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Aerobic training (AT) is more effective than aerobic plus resistance training (AT+RT) to improve anorexigenic/orexigenic factors in obese adolescents.

BACKGROUND The regulation of energy balance is influenced by physical exercise. Although some studies show a stimulation of hormones related to food intake, others show that exercise provides satiety. AIM The aim of this study was to compare the effects of aerobic training (AT) and aerobic plus resistance training (AT+RT) on anorexigenic and orexigenic factors in obese adolescents undergoing interdisciplinary weight loss therapy. METHODS A total of 26 obese adolescents, aged 15-19 years with BMI≥P95 were submitted to 12 months of interdisciplinary intervention (clinical support, nutrition, psychology and physical exercise) and divided into two groups, aerobic training (AT) (n=13) or aerobic plus resistance training (AT+RT) (n=13), which were matched according to gender and body mass. Blood samples were collected to analyze orexigenic factors (AgRP, NPY, MCH) and the anorexigenic factor alpha-MSH. RESULTS The AT and AT+RT groups significantly reduced body mass, body mass index and body fat mass (kg) during the therapy. The AT group showed no significant changes in body lean mass (kg), whereas the AT+RT group showed an increase in body lean mass (kg) during the interdisciplinary intervention. There was an increase in AgRP levels (ng/ml) only in the AT+RT group after 6 months of interdisciplinary intervention compared with baseline condition. Conversely, α-MSH levels (ng/ml) increased only in the AT group after 12 months of interdisciplinary intervention compared with baseline condition. CONCLUSION Aerobic training (AT) as part of an interdisciplinary therapy is more effective than aerobic plus resistance training (AT+RT) to improve secretion of anorexigenic/orexigenic factors in obese adolescents.

Linear and undulating periodized strength plus aerobic training promote similar benefits and lead to improvement of insulin resistance on obese adolescents

The present study compares the effectiveness of three types of physical training for obesity control in adolescents submitted to a long-term interdisciplinary therapy. Forty-five post-puberty obese adolescents (15-18yo) were randomly placed in three different groups of physical trainings: aerobic training (AT n=20), aerobic plus strength training with linear periodization (LP n=13) and aerobic plus strength training with daily undulating periodization (DUP n=12). The body composition was evaluated by air-displacement plethysmography; the rest metabolic rate was measured by indirect calorimetry; serum analysis was collected after an overnight fasting. The most important finding of this study was that both LP and DUP groups improved lipid profile, insulin sensitivity and adiponectin concentration (p<0.01). The linear regression showed a negative association between delta (%) adiponectin and delta (%) insulin (p<0.05). Each group presented a significant reduction in body mass, body mass index and fat mass (kg) after short and long-term intervention (p<0.01). However, the AT group reduced the fat-free mass after short-term intervention (p<0.01) and enhanced protein oxidation (p<0.01), whereas only LP group was able to increase the fat-free mass and maintain the rest metabolic rate (RMR). There was a negative correlation between percentage of protein oxidation and RMR (r=-0.75) in all groups. The interdisciplinary therapy models that included aerobic plus strength training were more effective than only aerobic training to improve lipid profile and insulin sensitivity, as well as the inflammatory state by increasing adiponectin. In all groups were observed an improvement on anthropometric profile.

Cut-off values of waist circumference to predict metabolic syndrome in obese adolescents

INTRODUCTION Metabolic syndrome (MetS) is a constellation of metabolic alteration related to abdominal obesity, inflammation and insulin resistance, which increase cardiovascular disease and mortality. The aims of the present study were to identify the prevalence of comorbidities and altered parameters in obese adolescents with and without MetS, and determine cut-off points of waist circumference to predict MetS. METHODS 195 obese adolescents were recruited and divided according to MetS diagnosis based on IDF criteria. Blood analyses of glucose, lipids, liver enzymes, adiponectin and leptin were measured. Insulin resistance was assessed by HOMA-IR, QUICKI and HOMA-AD. Visceral, subcutaneous and hepatic fat were ultrasonography obtained. Body composition was estimated by BOD POD system. RESULTS We observed a prevalence of 25% of MetS (n=50). The MetS group presented significant higher body mass, BMI, body fat (kg), free-fat mass (kg), waist circumference, visceral fat, glucose, insulin, insulin resistance, total-cholesterol, LDL-c, VLDL-c, triglycerides, liver enzymes, non-alcoholic fatty liver disease (NAFLD) and blood pressure. Significant lower QUICKI and adiponectin in MetS group were noted. MetS girls presented significant higher leptin/adiponectin ratio compared to Non-MetS girls. Cut-off points of 111.5 cm for boys and 104.6 cm for girls of waist circumference were suggested to predict metabolic syndrome. Moreover, waist circumference was positive correlated with visceral fat and the number of metabolic syndrome parameters. CONCLUSION MetS group presented significant higher metabolic alterations and inflammation compared to Non-MetS group. Waist circumference is considered an anthropometric measure predictor of metabolic syndrome in obese adolescents, being useful in clinical practice.

