Relationship between different fasting-based insulin sensitivity indices in obese children and adolescents

Data assimilation on mechanistic models of glucose metabolism predicts glycemic states in adolescents following bariatric surgery

Type 2 diabetes mellitus is a complex and under-treated disorder closely intertwined with obesity. Adolescents with severe obesity and type 2 diabetes have a more aggressive disease compared to adults, with a rapid decline in pancreatic β cell function and increased incidence of comorbidities. Given the relative paucity of pharmacotherapies, bariatric surgery has become increasingly used as a therapeutic option. However, subsets of this population have sub-optimal outcomes with either inadequate weight loss or little improvement in disease. Predicting which patients will benefit from surgery is a difficult task and detailed physiological characteristics of patients who do not respond to treatment are generally unknown. Identifying physiological predictors of surgical response therefore has the potential to reveal both novel phenotypes of disease as well as therapeutic targets. We leverage data assimilation paired with mechanistic models of glucose metabolism to estimate pre-operative physiological states of bariatric surgery patients, thereby identifying latent phenotypes of impaired glucose metabolism. Specifically, maximal insulin secretion capacity, σ, and insulin sensitivity, S_I, differentiate aberrations in glucose metabolism underlying an individual's disease. Using multivariable logistic regression, we combine clinical data with data assimilation to predict post-operative glycemic outcomes at 12 months. Models using data assimilation sans insulin had comparable performance to models using oral glucose tolerance test glucose and insulin. Our best performing models used data assimilation and had an area under the receiver operating characteristic curve of 0.77 (95% confidence interval 0.7665, 0.7734) and mean average precision of 0.6258 (0.6206, 0.6311). We show that data assimilation extracts knowledge from mechanistic models of glucose metabolism to infer future glycemic states from limited clinical data. This method can provide a pathway to predict long-term, post-surgical glycemic states by estimating the contributions of insulin resistance and limitations of insulin secretion to pre-operative glucose metabolism.

Coconut oil consumption improves fat-free mass, plasma HDL-cholesterol and insulin sensitivity in healthy men with normal BMI compared to peanut oil

BACKGROUND & AIMS

The existing scientific evidence on coconut oil consumption and its health effects remains inconclusive due to varied reasons. In this context, we conducted a well-controlled metabolic study, eliminating some of the confounding factors and assessed the effects of the consumption of coconut oil-based diet on various anthropometric, biochemical and inflammatory markers and compared with peanut oil-diet.

METHODS

Nine healthy male volunteers with BMI ≤25 kg/m² were enrolled for this study and given balanced diets prepared with coconut oil (CO; ~35 g) for a period of eight weeks. After a wash-out period of six weeks, the same subjects were provided with diets prepared with peanut oil (~35 g) for eight weeks. Except fat source, the composition of the diets was identical in all aspects.

RESULTS

Compared to basal values, there were significant increases in fat-free mass (p ≤ 0.022), plasma HDL-cholesterol (HDL-C) (p ≤ 0.047) and insulin sensitivity of the subjects at the end of CO-consumption. Further, compared to peanut oil, increase in plasma HDL-C was significant (p = 0.004) in CO treatment. On the other hand, plasma inflammatory markers-associated with cardiovascular diseases (CVD), namely soluble vascular cell adhesion molecule 1 (sVCAM1) and matrix metalloproteinase levels were reduced significantly by CO-intake. Further, these subjects displayed elevated levels of myristic acid (14:0) in plasma phospholipids at the end of CO-consumption, which correlated positively with HDL-C and negatively with sVCAM1. However, no such changes were observed after peanut oil diet consumption.

CONCLUSIONS

In conclusion, compared to peanut oil, the consumption of coconut oil in a balanced diet resulted in increased fat-free mass, plasma HDL-C, elicited favourable changes on insulin sensitivity and CVD risk-associated parameters in healthy men with normal BMI.

Using simple clinical measures to predict insulin resistance or hyperglycemia in girls with polycystic ovarian syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) includes insulin resistance (IR) and impaired glucose tolerance (IGT) in youth, and a greatly elevated risk of type 2 diabetes in adulthood. Identifying IR is challenging and documenting IGT requires an oral glucose tolerance test (OGTT).

OBJECTIVE

Identify easily applied surrogate measures for IR and IGT in girls with PCOS.

METHODS

We studied 28 girls with PCOS (body mass index [BMI] percentile 98 (83.99); 15.5 (14.5,16.6) years of age) and 20 with normal menses [BMI percentile (97 (88.99); 15.5 (13.3,16.1) years]. Hyperinsulinemic-euglycemic clamps (insulin dose of 80 μU/ml/min) to determine glucose infusion rate (GIR) and a 75 g OGTT were performed. Surrogates for IR including fasting insulin, homeostatic model assessment-insulin resistant (HOMA-IR), Matsuda index, and estimate of insulin sensitivity (e-IS) were compared to IGT status and GIR. Spearman correlations were performed between surrogates and GIR or IGT, and receiver operator curve (ROC) analysis to predict GIR below the median or IGT status.

