated TG synthesis, DNL, and adipocyte proliferation, respectively. Net TG synthesis and DNL in adipose cells were significantly lower in IR as compared with IS subjects, whereas adipocyte proliferation did not differ significantly. Plasma FFAs measured during an insulin suppression test were 2.5-fold higher in IR subjects, indicating resistance to insulin suppression of lipolysis. Adipose TG synthesis correlated directly with DNL but not with proliferation. These results provide direct in vivo evidence for impaired TG storage in subcutaneous adipose tissue of IR as compared with IS. Relative inability to store TG in the subcutaneous depot may represent a mechanism contributing to the development of insulin resistance in the setting of obesity.

Metabolic syndrome and diabetes for the urologist

Type 2 diabetes has a number of know urological consequences. Epidemiologic and clinical data suggest a link between metabolic syndrome and prostatic diseases, such as benign prostatic hyperplasia (BPH) and prostate cancer. Recent studies have identified metformin as a viable treatment for patients with type 2 diabetes and prostate cancer.

Overweight and Obesity before, during and after Pregnancy: Part 1: Pathophysiology, Molecular Biology and Epigenetic Consequences

Overweight and obesity before conception as well as excessive weight gain during pregnancy are associated with endocrinological changes of mother and fetus. Insulin resistance physiologically increases during pregnancy, additional obesity further increases insulin resistance. In combination with reduced insulin secretion this leads to gestational diabetes which may develop into type-2-diabetes. The adipose tissue produces TNF-alpha, interleukins and leptin and upregulates these adipokines. Insulin resistance and obesity induce inflammatory processes and vascular dysfunction, which explains the increased rate of pregnancy-related hypertension and pre-eclampsia in obese pregnant women. Between 14 and 28 gestational weeks, the fetal adipose tissue is generated and the number of fat lobules is determined. Thereafter, an increase in adipose tissue is arranged by an enlargement of the lobules (hypertrophy), or even an increase in the number of fat cells (hyperplasia). Human and animal studies have shown that maternal obesity "programmes" the offspring for further obesity and chronic disease. Pregnant women, midwives, physicians and health care politicians should be better informed about prevention, pathophysiological mechanisms, and the burden for society caused by obesity before, during and after pregnancy.

Weight reduction and maintenance with IQP-PV-101: a 12-week randomized controlled study with a 24-week open label period

OBJECTIVE

The safety and efficacy of IQP-PV-101, a proprietary extract of Phaseolus vulgaris, on weight management in two phases was evaluated here. The weight loss (WL) phase was conducted over 12 weeks and the weight maintenance (WM) phase took 24 weeks.

METHODS

In the double-blind WL phase, subjects were randomized to receive either IQP-PV-101 or placebo. All subjects adhered to a mildly hypocaloric diet. Body weight and other body composition parameters were measured at baseline and every 4 weeks thereafter. During the single arm, open label WM trial, energy intake was ad libitum. Efficacy parameters were measured at baseline, week 12 and week 24.

RESULTS

At the end of the WL study, the IQP-PV-101 group lost a mean of 2.91 ± 2.63 kg in body weight compared with 0.92 ± 2.00 kg in the placebo group (P < 0.001). During the WM phase, 36 out of 49 subjects (73.5%) were able to maintain their weight, even without dietary restrictions. No serious or related adverse events were reported over the combined period of 36 weeks.

CONCLUSIONS

Results indicate that IQP-PV-101 is safe and effective for weight loss and maintenance.

Subcutaneous adipose cell size and distribution: relationship to insulin resistance and body fat

OBJECTIVE

Metabolic heterogeneity among obese individuals may be attributable to differences in adipose cell size. We sought to clarify this by quantifying adipose cell size distribution, body fat, and insulin-mediated glucose uptake in overweight to moderately-obese individuals.

METHODS

A total of 148 healthy nondiabetic subjects with BMI 25-38 kg/m2 underwent subcutaneous adipose tissue biopsies and quantification of insulin-mediated glucose uptake with steady-state plasma glucose (SSPG) concentrations during the modified insulin suppression test. Cell size distributions were obtained with Beckman Coulter Multisizer. Primary endpoints included % small adipose cells and diameter of large adipose cells. Cell-size and metabolic parameters were compared by regression for the whole group, according to insulin-resistant (IR) and insulin-sensitive (IS) subgroups, and by body fat quintile.

