Childhood obesity

Childhood obesity: a new menace

Childhood obesity is increasing in prevalence in the United States. Comorbid diseases once thought of as adult issues such as hypertension, diabetes, and dyslipidemia, are now being encountered in the pediatric population as a result of obesity. Primary prevention is still the most cost-effective approach to this growing problem. In terms of management, the treatment of obesity in children is not identical to that in adults. Thus far, the only accepted weight loss therapy for children are diet, exercise, modification of eating behaviors and family education. Further options for morbidly obese children include weight loss medications or surgery, regarding which long-term benefits are still under investigation.

Socioeconomic disparities in insulin resistance: results from the Princeton School District Study

OBJECTIVES

The objectives of this study were to determine whether lower socioeconomic status (SES) is associated with changes in insulin resistance in adolescents over a 3-year period and explore moderators of this effect.

METHODS

A total of 1167 healthy non-Hispanic black and white participants in the Princeton School District Study, a longitudinal study of fifth to 12th graders in a suburban Midwestern public school district were included in this study. Inclusion criteria were a) physical examination and fasting morning blood draw at baseline and 3 years later, b) younger than 20 years old at follow up, and c) information available on SES provided by a parent. The influence of SES on insulin resistance and change in insulin resistance over time was examined using general linear models adjusting for multiple covariates. Models also assessed if race or baseline weight status changed the SES-insulin resistance relationship and explored the role of perceived stress.

RESULTS

Blacks and lower SES youth had higher body mass index z score and increased insulin resistance (p < .001). In multivariable models, lower parent education, but not household income, was associated with higher baseline insulin resistance (F = 7.84, p < .001) and worsening insulin resistance over time (F = 18.86, p < .001). Parent education's effect on change in insulin resistance was more pronounced for obese youth compared with nonobese (F interaction = 10.12, p < .001) even with adjustment for multiple covariates. Perceived stress did not alter these relationships.

CONCLUSIONS

Lower parent education appears to be related to increased insulin resistance both cross-sectionally and over time in black and white adolescents. Worsening insulin resistance is especially problematic for obese adolescents from families with low parent education.

Perceptions of children's body sizes among mothers living on the Texas-Mexico border (La Frontera)

OBJECTIVES

The objectives of this study were to quantify mothers' perceptions of their children's sizes and explore mothers' views of child growth, diet, activity, and health. Photographs of children from the Berkeley Longitudinal Growth Study (on Centers for Disease Control and Prevention [CDC] Web site) were used to stimulate discussion with mothers about child sizes.

DESIGN

A descriptive, cross-sectional study examined mothers' perceptions of their children's size and their beliefs about child size, growth, and health.

SAMPLE

The convenience sample included 25 mother-child dyads of 3-year-old children at two Head Start Centers in a county on the Texas-Mexico border. All mothers self-identified as Hispanic.

MEASUREMENT

Photographs of children were shown to elicit mothers' perceptions of children's body sizes. The children and mothers were weighed and measured and their body mass indices (BMIs) were computed. The mothers were interviewed about their beliefs on child health, growth, and feeding.

RESULTS

No congruence was found between mothers' perceptions of child sizes in the pictures and their children's sizes.

CONCLUSIONS

Using CDC photographs does not appear to be a useful way to educate mothers about child body sizes. A child who is happy, active, and can accomplish normal childhood activities is not considered by mothers as overweight, regardless of the child's BMI.

Obesidad Infantil. Recomendaciones del Comité de Nutrición de la Asociación Española de Pediatría Parte I. Prevención. Detección precoz. Papel del pediatra

Obesity is a pathologic entity characterized by an increase in fat body mass and is a global public health problem. In Spain, between 1984 (the Paidos study) and 2000 (the enKid study), the prevalence of childhood overweight and obesity increased and significant differences were found among the autonomous communities. Consequently prophylactic measures were implemented throughout the country and in 2005 the Ministry of Health developed the NAOS strategy (strategy for nutrition, physical activity and obesity prevention). Within the medical area of this intervention, primary care pediatricians acquire a key role. Aware of this, the Spanish Association of Pediatrics, through the Nutrition Committee, aims to provide information on the current situation concerning the etiopathogenesis and early identification of at-risk populations. The epidemiology and risk periods in the pediatric age group are reviewed and recommendations on healthy lifestyle are provided, bearing in mind diet and physical activity throughout childhood, with the aim of preventing overweight and obesity.