RESULTS

GIR was lower in PCOS (12.9 ± 4.6 vs 17.1 ± 5.1 mg/kg fat-free mass·min; P = 0.01). Within PCOS, HOMA-IR (r = -0.78, P < 0.0001), e-IS (r = 0.70, P < 0.001), and Matsuda (r = 0.533, P < 0.001) correlated with GIR. e-IS provided a good sensitivity (100%) and specificity (71%) to identify IR (e-IS cutoff: <6.3, ROC-area under curve = 0.898). Fasting insulin >22 IU/mL had the best sensitivity (88%), specificity (78%), and ROC (0.760) for IGT status.

CONCLUSIONS

Girls with PCOS have significant IR, and IGT is common. Both e-IS and fasting insulin are obtainable without an OGTT or clamp and could be used clinically to guide treatment in PCOS.

Systematic review to identify and appraise outcome measures used to evaluate childhood obesity treatment interventions (CoOR): evidence of purpose, application, validity, reliability and sensitivity

BACKGROUND

Lack of uniformity in outcome measures used in evaluations of childhood obesity treatment interventions can impede the ability to assess effectiveness and limits comparisons across trials.

OBJECTIVE

To identify and appraise outcome measures to produce a framework of recommended measures for use in evaluations of childhood obesity treatment interventions.

DATA SOURCES

Eleven electronic databases were searched between August and December 2011, including MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations; EMBASE; PsycINFO; Health Management Information Consortium (HMIC); Allied and Complementary Medicine Database (AMED); Global Health, Maternity and Infant Care (all Ovid); Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost); Science Citation Index (SCI) [Web of Science (WoS)]; and The Cochrane Library (Wiley) - from the date of inception, with no language restrictions. This was supported by review of relevant grey literature and trial databases.

REVIEW METHODS

Two searches were conducted to identify (1) outcome measures and corresponding citations used in published childhood obesity treatment evaluations and (2) manuscripts describing the development and/or evaluation of the outcome measures used in the childhood intervention obesity evaluations. Search 1 search strategy (review of trials) was modelled on elements of a review by Luttikhuis et al. (Oude Luttikhuis H, Baur L, Jansen H, Shrewsbury VA, O'Malley C, Stolk RP, et al. Interventions for treating obesity in children. Cochrane Database Syst Rev 2009;1:CD001872). Search 2 strategy (methodology papers) was built on Terwee et al.'s search filter (Terwee CB, Jansma EP, Riphagen II, de Vet HCW. Development of a methodological PubMed search filter for finding studies on measurement properties of measurement instruments. Qual Life Res 2009;18:1115-23). Eligible papers were appraised for quality initially by the internal project team. This was followed by an external appraisal by expert collaborators in order to agree which outcome measures should be recommended for the Childhood obesity Outcomes Review (CoOR) outcome measures framework.

RESULTS

Three hundred and seventy-nine manuscripts describing 180 outcome measures met eligibility criteria. Appraisal of these resulted in the recommendation of 36 measures for the CoOR outcome measures framework. Recommended primary outcome measures were body mass index (BMI) and dual-energy X-ray absorptiometry (DXA). Experts did not advocate any self-reported measures where objective measurement was possible (e.g. physical activity). Physiological outcomes hold potential to be primary outcomes, as they are indicators of cardiovascular health, but without evidence of what constitutes a minimally importance difference they have remained as secondary outcomes (although the corresponding lack of evidence for BMI and DXA is acknowledged). No preference-based quality-of-life measures were identified that would enable economic evaluation via calculation of quality-adjusted life-years. Few measures reported evaluating responsiveness.

LIMITATIONS

Proposed recommended measures are fit for use as outcome measures within studies that evaluate childhood obesity treatment evaluations specifically. These may or may not be suitable for other study designs, and some excluded measures may be more suitable in other study designs.

CONCLUSIONS

The CoOR outcome measures framework provides clear guidance of recommended primary and secondary outcome measures. This will enhance comparability between treatment evaluations and ensure that appropriate measures are being used. Where possible, future work should focus on modification and evaluation of existing measures rather than development of tools de nova. In addition, it is recommended that a similar outcome measures framework is produced to support evaluation of adult obesity programmes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Framework of outcome measures recommended for use in the evaluation of childhood obesity treatment interventions: the CoOR framework

INTRODUCTION

Consensus is lacking in determining appropriate outcome measures for assessment of childhood obesity treatments. Inconsistency in the use and reporting of such measures impedes comparisons between treatments and limits consideration of effectiveness. This study aimed to produce a framework of recommended outcome measures: the Childhood obesity treatment evaluation Outcomes Review (CoOR) framework.

