Metabolic inflexibility and insulin resistance in obese adolescents with non-alcoholic fatty liver disease.

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is a comorbidity of childhood obesity. OBJECTIVE We examined whole-body substrate metabolism and metabolic characteristics in obese adolescents with vs. without NAFLD. SUBJECTS Twelve obese (BMI ≥ 95th percentile) adolescents with and without NAFLD [intrahepatic triglyceride (IHTG) ≥5.0% vs. <5.0%] were pair-matched for race, gender, age and % body fat. METHODS Insulin sensitivity (IS) was assessed by a 3-h hyperinsulinemic-euglycemic clamp and whole-body substrate oxidation by indirect calorimetry during fasting and insulin-stimulated conditions. RESULTS Adolescents with NAFLD had increased (p < 0.05) abdominal fat, lipids, and liver enzymes compared with those without NAFLD. Fasting glucose concentration was not different between groups, but fasting insulin concentration was higher (p < 0.05) in the NAFLD group compared with those without. Fasting hepatic glucose production and hepatic IS did not differ (p > 0.1) between groups. Adolescents with NAFLD had higher (p < 0.05) fasting glucose oxidation and a tendency for lower fat oxidation. Adolescents with NAFLD had lower (p < 0.05) insulin-stimulated glucose disposal and lower peripheral IS compared with those without NAFLD. Although respiratory quotient (RQ) increased significantly from fasting to insulin-stimulated conditions in both groups (main effect, p < 0.001), the increase in RQ was lower in adolescents with NAFLD vs. those without (interaction, p = 0.037). CONCLUSION NAFLD in obese adolescents is associated with adverse cardiometabolic profile, peripheral insulin resistance and metabolic inflexibility.

Effect of a weight loss program in obese adolescents: a long-term follow-up

Objectives: Obesity during adolescence is an increasing health problem in industrial countries. The comorbidities associated with obesity include important metabolic diseases. Methods: To analyze the effect of a weight-loss program, we recruited 12 obese, male adolescents before entering this program. We determined body weight measures at baseline, 6-week and 36-month follow-up. Also, the long-term changes of blood pressure, HbAlc, and CRP were evaluated. Twenty healthy age-matched adolescents served as controls. Results: Within the intervention group ((body mass index [BMI, kg/m²] > 95th percentile for age and sex, age 13-17 years) the BMI and BMI-standard deviation score [SDS] were significantly reduced in the 6-week follow-up after completing the weight loss program. However, the significant weight-reduction effect was not persistent until the 36-month follow-up. Conclusion: The 6-week weight-loss program had beneficial short-term effects on body weight, BMI, and BMI-SDS in obese adolescents, but these effects could not be maintained until the 36-month follow-up.

Comparison between CDC and WHO BMI z-score and their relation with metabolic risk markers in Northern Portuguese obese adolescents

Growth-curves are an important tool for evaluating the anthropometric development in pediatrics. The different growth-curves available are based in different populations, what leads to different cut-offs. Pediatric obesity tracks into adulthood and is associated with increased cardiovascular risk. The accurate assessment of a child nutritional status using growth-curves can indicate individuals that are either obese or in risk of becoming obese, allowing an early intervention. Moreover, the association between the data obtained from growth-curves with specific metabolic risk factors further highlights the importance of these charts. This study aimed to evaluate the associations between body mass index z-score (BMIzsc), determined using the growth-curves from the Centre for Disease Control and Prevention (CDC) and from the World Health Organization (WHO), with cardiovascular risk factors, represented here by metabolic syndrome (MS) and insulin resistance (IR) related parameters. The study involved 246 obese adolescents (10-18 years, 122 females). MS was defined according to the International Diabetes Federation. IR was considered for HOMA-IR greater than 2.5.

Psychosocial predictors of eating disorder risk in overweight and obese treatment-seeking adolescents

This study explored eating disorder risk factors and possible psychosocial predictors of this risk in overweight and obese treatment-seeking adolescents. Prior to commencing treatment 108 overweight and obese adolescents aged 11 to 17 years (M = 14.31, SD = 1.57; 55% female) completed self-report measures of psychosocial factors. Females reported elevated levels of bulimic tendencies, body dissatisfaction, drive for thinness (p ≤ .001) and males reported elevated body dissatisfaction (p < .001). Age, sex and BMI-for-age z-score explained 15% (p < .001) of the variance in eating disorder risk and psychosocial predictors an additional 25%. Sex did not have a moderating effect on these relationships (p = .21). Among overweight and obese treatment-seeking adolescents, those experiencing lower self-esteem and elevated depression and anxiety symptomatology are at increased eating disorder risk. This highlights the need to consider psychosocial factors in preventing and treating overweight and obesity.

