Hormonal and metabolic consequences of childhood obesity

Childhood Obesity: An Updated Review

BACKGROUND

Childhood obesity is an important and serious public health problem worldwide.

OBJECTIVE

This article aims to familiarize physicians with the evaluation, management, and prevention of childhood.

METHODS

A PubMed search was conducted in May, 2021, in Clinical Queries using the key terms "obesity" OR "obese". The search included clinical trials, randomized controlled trials, case-control studies, cohort studies, meta-analyses, observational studies, clinical guidelines, case reports, case series, and reviews. The search was restricted to English literature and children. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Most obese children have exogenous obesity characterized by a growth rate for height above the 50th percentile, normal intelligence, normal genitalia, and lack of historical or physical evidence of an endocrine abnormality or a congenital syndrome. Obese children are at risk for dyslipidemia, hypertension, diabetes mellitus, non-alcoholic fatty liver disease, obstructive sleep apnea, psychosocial disturbances, impaired quality of life, and shorter life expectancy. The multitude of serious comorbidities necessitates effective treatment modalities. Dietary modification, therapeutic exercise, and behavioral modification are the fundamentals of treatment. Pharmacotherapy and/or bariatric surgery should be considered for obese individuals who do not respond to the above measures and suffer from a serious comorbid condition.

CONCLUSION

Childhood obesity, once established, is often refractory to treatment. Most treatment programs lead to a brief period of weight loss, followed by rapid re-accumulation of the lost weight after the termination of therapy. As such, preventive activity is the key to solving the problem of childhood obesity. Childhood obesity can be prevented by promoting a healthy diet, regular physical activity, and lifestyle modification. Parents should be encouraged to get involved in school and community programs that improve their children's nutritional status and physical activity.

Disrupted Circadian Rhythm of Epinephrine in Males With Youth-Onset Type 2 Diabetes

Context

Blood pressure and plasma catecholamines normally decline during sleep and rapidly increase in early morning. This is blunted in adults with type 2 diabetes (T2D).

Objective

We hypothesize that increased sympatho-adrenal activity during sleep differentiates youth with T2D from nondiabetic obese youth and lean youth.

Methods

Fasting spot morning and 24-hour urines were collected in obese adolescents with and without T2D, and normal-weight controls. Fractionated free urine catecholamines (epinephrine, norepinephrine, and dopamine) were measured, and the ratio of fasting spot morning to 24-hour catecholamines was calculated.

Results

Urinary 24-hour catecholamine levels were comparable across the 3 groups. Fasting morning epinephrine and the ratio of fasting morning/24-hour epinephrine were higher in youth with T2D (P = 0.004 and P = 0.035, respectively). In males, the ratio of fasting morning/24-hour epinephrine was also higher in youth with T2D (P = 0.005). In females, fasting morning norepinephrine and the ratio of fasting morning/24-hour dopamine were lower in obese youth with and without T2D (P = 0.013 and P = 0.005, respectively) compared with lean youth. Systolic blood pressure was higher in diabetic participants than other groups; males trended higher than females.

Conclusion

Circadian rhythm in catecholamines is disrupted in youth-onset T2D, with a blunted overnight fall in urinary epinephrine in males. Conversely, fasting morning norepinephrine and dopamine levels were lower in obese females with or without T2D. Higher nocturnal catecholamines in males with T2D might associate with, or predispose to, hypertension and cardiovascular complications. Lower catecholamine excretion in females with obesity might serve an adaptive, protective role.

Evaluation of clinical, endocrine and metabolic findings in obese children with and without hepatosteatosis

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is a common obesity-related comorbidity in childhood. In this study, we aimed to evaluate predictors of NAFLD by comparing clinical, endocrine and metabolic findings in obese children with and without hepatosteatosis.

METHODS

Two hundred and eight obese children aged 6-18 years were included. The patients were divided into group 1 (patients with NAFLD, n=94) and group 2 (patients without NAFLD, n=114). Anthropometric measurements, pubertal stage, lipid profiles, fasting glucose and insulin, homeostatic model of assessment for insulin resistance (HOMA-IR), uric acid, total bilirubin, alanine aminotransferase (ALT), blood urea nitrogen, thyroid-stimulating hormone and free thyroxine parameters were compared retrospectively.

