Insulin resistance in children and adolescents

The effects of exercise training on insulin resistance in children and adolescents with overweight or obesity: a systematic review and meta-analysis

Aim

The aim of present meta-analysis was to determine the effects of exercise training (Exe) on insulin resistance (IR) and body weight in children and adolescents with overweight or obesity.

Methods

PubMed, Web of Science, and Scopus were searched for original articles, published through October 2022 that included exercise versus control interventions on fasting glucose, insulin, HOMA-IR, and body weight outcomes in children and adolescents with overweight or obesity. Standardized mean differences (SMD) for fasting insulin, and weighted mean differences (WMD) for fasting glucose, HOMA-IR, body weight (BW), and 95% confidence intervals were determined using random effects models.

Results

Thirty-five studies comprising 1,550 children and adolescents with overweight and obesity were included in the present meta-analysis. Exercise training reduced fasting glucose (WMD=-2.52 mg/dL, p=0.001), fasting insulin (SMD=-0.77, p=0.001), HOMA-IR (WMD=-0.82, p=0.001), and BW (WMD=-1.51 kg, p=0.001), as compared to a control. Subgroup analyses showed that biological sex, intervention duration, type of exercise training, BMI percentile, and health status (with or without diagnosed condition), were sources of heterogeneity.

Conclusion

Exercise training is effective for lowering fasting glucose, fasting insulin, HOMA-IR, and BW in children and adolescents with overweight or obesity and could provide an important strategy for controlling IR and related factors. With clear evidence for the effectiveness of exercise interventions in this vulnerable population, it is important to determine effective approaches for increasing exercise training in children and adolescents with overweight or obesity.

Resting and exercise metabolic characteristics in obese children with insulin resistance

Purpose: This study aimed to explore the characteristics of resting energy expenditure (REE) and lipid metabolism during incremental load exercise in obese children and adolescents with insulin resistance (IR) to provide evidence for exercise intervention in obese children and adolescents with IR.

Method: From July 2019 to August 2021, 195 obese children and adolescents aged 13–17 were recruited through a summer camp. The participants were divided into IR (n = 67) and no-IR (without insulin resistance, n = 128) groups and underwent morphology, blood indicators, body composition, and resting energy consumption gas metabolism tests. Thirty participants each were randomly selected from the IR and no-IR groups to carry out the incremental treadmill test.

Results: Significant metabolic differences in resting and exercise duration were found between the IR and no-IR groups. In the resting state, the resting metabolic equivalents (4.33 ± 0.94 ml/min/kg vs. 3.91 ± 0.73 ml/min/kg, p = 0.001) and REE (2464.03 ± 462.29 kcal/d vs. 2143.88 ± 380.07 kcal/d, p < 0.001) in the IR group were significantly higher than in the no-IR group. During exercise, the absolute maximal fat oxidation (0.33 ± 0.07 g/min vs. 0.36 ± 0.09 g/min, p = 0.002) in the IR group was significantly lower than in the no-IR group; maximal fat oxidation intensity (130.9 ± 8.9 bpm vs. 139.9 ± 7.4 bpm, p = 0.040) was significantly lower in the IR group.

Conclusion: Significant resting and exercise metabolic differences were found between obese IR and no-IR children and adolescents. Obese IR children and adolescents have higher REE and lower maximal fat oxidation intensity than obese no-IR 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.

Insulin resistance in children

PURPOSE OF REVIEW

Insulin resistance (IR) is a clinical condition due to the decline in the efficiency of insulin promoting glucose uptake and utilization. The aim of this review is to provide an overview of the current knowledge on IR in children, focusing on its physiopathology, the most appropriate methods of measurement of IR, the assessment of risk factors, the effects of IR in children, and finally giving indications on screening and treatment.

RECENT FINDINGS

IR has evolved more and more to be a global public health problem associated with several chronic metabolic diseases.

SUMMARY

Detecting a correct measurement method and specific risk predictors, in order to reduce the incidence of IR, represents a challenging goal.

Triglyceride glucose index is superior biomarker for predicting type 2 diabetes mellitus in children and adolescents

The triglyceride-glucose (TyG) index is associated with predicting type 2 diabetes mellitus (T2DM), but its relationship with homeostatic model assessment of insulin resistance (HOMA-IR) in T2DM is not established. We aimed to investigate the role of TyG index for detection of T2DM in children and adolescents and compare it with HOMA-IR. A cross sectional study was performed in 176 overweight or obese children and adolescents with mean age of 11.34 ± 3.24 years. TyG index was calculated as ln (fasting triglyceride (TG) [mg/dL] × fasting glucose [mg/dL]/2). Of a total of 176 subjects, 57 (32%) were diagnosed with T2DM. Significant differences were observed in the TyG index between T2DM and non-T2DM (p < 0.001). The TyG index had a positive correlation with fasting glucose (r = 0.519, p < 0.001), HOMA-IR (r = 0.189, p < 0.017), HbA1c (r = 0.429, p < 0.001), total cholesterol (TC) (r = 0.257, p = 0.001), TG (r = 0.759, p < 0.001), and low-density lipoprotein cholesterol (LDL-C)(r = 0.152, p < 0.001), and a negative correlation with high-density lipoprotein cholesterol (HDL-C)(r = -0.107, p < 0.001) after controlling for sex, age and BMI standard deviation scores (SDS). In multiple regression analyses, 91.8% of the variance in TyG index was explained by age, glucose, HOMA-IR, TG, LDL-C, and HDL-C (p < 0.001). In the receiver operating characteristic (ROC) analysis, the TyG index [area under the curve (AUC) 0.839)] showed a better performance compared to HOMA-IR (AUC 0.645) in identifying patients with T2DM (p < 0.001). In conclusion, the TyG index had significant association with insulin resistance in T2DM and was superior to HOMA-IR in predicting T2DM in children and adolescents.

Effect of a high protein/low glycaemic index diet on insulin resistance in adolescents with overweight/obesity-A PREVIEW randomized clinical trial

BACKGROUND

Pubertal insulin resistance (IR) is associated with increased risk of type 2 diabetes mellitus development in adolescents with overweight/obesity.

OBJECTIVES

The PREVIEW study was a randomized parallel trial assessing the change in IR, analyzed by Homeostatic Model Assessment of IR (HOMA-IR), at 2 years after randomization to a high protein vs a moderate protein diet in adolescents with overweight/obesity. It was hypothesized that a high protein/low glycaemic index diet would be superior in reducing IR compared to a medium protein/medium GI diet, in insulin resistant adolescents with overweight or obesity.