METHODS

A systematic review including two searches was conducted to identify (1) existing trial outcome measures and (2) manuscripts describing development/evaluation of outcome measures. Outcomes included anthropometry, diet, eating behaviours, physical activity, sedentary time/behaviour, fitness, physiology, environment, psychological well-being and health-related quality of life. Eligible measures were appraised by the internal team using a system developed from international guidelines, followed by appraisal from national external expert collaborators.

RESULTS

A total of 25,486 papers were identified through both searches. Eligible search 1 trial papers cited 417 additional papers linked to outcome measures, of which 56 were eligible. A further 297 outcome development/evaluation papers met eligibility criteria from search 2. Combined, these described 191 outcome measures. After internal and external appraisal, 52 measures across 10 outcomes were recommended for inclusion in the CoOR framework.

CONCLUSION

Application of the CoOR framework will ensure greater consistency in choosing robust outcome measures that are appropriate to population characteristics.

Diabetes, pre-diabetes and insulin resistance screening in Native American children and youth

OBJECTIVES

Early identification of pre-diabetes and insulin resistance (IR) provides an important window of opportunity for diabetes prevention. Little is known about the prevalence of pre-diabetes and IR in Native American (NA) youth. We designed a cross-sectional, community-based study of NA children to estimate the prevalence of diabetes, pre-diabetes and IR and their association with other diabetes risk factors.

STUDY DESIGN

NA children (5-18 years) were screened with body mass index (BMI), blood pressure, oral glucose tolerance test (OGTT), lipids, insulin and highly sensitive C-reactive protein (hsCRP), and calculated homeostatic model assessment of IR (HOMA-IR).

RESULTS

Mean age of the cohort (n=201) was 10.8 ± 3.8 years (± s.d.; 94/107 M/F). BMI percentile for age and sex (BMI%) was elevated (≥ 85 th percentile) in 58.6% of 5-11 years and 51.1% of 12-18 years, and positively correlated with HOMA-IR, blood pressure, triglycerides and hsCRP (P<0.05). The prevalence rate for pre-diabetes and diabetes were 6.5% (3.5-10.8%) and 1.0% (0.1-3.6%), respectively. Mean HOMA-IR was greater in the older than younger age group while prevalence of pre-diabetes was the same. Those with pre-diabetes and diabetes had a greater HOMA-IR, abdominal circumference and BMI% than normal youth.

CONCLUSION

In the first prospective, community-based screening for pre-diabetes, IR and diabetes in United States NA youth using OGTT, while the number of diabetes cases was low, pre-diabetes was found in a significant number of youth, particularly in those with BMI ≥ 95 th%. As proportions of pre-diabetes were similar in 5-11 and 12-18 year olds, diabetes risk begins early in NA youth.

Systemic inflammation in childhood obesity: circulating inflammatory mediators and activated CD14++ monocytes

AIMS/HYPOTHESIS

In adults, circulating inflammatory mediators and activated CD14(++) monocytes link obesity to its metabolic and cardiovascular complications. However, it is largely unknown whether these inflammatory changes already occur in childhood obesity. To survey inflammatory changes during the early stages of obesity, we performed a comprehensive analysis of circulating inflammatory mediators, monocyte populations and their function in childhood obesity.

METHODS

In lean and obese children aged 6 to 16 years (n = 96), 35 circulating inflammatory mediators including adipokines were measured. Hierarchical cluster analysis of the inflammatory mediator profiles was performed to investigate associations between inflammatory mediator clusters and clinical variables. Whole-blood monocyte phenotyping and functional testing with the toll-like receptor 4 ligand, lipopolysaccharide, were also executed.

RESULTS

First, next to leptin, the circulating mediators chemerin, tissue inhibitor of metalloproteinase 1, EGF and TNF receptor 2 were identified as novel inflammatory mediators that are increased in childhood obesity. Second, cluster analysis of the circulating mediators distinguished two obesity clusters, two leanness clusters and one mixed cluster. All clusters showed distinct inflammatory mediator profiles, together with differences in insulin sensitivity and other clinical variables. Third, childhood obesity was associated with increased CD14(++) monocyte numbers and an activated phenotype of the CD14(++) monocyte subsets.

CONCLUSIONS/INTERPRETATION

Inflammatory mediator clusters were associated with insulin resistance in obese and lean children. The activation of CD14(++) monocyte subsets, which is associated with increased development of atherosclerosis in obese adults, was also readily detected in obese children. Our results indicate that inflammatory mechanisms linking obesity to its metabolic and cardiovascular complications are already activated in childhood obesity.