RESULTS

The mean body weight, body mass index (BMI), height, tri-ponderal mass index (TMI), insulin, HOMA-IR, triglyceride, ALT and uric acid values were significantly higher, while high-density lipoprotein-cholesterol (HDL-C) values were significantly lower in group 1. The 70.7% of obese children with hepatosteatosis and 83.9% of those without hepatosteatosis were correctly estimated by parameters including age, gender, ALT, HDL-C, fasting insulin and uric acid values.

CONCLUSIONS

Since obesity-associated hepatosteatosis induces various long-term metabolic impacts in children, early detection is of critical importance. Age, gender, TMI, BMI, ALT, HDL-C, fasting insulin and uric acid values may help to predict the risk of hepatosteatosis. Besides, we assessed whether TMI compared to BMI does not have a better utility in estimating obesity-induced hepatosteatosis in children. This is the first study to show the association between TMI and hepatosteatosis in children.

Impact of lifestyle Intervention on branched-chain amino acid catabolism and insulin sensitivity in adolescents with obesity

Insulin resistance in adolescents with obesity associates with a sex‐dependent metabolic ‘signature’ comprising branched‐chain amino acids (BCAAs), glutamate and C3/C5 acylcarnitines (C3/C5), implicating altered flux through BCAA catabolic pathways. Here, we investigated the effects of lifestyle intervention on BCAA catabolism and insulin sensitivity. We hypothesized (1) weight reduction and improved insulin sensitivity associate with enhanced BCAA catabolism; (2) baseline BCAAs and their metabolic by‐products predict changes in weight and insulin sensitivity during lifestyle intervention.

Comparison of Growth Velocity Among School Age Children With Different Body Mass Index From Childhood Into Early Adolescence in Hualien County, Taiwan: A Retrospective Cohort Study

Objective: This study aimed to investigate the contribution of high body mass index (BMI) to growth velocity among school-aged children who remained in the same BMI categories for a 6-year period. Methods: This retrospective cohort study included children who enrolled in the school year 2009 and remained in the same BMI categories during their 1st, 4th, and 7th grades (6-7, 9-10, 12-13 years of age). Annual linear growth velocity and weight gain were calculated and compared between sexes, BMI groups, and different times. Risk analysis and repeated measures analysis of variance were performed to identify the impact of BMI on growth velocity. Results: Of the 1,637 subjects, 53.0% were male, and 2.5% and 10.9% belonged to BMI groups of overweight and obese, respectively. In students between 6 and 13 years of age, obesity was associated with higher annual weight gain and height gain. Risk analysis showed that obese subjects had higher linear growth velocity than normal BMI groups of both sexes between 6 and 9 years of age. Unexpectedly, overweight and obese girls between 9 and 13 years of age had less linear growth velocity than underweight girls at the same interval. Repeated measures analysis of variance in both sexes showed a significant statistical association between BMI and different times of growth. However, the effect was less in girls between 9 and 13 years of age. Conclusion: Puberty may dominate over BMI as the main contributor to high growth velocity in girls with underweight BMI emerging into pubertal age.

Prepubertal Adiposity, Vitamin D Status, and Insulin Resistance

OBJECTIVE

To evaluate the following from prepuberty to the puberty-onset: (1) changes in serum 25-hydroxyvitamin-D (25[OH]D), adiposity, and insulin resistance (IR); (2) the effect of prepubertal adiposity on serum 25(OH)D changes; and (3) the combined effect of prepubertal obesity and suboptimal-25(OH)D on IR at puberty-onset.

METHODS

A total of 426 prepubertal children (∼54% girls) were followed during pubertal-onset assessing before and after puberty-onset serum 25(OH)D, adiposity (BMI and waist circumference) and IR indicators (homeostasis-model-assessment of IR [HOMA-IR]). Associations were tested using multiple and logistic regression models adjusted by age, gender, and seasonality.