Obesity and obstructive sleep apnea in children

The prevalence and severity of obesity in children and adolescent is dramatically increasing worldwide with a corresponding increase in the prevalence of obesity-associated morbidities particularly those involving OSAS and metabolic and cardiovascular sequelae. Obstructive sleep apnea and obesity hypoventilation syndrome are important and serious consequences of obesity, and may in fact mediate components of the association between obesity and metabolic and cardiovascular morbidities, most likely via potentiation of inflammatory cascades. It is anticipated that the increased prevalence of obesity in children and adolescents in our society will be accompanied by a steady increase in the incidence of OSAS. In this review, we will examine our current understanding of sleep-disordered breathing and associated morbidities in obese children, and summarize the range of therapeutic modalities currently available for this high-risk population.

Childhood obesity increases duration of therapy during severe asthma exacerbations

OBJECTIVES

Childhood obesity contributes to a wide array of medical conditions, including asthma. There is also increasing evidence in adult patients admitted to the intensive care unit (ICU) that obesity contributes to increased morbidity and to a prolonged length of stay. We hypothesized that obesity is associated with the need for increased duration of therapy in children admitted to the ICU with status asthmaticus.

DESIGN

Retrospective cohort study.

SETTING

A tertiary pediatric ICU in a university-affiliated children's hospital.

PATIENTS

We retrospectively examined data from all children older than 2 yrs admitted to the ICU with status asthmaticus between April 1997 and June 2004. Children were classified as normal weight (<95% weight-for-age percentile) or obese (>95% weight-for-age).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 209 children admitted to the ICU with asthma, 45 (22%) were obese. Compared with children of normal weight, the obese children were older (9.7 +/- 4.4 vs. 8.0 +/- 4.3 yrs, p = .02), more likely to be female (60% vs. 37%, p < .01), and more likely to have been admitted to the ICU previously (40% vs. 20%, p = .01). The obese children also had a statistically significant difference in race (more likely to be Hispanic) and in baseline asthma classification (more likely to have persistent asthma). Despite similar severity of illness at ICU admission, obese children had a significantly longer ICU length of stay (116 +/- 125 hrs vs. 69 +/- 57 hrs, p = .02) and hospital length of stay (9.8 +/- 7.0 vs. 6.5 +/- 3.4 days, p < .01). Obese children also received longer courses of supplemental oxygen, continuous albuterol, and intravenous steroids.

CONCLUSIONS

Childhood obesity significantly affects the health of children with asthma. Obese children with status asthmaticus recovered more slowly from an acute exacerbation, even after adjustment for baseline asthma severity and admission severity of illness.

Linear growth and body mass index in pediatric patients with Cushing's disease or simple obesity

BACKGROUND

Increasing prevalence of childhood obesity has resulted in an accelerating rate of referrals of overweight patients to pediatric clinics for exclusion of endocrine or metabolic etiologies. The exclusion of Cushing's disease (CD) requires complex and potentially invasive investigations.

OBJECTIVE

To evaluate the sensitivity of accurate measurements of height, weight and body mass index (BMI) in discriminating between simple obesity and CD.

METHODS AND PATIENTS

Height, weight and BMI were measured at diagnosis in 25 patients with CD; 14 males, 11 females, mean age 12.9 yr (6.4-17.8) and 41 patients with simple obesity (SO), defined as BMI >2.0 SD; 20 males, 21 females, mean age 9.4 yr (3.5-15.6).

RESULTS

Mean (+/-SE) BMI SDS in the CD patients was 2.41+/-0.5 and in the SO patients 3.71+/-1.3. Height SDS in the CD patients was -1.88+/-0.24 and in the SO patients 1.18+/-0.19 (p<0.05). The mean (+/-SE) BMI SDS to height SDS ratio was significantly decreased in the CD compared with the SO patients; -1.81+/-0.54 vs +0.90+/-1.17 (p<0.0001).

CONCLUSIONS

Simple, accurate measurement of height and BMI SDS values provides a quick, and sensitive diagnostic discriminator in pediatric patients with CD or SO, thus potentially avoiding complex investigations.

The prevalence of overweight and obesity in pediatric survivors of cancer

OBJECTIVE

To compare the prevalence of overweight in a cohort of pediatric survivors of cancer with that in the general population.