The absence of insulin resistance in metabolic syndrome definition leads to underdiagnosing of metabolic risk in obese patients

This study explores in a group of obese children and adolescents aged 10 to 16 years, the prevalence of metabolic syndrome (MS) according to the criteria of International Diabetes Federation (IDF). In addition, the prevalence of insulin resistance (IR) was investigated to find correlations between MS and IR. IDF definition was compared to a modified WHO definition. A total of 159 obese patients (74 male and 85 female; median age 12.7 years) were included in the study. Anthropometric measurements, blood pressure, and serum fasting lipids were evaluated. An oral glucose tolerance test (OGTT) was performed, and serum glucose and insulin levels were measured at 0, 30, 60, 90, and 120 min. Homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), fasting glucose/insulin ratio (FGIR), Matsuda index, and total insulin levels during OGTT were calculated. For the IR diagnosis, we used cutoff values described in previous publications (HOMA-IR of >3.16, QUICKI of <0.357, FGIR of <7, and/or the sum of insulin levels during OGTT of >300 mIU/mL). MS prevalence, defined according to IDF criteria, was 34.6 %. Using the IDF definition, there was no statistically significant difference for the surrogate IR indices between patients with or without MS (QUICKI, 94.5 vs. 83.7 %), FGIR (81.1 vs. 78.8 %), HOMA-IR (70.9 vs. 63.5 %), and total insulin levels during OGTT (61.8 vs. 51.9 %). The Matsuda index values, the prevalence of fasting hyperinsulinemia, and impaired glucose tolerance were also similar in these two groups. In conclusion, IR was prominent in obese patients with and without MS. IDF definition of MS fails to discover individuals with IR, unless it is specifically investigated.

Relationship of insulin resistance to psychobehavioral characteristics of overweight and obese African American children

OBJECTIVES

The objective of this study was to evaluate the relationships of insulin resistance to positive as well as negative dimensions of the child's emotions, behavior and personality (hereafter referred to as "psychobehavioral characteristics") in a convenience sample of inner-city, overweight and obese, African American children.

METHODS

A secondary analysis was performed on a sample of 127 children ages 9-12 yr old who were participating in a community-based, Type 2 diabetes prevention program. Psychobehavioral characteristics of children were assessed using both child and parent ratings derived from the Behavioral Assessment for Children, 2nd edition (BASC-2). Body fatness was evaluated using anthropometric techniques, and insulin resistance (HOMA-IR) was calculated from fasting glucose and insulin concentrations. Hierarchical multiple linear regression models were employed with BASC scales as dependent variables and HOMA-IR as the independent variable of interest.

RESULTS

After adjusting for child age, pubertal stage, gender, family socioeconomic index, and intervention group assignment, child HOMA-IR was related at p<0.05 to less favorable scores for parent-report of behavioral symptoms and externalizing problems composites, and to content scales for bullying and negative emotionality. Additionally, child HOMA-IR was related at p<0.01 to less favorable scores for child-report inattention/hyperactivity composite. Body fatness suppressed the unfavorable relationship between HOMA-IR and these and other psychobehavioral characteristics as the degree of significance was higher following adjustment for body fatness in this cohort.

CONCLUSION

More than one psychobehavioral characteristic were associated with body fatness and insulin resistance in the overweight children of this study. Whether the associations are due to several, or only one, of these psychobehavioral characteristics could not be determined. A much larger and future study will be needed to determine which, if any, of these psychobehavioral characteristics are independently associated with insulin resistance in overweight children.

Limited Weight Loss or Simply No Weight Gain following Lifestyle-Only Intervention Tends to Redistribute Body Fat, to Decrease Lipid Concentrations, and to Improve Parameters of Insulin Sensitivity in Obese Children

Objectives. To investigate whether lifestyle-only intervention in obese children who maintain or lose a modest amount of weight redistributes parameters of body composition and reverses metabolic abnormalities. Study Design. Clinical, anthropometric, and metabolic parameters were assessed in 111 overweight or obese children (CA of 11.3 ± 2.8 years; 63 females and 48 males), during 8 months of lifestyle intervention. Patients maintained or lost weight (1-5%) (group A; n: 72) or gained weight (group B). Results. Group A patients presented with a decrease in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (P < .005 and P < .05, resp.), BMI (P < .0001), z-score BMI (P < .0001), waist circumference (P < .0001), fat mass (P < .005), LDL-C (P < .05), Tg/HDL-C ratio (P < .05), fasting and postprandial insulin (P < .005), and HOMA (P < .005), while HDL-C (P < .05) and QUICKI increased (P < .005). Conversely, group B patients had an increase in BMI (P < .0001), waist circumference (P < .005), SBP (P < .005), and in QUICKI (P < .005), while fat mass (P < .05), fasting insulin (P < .05), and HOMA (P < .05) decreased. Lean mass, DBP, lipid concentrations, fasting and postprandial glucose, postprandial insulin, and ultrasensitive C-reactive protein (CRP) remained stable. Conclusions. Obese children who maintain or lose a modest amount of weight following lifestyle-only intervention tend to redistribute their body fat, decrease blood pressure and lipid levels, and to improve parameters of insulin sensitivity.