RESULTS

At puberty-onset, mean serum 25(OH)D decreased (32.2 ± 8.9 Tanner I vs 25.2 ± 8.3 ng/mL Tanner II) and total and central obesity increased (BMI-for-age-z-score ≥2 SD [%]: 16.4 vs 22.1; waist-circumference ≥75th percentile [%]: 27.2 vs 37.1, all P < .05). Children with higher adiposity before puberty onset had higher risk of suboptimal-25(OH)D (<30 ng/mL) in Tanner II (ie, odds ratio = 2.7 [1.1-6.7] for obesity and 2.7 [1.4-5.5] for central-obesity) after adjusting for relevant covariates. Children with higher adiposity and suboptimal-25(OH)D before puberty-onset had higher HOMA-IR compared with their counterparts in Tanner II (HOMA-IR: 2.8 [2.5-3.1] if central-obese and suboptimal-25[OH]D vs 2.1 [1.9-2.3] no central-obesity and optimal-25[OH]D).

CONCLUSIONS

We found that serum 25(OH)D declined with puberty-onset, likely because of adiposity increase. Moreover, children with the combined condition of central-obesity and suboptimal-25(OH)D before puberty-onset had higher pubertal IR. These results highlight the need of ensuring adequate-25(OH)D status before pubertal-onset, particularly in obese children.

Association Between Overweight or Obesity and Lumbar Disk Diseases: A Meta-Analysis

STUDY DESIGN

A meta-analysis.

OBJECTIVE

We performed this meta-analysis to evaluate the association between overweight and lumbar disease.

SUMMARY OF BACKGROUND DATA

An extensive English language literature retrieval regarding the association between overweight and the risk of lumbar disease was conducted on Public Medline and Excerpta Medica Database until May 2014.

METHODS

Meta-analysis for all the included literatures was performed by STATA 11.0 to summarize test performance with forest plots after heterogeneity test. Moreover, subgroup and sensitivity analyses were performed to examine the potential candidate effect factors. Afterward, the likelihood of publication bias was assessed by constructing funnel plots and performing Begg rank correlation test and Egger linear regression method.

RESULTS

A total of 5 studies satisfied the predefined eligibility criteria, including 1749 cases with lumbar disk diseases and 1885 controls. Altogether, overweight was associated with increased risk of lumbar disease [odds ratio (OR)=1.45; 95% confidence interval (CI), 1.27, 1.66; P<0.001]. Moreover, subgroup analysis proved that overweight was a predominant factor in development of lumbar disease compared with age and sex. Although significant publication bias was observed in our meta-analysis, we proved high credibility of meta-analysis result using trim and fill method (OR=1.27; 95% CI, 1.06, 1.53).

CONCLUSIONS

We suggest that overweight might increase the risk of lumbar diseases, and weight control should be considered for overweight or obese population to reduce the occurrence and development of lumbar disease.

Geometric indices of hip bone strength in obese, overweight, and normal-weight adolescent girls

The aim of this study was to compare hip bone strength indices in obese, overweight, and normal-weight adolescent girls using hip structure analysis (HSA). This study included 64 postmenarcheal adolescent girls (14 obese, 21 overweight, and 29 normal weight). The 3 groups (obese, overweight, and normal weight) were matched for maturity (years since menarche). Body composition and bone mineral density (BMD) of whole body, lumbar spine, and proximal femur were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at the femoral neck (FN) at its narrow neck (NN) region, the intertrochanteric (IT), and the femoral shaft (FS) by the HSA program. Cross-sectional area and section modulus were measured from hip BMD profiles. Total hip BMD and FN BMD were significantly higher in obese and overweight girls in comparison with normal-weight girls (p < 0.05). However, after adjusting for weight, using a one-way analysis of covariance, there were no significant differences among the 3 groups regarding HSA variables. This study suggests that in obese and overweight adolescent girls, axial strength and bending strength indices of the NN, IT, and FS are adapted to the increased body weight.