METHODS

Adolescents with overweight/obesity and IR from the Netherlands, United Kingdom and Spain were randomized into a moderate protein/moderate GI (15/55/30En% protein/carbohydrate/fat, GI ≥ 56) or high protein/low GI (25/45/30En% protein/carbohydrate/fat, GI < 50) diet. Anthropometric and cardiometabolic parameters, puberty, dietary intake and physical activity (PA) were measured and effects on HOMA-IR were analyzed.

RESULTS

126 adolescents were included in this study (13.6 ± 2.2 years, BMI z-score 3.04 ± 0.66, HOMA-IR 3.48 ± 2.28, HP n = 68, MP n = 58). At 2 years, changes in protein intake were not significantly different between timepoints or intervention groups and no effects of the intervention on IR were observed. The retention rate was 39%, while no compliance to the diets was observed.

CONCLUSIONS

The PREVIEW study observed no effect of a high protein/low GI diet on IR in adolescents with overweight/obesity and IR because of lack of feasibility, due to insufficient retention and dietary compliance after 2 years.

Cross-Sectional and Longitudinal Examination of Insulin Sensitivity and Secretion across Puberty among Non-Hispanic Black and White Children

BACKGROUND

Few studies using criterion measures of insulin sensitivity (SI) and insulin secretory capacity (ISC) have been conducted across puberty to adulthood. We examined how SI and ISC change from pre-puberty through adulthood.

METHODS

Hyperglycemic clamp studies were performed in a convenience sample of non-Hispanic Black (NHB) and White children evaluated at age 6 to 12 years and at approximately 5-year intervals into adulthood (maximum age 27 years). SI and ISC (first-phase and steady-state insulin secretion) were determined cross-sectionally in 133 unique participants across puberty and in adulthood. Additionally, longitudinal changes in SI and ISC were compared at two timepoints among three groups defined by changes in pubertal development: pre-pubertal at baseline and late-pubertal at follow-up (n=27), early-pubertal at baseline and late-pubertal at follow-up (n=27), and late-pubertal at baseline and adult at follow-up (n=24).

RESULTS

Cross-sectionally, SI was highest in pre-puberty and early puberty and lowest in mid-puberty (analysis of covariance [ANCOVA] P=0.001). Longitudinally, SI decreased from pre-puberty to late puberty (P<0.001), then increased somewhat from late puberty to adulthood. Cross-sectionally, first-phase and steady-state ISC increased during puberty and decreased in adulthood (ANCOVA P<0.02). Longitudinally, steady-state and first-phase ISC increased from pre-puberty to late puberty (P<0.007), and steady-state ISC decreased from late puberty to adulthood. The NHB group had lower SI (P=0.003) and greater first-phase and steady-state ISC (P≤0.001), independent of pubertal development.

CONCLUSION

This study confirms that SI decreases and ISC increases transiently during puberty and shows that these changes largely resolve in adulthood.

Cardiorespiratory fitness is associated with body composition and insulin resistance in European adolescents: HELENA study

BACKGROUND

The present study aimed to examine the independent association between cardiorespiratory fitness, sedentary time and insulin resistance in European adolescents.

METHODS

A subset (N.=1097) of a large multicenter European study (HELENA-CSS study) was used in the present study. Serum concentrations of glucose (G<inf>F</inf>) and insulin (I<inf>F</inf>) were measured after overnight fast and homeostasis model assessment (HOMA-IR) was calculated. Sedentary time and time spent on moderate-to-vigorous physical activity (MVPA) was objectively measured by accelerometers. Moreover, sedentary activities were self-reported via questionnaires.

RESULTS

Multilevel linear regression analysis revealed that adolescents watching TV≥2 h/day had higher HOMA-IR (P=0.007). Further adjustment for MVPA, showed that watching TV≥2 h/day remained significantly associated with IR (P=0.002). In this model, MVPA was inversely associated with HOMA-IR (P=0.001). Further controlling for waist circumference showed that adolescents watching TV≥2 h/day continued to have higher HOMA-IR levels (P=0.002). Stratified analysis by weight status, revealed that watching TV≥2 h/day was independently associated with HOMA-IR only in normal weight adolescents, while MVPA was inversely associated with HOMA-IR in both overweight/obese and normal weight adolescents. Only the volume of maximum oxygen consumption (VO<inf>2</inf>max) over body fat mass ratio was inversely associated with HOMA-IR after controlling for several confounders.

CONCLUSIONS

The present study showed that watching TV≥2 h/day and MVPA were associated with HOMA-IR. However, after controlling for several confounders, only VO<inf>2</inf>max/body fat mass ratio remained negatively associated with HOMA-IR. Future interventions should aim both to promote physical activity and reduce sedentary time in adolescents to improve their cardiorespiratory fitness and postpone the onset of diabetes in adulthood.

Long-term metformin treatment in adolescents with obesity and insulin resistance, results of an open label extension study

Background/Objectives

Off-label metformin is nowadays frequently used for the treatment of obesity in adolescents. However, studies on long-term metformin treatment in adolescents with obesity are scarce. Therefore, an 18 month open label extension study following an 18 months randomized placebo-controlled trial (RCT) on the efficacy, safety, and tolerability of metformin in adolescents with obesity and insulin resistance was performed.

Subjects/Methods

After completion of the RCT, metformin was offered to all participants with a body mass index standard deviation score (BMI-sds) > 2.3 and Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) ≥ 3.4. Endpoints were change in BMI and HOMA-IR.

Results

Overall, 31/42 participants completed the extension study (74% girls, median age 14.8 (11.6 – 17.9), BMI 31.2 (22.3 – 45.1), HOMA-IR 3.4 (0.2 – 8.8)). At start, 22/42 (52.4%) participants were eligible for metformin of which 13 (59.0%) agreed with treatment. In participants who continued metformin, an increase was observed in BMI (+2.2 (+0.2 to +9.0)) and HOMA-IR (+13.7 (+1.6 to +48.3)). In metformin naive participants, BMI stabilized after an initial decrease (+0.5 (−2.1 to +5.1)). For HOMA-IR, a decrease was observed (−1.1 (−4.6 to +1.4)).

Conclusion

While metformin treatment in metformin naive participants seems to result in an initial decrease in BMI and HOMA-IR, there is no evidence for sustained effect after prolonged use in adolescents. Limited compliance and/or insufficient dose may explain the differences in long-term effects between adolescents and adults.