RESULTS

Both large and small adipose cells were present in nearly equal proportions. Percent small cells was associated with SSPG (r = 0.26, P = 0.003). Compared to BMI-matched IS individuals, IR counterparts demonstrated fewer, but larger large adipose cells, and a greater proportion of small-to-large adipose cells. Diameter of the large adipose cells was associated with % body fat (r = 0.26, P = 0.014), female sex (r = 0.21, P = 0.036), and SSPG (r = 0.20, P = 0.012). In the highest versus lowest % body fat quintile, adipose cell size increased by only 7%, whereas adipose cell number increased by 74%.

CONCLUSIONS

Recruitment of adipose cells is required for expansion of body fat mass beyond BMI of 25 kg/m2 . Insulin resistance is associated with accumulation of small adipose cells and enlargement of large adipose cells. These data support the notion that impaired adipogenesis may underlie insulin resistance.

Ketogenic diet for obesity: friend or foe?

Obesity is reaching epidemic proportions and is a strong risk factor for a number of cardiovascular and metabolic disorders such as hypertension, type 2 diabetes, dyslipidemia, atherosclerosis, and also certain types of cancers. Despite the constant recommendations of health care organizations regarding the importance of weight control, this goal often fails. Genetic predisposition in combination with inactive lifestyles and high caloric intake leads to excessive weight gain. Even though there may be agreement about the concept that lifestyle changes affecting dietary habits and physical activity are essential to promote weight loss and weight control, the ideal amount and type of exercise and also the ideal diet are still under debate. For many years, nutritional intervention studies have been focused on reducing dietary fat with little positive results over the long-term. One of the most studied strategies in the recent years for weight loss is the ketogenic diet. Many studies have shown that this kind of nutritional approach has a solid physiological and biochemical basis and is able to induce effective weight loss along with improvement in several cardiovascular risk parameters. This review discusses the physiological basis of ketogenic diets and the rationale for their use in obesity, discussing the strengths and the weaknesses of these diets together with cautions that should be used in obese patients.

Prevalence of insulin resistance and cardiometabolic risk in Korean children and adolescents: a population-based study

AIMS

We aimed to establish normal reference values of serum insulin and the homeostasis model assessment of insulin resistance (HOMA-IR). We also aimed to verify HOMA-IR "cut-off values" in predicting cardiometabolic risk among Korean children and adolescents.

METHODS

Data from 2716 Korean subjects (1421 male and 1295 female, aged 10-20 years) were evaluated. Insulin resistance was defined as HOMA-IR >95th percentile. The odds ratios of cardiometabolic risk were assessed based on the state of insulin resistance.

RESULTS

Reference values of insulin and HOMA-IR were determined according to sex and age, based on data obtained from normal-weight subjects with normal fasting glucose levels. HOMA-IR values appeared to peak at the age of 14-15 years in male subjects and at the age of 12-13 years in female subjects. The prevalence of insulin resistance in the subjects was 9.8% (male=10.9%, female=8.6%). The prevalence of insulin resistance in normal-weight, overweight, and obese subjects were 4.7%, 25.6%, and 47.1% respectively. Subjects with insulin resistance had a higher prevalence of metabolic syndrome (odds ratios=18.33; 95% confidence interval, 9.62-34.94) and its components, especially hyperglycemia and hypertriglyceridemia.

CONCLUSION

We established reference values of serum insulin and HOMA-IR according to age and sex. Obesity is the most important risk factor for insulin resistance and metabolic syndrome. However, insulin resistance independently increases cardiometabolic risk. This information may be useful for Korean as well as other Asian in planning programs for the prevention of type 2 diabetes.