Dietary and physical activity/inactivity factors associated with obesity in school-aged children

Diet and physical activity (PA) are essential components of nutritional status. Adequate nutrition and an active lifestyle are key factors during childhood, because food habits track into adulthood. Children spend more time in school than in any other environment away from home. Studying the diet factors and patterns of PA that affect obesity risk in children during school hours and the complete school day can help identify opportunities to lower this risk. We directly measured the time children spent performing moderate to vigorous PA (MVPA) at school, compared the amount and intensity of PA during school hours with after-school hours, and tried to determine if diet behaviors and PA or inactivity were associated with excess weight and body fat. This cross-sectional study included 143 normal-weight (NLW) and 48 obese children aged 8-10 y. Diet data were obtained from two 24-h recalls. Body composition was measured by bioimpedance. Screen time and sports participation data were self-reported. NLW children drank/ate more dairy servings than the obese children, who consumed more fruit-flavored water than the NLW group. Consumption of soft drinks, sugar-added juices, and fresh juices was low in both groups. Children were less active during school hours than after school. MVPA was lower during school hours in the obese group than in the NLW group. Schools, parents, and authorities should be more involved in promoting strategies to improve the dietary habits and PA levels of school-aged children, because this group is not achieving the recommended level of daily MVPA.

Geometric indices of hip bone strength in obese, overweight, and normal-weight adolescent boys

The aim of this study was to compare hip bone strength indices in obese, overweight, and normal-weight adolescent boys using hip structure analysis. After adjusting for weight, obese boys displayed lower intertrochanteric cross-sectional moment of inertia and femoral shaft cross-sectional moment of inertia and section modulus in comparison to normal-weight and overweight boys. This study suggests that in obese adolescent boys, femoral shaft bending strength is not adapted to the increased body weight.

INTRODUCTION

The influence of being obese or overweight on bone strength in adolescents remains controversial. The main aim of this study was to compare hip bone strength indices in obese, overweight, and normal-weight adolescent boys using hip structure analysis. The second aim of this study was to explore the influence of lean mass and fat mass on hip bone strength indices in the same population.

METHODS

This study included 70 adolescent boys (25 obese, 25 normal weight, and 20 overweight). The three groups (obese, overweight, and normal weight) were matched for maturity (Tanner stage) and age. Body composition and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at the femoral neck (FN), the intertochanteric (IT), and the femoral shaft (FS) by the Hip Structure Analysis (HSA) program. Cross-sectional area (CSA), an index of axial compression strength, section modulus (Z), an index of bending strength, and cross-sectional moment of inertia (CSMI), an index of structural rigidity were measured from bone mass profiles.

RESULTS

Body weight, lean mass, fat mass and BMI were significantly higher in obese and overweight boys in comparison to normal-weight boys (P < 0.05). Total hip (TH) BMD and femoral neck (FN) BMD were significantly higher in obese and overweight boys in comparison to normal-weight boys (P < 0.05). After adjusting for age or maturation index, obese and overweight boys displayed significantly higher TH and FN BMD, CSA, CSMI, and Z of the three sites (FN, IT, and FS) in comparison to normal-weight boys (P < 0.05). However, after adjusting for weight, obese boys displayed significantly lower IT CSMI and FS CSMI and Z in comparison to normal-weight and overweight boys (P < 0.05).

CONCLUSIONS

This study suggests that in obese adolescent boys, intertrochanteric structural rigidity and femoral shaft structural rigidity and bending strength are not adapted to the increased body weight.

Autonomic nervous system dysfunction in obesity and Prader-Willi syndrome: current evidence and implications for future obesity therapies

The autonomic nervous system (ANS) controls essential functions like breathing, heart rate, digestion, body temperature and hormone levels. Evidence suggests that ANS dysfunction is associated with adult and childhood obesity and plays a role in the distribution of total body fat and the development of obesity-related complications in humans. This review summarizes our current understanding of ANS involvement in the pathogenesis of obesity and Prader-Willi syndrome. Available evidence of ANS dysfunction in the control of energy balance is limited and, in some cases, contradictory. Further investigation in this area is warranted in order to better understand the important contributions of the ANS to regulation of body fat, development of obesity and its comorbidities. Results from these studies will guide the development of novel obesity therapeutics targeting specific ANS dysfunction.