Impaired glucose tolerance in pediatric burn patients at discharge from the acute hospital stay

Hyperglycemia, secondary to the hypermetabolic stress response, is a common occurrence after thermal injury. This stress response has been documented to persist up to 9 months postburn. The purpose of this study was to measure insulin sensitivity in severely burned children before discharge when wounds are 95% healed. Twenty-four children, aged 4 to 17 years, with burns > or = 40% TBSA underwent a 2-hour oral glucose tolerance test before discharge from the acute pediatric burn unit. Plasma glucose and insulin levels as well as the Homeostasis Model Assessment for Insulin Resistance (HOMAIR) were compared with published oral glucose tolerance test data from healthy, nonburned children. There was a significant difference between severely burned children and nonburned, healthy children with respect to the HOMAIR. Severely burned children had a HOMAIR of 3.53 +/- 1.62 compared with the value in nonburned, healthy children of 1.28 +/- 0.16 (P < .05). Insulin resistance secondary to the hypermetabolic stress response persists in severely burned children when burn wounds are at least 95% healed. The results of this study warrant future investigations into therapeutic options for the burned child during the rehabilitative phase of their care after injury.

Insulin resistance and self-perceived scholastic competence in inner-city, overweight and obese, African American children

PURPOSE

scholastic competence is a predictor of future achievement, yet there is little research about health factors that influence the development of self-perceived scholastic competence (SPSC). This study examined the relationship of insulin resistance and body fatness with SPSC in low-income, overweight and obese, African American children.

METHODS

data were analyzed from a convenience sample of 9-10years old African American children (89 boys and 113 girls) enrolled in a type 2 diabetes prevention study. Health variables analyzed for their influence on SPSC (Harter scale) included insulin resistance (Homeostatic model-derived insulin sensitivity, HOMA-IR) and body fatness (% body fat). Adjustments were made for self-esteem (Global Self Worth).

RESULTS

there was a significant gender by insulin resistance interaction effect on the child's SPSC, so separate regression models were developed for each gender. In boys, neither insulin resistance nor body fatness was related to SPSC. In girls, however, insulin resistance was negatively related to SPSC scores, and the significance of the relationship increased further after adjusting for body fatness. Body fatness alone was not significantly related to SPSC in girls, but after adjusting for insulin resistance, body fatness was positively related to SPSC. Thus, insulin resistance and body fatness mutually suppressed SPSC in girls.

CONCLUSION

high SPSC was associated with lower insulin resistance and, with insulin resistance held constant, with higher body fatness in girls but not in boys. These relationships were not influenced by self-esteem in these children.

Body mass index percentile more sensitive than acanthosis nigricans for screening Native American children for diabetes risk

BACKGROUND

Many Native American tribes use acanthosis nigricans to screen for type 2 diabetes risk. We hypothesized that acanthosis nigricans misses many children at risk for type 2 diabetes.

METHODS

We evaluated 5- to 18-year-old Native American children and youth to assess the sensitivity and specificity of acanthosis nigricans as a marker for insulin resistance.

RESULTS

In a cohort of 161 youth (72 males/89 females), mean age was 10.7 years + 3.9. Mean body mass index (BMI) percentile was 76.8 +/- 23.3, and 54% had a BMI at or above the 85th percentile. Acanthosis nigricans was present in 21.7% of the participants and was more common in 12-to 18-year-olds than in 5 to 11-year-olds (p = .02). Of those with acanthosis nigricans, 82.4% had insulin resistance (homeostatic model assessment of insulin resistance >4), but only 48.3% of those with insulin resistance had acanthosis nigricans. In contrast, BMI at or above the 85th percentile had a high sensitivity (74%) for insulin resistance, even though its specificity was lower (58%).

CONCLUSIONS

The presence of acanthosis nigricans alone was a specific, but not a sensitive, screening tool for identifying youth with insulin resistance. BMI at or above the 85th percentile was a more sensitive screening tool than acanthosis nigricans alone, or acanthosis nigricans and BMI together for identifying children and youth with IR who are at increased risk for type 2 diabetes.