Improved Generalized Predictive Control Algorithm for Blood Glucose Control of Type 1 Diabetes

Artificial pancreas (AP) is an important treatment for patients with Type 1 diabetes (T1D). The control algorithm adopted in an AP system determines its reliability and accuracy. The generalized predictive control (GPC) is a representative adaptive control algorithm and has been widely applied to AP systems. However, we found that the traditional GPC controller does not work well for adolescents with T1D because of their high-fluctuating blood glucose and high insulin resistance. Here, we propose an improved GPC algorithm with an adaptive reference glucose trajectory and an adaptive softening factor. The slopes of the reference trajectory and the value of softening factor are calculated real-time on the basis of the blood glucose concentration (BGC) variations. In silico testing was done using the US Food and Drug Administration (FDA) approved virtual patient software T1D mellitus. The BGC trace and density of 20 patient-subjects (10 adults and 10 adolescents) were recorded. Results showed that the average BGC percentage within the target regions (70-180 mg/dL) of the tests with adaptive reference glucose trajectory and softening factor for adolescents (0.93 ± 0.07) was significantly higher than that of the traditional GPC algorithm tests (0.88 ± 0.11), suggesting that the control quality of the blood glucose of adolescents is significantly improved with our GPC algorithm. Therefore, our improved GPC controller is effective and should have a good applicability in AP systems.

Metabolic Profiles in Obese Children and Adolescents with Insulin Resistance

BACKGROUND:

In the past several decades, the increasing frequency of overweight and obese children and adolescents in the world has become a public health problem. It has contributed significantly to the already high tide of diabetes, cardiovascular and cerebrovascular diseases.

AIM:

To investigate the frequency of insulin resistance and to evaluate the metabolic profile of insulin resistant and non-insulin resistant obese children and adolescents.

SUBJECTS AND METHODS:

The study included 96 (45 boys, 51 girls) obese children and adolescents aged 4-17 years old (10.50 ± 2.87 years). Only participants with Body Mass Index ≥ 95 percentile were included. We analysed sera for fasting insulin levels (FI), fasting serum triglycerides (TG), total serum cholesterol (TC), fasting plasma glucose (FPG) and plasma glucose 2 hours after the performance of the oral glucose tolerance test (2-h G). Homeostatic model assessment for insulin resistance (HOMA-IR) index was calculated as fasting insulin concentration (microunits per millilitre) x fasting glucose concentration (millimolar)/22.5. The value of HOMA-IR above 3.16 was used as a cut-off value for both genders.

RESULTS:

Insulin resistance was determined in 58.33% of study participants. Insulin resistant participants had significantly higher level of 2-h G (p = 0.02), FI level (p = 0.000) as well as TG levels (p = 0.01), compared to non-insulin resistant group. Strikingly, 70.73% of the pubertal adolescents were insulin resistant in comparison to 49.09% of the preadolescents (p = 0.03). Significantly higher percentage of insulin-resistant participants were girls (p = 0.009). Moreover, a higher percentage of the girls (70.59%) than boys (44.44%) had HOMA-IR above 3.16 and had elevated FI levels (70.59% vs 48.89%). The difference in the frequency of insulin resistance among obese versus severely obese children and adolescents was not significant (p = 0.73, p > 0.05). Our study results also showed positive, but weak, correlation of HOMA-IR with age, FPG, TG and BMI of the participants (p < 0.05).

CONCLUSION:

Higher percentage of insulin-resistant participants was of female gender and was adolescents. In general, insulin resistant obese children and adolescents tend to have a worse metabolic profile in comparison to individuals without insulin resistance. It is of note that the highest insulin resistance was also linked with the highest concentrations of triglycerides.

Differential effects of age and sex on insulin sensitivity and body composition in adolescent offspring of women with type 1 diabetes: results from the EPICOM study

AIMS/HYPOTHESIS

The aim of this study was to investigate the influence of age and sex on insulin sensitivity and insulin secretion in the adolescent offspring of women with type 1 diabetes, compared with the background population.

METHODS

This was a prospective nationwide follow-up study (Epigenetic, Genetic and Environmental Effects on Growth, Cognitive Functions and Metabolism in Offspring of Women with Type 1 Diabetes [EPICOM]) in a Danish population. We examined 278 offspring of women with type 1 diabetes from the Danish Diabetes Association Register born during 1993-1999 (index offspring) and 303 control offspring, identified through the Danish Central Office of Civil Registration and matched to the index offspring with respect to date of birth, sex and postal code. The offspring had an overall mean age of 16.7 years (range 13.0-20.4 years). The main outcomes were age-related changes in fasting OGTT-derived indices for insulin sensitivity (BIGTT-SI_0-30-120, Matsuda index, HOMA-IR) and insulin secretion (acute insulin response [BIGTT-AIR_0-0-30-120], insulinogenic index, HOMA of insulin secretory function [HOMA-β], disposition index) and physical activity (International Physical Activity Questionnaire). In addition, we determined total body fat (TBF) percentage using dual-energy x-ray absorptiometry.

RESULTS

We observed significantly lower insulin sensitivity in index offspring compared with control offspring, increasing with age. The differences were attenuated after adjustment for TBF percentage, but were still significant at 17 and 18 years of age. We also observed decreased disposition index and insulin secretion-sensitivity index-2 in index offspring at the same age, but we found no significant differences in other indices of insulin secretion compared with control offspring. With age, TBF percentage became increasingly more divergent between index and control offspring, and was consistently higher among female but not male index offspring.

CONCLUSIONS/INTERPRETATION

Differences in insulin sensitivity between the offspring of women with type 1 diabetes and control offspring increased with age. This was only partially explained by higher adiposity in the index offspring.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01559181.

Retrospective Evaluation of Metformin and/or Metformin Plus a New Polysaccharide Complex in Treating Severe Hyperinsulinism and Insulin Resistance in Obese Children and Adolescents with Metabolic Syndrome

Background: Pharmacological treatment of obesity and glucose-insulin metabolism disorders in children may be more difficult than in adults. Thus, we evaluate the effects of metformin in comparison with metformin plus a polysaccharide complex (Policaptil Gel Retard^®, PGR) on body weight and metabolic parameters in obese children and adolescents with metabolic syndrome (MetS). Patients and methods: We retrospectively collected 129 children and adolescents (67 girls, 62 boys; median age 12.6 years) treated for a minimum of two years with metformin and low glycemic index (LGI) diet. Of these, 71 patients were treated with metformin plus PGR after at least 12 months of metformin alone. To minimize the confounding effect of the LGI on auxological and metabolic parameters, the patients were compared with age-, sex-, and BMI-matched control group with obesity and MetS (51 subjects; 24 males, 27 females) treated only with a LGI diet. Assessments included lipids, glucose and insulin (fasting and after oral glucose tolerance test) concentrations. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), Matsuda, insulinogenic and disposition indices were calculated. Results: Metformin treatment led to a significant reduction in BMI SDS (p < 0.0001), with a significant difference in ΔBMI SDS between patients and controls (p < 0.0001). Moreover, metformin treated patients showed a reduction in HOMA-IR (p < 0.0001), HbA1c levels (p < 0.0001) and a significant increase in Matsuda index (p < 0.0001) in respect to the reduction discovered in controls (p < 0.05). Moreover, in contrast to the group treated with metformin alone and controls, patients treated with metformin plus PGR showed a further reduction in BMI SDS (p < 0.0001), HOMA-IR (p < 0.0001), HbA1c (p < 0.0001), total, HDL and LDL cholesterol (p < 0.0001), as well as an increase in Matsuda (p < 0.0001), disposition (p < 0.005) and insulinogenic (respectively, p < 0.05 and p < 0.0001) indices. Conclusions: Metformin appears to show short-term efficacy in reducing BMI, adiposity and glucose and insulin parameters in obese children and adolescents with MetS. However, PGR added to metformin may be useful to potentiate weight loss and to improve glucose-insulin metabolism and adiposity parameters in these patients.