The risky body mass index ranges for significant hepatitis B viral load: A campus-based study

SUMMARY

Significant hepatitis B viral load (≥10,000 copies/mL) was established to increase risk of advanced liver diseases. The aim of this study was to explore the metabolic risk factors for significant hepatitis B viral load. A campus-based cohort consisting of 146 participants of chronic hepatitis B virus (HBV) infection in Northern Taiwan was investigated in 2009. Clinical profiles including serum levels of deoxyribonucleic acid of hepatitis B virus (HBV DNA) were collected. Hepatitis B e antigen (HBeAg) serostatus, high alanine aminotransferase level, body mass index (BMI) ranges, and insulin resistance were related to significant HBV DNA levels in univariate analysis. Compared to individuals with BMI 23-24.9 kg/m(2) in multivariate analysis, those with BMI ≥25 kg/m(2) (OR = 3.86, 95% CI = 1.38-10.8, P = 0.010) and those with BMI <23 kg/m(2) (OR = 4.47, 95% CI = 1.32-15.2, P = 0.016) were at higher risk for significant HBV DNA levels. This phenomenon was also manifest in HBeAg seronegatives, who contributed to a majority of significant viral load in our study. Furthermore, insulin resistance and BMI ≥25 kg/m(2) had positive additive effects on significant HBV DNA levels (adjusted OR = 9.34, 95% CI = 1.74-50.3, P = 0.009). In conclusion, having certain BMI ranges (BMI ≥25 kg/m(2) or BMI <23 kg/m(2)) could be a risk factor of significant HBV DNA levels.:

Altered subcutaneous abdominal adipose tissue lipid synthesis in obese, insulin-resistant humans

The purpose of this study was to evaluate the variability of subcutaneous abdominal adipose tissue (AT) dynamics in obese subjects with a wide range of insulin sensitivity (IS) and the correlation between these two metabolic measures. Ten obese (BMI 30-40 kg/m²) nondiabetic subjects with (n = 6) and without (n = 4) the metabolic syndrome were studied following a 12-wk ²H₂O labeling period. Subcutaneous abdominal AT biopsies were collected. Deuterium incorporation into triglyceride (TG)-glycerol and TG-palmitate were measured by gas chromatography-mass spectrometry for the calculation of fractional TG synthesis (fTG) and fractional de novo lipogenesis (fDNL). Muscle IS and insulin-mediated nonesterified fatty acid (NEFA) suppression (a measure for adipose IS) indexes were derived from the oral glucose tolerance test (OGTT). The ability of subcutaneous abdominal AT to synthesize lipids varied significantly in obese subjects (fTG range 7-28%, fDNL range 1.1-4.6%) with significantly lower values (>35% reduction) for both parameters in obese with the metabolic syndrome. fTG correlated positively with muscle IS (r = 0.64, P = 0.04) and inversely with NEFA suppression during the OGTT (r = -0.69, P = 0.03). These results demonstrate a large variability in subcutaneous abdominal AT lipid turnover in obesity. Moreover, a reduced capacity for subcutaneous abdominal AT fat storage is associated with muscle and adipose tissue insulin resistance as well as with the metabolic syndrome, thus identifying a form of obesity at heightened risk for type 2 diabetes and cardiovascular disease.

Adiposity and cardiovascular risk clustering in South Asians

BACKGROUND

South Asians have increased risk for type-2 diabetes and cardiovascular disease, but the relationship between metabolic health and weight has not been described. This study establishes the prevalence of metabolic abnormalities in normal weight, overweight, and obese South Asians.

METHODS

Participants were categorized by body mass index and waist circumference. Subjects with two or more cardiometabolic risk factors (blood pressure, glucose, insulin, triglycerides, high-density lipoprotein cholesterol, and C-reactive protein) were defined as metabolically abnormal.

RESULTS

Forty-one percent of the sample (n=1015) was metabolically abnormal, and 12% of those were normal weight. Of metabolically healthy individuals, 58% were overweight or obese. At a normal level of adiposity, women were more likely to be metabolically unhealthy, whereas men were more likely to be unhealthy with increasing adiposity.

CONCLUSIONS

Similar to other ethnic groups, a significant number of normal weight South Asians can be metabolically unhealthy.

U-shaped association between body mass index and proteinuria in a large Japanese general population sample

BACKGROUND

There is little data on the association between body mass index (BMI) and proteinuria.

METHODS

This was a cross-sectional cohort study assessing the association between BMI and proteinuria in a large Japanese population. Using a nationwide health check-up database of 212,251 Japanese aged >20 years with no pre-existing cardiovascular diseases (185,183 men, median age 66 years; 127,068 women, median age 65 years), we examined the association between BMI and proteinuria (≥ 1+ on dipstick).