Bone mineral content and density in obese, overweight, and normal-weighted sedentary adolescent girls

PURPOSE

The aim of this study was to compare the whole body (WB) bone mineral content (BMC) and bone mineral density (BMD) in obese, overweight, and normal-weighted adolescent sedentary girls.

METHODS

This study included 17 obese, 27 overweight, and 21 normal-weighted adolescent (aged, 12-20) sedentary (practicing less than 2 hours of physical activity/week) girls. The three groups (obese, overweight, and normal) were matched for age and maturation index (years since menarche). BMC, bone mineral area (BMA), BMD, and body composition were assessed by dual-energy X-ray asborptiometry. Bone mineral apparent density (BMAD) was calculated for the WB.

RESULTS

Obese girls had higher BMC values than overweight and normal-weighted girls (p < .05 and p < .001, respectively). Overweight girls had higher BMC values than normal-weighted girls (p < .05). BMD values were not different among the three groups. However, obese and overweight girls had lower BMAD and higher BMC/height values in comparison with normal-weighted girls (p < .05). Finally, after adjustment for lean mass, BMC, BMA, BMD, and BMAD were not different among the three groups.

CONCLUSION

In this population, overweight and obesity are associated with higher BMC, BMC/height, and lower BMAD of the WB. This study suggests that BMD, BMC, BMA, and BMAD of the WB are not significantly different among the three groups (obese, overweight, and normal) after adjustment for lean mass. Therefore, our results suggest that the skeleton of the overweight and the obese girls adapts to the increased lean mass.

Accelerated growth in early life and obesity in preschool Chilean children

In Chile, childhood obesity rates are high. The purpose of this article is to compare BMI growth characteristics of normal (N), overweight (OW), and obese (OB) 5-year olds from 0 to 5 years and explore the influence of some prenatal factors on these patterns of growth. The study was done on a retrospective cohort of 1,089 5-year olds with birth weight >2,500 g. Weight and height were obtained from records at nine occasions (0-36 months); at 52 and 60 months, we measured them. At 60 months, children were classified as N, OW, and OB. At each age, BMI and z-score of BMI (BMI Z) differences were compared among groups. The influence of birth weight, pre-pregnancy BMI, and prenatal variables (weight gain, smoking, and presence of diabetes and preeclampsia) on BMI Z differences between N and OB was also explored. Adiposity rebound (AR) was not observed for the N, although for the OW, it occurred approximately 52 months and for the OB at approximately 24 months. BMI Z differences between N and OB were significant from birth, but were greatest between 6-12 and 36-52 months. Additional adjustment by birth weight, pre-pregnancy BMI, and prenatal variables decreased the BMI Z differences for the first 24 months with virtually no effect after this age. Accelerated growth in OB children from post-transition countries occurs immediately after birth, much earlier than the AR. The influence of prenatal factors on adiposity acquisition may extend at most until 2 years of life, although BMI gains thereafter are more related to postnatal variables.

Total body, lumbar spine and hip bone mineral density in overweight adolescent girls: decreased or increased?

Despite the epidemic of overweight adolescents, the effect of being overweight on bone mineral density (BMD) during this period is poorly understood. However, recent studies have suggested that overweight adolescents have lower BMD compared to normal-weighted adolescents after adjusting for body weight. The aim of this study was to determine the influence of being overweight on bone status in a group of adolescent girls. This study included 22 overweight (BMI >25 kg/m(2)) adolescent girls (15.4 +/- 2.4 years old) and 20 maturation-matched (15.2 +/- 1.9 years old) controls (BMI <25 kg/m(2)). Bone mineral area, bone mineral content, BMD at the whole body (WB), lumbar spine (L2-L4), femoral neck (FN), total hip (TH) and body composition (lean mass and fat mass) were assessed by dual-energy X-ray absorptiometry (DXA). Calculation of the bone mineral apparent density (BMAD) was completed for the WB and for L2-L4. Expressed as crude values, DXA measurements of BMD at all bone sites (TB, L2-L4, TH and FN) were higher in overweight adolescent girls compared to controls. After adjusting for either body weight, lean mass or fat mass, these differences disappeared. Finally, BMAD of the L2-L4 remained higher in overweight girls compared to controls after adjusting for lean mass. We conclude that overweight adolescent girls do not have lower BMD when compared with controls, even when BMD values are adjusted for weight, lean mass or fat mass.