Insulin resistance and its association with catch-up growth in Chinese children born small for gestational age

OBJECTIVE

To assess insulin resistance and β-cell function from birth to age 4 years and to examine their associations with catch-up growth (CUG) in Chinese small-for-gestational-age (SGA) children.

METHODS

Weight and height were measured yearly from birth to age 4 years, and transformed into age- and gender-adjusted SD scores. Fasting serum insulin and glucose were measured, and fasting insulin resistance and β-cell function were estimated using the homeostasis model assessment (HOMA).

RESULTS

The mean HOMA-IR of the SGA group was significantly lower than that of the appropriate-for-gestational-age (AGA) group at ages 2 and 3 years old, and the mean HOMA% of the SGA group was significantly lower than that of the AGA group at age 4 years old. At 4 years of age, HOMA for insulin resistance was positively correlated with the height gain and SD of height gain between 0 and 5 months, and HOMA% was positively correlated with the weight gain and SD of weight gain between 6 and 12 months in SGA children.

CONCLUSIONS

SGA children with CUG show a greater propensity to develop insulin resistance than AGA children between ages 2 and 4 years old. HOMA parameters are related to CUG in the first year of life.

Predictors of Insulin Resistance in Children versus Adolescents with Obesity

INTRODUCTION

Obesity is a risk factor to develop metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM). Insulin resistance (IR) plays a major part in both. With increasing incidence of childhood obesity, this retrospective study aimed to identify predictors of IR in children/adolescents with obesity to optimize screening for IR.

METHOD

Patients aged ≥ 2-≤ 18 years with obesity (BMI-SDS > 2.3) were included. IR was defined as HOMA-IR ≥ 3.4, and MetS if ≥3 of the following criteria were present: waist circumference and blood pressure ≥ 95th age percentile, triglycerides ≥ 1.7 mmol/l, HDL < 1.03 mmol/l, and fasting plasma glucose ≥ 5.6 mmol/l.

RESULTS

In total, 777 patients were included. Of the 306 children, 51, 38, and 0 were diagnosed with IR, MetS, and T2DM, respectively. Of the 471 adolescents, 223, 95, and 0 were diagnosed with IR, MetS, and T2DM, respectively. In the multivariable regression model, BMI-SDS, preterm birth, and Tanner stage were associated with IR in children (6.3 (95% CI 1.3-31.1), 5.4 (95% CI 1.4-20.5), 2.2 (95% CI 1.0-4.8)), and BMI-SDS and waist circumference in adolescents (4.0 (95% CI 1.7-9.2), 3.7 (95% CI 1.5-9.4)).

CONCLUSION

Different IR predictors were observed in children/adolescents with obesity. These predictors can be used to optimize screening for IR in pediatric populations.

Williams-beuren syndrome is a genetic disorder associated with impaired glucose tolerance and diabetes in childhood and adolescence: new insights from a longitudinal study

BACKGROUND

In adults with Williams-Beuren syndrome (WBS), a common endocrine abnormality is type 2 diabetes mellitus (T2DM) or impaired glucose tolerance (IGT). However, few and sporadic data are available in children, adolescents, and young adults with WBS.

AIM

To evaluate the frequency of IGT and T2DM in a cohort of children and young patients with WBS.

PATIENTS AND METHODS

We longitudinally evaluated 27 patients (9 males and 18 females, median age at study onset 13.6 years) with WBS. The median follow-up was 3.6 years. Variables of insulin resistance and β-cell function were evaluated in all subjects using an oral glucose tolerance test. The homeostasis model assessment (HOMA) of insulin resistance and the Matsuda index of insulin sensitivity were calculated. The study of the GCK and HNF1Α genes was performed in patients with glucose metabolism abnormalities. 45 age- and sex-matched healthy subjects and 51 age-, sex- and BMI-matched subjects were recruited as two control groups.

RESULTS

Considering nutritional status, 7 (25.9%) patients were obese, 9 (33.3%) overweight, and 11 (40.8%) normal-weight. One (3.1%) patient had acanthosis nigricans. IGT was diagnosed in 7 (25.9%) WBS patients and T2DM in 3 (11.1%). Considering all WBS patients, the median value of HOMA was 5.23 (range 2.93-14.89; insulin 24.73 ± 14.67 μU/ml; glucose 104.98 ± 16.06 mg/dl). Considering BMI values, HOMA was 11.00 (range 6.53-12.56), 5.64 (range 3.54-7.95), and 4.54 (range 3.21-5.43), and insulin was 34.53 ± 6.84, 22.76 ± 8.91, and 19.47 ± 6.01 μU/ml in obese, overweight, and normal-weight WBS patients, respectively. Comparing the results with the two control groups, WBS patients showed higher insulin values than healthy controls (p < 0.001), but similar values as the BMI-matched control group (p = n.s.). However, WBS patients showed significantly higher values of glycemia (healthy control group, p < 0.001; BMI-matched control group, p < 0.05) and HOMA (healthy control group, p < 0.001; BMI-matched control group, p < 0.05) than the two control groups. Finally, among WBS patients there was a higher number of subjects with IGT and T2DM than among healthy controls (p < 0.0001) and the BMI-matched control group (p = 0.0002).

CONCLUSION

Our data strongly suggest that IGT and T2DM may be frequently discovered in children, adolescents, and young adults with WBS. WBS should be included among the genetic syndromes associated with T2DM. Further studies are necessary to evaluate the etiopathogenesis of this aspect.

Policaptil Gel Retard significantly reduces body mass index and hyperinsulinism and may decrease the risk of type 2 diabetes mellitus (T2DM) in obese children and adolescents with family history of obesity and T2DM

Background

Treatments for childhood obesity are critically needed because of the risk of developing co-morbidities, although the interventions are frequently time-consuming, frustrating, difficult, and expensive.