NUTRIOSE dietary fiber supplementation improves insulin resistance and determinants of metabolic syndrome in overweight men: a double-blind, randomized, placebo-controlled study

The influence of dietary fiber on determinants of metabolic syndrome is controversial. The objective of this study was to determine the effects of NUTRIOSE supplementation on insulin resistance and the determinants of metabolic syndrome in overweight men. In this double-blind, randomized, placebo-controlled study, we supplemented the diets of overweight Chinese men with 250 mL of fruit juice that contained NUTRIOSE (Test group: n = 60, age = 30.4 ± 4.3 years, body mass index (BMI) = 24.5 ± 0.2 kg·m–2) or a maltodextrin placebo (Control group: n = 60, age = 31.6 ± 4.1 years, BMI = 24.5 ± 0.3 kg·m–2) at a dosage of 17 g twice daily for 12 weeks. Daily caloric intake, body composition, blood chemistry, and blood pressure were evaluated every 4 weeks during the trial. Test subjects consumed fewer calories per day and had greater reductions in body weight, BMI, body fat percentage, and waist circumference than Control subjects. All markers of glucose metabolism improved in the Test group, with increases in adiponectin and reductions in glucose, insulin, homeostasis model assessment-estimated insulin resistance, glycosylated hemoglobin, and glycated albumin (all p < 0.01). Similarly, all lipid measures improved with increases in high-density lipoprotein cholesterol and reductions in total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglycerides (all p < 0.01). No changes were observed in systolic blood pressure between groups. Most components of glucose metabolism and the lipid profile were significantly better in the Test than in the Control subjects. No adverse events or gastrointestinal complaints were reported in either group. Supplementation with NUTRIOSE for 12 weeks is well tolerated, lowers insulin resistance, and improves determinants of metabolic syndrome in overweight men.

Taking Action Together: a YMCA-based protocol to prevent type-2 diabetes in high-BMI inner-city African American children

Background

Associated with a tripling in obesity since 1970, type 2 diabetes mellitus (T2DM) in children has risen 9-10 fold. There is a critical need of protocols for trials to prevent T2DM in children.

Methods/Design

This protocol includes the theory, development, evaluation components and lessons learned from a novel YMCA-based T2DM prevention intervention designed specifically for high-BMI African American children from disadvantaged, inner-city neighborhoods of Oakland, California. The intervention was developed on the basis of: review of epidemiological and intervention studies of pediatric T2DM; a conceptual theory (social cognitive); a comprehensive examination of health promotion curricula designed for children; consultation with research, clinical experts and practitioners and; input from community partners. The intervention, Taking Action Together, included culturally sensitive and age-appropriate programming on: healthy eating; increasing physical activity and, improving self esteem.

Discussion

Evaluations completed to date suggest that Taking Action Together may be an effective intervention, and results warrant an expanded evaluation effort. This protocol could be used in other community settings to reduce the risk of children developing T2DM and related health consequences.

Trial registration

ClinicalTrials.gov NCT01039116.

Macronutrient intakes and cardio metabolic risk factors in high BMI African American children

BACKGROUND

The aim of this study was to evaluate the relationship between intakes of energy-providing macronutrients, and markers of cardio metabolic risk factors in high BMI African American (AA) children.

METHODS

A cross sectional analysis of a sample of 9-11 year old children (n = 80) with BMI greater then the 85th percentile. Fasting hematological and biochemical measurements, and blood pressure were measured as selected markers of cardio metabolic risk factors and their relationships to dietary intakes determined.

RESULTS

After adjusting for gender, pubertal stage and waist circumference (WC), multivariate regression analysis showed that higher total energy intakes (when unadjusted for source of energy) were associated with higher plasma concentrations of intermediate density lipoprotein cholesterol (IDL-C) and very low density lipoprotein cholesterol (VLDL-C). Higher intakes of carbohydrate energy (fat and protein held constant) were associated with higher IDL-C, VLDL-C, triglycerides (TG) and homeostasis model assessment of insulin resistance (HOMA-IR). Higher intakes of fat (carbohydrate and protein held constant), however, were associated with lower IDL-C; and higher protein intakes (fat and carbohydrate held constant) were associated with lower HOMA-IR.

CONCLUSION

The specific macronutrients that contribute energy are significantly associated with a wide range of cardio metabolic risk factors in high BMI AA children. Increases in carbohydrate energy were associated with undesirable effects including increases in several classes of plasma lipids and HOMA-IR. Increases in protein energy were associated with the desirable effect of reduced HOMA-IR, and fat energy intakes were associated with the desirable effect of reduced IDL-C. This analysis suggests that the effect of increased energy on risk of developing cardio metabolic risk factors is influenced by the source of that energy.

Glucose metabolism in overweight Hispanic adolescents with and without polycystic ovary syndrome

OBJECTIVES

About one third of overweight women with polycystic ovary syndrome (PCOS) have either impaired glucose tolerance (IGT) or type 2 diabetes mellitus (DM) by the age of 30. We sought to determine if overweight Hispanic adolescents with PCOS are more likely to be insulin resistant and glucose intolerant than those without PCOS.