Successes and barriers for a youth weight-management program

A patient recruiting process was developed for a youth weight-management program in a metropolitan area, and the clinical effects of the program on overweight and obese children aged 7 to 17 years old were assessed. During the 12-month effort, 68 overweight children were enrolled. The program included exercise, nutrition coaching, and behavior change counseling. Clinical outcomes were measured. Patient recruiting methods were monitored and included working with physicians and schools and marketing to consumers. Program adherence was 71% attendance, 5% noncompliance, and 5% drop out rates. Clinical outcomes were excellent: 68% of participants lowered their body mass index by an average of 2.5% (mean, 24 weeks). The program was clinically successful, but patient recruitment initiatives were unsuccessful and the program was discontinued. Parents were the largest obstacle to patient recruiting efforts. For children's weight-management programs to be commercially viable, new models of patient recruiting and promotion of parental acceptance are needed.

Treatment of childhood obesity

PURPOSE OF REVIEW

To provide an overview of treatments for childhood obesity, highlighting recent advances and recommendations.

RECENT FINDINGS

The three main treatment modalities are lifestyle interventions, medications, and bariatric surgery. Recent data support the short-term effectiveness of lifestyle interventions, and show that continued behavioral intervention increases the likelihood of a sustained effect for up to 2 years. New studies and regulatory decisions on medications for obesity (including orlistat, sibutramine, and metformin) are discussed. Emerging data suggest substantial weight loss after bariatric surgery in morbidly obese adolescents but also indicate adverse effects. An expert panel recently provided guidelines that alter definitions of obesity and offer a framework for obesity management. These guidelines are compared with others, and integrated recommendations presented.

SUMMARY

While primary prevention of childhood obesity is important, broadly effective methods to do so are not yet available. Given the large population of obese children and the risks they face, an emphasis on treatment is also critical. We suggest a staged approach, emphasizing early intervention and lifestyle changes. We also suggest limiting bariatric surgery to selected adolescents in Institutional Review Board-approved research studies. Health-policy interventions can facilitate both prevention and treatment of childhood obesity.

Menstrual health and the metabolic syndrome in adolescents

The metabolic syndrome, a constellation of interrelated risk factors for cardiovascular disease and type 2 diabetes mellitus, has become a major public health concern against the backdrop of increasing rates of obesity. Insulin resistance plays a pivotal role as the underlying pathophysiological linchpin of the various components of the syndrome. The metabolic syndrome is well recognized in adults, and there is convincing evidence that it starts in childhood, with progressive clustering of the various components over time and tracking through adulthood. Adult women and adolescents with polycystic ovary syndrome (PCOS) have higher prevalence rates of the metabolic syndrome compared with the general population. Several anthropometric (obesity, particularly abdominal obesity), metabolic (insulin resistance/hyperinsulinemia, dyslipidemia) and hormonal (low IGFBP1, IGFBP2 and low sex hormone binding globulin) features of adolescents with PCOS are also features of the metabolic syndrome. Insulin resistance, believed to be a key pathogenic factor in both PCOS and the metabolic syndrome, may be the thread that links the two conditions. Menstrual health in adolescents could be viewed as yet another component in the evaluation of the metabolic syndrome. Careful assessment of menstrual history and appropriate laboratory work-up could reveal the presence of PCOS in obese at-risk adolescent girls with a family history of the metabolic syndrome.