STUDY DESIGN

We reviewed the charts of 441 cancer survivors followed at a Canadian tertiary care pediatric hospital and calculated their most recent body mass index. We compared this cohort with population data generated from the Canadian Community Health Survey.

RESULTS

At a median age of 14.7 years (range, 3.4 to 19.5 years) and a median time from diagnosis of 9.7 years (range, 3.4 to 19.2 years), 140 of 441 patients (31.7%) were overweight or obese. Only 12 of the 441 patients (2.7%) were underweight. Males age 6 to 11 years (odds ratio [OR] = 2.29; 95% confidence interval [CI] = 1.36 to 3.86; P < .001) and male survivors of acute lymphoblastic leukemia (OR = 1.55; 95% CI = 1.03 to 2.52; P = .04) were more likely to be overweight than the general population. No other age or diagnostic group had an increased risk of overweight.

CONCLUSIONS

The prevalence of overweight was not increased in this cohort compared with the general population. However, almost 1/3 of these patients are overweight, necessitating a clinical and research focus on preventing and combating overweight in childhood cancer survivors.

Heterozygosity for a POMC-null mutation and increased obesity risk in humans

Congenital deficiency of proopiomelanocortin (POMC) results in a syndrome of hypoadrenalism, severe obesity, and altered skin and hair pigmentation. The concept that subtle variation in POMC expression and/or function might contribute to common obesity is suggested by studies reporting linkage of obesity-related traits to a locus on chromosome 2p22 encompassing the POMC gene. We identified a novel homozygous frameshift (C6906del) mutation in POMC in a child of Turkish origin with severe obesity and hypoadrenalism. This mutation would be predicted to lead to the loss of all POMC-derived peptides. The availability of a large extended pedigree provided the opportunity to address whether loss of one copy of the POMC gene was sufficient to alter obesity risk. Twelve relatives were heterozygous for the mutation and 7 were wild type. Of the heterozygotes, 11 of 12 heterozygotes were obese or overweight compared with only 1 of 7 of the wild-type relatives. The mean BMI SD score was 1.7 +/- 0.5 in heterozygotes and 0.4 +/- 0.4 in the wild-type relatives. Parametric linkage analysis of the trait "overweight" provided statistically significant evidence of linkage with this locus, with a maximum "location score" (comparable with multipoint logarithm of odds scores) of 3.191. We conclude that loss of one copy of the POMC gene predisposes to obesity in humans. Thus, genetic variants having relatively subtle effects on POMC expression and function could influence susceptibility to obesity.

WATCH IT: a community based programme for obese children and adolescents

BACKGROUND

The WATCH IT programme was developed to address the needs of obese children from disadvantaged communities in Leeds and has been running since January 2004. Results of the pilot phase, prior to a randomised controlled trial, are presented.

METHODS

A process evaluation to assess success of implementation was conducted in December 2004. User views (parent and child) were obtained by semi-structured interviews and focus groups. Change in BMI SD score was calculated for children attending between January 2004 and November 2005.

RESULTS

A total of 94 children (49 girls, 45 boys), mean age (SD) 12.2 (2.0) years attended. They were moderately to severely obese (mean BMI SDS 3.09 (0.45), with low quality of life and self-image scores. There was a significant reduction in overweight at 6 months (DeltaBMI SD -0.07), especially for teenagers (DeltaBMI SD -0.13) and girls (DeltaBMI SD -0.07). The programme was successfully implemented. By December 2004 mean attendance was 2.1 (0.7) clinics per month, and sports sessions 3.3 (1.7) sessions per month. Fourteen children dropped out and non-attendance was low (only 7.5% sessions missed in 12 months). Qualitative research indicated significant appreciation of the service, with reported increase in self-confidence and friendships, and reduction in self-harm.

CONCLUSION

WATCH IT offers a model for a community based service for obese children. The programme suggests that effective care can be delivered by health trainers supervised by health professionals, and so potentially provides a cost effective programme within children's communities. These findings are encouraging, and need to be substantiated by extension to other locations and evaluation by randomised controlled trial.