Patients and methods

We conducted a longitudinal, randomised, clinical study, based on a per protocol analysis, on 133 obese children and adolescents (n = 69 males and 64 females; median age, 11.3 years) with family history of obesity and type 2 diabetes mellitus (T2DM). The patients were divided into three arms: Arm A (n = 53 patients), Arm B (n = 45 patients), and Arm C (n = 35 patients) patients were treated with a low-glycaemic-index (LGI) diet and Policaptil Gel Retard®, only a LGI diet, or only an energy-restricted diet (ERD), respectively. The homeostasis model assessment of insulin resistance (HOMA-IR) and the Matsuda, insulinogenic and disposition indexes were calculated at T₀ and after 1 year (T₁).

Results

At T₁, the BMI-SD scores were significantly reduced from 2.32 to 1.80 (p < 0.0001) in Arm A and from 2.23 to 1.99 (p < 0.05) in Arm B. Acanthosis nigricans was significantly reduced in Arm A (13.2% to 5.6%; p < 0.05), and glycosylated-haemoglobin levels were significantly reduced in Arms A (p < 0.005). The percentage of glucose-metabolism abnormalities was reduced, although not significantly. However, the HOMA-IR index was significantly reduced in Arms A (p < 0.0001) and B (p < 0.05), with Arm A showing a significant reduction in the insulinogenic index (p < 0.05). Finally, the disposition index was significantly improved in Arms A (p < 0.0001) and B (p < 0.05).

Conclusions

A LGI diet, particularly associated with the use of Policaptil Gel Retard®, may reduce weight gain and ameliorate the metabolic syndrome and insulin-resistance parameters in obese children and adolescents with family history of obesity and T2DM.

Insulin sensitivity and brain reward activation in overweight Hispanic girls: a pilot study

BACKGROUND

Insulin resistance is a link between obesity and the associated disease risk. In addition to its role as an energy regulatory signal to the hypothalamus, insulin also modulates food reward.

OBJECTIVE

To examine the relationship of insulin sensitivity (SI) and fasting insulin with cerebral activation in response to food and non-food cues in children.

METHODS

Twelve overweight Hispanic girls (age: 8-11) participated in two study visits, a frequently sampled intravenous glucose tolerance test and a functional neuroimaging session (GE HDxt 3.0Tesla) with visual stimulation tasks. Blocks of images (high calorie [HC], low calorie [LC] and non-food [NF]) were presented in randomized order.

RESULTS

Comparing HC with NF, SI was inversely associated with activation in the anterior cingulate (r(2)  = 0.65; P < 0.05), the insula (r(2)  = 0.69; P < 0.05), the orbitofrontal cortex (r(2)  = 0.74; P < 0.05), and the frontal and rolandic operculum (r(2)  = 0.76; P < 0.001). Associations remained significant after adjustment for body mass index. Association of fasting insulin and cerebral activation disappeared after adjustment for waist circumference.

CONCLUSION

In addition to weight loss, insulin sensitivity may pose an important target to regulate neural responses to food cues in the prevention of excessive weight gain.

Dietary patterns and breakfast consumption in relation to insulin resistance in children. The Healthy Growth Study

OBJECTIVE

Insulin resistance is a significant cross-point for the manifestation of several chronic diseases in children and adults. The aim of the present study was to investigate the possible relationship of certain dietary patterns and breakfast consumption habits with insulin resistance in children.

SUBJECTS

A representative sample of 1912 schoolchildren (aged 9-13 years) participated in a cross-sectional epidemiological study, the Healthy Growth Study, which was initiated in May 2007 and completed in June 2009.

SETTING

It was conducted in seventy-seven primary schools in four large regions in Greece.

DESIGN

Dietary intake, breakfast consumption, anthropometric and physical examination data, biochemical indices and socio-economic information collected from parents were assessed in all children. Principal components analysis was used to identify dietary patterns.

RESULTS

A dietary pattern of increased consumption of margarine, sweets (candies, lollipops, jellies, traditional fruit in heavy syrup) and savoury snacks (chips, cheese puffs and not home-made popcorn) was associated with homeostasis model assessment of insulin resistance index (HOMA-IR; β = 0·08, P < 0·001) in multivariate models. Children in the third tertile of this dietary pattern had a 2·51 (95 % CI 1·30, 4·90) times higher risk of insulin resistance (HOMA-IR > 3·16) than those in the first tertile. Breakfast consumption had an inverse correlation with insulin resistance, but the correlation lost its significance after adjustments for waist circumference, birth weight, parental BMI and socio-economic status.

CONCLUSIONS

Increased consumption of margarine, sweets and savoury snacks, which is a common dietary pattern in childhood, was positively associated with insulin resistance, while breakfast consumption had an inverse association with HOMA-IR, in schoolchildren (aged 9-13 years). Identification of dietary behaviours that might affect insulin resistance in children offers valuable advice in cardiometabolic risk prevention strategies.

Increased leptin/adiponectin ratio and free leptin index are markers of insulin resistance in obese girls during pubertal development

BACKGROUND

Modifications in body fat in obese patients during puberty determine changes in adipokines that affect insulin sensitivity.

AIMS

We hypothesized that the leptin/adiponectin (L/A) ratio and free leptin index (FLI) are good markers of insulin resistance (IR) and total body fat (TBF) during pubertal development.

METHODS

A prospective study of 32 obese girls (OG) and age-matched control girls (CG) was performed. OG were divided into those that maintained a weight loss (WL) of >1 SD of initial body mass index (BMI) (WL group, n = 25) and those without WL (NWL group, n = 7). Oral glucose tolerance tests (OGTT) were performed to evaluate IR. Correlations of adipokines, L/A, and FLI with BMI, waist circumference, percentage of TBF (%TBF) and IR were performed over pubertal development.

RESULTS

The L/A ratio and FLI were increased in OG at baseline. Both indexes decreased in the WL group as puberty progressed, with no change in CG or NWL. In the WL group, a correlation between L/A and FLI with OGTT and %TBF, and L/A and homeostasis model assessment (HOMA) was found throughout the study.

CONCLUSION

The L/A ratio and FLI are good markers to follow changes in IR and %TBF after WL during puberty. Insulin more accurately reflects the changes in IR than HOMA.

Insulin resistance and inflammation markers: correlations in obese adolescents

AIMS AND OBJECTIVES

To ascertain whether inflammation markers also correlate with parameters related to insulin resistance and the metabolic syndrome in a group of adolescents.

BACKGROUND

Obesity is now considered a chronic low-grade inflammatory process, characterised by alterations in the systemic concentrations of some inflammation markers. Adiponectin, leptin and other inflammatory proteins have been shown to correlate with insulin resistance and the metabolic syndrome in adults.

DESIGN

Cross-sectional study in two groups of obese and normal weight adolescents.

METHODS

Serum levels of adiponectin, leptin, ceruloplasmin and insulin levels were determined and correlated among them and with anthropometric parameters, blood pressure body mass index and body mass index z-score.