LEPR polymorphism may affect energy balance during weight loss among Brazilians obese adolescents

OBJECTIVE Leptin is an adipokine released mainly by adipose tissue, with many functions including regulation of energy balance. However, little is known about the effect of LEPR polymorphism on orexigenic and anorexigenic neuropeptides. Thus, the aim of the present study is to verify the influence of LEPR polymorphism (rs2767485) on serum orexigenic (NPY, MCH and AgRP) and anorexigenic (Leptin and α-MSH) neuropeptides levels among obese adolescents submitted to 1year of multicomponent weight loss therapy. METHODS Seventy-six adolescents with obesity were enrolled in 1year of weight loss therapy including clinical, nutritional, psychological and exercise-related. Blood samples were collected to analyze neuropeptides (NPY, MCH, AgRP and leptin) and LEPR genotyping. Visceral fat was measured by ultrasound and body composition was measured by plethysmography. The parameters were measured at baseline and after one year. Adolescents were grouped according to genotype (TT or CT+CC group). Effect of the weight loss therapy was analyzed through ANOVA and Wilcox, according to normality. Statistic value was set at <0.05. RESULTS C-allele carriers have the orexigenic neuropeptides (NPY, AgRP and MCH) levels statistically higher when compared with TT group, at baseline. Furthermore, TT group seems to respond better to the therapy by a greater delta on BMI. Indeed, the data suggest a concomitant increased of AgRP levels in CT+CC genotypes, after weight loss therapy. CONCLUSION Both groups responded to the weight loss intervention, however wildtypes (TT) appear to respond to the intervention most optimally with C carries, where post intervention reduction in BMI was significantly greater in wildtypes. The leptin receptor polymorphism seems to affect neuroendocrine regulation of energy balance among adolescents with obesity.

Different metabolic responses induced by long-term interdisciplinary therapy in obese adolescents related to ACE I/D polymorphism

Introduction: The main purpose of the present study was to investigate whether I/D polymorphism of the ACE gene might affect metabolic changes related to the metabolic syndrome through a long-term interdisciplinary therapy in obese adolescents. Methods: In total, 125 obese adolescents who entered the interdisciplinary obesity programme were assigned to the following two subgroups: metabolic syndrome or non-metabolic syndrome. They were evaluated at baseline and after 1 year. Genomic DNA was extracted from circulating leukocytes. Results: Subjects with the II genotype in the non-metabolic syndrome group were only to increase their fat-free mass after therapy. Regarding lipid profile, subjects with ID and DD genotypes from both groups reduced their low-density lipoprotein cholesterol levels significantly. The metabolic parameters from the ID and DD genotypes of the non-metabolic syndrome group showed a significantly improved insulin response. Conclusion: In the present study, we showed that the ACE polymorphism was able to influence the fat-free mass in the I-carry allele in the non-metabolic syndrome group positively. In addition, the I-carry allele was able to improve the insulin resistance of the metabolic syndrome group significantly. These results suggest that the ACE I/D genotypes can influence, in different ways, the specific parameters of metabolism among obese adolescents submitted for long-term interdisciplinary therapy.