Assessment of metabolic profile in a clinical setting

PURPOSE OF REVIEW

The metabolic syndrome, a clustering of abnormalities such as hyperglycemia, insulin resistance, hypertension, dyslipidemia, and central obesity, is a principal risk factor for cardiovascular disease, the leading cause of morbidity and mortality in the Western world. There are several definitions of the metabolic syndrome, all aiming at including as many persons at risk as possible. The assessment and, hence, the identification of such persons in a clinical setting is of utmost importance.

RECENT FINDINGS

Clinicians should document the presence of central obesity, assessed by waist circumference measurement or determination of body composition using dual X-ray absorptiometry or measurement of visceral fat using computed tomography or magnetic resonance imaging. The presence of dyslipidemia, insulin resistance, and arterial hypertension constitutes the full profile of the metabolic syndrome. Nevertheless, elevated uric acid levels or presence of nonalcoholic fatty liver, or the diagnosis of the polycystic ovary syndrome in women of reproductive age, all are reflected in high risk of later occurrence of the full metabolic syndrome and atherosclerotic cardiovascular disease.

SUMMARY

Although no unified definition for the metabolic syndrome exists, it is important to identify persons at risk, in order to reduce the resultant high morbidity and mortality rates.

Family-based behavioural treatment of obesity: acceptability and effectiveness in the UK

OBJECTIVE

To assess the acceptability and impact of family-based behavioural treatment (FBBT) for childhood obesity in a clinical setting in the UK.

DESIGN

Pre- and post-treatment assessment for four consecutive treatment groups.

SETTING

Treatment groups took place at Great Ormond Street Hospital, London.

PATIENTS

Participants were 33 families with obese (BMI >or=98th centile for age and sex) children aged 8-13 years.

INTERVENTION

FBBT was delivered over 12 sessions.

MAIN OUTCOME MEASURES

Overweight (percentage BMI), self-esteem, mood and eating attitudes were assessed before and after treatment; overweight was re-assessed at 3-month follow-up for those who completed treatment.

RESULTS

The FBBT programme materials translated easily to the UK setting and the programme was well-liked by participants. Twenty-seven out of 33 families (82%) completed the sessions. Children lost 8.4% BMI over the time of treatment, and this was maintained at 3-month follow-up. Self-esteem and depression improved significantly and there was no change in food pre-occupation, anorexia or bulimia on the ChEAT.

CONCLUSIONS

These results establish that FBBT is feasible and acceptable in a clinical setting in Britain. They indicate that significant loss of overweight can be achieved using the programme without adverse psychological consequences.

High prevalence of overweight and obesity in 11-15-year-old children from Sicily

BACKGROUND AND AIM

To evaluate the prevalence of overweight and obesity in children and adolescents from Sicily, we carried out a cross-sectional study in a large cohort of 48,897 (24,119 males and 24,778 females) randomly selected 11-15-year-old Sicilian schoolchildren.

METHODS AND RESULTS

Anthropometric data (weight and height) were obtained in all children. Urban vs. rural areas were taken into account. Centiles were obtained using the LMS method. Obesity and overweight prevalence were defined using as references both the values of the National Center for Disease Control (CDC 2000) in the United States and those of the International Obesity Task Force (IOTF). Median body mass index (BMI) values in Sicily were comparable to values observed in South and Center-North Italy. BMI cut-off values in Sicilian children were higher than reference values established in the U.S. CDC growth chart 2000. Using both the IOTF or the U.S. CDC 2000 cut-off values the prevalence of overweight and obesity in 11-15-year-old Sicilian children was very high: nearly 40% at age 11 and, although progressively decreasing with age increase, still over 25% at age 15.

CONCLUSIONS

The prevalence of overweight and obesity in 11-15-year-old Sicilian schoolchildren is one of the highest ever reported. The prevalence is much higher at a younger age; thereafter it progressively decreases and values tend to reconcile with those observed in other geographical areas at age 14-15.

Definitions of childhood obesity: current practice

OBJECTIVE

To review current practice in the definition of childhood obesity based on body mass index (BMI), in order to understand why the recommendations of the International Task Force on Obesity (IOTF) have not been fully adopted.

DESIGN

Literature search using MEDLINE to identify papers on childhood obesity published in the first 4 months of 2005, and a cited reference search on the recommendations of the IOTF.

RESULTS

Citations of the IOTF definition have increased since publication, but less than half of papers on childhood obesity published in the period used the definition. Most used the 95th centile of a national distribution to define obesity.