Metabolic syndrome risk factors in overweight, obese, and extremely obese brazilian adolescents

Background: Obesity in infancy and adolescence has acquired epidemic dimensions worldwide and is considered a risk factor for a number of disorders that can manifest at an early age, such as Metabolic Syndrome (MS). In this study, we evaluated overweight, obese, and extremely obese adolescents for the presence of MS, and studied the prevalence of single factors of the syndrome in this population. Methods. A total of 321 adolescents (174 females and 147 males) aged 10 to 16 years, attending the Adolescent Outpatient Clinic of Botucatu School of Medicine, Brazil, between April 2009 and April 2011 were enrolled in this study. Adolescents underwent anthropometric evaluation (weight, height, and abdominal circumference) and Body Mass Index (BMI) was estimated according to age and gender, following Disease Control and Prevention Centers recommendations (CDC, 2000). Blood pressure was measured and individuals with BMI ≥ 85§ssup§th§esup§ percentile were submitted to laboratory evaluation for Total Cholesterol, HDL and LDL Cholesterol, Triglycerides, Fasting Insulinemia, and Fasting Glycemia to identify MS factors, according to the criteria suggested by the International Diabetes Federation. Insulin resistance was calculated by HOMA-IR, Quicki, and Fasting Glycemia/Fasting Insulinemia (FGI). Results and discussion. Of the 321 adolescents, 95 (29.6%) were overweight, 129 (40.2%) were obese, and 97 (30.2%) were extremely obese. Around 18% were diagnosed with MS. The most prevalent risk factors were abdominal circumference ≥90§ssup§th§esup§ percentile (55%), HDL < 40 mg/dL (35.5%), High Pressure ≥130/85 mm/Hg (21%), Triglycerides ≥150 mg/dL (18.5%), and Fasting Glycemia ≥100 mg/dL (2%). Insulin resistance was observed in 65% of the adolescents. Conclusion: An increased prevalence of overweight and obesity, together with cardiometabolic risk factors such as dyslipidemia and abnormal blood pressure, were observed in adolescents, contributing to the onset of metabolic syndrome at younger ages. Risk factors for MS were more prevalent in females. © 2013 Rizzo et al.; licensee BioMed Central Ltd.

Bone speed of sound in overweight and normal-weight girls and adolescents

Over the last two decades, the prevalence of obesity in the general population has been steadily increasing. Obesity is a major issue in scientific research because it is associated with many health problems, one of which is bone quality. In adult females, adiposity is associated with increased bone mineral density, suggesting that there is a protective effect of fat on bone. However, the association between adiposity and bone strength during childhood is not clear. Thus, the purpose of this study was to compare bone strength, as reflected by speed of sound (SOS), of overweight and obese girls and adolescents with normal-weight age-matched controls. Data from 75 females included normal-weight girls (G-NW; body fat:::; 25%; n = 21), overweight and obese girls (GOW; body fat ~ 28%; n = 19), normal-weight adolescents (A-NW, body fat:::; 25%; n = 13) and overweight and obese adolescents (A-OW; body fat ~ 28%; n = 22). Nutrition was assessed with a 24-hour recall questionnaire and habitual physical activity was measured for one week using accelerometry. Using quantitative ultrasound (QUS; Sunlight Omnisense™), bone SOS was measured at the distal radius and mid-tibia. No differences were found between groups in daily total energy, calcium or vitamin D intake. However, all groups were below the recommended daily calcium intake of 1300 mg (Osteoporosis Canada, 2008). Adolescents were significantly less active than girls (14.7 ± 0.6 vs. 6.3 ± 0.6% active for G and A, respectively). OW accumulated significantly less minutes of moderate-to-very vigorous physical activity per day (MVPA) than NW in both age groups (114 ± 6 vs. 57 ± 5 min/day for NW and OW, i respectively). Girls had significantly lower radial SOS (3794 ± 87 vs. 3964 ± 64 mls for G-NW and A-NW, respectively), and tibial SOS (3678 ± 86 vs. 3878 ± 52 mls for G-NW and A-NW, respectively) than adolescents. Radial SOS was similar in the two adiposity groups within each age group. However, tibial SOS was lower in the two overweight groups (3601 ± 75 mls vs. 3739 ± 134 mls for G-OW and A-OW, respectively) compared with the age-matched normal-weight controls. Body fat percentage negatively correlated with tibial SOS in the study sample as a whole (r = -0.30). However, when split into groups, percent bo~y fat correlated with tibial SOS only in the A-OW group (r = -0.53). MVPA correlated with tibial SOS (r = 0.40), once age was partialed out. In conclusion, in contrast withthe higher bone strength characteristic of obese adult women, overweight and obese girls and adolescents are characterized by low tibial bone strength, as assessed with QUS. The differences between adiposity groups in tibial SOS may be at least partially due to the reduced weight-bearing physical activity levels in the overweight girls and adolescents. However, other factors, such as hormonal influences associated with high body fat may also playa role in reducing bone strength in overweight girls. Further research is required to reveal the mechanisms causing low bone strength in overweight and obese children and adolescents.