RESULTS

Waist circumference, body mass index and blood pressure values correlated significantly with both homoeostasis model assessment for insulin resistance and insulin levels. Ceruloplasmin also correlated with both parameters with a high level of significance. However, leptin levels did not correlate with either homoeostasis model assessment for insulin resistance or insulin, and adiponectin correlated with homoeostasis model assessment for insulin resistance but not insulin. All inflammation markers studied correlated with the body mass index z-score. These correlations were stronger in the group of obese individuals compared to lean ones.

CONCLUSIONS

We found a relationship between insulin resistance and some inflammation in adolescents, which was particularly strong in obese individuals and was associated with the development of metabolic syndrome. Among the inflammation markers studied, ceruloplasmin revealed as a potential string marker of insulin resistance in obese adolescents.

RELEVANCE TO CLINICAL PRACTICE

The results obtained in this study imply a significant advance in the field of clinical practice of nursing. The adequate understanding by nursing personnel of the inflammatory processes inherent to obesity constitutes a key factor for the prevention of the disease and its complications in adolescents.

Update on statural growth and pubertal development in obese children

Childhood obesity is a growing and alarming problem, associated with several short-term and long-term metabolic and cardiovascular complications. In addition, it has also been suggested that excess adiposity during childhood influences growth and pubertal development. Several studies have shown that during pre-pubertal years, obese patients present higher growth velocity and that this pre-pubertal advantage tends to gradually decrease during puberty, leading to similar final heights between obese and non-obese children. Excess body weight might also influence pubertal onset, leading to earlier timing of puberty in girls. In addition, obese girls are at increased risk of hyperandrogenism and polycystic ovary syndrome. In boys, a clear evidence does not exist: some studies suggesting an earlier puberty associated with the obesity status, whereas other have found a delayed pubertal onset. Overall, the existing evidence of an association between obesity and modification of growth and pubertal patterns underlines a further reason for fighting the epidemics of childhood obesity.

Innate immune activation in obesity

The innate immune system is a prewired set of cellular and humoral components that has developed to sense perturbations in normal physiology and trigger responses to restore the system back to baseline. It is now understood that many of these components can also sense the physiologic changes that occur with obesity and be activated. While the exact reasons for this chronic immune response to obesity are unclear, there is strong evidence to suggest that innate inflammatory systems link obesity and disease. Based on this, anti-inflammatory therapies for diseases like type 2 diabetes and metabolic syndrome may form the core of future treatment plans. This review will highlight the components involved in the innate immune response and discuss the evidence that they contribute to the pathogenesis of obesity-associated diseases.

Daily sugar-sweetened beverage consumption and insulin resistance in European adolescents: the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study

OBJECTIVE

The present study aimed to evaluate the relationship between the consumption of selected food groups and insulin resistance, with an emphasis on sugar-sweetened beverages (SSB).

DESIGN

The present research is a large multicentre European study in adolescents, the HELENA-CSS (Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study).

SETTING

Homeostasis model assessment-insulin resistance index (HOMA-IR) was calculated. Several anthropometric and lifestyle characteristics were recorded. Dietary assessment was conducted by using a short FFQ.

SUBJECTS

The participants were a subset of the original sample (n 546) with complete data on glucose, insulin and FFQ. All participants were recruited at schools.

RESULTS

Median (25th, 75th percentile) HOMA-IR was 0.62 (0.44, 0.87). Mean HOMA-IR was significantly higher among adolescents consuming brown bread ≤1 time/week than among those consuming 2-6 times/week (P = 0·011). Mean values of HOMA-IR were also higher in adolescents consuming SSB >5 times/week compared with those consuming less frequently, although a statistically significant difference was detected between those consuming SSB 5-6 times/week and 2-4 times/week (P = 0.049). Multiple linear regression analysis showed that only the frequency of SSB consumption was significantly associated with HOMA-IR after controlling for potential confounders. In particular, it was found that HOMA-IR levels were higher among adolescents consuming SSB 5-6 times/week and ≥1 time/d compared with those consuming ≤1 time/week by 0.281 and 0.191 units, respectively (P = 0.009 and 0.046, respectively).

CONCLUSIONS

The present study revealed that daily consumption of SSB was related with increased HOMA-IR in adolescents.

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.

Poor zinc status is associated with increased risk of insulin resistance in Spanish children

Zn plays a key role in the synthesis and action of insulin. The aim of the present work was to determine whether a poorer Zn status was associated with insulin resistance in a group of 357 Spanish schoolchildren. Zn intake was determined by using a 3 d food record (i.e. Sunday to Tuesday). The body weight, height and waist and hip circumferences of all subjects were recorded and fasting plasma glucose, insulin and Zn concentrations were determined. Insulin resistance was determined using the homoeostasis model assessment (HOMA) marker. Children (11·5 %) with Zn deficiency (serum Zn concentration < 10·7 μmol/l) had higher HOMA values than those with a more satisfactory Zn status (1·73 (sd0·93)) compared with 1·38 (sd0·90;P < 0·05). An inverse correlation was found between the HOMA value and the serum Zn concentration (r− 0·149,P < 0·05). The risk of having a greater insulin resistance value (HOMA greater than the 75th percentile) increased with age (OR 1·438; 95 % CI 1·021, 2·027) and BMI (OR 1·448; 95 % CI 1·294, 1·619) and decreased as Zn serum levels increased (OR 0·908; 95 % CI 0·835, 0·987;P < 0·001). Moreover, an inverse relationship was observed between HOMA values and Zn dietary density (r− 0·122), and the Zn intakes of male children with a HOMA value of >3·16 made a significantly smaller contribution to the coverage of those recommended (59·7 (sd14·7) %) than observed in children with lower HOMA values (73·6 (sd18·2) %;P < 0·05). Taking into account that Zn intake was below than that recommended in 89·4 % of the children, it would appear that increasing the intake of Zn could improve the health and nutritional status of these children, and thus contribute to diminish problems of insulin resistance.

Association of genetic Loci with glucose levels in childhood and adolescence: a meta-analysis of over 6,000 children

OBJECTIVE

To investigate whether associations of common genetic variants recently identified for fasting glucose or insulin levels in nondiabetic adults are detectable in healthy children and adolescents.

RESEARCH DESIGN AND METHODS

A total of 16 single nucleotide polymorphisms (SNPs) associated with fasting glucose were genotyped in six studies of children and adolescents of European origin, including over 6,000 boys and girls aged 9-16 years. We performed meta-analyses to test associations of individual SNPs and a weighted risk score of the 16 loci with fasting glucose.