CONCLUSIONS

Reasons for using centiles of a national distribution included the need for z-scores or centiles to define underweight or extreme obesity, not available in conjunction with the IOTF definition, inclusion of children under 2 years, and concerns about over- or underestimation of the prevalence of obesity. None of these preclude use of the principle underlying the IOTF definition, that of continuity with the adult definition of BMI of 30 kg/m2 or more. Adoption of either the IOTF definition or corresponding centiles of a national distribution would enable comparisons of prevalence between countries and over time.

The role of insulin in chondrogenesis

The ATDC5 chondrogenic cell line is typically induced to differentiate by exposure to insulin at high concentration (10 microg/ml, approximately 1600 nM). Differentiation can also be induced by physiological concentrations of insulin-like growth factor-I (IGF-I). Unlike previous reports, we observed a stimulation of differentiation, as measured by collagen X expression and Alcian Blue staining for proteoglycan synthesis, upon exposure to insulin at concentrations (10-50 nM) consistent with signaling via the insulin receptor. Analysis of lysates from proliferating and hypertrophic ATDC5 cells demonstrated that exposure to 50 nM insulin induced tyrosine phosphorylation of insulin receptors but not IGF-I receptors or hybrid receptors. In contrast to the potent effects of IGF-I to stimulate both ATDC5 proliferation and differentiation, insulin was not as potent as IGF-I as a proliferating agent but more selectively a differentiating agent. Consistent with this result, insulin was less potent than IGF-I in inducing activation of the Erk1/Erk2 mitogenic signaling pathway. Furthermore, Erk pathway inhibition did not enhance the differentiating effects of insulin as it does in the case of IGF-I exposure. Extending our observations to fetal rat metatarsal explants, we observed significant stimulation of bone growth by 50 nM insulin. This could be accounted for by a disproportionate stimulatory effect on growth of the hypertrophic zone. The proliferative zone was not significantly affected. Based on our results in both ATDC5 cells and metatarsal explants, we conclude that the insulin functioning through insulin receptor has a dominant effect as an inducer of chondrocyte differentiation. These results support assignment of a physiological role for this hormone in linear bone growth.

Gender-related differences in urinary 6-sulfatoxymelatonin levels in obese pubertal individuals

The objective of this study was to measure the urinary excretion of the main melatonin metabolite 6-sulfatoxymelatonin in obese and normal weight (wt) boys and girls. The study included 94 subjects, aged 4-15.7 yr (50 obese and 44 normal wt; 48 boys) classified as: mid-childhood (4-7.99 yr), late-childhood (8-12 yr) and pubertal (10.1-15.7 yr, Tanner II-IV). Normal wt subjects were children with a body mass index (BMI) between the 25th and 75th percentiles, and the group of obese subjects included children whose BMI was above the 97th percentile. A 24-hr urine sample was collected during two intervals: (i) 18:00-08:00 hr, and (ii) 08:00-18:00 hr. Analysis of urinary 6-sulfatoxymelatonin levels was performed by radioimmunoassay. Excretion of 6-sulfatoxymelatonin was expressed as: (i) total amount excreted (microg); (ii) mug excreted per time interval, nocturnal or diurnal; and (iii) the difference between nocturnal and diurnal samples (microg, estimated amplitude). A factorial analysis of variance indicated that nocturnal 6-sulfatoxymelatonin excretion and amplitude were significantly higher in the obese individuals. A significant interaction 'BMI x age' was detected, i.e. the effect of BMI was significant in the pubertal group only. Total, nocturnal and diurnal 6-sulfatoxymelatonin excretion was significantly higher in girls. The increase in 6-sulfatoxymelatonin excretion found in obesity occurred only in boys and at the pubertal age. To what extent this increase in melatonin production contributes to a delayed puberty in some pubertal obese males remains to be established.

Nondiabetic consequences of obesity on kidney

There has been a major increase in obesity among children over the past twenty years. Obesity is associated with glomerular hyperperfusion and hyperfiltration from physiological (mal)adaptation resulting from afferent arteriolar vasodilatation. The renal injury from hyperfiltration in obesity is further exacerbated by concomitant presence of dyslipidemia, hyperglycemia and/or insulin resistance, inflammation and hypertension. The renal injury clinically manifests as microalbuminuria, proteinuria and/or poor renal function, and is histologically characterized by glomerulomegaly, mesangial expansion and/or sclerosis, which has been termed "obesity related glomerulopathy". Obesity portends a poor prognosis in subjects with chronic kidney diseases, IgA nephropathy and nephrectomy. Obese individuals on dialysis and renal transplant have mixed outcomes. The purpose of this review is to highlight the nondiabetic consequences of obesity on kidney for the pediatric nephrology community as we begin to address the obesity epidemic in children.