RESULTS

Subjects were divided into 11 subgroups by BMI grading in 1 kg/m(2) intervals from 18.5-27.5 kg/m(2). A BMI of approximately 22 ± 0.5 kg/m(2) was considered optimal for Japanese; therefore, this subgroup was set as a reference when logistic analysis was applied. Age, waist circumference, height, weight, smoking and drinking habits, use of medications such as antihypertensive, antidiabetic, or antihyperlipidemic, as well as proteinuria, estimated glomerular filtration rate (eGFR), chemistry data, and blood pressure levels were significantly different between subgroups in both genders. The odds ratio for proteinuria showed a U-shape in men and women, even after adjustment for significant covariates such as age, waist circumference, systolic blood pressure, eGFR, fasting plasma glucose, triglyceride, low-density lipoprotein, antihypertensive use, antidiabetic use, antihyperlipidemic use, and lifestyle factors (smoking and drinking). Gender differences were also prominent--a BMI <20.4 kg/m(2) was significantly associated with proteinuria in men compared to a BMI <18.4 kg/m(2) in women. On the other hand, a BMI ≥ 25.5 kg/m(2) was also significantly associated with proteinuria in men compared to a BMI ≥ 22.5 kg/m(2) in women.

CONCLUSIONS

We found that BMI levels were associated with proteinuria in a U-shaped manner and showed marked gender differences. Health guidance should not only focus on higher BMI subjects, but also on thin subjects, in terms of the prevention of chronic kidney disease.

HbA1c in pulmonary arterial hypertension: a marker of prognostic relevance?

BACKGROUND

Patients with pulmonary arterial hypertension (PAH) exhibit impaired glucose metabolism and increased insulin resistance. The clinical consequences of these metabolic changes are not known.

METHODS

We assessed HbA1c levels in 115 patients newly diagnosed with PAH (79 females and 36 males; mean age 49.2 years; idiopathic n = 67, collagen vascular disease n = 16, congenital heart defect n = 19, pulmonary veno-occlusive disease n = 8, portopulmonary n = 5). No patients had diabetes or were receiving anti-diabetic medication or systemic steroids. After initiation of pulmonary vasoactive treatment, patients remained in long-term follow-up.

RESULTS

Initially, patients were in an advanced stage of disease (mean pulmonary arterial pressure 53 ± 18 mm Hg, cardiac index 2.3 ± 0.8 liters/min/m2) with a 6-minute-walk distance of 337 ± 123 meters, and in NYHA Functional Class 3.0 ± 0.7. The HbA1c was 5.73 ± 0.75%. A moderate but statistically significant positive correlation was observed between HbA1c levels and BNP (r(p) = 0.41, p = 0.014), but no correlation was found with hemodynamics or 6-minute-walk distance. The 5-year survival rate for the entire group was 68%. Kaplan-Meier analysis and multivariate Cox proportional hazard models correcting for demographic and clinical covariates revealed that patients with HbA1c < 5.7% had a significantly better 5-year survival compared with those having higher initial values (85.1% vs. 55.9%; log rank p = 0.002). HbA1c was a predictor of all-cause mortality with a hazard ratio of 2.23 (95% CI 1.06 to 4.70; p = 0.034) per 1-unit increase of HbA1c.

CONCLUSIONS

In patients with pulmonary arterial hypertension, the HbA1c level at time of diagnosis is an independent predictor of long-term prognosis.