METHODS

A retrospective chart review of 101 subjects with PCOS and 40 without PCOS was conducted. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), Quantitative Insulin Sensitivity Check Index (QUICKI), and fasting glucose/insulin ratio (FGIR) values were calculated by using fasting glucose and insulin levels. Insulin resistance (IR) was defined as a fasting insulin level of >15 microU/mL, a 2-hour insulin level of >75 microU/mL, a HOMA-IR value of >3.16, a QUICKI value of <0.357, and/or a FGIR value of <7.

RESULTS

Of the 101 overweight subjects with PCOS (BMI: 33.2 +/- 5.9 kg/m(2)), 4 had IGT and 2 had DM versus none of the 40 subjects without PCOS (BMI: 32.4 +/- 5.3 kg/m(2)). IR was more frequent in the overweight PCOS than in the overweight non-PCOS group (QUICKI: 68.4% vs 14.3%, P = .014) and FGIR (47.4% vs 0%, P = .024). Of the 6 subjects with glucose intolerance, only the QUICKI value was abnormal in all.

CONCLUSIONS

This retrospective study demonstrated that overweight Hispanic adolescents with PCOS had more IR, IGT and DM than their non-PCOS counterparts. As the QUICKI Index was abnormal in all subjects with IGT and DM, we suggest its use as the first step in deciding which overweight Hispanic adolescents with PCOS should be further tested with an OGTT.

Insulin resistance, secretion and breakdown are increased 9 months following severe burn injury

Insulin resistance in the acute burn period has been well described, however, it is unknown if alterations in glucose metabolism persist beyond discharge from the acute injury. To measure the duration of insulin resistance following recovery from the acute burn injury, we performed a prospective cross-sectional study with a standard 2-h oral glucose tolerance test in 46 severely burned children at 6, 9 or 12 months following initial injury. Glucose uptake and insulin secretion were assessed following the glucose load. Results were compared to those previously published in healthy children. At 6 months after burn, the 2-h glucose concentration was significantly (P<0.001) greater than controls, and the area under the curve (AUC) of glucose was significantly higher compared to 12 months and to healthy children (P=0.027 and P<0.001, respectively). The 9-month AUC glucose was higher than controls (P<0.01). The 6-month 2-h insulin was significantly higher than controls, as was the AUC of insulin in all time points post-burn. The AUC of C-peptide was significantly greater at 6 months after injury compared to 9 and 12 months (P<0.01 for both). Increased 2h and AUC glucose and insulin indicate that glucose metabolism is still affected at 6 and 9 months after injury, and coincides with previously documented defects in bone and muscle metabolism at these time points. Insulin breakdown is also still increased in this population. Further study of this population is warranted to determine if specific treatment is needed.

The triglyceride/HDL-cholesterol ratio as a marker of cardiovascular risk in obese children; association with traditional and emergent risk factors

OBJECTIVES

To determine the presence of traditional and emergent cardiovascular risk factors and to evaluate the triglyceride/high-density lipoprotein cholesterol (Tg/HDL-C) ratio as a marker for cardiovascular disease and metabolic syndrome (MS) in obese children.

MATERIAL AND METHODS

Sixty-seven prepubertal children of both sexes, between the ages of 6 and 12 yr, 20 normal-weight children, 18 overweight, and 29 obese subjects, were studied. Anthropometric measures, blood pressure, body mass index (BMI), and fat mass (FM), were measured. Plasma glucose, serum insulin, lipid profile, C-reactive protein (CRP), and leptin concentrations were quantified. Glucose and insulin concentrations 2 h post-glucose load were determined. The Tg/HDL-C ratio, homeostasis model assessment index (HOMA), and quantitative insulin sensitivity check index (QUICKI) were calculated.

RESULTS

Systolic, diastolic, and mean blood pressures (MBP), low-density lipoprotein cholesterol (LDL-C), Tg/HDL-C, total cholesterol/HDL-C, LDL-C/HDL-C ratios, basal and 2 h postload insulin, CRP, and leptin were significantly higher and the QUICKI index were lower in the obese group. MBP, Tg/HDL-C ratio, HOMA, CRP, and leptin levels showed a positive and significant correlation and QUICKI a negative correlation with abdominal circumference, BMI, and FM. The Tg/HDL-C ratio correlated positively with MBP. The frequency of MS in the obese group was 69%. While Tg/HDL-C ratio, CRP, and leptin were higher and the values of QUICKI were lower in subjects with MS, it was the Tg/HDL-C ratio and the BMI that significantly explained the MS.

CONCLUSIONS

Obesity increases the cardiovascular risk in childhood. The Tg/HDL-C ratio could be a useful index in identifying children at risk for dyslipidemia, hypertension, and MS.