The hypothalamus, hormones, and hunger: alterations in human obesity and illness

Obesity is a major global epidemic, with over 300 million obese people worldwide, and nearly 1 billion overweight adults. Being overweight carries significant health risks, reduced quality of life, and impaired socioeconomic success, with profound consequences for health expenditure. The most successful treatment for obesity is gastric bypass surgery, which acts in part by reducing appetite through alterations in gut hormones. Circulating gut hormones, secreted or suppressed after eating food, act in the brain, particularly the hypothalamus, to alter hunger and fullness. Stomach-derived ghrelin increases food intake even in those with anorexia from chronic illness, while pancreatic polypeptide (PP), intestinal peptide YY 3-36 (PYY), oxyntomodulin, and other hormones reduce food intake and appetite. While obese subjects have appropriate reductions in orexigenic ghrelin, other gut-hormone disturbances may contribute to obesity such as reduced anorexigenic PYY and PP. Prader-Willi syndrome (PWS) arises from the loss of paternally inherited genes on chromosome 15q11-13, leading to life-threatening insatiable hunger and obesity from early childhood, through developmental brain, particularly hypothalamic defects. The study of genetically homogenous causes of abnormal-feeding behavior helps our understanding of appetite regulation. PWS subjects have inappropriately elevated plasma ghrelin for their obesity, at least partly explained by preserved insulin sensitivity. It remains unproven if their hyperghrelinemia or other gut-hormone abnormalities contribute to the hyperphagia in PWS, in addition to brain defects. Postmortem human hypothalamic studies and generation of animal models of PWS can also provide insight into the pathophysiology of abnormal-feeding behavior. Changes in orexigenic NPY and AGRP hypothalamic neurons, or anorexigenic oxytocin neurons have been found in illness and PWS. Functional neuroimaging studies, using PET and fMRI, will also allow us to tease apart the hormonal and brain pathways responsible for controlling human appetite, and their defects in obesity.

Reduced exercise-associated response of the GH-IGF-I axis and catecholamines in obese children and adolescents

Obesity blunts catecholamine and growth hormone (GH) responses to exercise in adults, but the effect of obesity on these exercise-associated hormonal responses in children is unclear. Therefore, the aim of the present study was to asses the effect of childhood obesity on the counterregulatory hormonal response to acute exercise. Twenty-five obese children (Ob; body mass index > 95%), and 25 age, gender, and maturity-matched normal-weight controls (NW) participated in the study. Exercise consisted of ten 2-min bouts of constant-cycle ergometry above the anaerobic threshold, with 1-min rest intervals between each bout. Pre-, post-, and 120-min postexercise blood samples were collected for circulating components of the GH-IGF-I axis and catecholamines. There were no differences in peak exercise heart rate, serum lactate, and peak O2 uptake normalized to lean body mass between the groups. Obesity attenuated the GH response to exercise (8.9 +/- 1.1 vs. 3.4 +/- 0.7 ng/ml in NW and Ob participants, respectively; P < 0.02). No significant differences in the response to exercise were found for other components of the GH-IGF-I axis. Obesity attenuated the catecholamine response to exercise (epinephrine: 52.5 +/- 12.7 vs. 18.7 +/- 3.7 pg/ml, P < 0.02; norepinephrine: 479.5 +/- 109.9 vs. 218.0 +/- 26.0 pg/ml, P < 0.04; dopamine: 17.2 +/- 2.9 vs. 3.5 +/- 1.9 pg/ml, P < 0.006 in NW and Ob, respectively). Insulin levels were significantly higher in the obese children and dropped significantly after exercise in both groups. Despite the elevated insulin levels and the blunted counterregulatory response, none of the participants developed hypoglycemia. Childhood obesity was associated with attenuated GH and catecholamine response to acute exercise. These abnormalities were compensated for, so that exercise was not associated with hypoglycemia, despite increased insulin levels in obese children.