RESULTS

Nine loci were associated with glucose levels in healthy children and adolescents, with four of these associations reported in previous studies and five reported here for the first time (GLIS3, PROX1, SLC2A2, ADCY5, and CRY2). Effect sizes were similar to those in adults, suggesting age-independent effects of these fasting glucose loci. Children and adolescents carrying glucose-raising alleles of G6PC2, MTNR1B, GCK, and GLIS3 also showed reduced β-cell function, as indicated by homeostasis model assessment of β-cell function. Analysis using a weighted risk score showed an increase [β (95% CI)] in fasting glucose level of 0.026 mmol/L (0.021-0.031) for each unit increase in the score.

CONCLUSIONS

Novel fasting glucose loci identified in genome-wide association studies of adults are associated with altered fasting glucose levels in healthy children and adolescents with effect sizes comparable to adults. In nondiabetic adults, fasting glucose changes little over time, and our results suggest that age-independent effects of fasting glucose loci contribute to long-term interindividual differences in glucose levels from childhood onwards.

Maternal vitamin D status during pregnancy and body composition and cardiovascular risk markers in Indian children: the Mysore Parthenon Study

BACKGROUND

Metabolic consequences of vitamin D deficiency have become a recent research focus. Maternal vitamin D status is thought to influence musculoskeletal health in children, but its relation with offspring metabolic risk is not known.

OBJECTIVE

We aimed to examine the association between maternal vitamin D status and anthropometric variables, body composition, and cardiovascular risk markers in Indian children.

DESIGN

Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured at 28-32 wk gestation in 568 women who delivered at Holdsworth Memorial Hospital, Mysore, India. Anthropometric variables, glucose and insulin concentrations, blood pressure, and fasting lipid concentrations were measured in the offspring at 5 and 9.5 y of age. Muscle-grip strength was measured by using a hand-held dynamometer at age 9.5 y. Arm-muscle area was calculated as a measure of muscle mass. Fasting insulin resistance was calculated by using the homeostasis model assessment equation.

RESULTS

Sixty-seven percent of women had vitamin D deficiency [serum 25(OH)D concentration <50 nmol/L]. At ages 5 and 9.5 y, children born to vitamin D-deficient mothers had smaller arm-muscle area in comparison with children born to mothers without deficiency (P < 0.05). There was no difference in grip strength between offspring of women with and without vitamin D deficiency. At 9.5 y, children of vitamin D-deficient mothers had higher fasting insulin resistance than did children of nondeficient women (P = 0.04). There were no associations between maternal vitamin D status and other offspring risk factors at either age.

CONCLUSION

Intrauterine exposure to low 25(OH)D concentrations is associated with less muscle mass and higher insulin resistance in children.

Preliminary data on the association between waist circumference and insulin resistance in children without a previous diagnosis

The aim of the present work was to study the association between different anthropometric parameters and insulin resistance (IR) in Spanish schoolchildren without a previous diagnosis. A total of 443 Spanish schoolchildren (9-11 years of age) were studied in this cross-sectional study. The anthropometric measurements collected were weight, height, body circumferences and skinfolds. Body mass index (BMI), waist/hip ratio, percentage body fat and fat-free body mass were determined. Overnight-fasted blood lipids, insulin and glucose levels were analysed, and estimation of IR, taking into account the homeostasis model assessment (HOMA), was calculated. The children with IR had higher serum triglycerides and insulin levels, were heavier and taller, and had a higher BMI, a larger waist circumference, a larger hip circumference, a larger waist/hip ratio and thicker bicipital and tricipital skinfolds than those who did not have IR. Age, sex, BMI and waist circumference explained 32.0% of the variance in the HOMA values; only sex, triglycerides and waist circumference independently influenced this variable. A 1-cm increase in waist circumference was associated with approximately a 3.8% increase in the mean HOMA value. The children with a waist circumference of over the p90 for their age and sex were at greater risk of showing IR as measured by the HOMA: odds ratio = 6.94 (2.01-23.91; P < 0.001). In conclusion, according to these results, waist circumference is the best anthropometric parameter associated with IR in children, and those with a waist circumference of over the p90 for their age and sex would appear to be at particular risk.

Obesity and the pubertal transition in girls and boys

Childhood obesity has become a major health concern in recent decades, especially with regard to metabolic abnormalities that impart a high risk for future cardiovascular disease. Recent data suggest that excess adiposity during childhood may influence pubertal development as well. In particular, excess adiposity during childhood may advance puberty in girls and delay puberty in boys. Obesity in peripubertal girls may also be associated with hyperandrogenemia and a high risk of adolescent polycystic ovary syndrome. How obesity may perturb various hormonal aspects of pubertal development remains unclear, but potential mechanisms are discussed herein. Insulin resistance and compensatory hyperinsulinemia may represent a common thread contributing to many of the pubertal changes reported to occur with childhood obesity. Our understanding of obesity's impact on pubertal development is in its infancy, and more research into pathophysiological mechanisms and longer-term sequelae is important.

Common genetic determinants of glucose homeostasis in healthy children: the European Youth Heart Study

OBJECTIVE

The goal of this study was to investigate whether the effects of common genetic variants associated with fasting glucose in adults are detectable in healthy children.

RESEARCH DESIGN AND METHODS

Single nucleotide polymorphisms in MTNR1B (rs10830963), G6PC2 (rs560887), and GCK (rs4607517) were genotyped in 2,025 healthy European children aged 9-11 and 14-16 years. Associations with fasting glucose, insulin, homeostasis model assessment (HOMA)-insulin resistance (IR) and HOMA-B were investigated along with those observed for type 2 diabetes variants available in this study (CDKN2A/B, IGF2BP2, CDKAL1, SLC30A8, HHEX-IDE, and Chr 11p12).

RESULTS

Strongest associations were observed for G6PC2 and MTNR1B, with mean fasting glucose levels (95% CI) being 0.084 (0.06-0.11) mmol/l, P = 7.9 x 10(-11) and 0.069 (0.04-0.09) mmol/l, P = 1.9 x 10(-7) higher per risk allele copy, respectively. A similar but weaker trend was observed for GCK (0.028 [-0.006 to 0.06] mmol/l, P = 0.11). All three variants were associated with lower beta-cell function (HOMA-B P = 9.38 x 10(-5), 0.004, and 0.04, respectively). SLC30A8 (rs13266634) was the only type 2 diabetes variant associated with higher fasting glucose (0.033 mmol/l [0.01-0.06], P = 0.01). Calculating a genetic predisposition score adding the number of risk alleles of G6PC2, MTNR1B, GCK, and SLC30A8 showed that glucose levels were successively higher in children carrying a greater number of risk alleles (P = 7.1 x 10(-17)), with mean levels of 5.34 versus 4.91 mmol/l comparing children with seven alleles (0.6% of all children) to those with none (0.5%). No associations were found for fasting insulin or HOMA-IR with any of the variants.

CONCLUSIONS

The effects of common polymorphisms influencing fasting glucose are apparent in healthy children, whereas the presence of multiple risk alleles amounts to a difference of >1 SD of fasting glucose.