Dietary glycemic index and the risk of birth defects

Prepregnancy diabetes and obesity have been identified as independent risk factors for several birth defects, providing support for a mechanism that involves hyperglycemia and hyperinsulinemia in the development of malformations. Data from the National Birth Defects Prevention Study from 1997 to 2007 were used to investigate the association between the maternal dietary glycemic index (DGI) and the risk of birth defects among nondiabetic women. DGI was categorized by using spline regression models and quartile distributions. Adjusted odds ratios and 95% confidence intervals were calculated. The joint effect of DGI and obesity was also examined. Among the 53 birth defects analyzed, high DGI, categorized by spline regression, was significantly associated with encephalocele (adjusted odds ratio (aOR) = 2.68), diaphragmatic hernia (aOR = 2.58), small intestinal atresia/stenosis (aOR = 2.97) including duodenal atresia/stenosis (aOR = 2.48), and atrial septal defect (aOR = 1.37). Using quartiles to categorize DGI, the authors identified associations with cleft lip with cleft palate (aOR = 1.23) and anorectal atresia/stenosis (aOR = 1.40). The joint effect of high DGI and obesity provided evidence of a synergistic effect on the risk of selected birth defects. High DGI is associated with an increased risk of a number of birth defects under study. Obesity coupled with high DGI appears to increase the risk further for some birth defects.

Impact of visceral adipose tissue and subcutaneous adipose tissue on insulin resistance in middle-aged Japanese

AIM

The enlargement of visceral adipose tissue (VAT) is considered to mediate the close relationship between obesity and insulin resistance. We aimed to determine whether a stronger association of VAT compared to subcutaneous adipose tissue (SAT) with insulin resistance could be confirmed and generalized in non-diabetic Japanese men and women.

METHODS

Participants were 912 non-diabetic Japanese (636 men and 276 women, mean age 52.4±7.0 years, and mean BMI 24.9±3.1 kg/m(2)). VAT and SAT were measured through the use of computed tomography scanning. Homeostatic model for the assessment of insulin resistance (HOMA-IR) and Matsuda insulin sensitivity index (ISI) were calculated based on results from the oral glucose tolerance test.

RESULTS

For both genders, subjects in higher tertiles of SAT as well as VAT showed significantly higher levels of HOMA-IR and lower levels of Matsuda ISI (p<0.001). In multiple regression analyses with VAT and SAT included in the model, only VAT, but not SAT, was independently associated with Matsuda ISI in women (p<0.001), whereas both SAT and VAT were independently associated with HOMA-IR and with Matsuda ISI in men (p<0.001). When VAT and waist circumference were jointly included in the model, only VAT, but not waist circumference, was independently associated with Matsuda ISI in women (p<0.001) but not in men.

CONCLUSION

VAT had a stronger association with insulin resistance than SAT or waist circumference in women but not in men. BMI showed a comparable association with insulin resistance to VAT in this population.

Metabolic heterogeneity of obesity: role of adipose tissue

Obesity is not synonymous with insulin resistance. Why some but not all individuals develop insulin resistance with weight excess is not clear, but a number of plausible hypotheses with ample support now exist. This article reviews regional fat distribution, inflammation, lipotoxicity/ectopic fat and impaired adipogenesis as leading theories as to why excess body weight has the potential to promote insulin resistance.

Glucose metabolism in outpatients with new-onset hypertension in Chinese Han population

The aim of this study was to assess the prevalence of glucose abnormalities in a Chinese Han population with untreated new-onset hypertension. Four hundred and ninety-nine new-onset hypertensive patients without diabetes were enrolled in this study. An abnormal glucose metabolism was diagnosed in 57.1% of the new-onset hypertensive patients without previously diagnosed diabetes. Stratified by age, the prevalence of diabetes and prediabetes were increased with aging. Male sex, advanced age, higher serum triglycerides, and homeostasis model assessment of insulin resistance levels were all significantly associated with the increased risks of pre-diabetes or diabetes in new-onset hypertensive patients when analyzed by the logistic regression analysis.

Melatonin and the metabolic syndrome: a tool for effective therapy in obesity-associated abnormalities?

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities associated with increased risk for cardiovascular diseases. Apart from its powerful antioxidant properties, the pineal gland hormone melatonin has recently attracted the interest of various investigators as a multifunctional molecule. Melatonin has been shown to have beneficial effects in cardiovascular disorders including ischaemic heart disease and hypertension. However, its role in cardiovascular risk factors including obesity and other related metabolic abnormalities is not yet established, particularly in humans. New emerging data show that melatonin may play an important role in body weight regulation and energy metabolism. This review will address the role of melatonin in the MetS focusing on its effects in obesity, insulin resistance and leptin resistance. The overall findings suggest that melatonin should be exploited as a therapeutic tool to prevent or reverse the harmful effects of obesity and its related metabolic disorders.