PONTOS DE CORTE DE CIRCUNFERÊNCIA DA CINTURA DE ACORDO COM O ESTADIAMENTO PUBERAL PARA IDENTIFICAR SOBREPESO EM ADOLESCENTES

ABSTRACT Objective: To establish waist circumference cut off points according to pubertal staging to identify overweight in adolescents. Methods: Longitudinal study approved by the Ethics Research Committee and conducted with 557 adolescents, aged 10 to 15 years old, selected from public schools. Waist, arm, neck and hip circumferences, body fat percentage, body mass index (BMI), height and blood pressure were measured. Pubertal staging was evaluated by Tanner self assessment scale. The Receiver Operating Characteristic Curve (ROC curve) was used to determine predictive power, sensitivity, specificity and waist circumference cut off points to detect overweight. Results: There was a positive correlation between waist circumference and weight, BMI, upper arm and hip circumferences, waist-to-hip ratio and blood pressure in both sexes. Cut off points for waist circumference according to pubertal stage as related to overweight in adolescents with the best performances in ROC curve were: 71.65 cm for prepubescent girls, 67.90 cm for pubescent girls, 70.25 cm for post pubescent girls, and 66.45 cm for pubescent boys. Age, weight, height, BMI, body fat percentage, arm and hip circumferences were associated to altered waist circumference. Conclusions: The establishment of cut off points for waist circumference according to pubertal staging was proven a good means to identify overweight. These cut off points can be considered reliable for the Brazilian adolescent population, as the isolated use of chronological age in adolescents may underestimate their nutritional status.

The Long-Term Impact of High Levels of Alpha-Melanocyte-Stimulating Hormone in Energy Balance Among Obese Adolescents

Background: Deregulation of orexigenic and anorexigenic pathways occurs among adolescents with obesity. Alpha-melanocyte-stimulating hormone (α-MSH) is a key catabolic mediator of energy homeostasis and an important anorexigenic neuropeptide in the control of energy balance and thermogenesis. However, it was not well explored if α-MSH can modulate long-term weight loss therapy responses in a dependent manner according to its concentration. Our hypothesis is that a high α-MSH concentration at baseline promotes better modulation of anorexigenic/orexigenic pathways in obese adolescents. Methods: One hundred ten post-pubertal obese adolescents (body mass index >95th percentile) were submitted to 1 year of interdisciplinary therapy (clinical, nutritional, psychological, physical exercise, and physiotherapy support). Body composition and plasma levels of α-MSH, neuropeptide Y (NPY), melanin-concentrating hormone, and agouti-related peptide (AgRP) were measured before and after therapy. The volunteers were grouped on the basis of Tertiles of α-MSH concentration: Low (<0.75 ng/mL), Medium (≤0.76 to ≥1.57 ng/mL), and High (>1.57 ng/mL). Significance was set as p < 0.05. Results: The treatment promoted a significant improvement in body adiposity and fat free mass for all groups. It is important to note that only in the high α-MSH group, a significant increase of the α-MSH/NPY ratio and decrease NPY/AgRP ratio post treatment were observed. Conclusion: The high α-MSH concentration promotes better modulation of anorexigenic/orexigenic pathways in obese adolescents following long-term weight loss therapy and this is important in clinical practice.

Waist circumference as a marker for screening nonalcoholic fatty liver disease in obese adolescents

Abstract Objective: To assess the relationship between the degree of waist circumference (WC) and nonalcoholic fatty liver disease (NAFLD) in obese adolescents of both genders, analyzed according to quartiles of WC. Methods: Cross-sectional study that involved 247 obese adolescents aged 12–19 years. Mean values of the nutritional parameters and serum analyses were compared with the groups using the independent t-test. Pearson correlation coefficient was used to determine the relationship of the parameters studied. Chi-square test for trend was used to determine the relationship between the prevalence of the NAFLD and WC quartile by gender. Results: NAFLD were presented in 60% of the study participants. Obese adolescents in the 3rd and 4th quartiles of WC presented higher prevalence of NAFLD when compared with that in the 1st quartile in both genders. The NAFLD patients had significantly higher values for body weight, BMI (body mass index), BAZ-score (BMI-for-age z-scores), total fat (% and kg), WC, visceral fat, insulin, insulin resistance index (HOMA-IR), aspartate aminotransferase and alanine aminotransferase, when compared with non-NAFLD obese adolescents. Conclusions: In conclusion, the results presented here suggest that an increase in WC can reliably predict the risk of NAFLD in obese adolescents. This is a low cost and easy-to-use tool that can help in screening in adolescents.