Baseline correlates of insulin resistance in inner city high-BMI African-American children

To characterize the influence of diet-, physical activity-, and self-esteem-related factors on insulin resistance in 8- 10-year-old African-American (AA) children with BMI greater than the 85th percentile who were screened to participate in a community-based type 2 diabetes mellitus (T2DM) prevention trial. In 165 subjects, fasting glucose- and insulin-derived values for homeostasis model assessment of insulin resistance (HOMA-IR) assessed insulin resistance. Body fatness was calculated following bioelectrical impedance analysis, and fitness was measured using laps from a 20-m shuttle run. Child questionnaires assessed physical activity, dietary habits, and self-esteem. Pubertal staging was assessed using serum levels of sex hormones. Parent questionnaires assessed family demographics, family health, and family food and physical activity habits. Girls had significantly higher percent body fat but similar anthropometric measures compared with boys, whereas boys spent more time in high-intensity activities than girls. Scores for self-perceived behavior were higher for girls than for boys; and girls desired a more slender body. Girls had significantly higher insulin resistance (HOMA-IR), compared with boys (P < 0.01). Adjusting for age, sex, pubertal stage, socioeconomic index (SE index), and family history of diabetes, multivariate regression analysis showed that children with higher waist circumference (WC) (P < 0.001) and lower Harter's scholastic competence (SC) scale (P = 0.044) had higher insulin resistance. WC and selected self-esteem parameters predicted insulin resistance in high-BMI AA children. The risk of T2DM may be reduced in these children by targeting these factors.

Serum Amyloid A concentration is increased in obese children and adolescents

OBJECTIVE

To compare the circulating concentrations of the acute-phase protein serum amyloid A (SAA) in lean, overweight, and obese children and adolescents and analyze the influence of body fat.

STUDY DESIGN

A total of 63 children and adolescents (65% girls) with an average age of 12.1 +/- 2.7 years (range, 6 to 18 years) were included in the study. Each child was classified on the basis of age- and sex-specific body mass index (BMI) percentile as normal weight (BMI <85th percentile; n = 17), overweight (BMI >/=85th and <95th percentiles; n = 26), or obese (BMI >/=95th percentile; n = 20). Body fat was estimated by air-displacement plethysmography.

RESULTS

Both overweight and obese children exhibited significantly increased circulating SAA concentrations (log SAA: lean, 0.66 +/- 0.20; overweight, 0.83 +/- 0.29; obese, 0.96 +/- 0.21; P = .002) compared with the lean children. Significant correlations were found between log SAA and body fat (r = 0.48; P < .0001). In multiple linear regression analysis, log C-reactive protein (CRP) (P = .014) and body fat (P = .031) emerged as significant predictors of log SAA.

CONCLUSIONS

Plasma SAA concentrations are elevated in overweight and obese children, being strongly related to adiposity and log CRP. This finding suggests that increased body fat may contribute to the development of a low-grade chronic proinflammatory state at an early age, possibly contributing to the obesity-associated cardiovascular disease risk.

Glucose dysregulation in obese children: predictive, risk, and potential protective factors

OBJECTIVE

The aim of our study was to determine the prevalence of impaired glucose tolerance (IGT) and type 2 diabetes (DM2) in obese children and adolescents of Greek origin and compare our data with pertinent literature findings in an attempt to uncover predictive, risk, and preventive factors.

RESEARCH METHODS AND PROCEDURES

A total of 117 obese children and adolescents 12.1+/-2.7 years old underwent a 2-hour oral glucose tolerance test (OGTT). Insulin resistance (IR) and beta-cell function were estimated using the homeostasis model assessment (HOMA)-IR and the insulinogenic index, respectively.

RESULTS

A total of 17 patients (14.5%) had IGT, and none had DM2. The overall prevalence rates of both IGT and DM2 in our subjects were lower than those reported in a recent multiethnic U.S. study. Nevertheless, the difference between our IGT data and those of the U.S. study was due mostly to the prepubertal subjects (9% vs. 25.4%), whereas no difference was observed in the pubertal population (18% vs. 21%). Fasting glucose, insulin, and HOMA-IR values were not predictive of IGT. The absolute value of insulin at 2 hours of the OGTT combined with the time-integrated glycemia (AUCG) can strongly predict IGT, whereas higher area under the curve for insulin (AUCI) values were found to be protective.

DISCUSSION

In ethnic groups less prone to diabetes development, IGT or DM2 in obese subjects is more likely to develop at puberty than at the prepubertal stage. It is advisable that physicians caring for obese adolescents perform an OGTT for early detection of IGT because HOMA-IR values, although higher in IGT subjects and indicative of IR, cannot predict IGT.