Medical versus surgical interventions for the metabolic complications of obesity in children

The global epidemic of obesity has not spared children. Although prevention of obesity is commendable, we cannot hide from the pressing need to identify, assess, and actively manage children seriously afflicted by obesity and its associated conditions. Sustained weight loss (or, for children, lowering of body mass index standard deviation score) delivers major health benefit, but in children has been difficult to achieve. In adults, the success of the diabetes prevention programs using practical lifestyle interventions is indisputable. Medical therapy, although currently limited in it scope, provides some promise for older children. There is now accumulating evidence, generally of poor quality that surgical interventions (laparoscopic adjustable gastric banding and Roux-en-Y gastric bypass) provide excellent sustained weight loss and improvement in comorbidity and quality of life in selected older children. Their benefits in adults are well demonstrated. Surgery comes with risk, both immediate and in the future, as does severe obesity. Carefully weighing risk and benefit is challenging for the individual and for health service providers. Careful health outcomes research with registries and well-conducted trials will provide better direction in the future. In the meantime, we should move forward ethically and cautiously in providing more intensive obesity management in children.

Association between insulin, leptin, adiponectin and blood pressure in youth

OBJECTIVE

To examine whether insulin, leptin and adiponectin are independent correlates of blood pressure (BP) in a large population-based sample of children and adolescents.

METHODS

We studied 655 boys and 667 girls aged 9, 13 and 16 years who participated in the Quebec Child and Adolescent Health and Social Survey, a province-wide school-based survey conducted in 1999.

RESULTS

Strong, positive univariate associations between BMI, insulin and leptin Z-scores, and both systolic and diastolic BP were found in both sexes. Adiponectin Z-scores were negatively associated with systolic BP in girls only. In multivariate analyses only BMI and insulin Z-scores were significantly associated with systolic BP. In boys, each 1 SD increase in BMI was associated with a 4 mmHg increase in mean systolic BP; each 1 SD increase in insulin was associated with a 1 mmHg increase in mean systolic BP. Only insulin Z-scores were independently associated with diastolic BP in both sexes. For each 1 SD increase in insulin, there was a 1 mmHg increase in mean diastolic BP in boys. Similar to systolic BP, the magnitude of the effect of insulin Z-scores on diastolic BP increased as a function of BMI Z-scores in girls.

CONCLUSION

Independently of BMI, insulin is a strong correlate of systolic and diastolic BP in youth. Although animal studies support a role for leptin and adiponectin in controlling BP, they are not independently associated with BP in youth.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Alternative methods of insulin sensitivity assessment in obese children and adolescents

OBJECTIVE

To validate fasting indexes against minimal model analysis (MMOD) of the frequently sampled intravenous glucose tolerance test (FSIVGTT) in an obese pediatric population.

RESEARCH DESIGN AND METHODS

FSIVGTT-MMOD results were compared with homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin with the sample stratified by sex, puberty, and sensitivity index (S(i)) median in 191 children (82 males and 109 females, 13.9 +/- 2.9 years of age, BMI 36.9 +/- 6.2 kg/m(2), BMI SD score 6.1 +/- 1.6).

RESULTS

Across pubertal groups, correlation coefficients between S(i) and HOMA-IR ranged from -0.43 to -0.78 in males and from -0.53 to -0.57 in females (age and BMI adjusted, P < 0.05 in all instances). Similar results were seen for fasting insulin. In females, the relationship was significantly weaker in more-insulin-resistant subjects.

CONCLUSIONS

The validity of fasting indexes in explaining S(i) was sex dependent, varied with pubertal stage, and in females was influenced by degree of insulin sensitivity. In obese pediatric populations, we generally discourage the use of fasting indexes, although the validity varies within subgroups.

Management approaches for pediatric obesity

Childhood obesity is a worldwide problem that has reached epidemic proportions, resulting in an increased prevalence of premature obesity-related morbidities, and, thus, probable increased health-care costs to treat children. The development of viable approaches to manage this epidemic is crucial. Most experts in the field of childhood obesity agree that the prevention of obesity in children should be the first line of management. Pediatricians must be adept at recognizing children at risk of obesity, calculating and plotting the BMI at all visits, using a change in the BMI to identify excessive weight gain, and monitoring for comorbidities associated with obesity. If obesity is present, the cornerstone of treatment is modification of dietary and exercise habits. Practice-based counseling and community-based programs that support and encourage lifestyle modifications have yielded promising short-term results. Children with severe comorbidities who are unable to achieve lifestyle modifications can be considered for either pharmacologic therapy or surgery, but these options should be considered as a last resort. Early intervention and prevention strategies are the most cost-effective methods of dealing with this issue.

Asthma and insulin resistance in morbidly obese children and adolescents

BACKGROUND

Obesity is well recognized as a state of increased insulin resistance and has been implicated as a significant risk factor for both asthma prevalence and asthma severity in children and adolescents. However, little is known about the specific factors that relate asthma and obesity. Recently, the pro-inflammatory state in obesity and its association with insulin resistance have been recognized. We hypothesize that the effect of morbid obesity on asthma is related to insulin resistance.

METHODS

The patient cohort in the obesity management program at the Children's Hospital of Wisconsin was retrospectively reviewed. Variables were collected from the program data base and chart review was done for missing variables. Patients were considered to have asthma if the evaluating physician confirmed the diagnosis through history and/or the patient had been on inhaled corticosteroids. Insulin resistance (IR) was calculated using a homeostasis model assessment (HOMA). Multivariate logistic regression was performed to identify variables that were significantly related to the odds of having asthma.

RESULTS

Of the 415 patients included in the study, 146 (35%) were asthmatic and 269 (65%) were non-asthmatic. The asthma (AG) and non-asthma (NAG) groups were similar with respect to mean age (11.3 vs. 11.5 years), gender (45% vs. 43% males), mean body mass index (BMI) (36.4 vs. 34.9), and exposure to smoking (43% vs. 42%). Fhx of asthma was significantly higher in AG (71%) compared to NAG (40%). IR level+/-SD was 8.5+/-9.7 in AG compared to 5.3+/-6.7 in NAG (p<0.0001). Multivariate regression analysis found the following variables to be associated with having asthma: younger age (p<0.05), smoking exposure (p<0.05), positive Fhx of asthma (p<0.0001, odds ratio of 3.1), and IR (p<0.0001, odds ratio of 4.1).

CONCLUSION

Morbidly obese asthma patients have a higher degree of insulin resistance compared to morbidly obese non-asthma patients. We speculate that the pro-inflammatory state of insulin resistance may contribute to the pathogenesis of asthma in obese patients. Future prospective studies should address insulin resistance as a possible risk factor for asthma in obese children and adolescents.