Regulation of appetite in lean and obese adolescents after exercise: role of acylated and desacyl ghrelin

CONTEXT

Increased physical activity is an integral part of weight loss programs in adolescents. We hypothesized that exercise could affect appetite-regulating hormones and the subjective desire to eat, which could partly explain the poor success rate of the existing interventions.

OBJECTIVE

The objective of this study was to investigate prospectively the effects of exercise on acylated ghrelin (AG) and desacyl ghrelin (DG) concentrations and on appetite.

SETTING

The setting for this study was a tertiary care center.

PARTICIPANTS

Normal-weight [NW; body mass index (mean +/- se), 20.7 +/- 0.5 kg/m2] and overweight (OW; body mass index, 32.4 +/- 1.7) male adolescents (n = 17/group, age 15.3 +/- 0.2 yr) were studied.

INTERVENTION

Those studied participated in 5 consecutive days of aerobic exercise (1 h/d).

MAIN OUTCOME

Changes in AG and DG concentrations and in appetite during a test meal were studied.

RESULTS

Exercise did not significantly affect insulin sensitivity or body weight. Fasting total (AG and DG) ghrelin concentrations were lower in OW (600 +/- 33 pg/ml) compared with NW (764 +/- 33 pg/ml, P < 0.05) boys and were not affected by exercise. In contrast, there was a differential effect of exercise on both AG and DG (P <or= 0.019). AG significantly increased after exercise, and this increase was greater in NW compared with OW adolescents (P < 0.05). Higher AG concentrations were correlated with an increase in markers of appetite (P < 0.05).

CONCLUSION

Exercise differentially affects AG and DG in NW and OW male adolescents. Our data suggest that total ghrelin does not adequately reflect AG and DG concentrations and that the influence of exercise-induced hormonal changes should be considered to ensure success in weight management.

High plasma concentration of remnant lipoprotein cholesterol in obese children and adolescents

OBJECTIVE

Remnant lipoproteins (RLPs) are the products of the lipolytic degradation of triglyceride-rich lipoproteins produced by the liver and intestine. Recent studies have demonstrated that RLPs are correlated with cardiovascular risk. We assessed the relationship between obesity and RLP and evaluated the factors related to RLP in children and adolescents.

RESEARCH DESIGN AND METHODS

We measured BMI, waist circumference, blood pressure, body fat mass, total abdominal fat, visceral and subcutaneous fat areas, fasting glucose, insulin, total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and RLP cholesterol in 135 children and adolescents (67 boys and 68 girls). Plasma RLP fractions were isolated using an immunoaffinity gel containing specific anti-apolipoprotein (apo) B-100 and anti-apoA-I antibodies. Based on the BMI percentile, the subjects were divided into two groups: normal (< 85th percentile) and overweight (> or = 85th percentile).

RESULTS

RLP cholesterol was significantly correlated with age, sex, BMI, waist circumference, systolic and diastolic blood pressures, visceral and subcutaneous fat areas, visceral-to-subcutaneous fat area ratio, total cholesterol, triglycerides, HDL cholesterol, apoB, and homeostasis model assessment of insulin resistance (HOMA-IR). According to the multivariate regression analysis, triglycerides (beta = 0.928, P < 0.001) were independently correlated with RLP cholesterol. After excluding lipid profiles as an independent variable, the multivariate regression analysis revealed that HOMA-IR (beta = 0.231, P = 0.007) and systolic blood pressure (beta = 0.169, P = 0.046) were independently associated with RLP cholesterol.

CONCLUSIONS

RLP cholesterol was significantly higher in obese children and adolescents. Triglycerides, systolic blood pressure, and insulin resistance were related to RLP cholesterol.

Childhood obesity and the metabolic syndrome

The current epidemic of obesity reflects environmental changes that have an impact on a genetically susceptible population. The scope of obesity and its associated comorbidities warrants its position among the most crucial global public health problems faced today. Society has gained better appreciation for the significance of this problem yet still has much to learn regarding how best to address the obesity crisis. Although strategies for treating individuals who have weight problems successfully continue to evolve, the most profound impacts ultimately will arise from societal changes dictating that all individuals strive to adopt a healthy lifestyle.