Calcium intake and its relationship with adiposity and insulin resistance in post-pubertal adolescents

Background Dietary calcium intake has been described as being a negative contributor to adiposity. In adolescents, this relationship is not well established. The objectives of the present study were to compare the calcium intake of normal-weight and obese adolescents and to evaluate its relationship with adiposity and insulin resistance. Methods A cross-sectional analysis of 96 post-pubertal adolescents; 47 normal weight and 49 obese, mean age 16.6 (SD +/- 1.3) years. Body composition was assessed by dual-energy X-ray absorptiometry. Dietary intake was evaluated using a 3-day dietary record. The biochemical evaluation comprised the measurements of serum lipids, lipoproteins, glucose and insulin. Insulin resistance was calculated using the Homeostasis Model Assessment of Insulin resistance (HOMA-IR). Results The mean calcium intake, adjusted for energy, was lower in obese adolescents, 585.2 (+/- 249.9) mg, than in normal weight adolescents, 692.1 (+/- 199.5) mg. Only 4% of adolescents had an adequate intake of calcium. Calcium intake was inversely associated with body trunk fat, insulin and HOMA-IR in the obese group. The quartile analysis of calcium intake provided evidence that girls in the highest quartile had decreased adiposity and insulin resistance. Conclusions This study showed a negative relationship between calcium intake and body fat and insulin resistance, mainly in obese girls, and demonstrates the importance of an increased dietary calcium intake.

Understanding the correlates of adolescents' TV viewing : a social ecological approach

Objective. To examine associations between social ecological factors and Dutch adolescents’ TV viewing. Design. Cross-sectional examination of predictors of adolescents’ TV viewing.

Participants. A total of 338 adolescents, aged 14 years (55% boys).

Measurements. Adolescents self-reported their age, ethnicity and TV viewing (dichotomized at two hours/day) and responded to items from all three social ecological domains; individual (cognitions based on the Theory of Planned Behaviour and TV viewing habit strength, and other behaviours, such as computer use), social (parental rules about TV viewing and parental TV viewing behavior) and physical environmental factors (TV in bedroom, physical activity equipment available). Parents reported demographic factors (e.g., ethnicity, education level), and their own TV viewing (mins/day); adolescents’ weight status (not overweight vs. overweight/obese) was calculated from objective measures of height and weight. Logistic regression analyses examined associations between socio-ecological factors and adolescents’ TV viewing, and whether associations were moderated by adolescents’ sex, parents’ education and ethnicity.

Results. Compared with others, overweight/obese adolescents (odds ratio (OR)=3.0; p≤0.001), those with high computer use (OR=2.3; p≤0.0001), with high TV viewing habit strength (OR=1.3; p≤0.0001), and those whose parents had high levels of TV viewing (OR=2.4; p≤0.01) were more likely to exceed two hours of TV viewing per day. The association with habit strength was moderated by gender, and the association with parents’ TV viewing was moderated by parents’ education and ethnicity.

Conclusions. Interventions should target parents’ TV viewing behaviors and aim to amend habitual, ‘mindless’ TV viewing among adolescents.

Self-monitoring in the treatment of overweight adolescents

The aim of this study was to explore the relationship between the quantity and quality of self-monitoring and per cent fat loss in overweight and obese adolescents participating in a weight-loss intervention. Participants were 55 (33F) overweight and obese adolescents taking part in a 20-week cognitive–behavioural intervention aimed at improving eating and physical activity behaviours. Food and physical activity self-monitoring from the first 9 weeks of the intervention was coded using 24 components assessing the quantity (20) and quality (4) of selfmonitoring. Those who completed treatment (n = 42) were split into groups: Losers (n = 30) and Gainers (n = 12) of per cent body fat as measured by DXA. Group analyses showed that Losers and Gainers could be differentiated by both quantitative and qualitative measures of self-monitoring. The strongest associations were with the classifications of food and drink items into food groups. The number of days monitored and the average number of items recorded did not differentiate the groups. Quantity and quality measures of self-monitoring completed early in treatment could also differentiate those who completed treatment and those who did not complete treatment (n = 13), and the strongest associations were with the amounts of food and drink items recorded, an association not found with treatment outcome. The results indicate that both quantity and quality of self-monitoring may be important predictors of both treatment completion and outcome. Based on these findings a framework of self-monitoring requirements is offered to reduce homework burden while maximising treatment efficacy.

Weight perception in overweight adolescents: Associations with body change intentions, diet and physical activity

This study examined the association of weight perception and weight satisfaction with body change intentions and weight-related behaviours in 928 overweight adolescents (aged 11-18 years, 44% female). Accurate perception of weight was associated with trying to lose weight and inaccurate perception was associated with trying to gain muscle. Weight dissatisfaction was associated with trying to lose weight and gain muscle. Accurate weight perception and weight dissatisfaction were not associated with healthy weight-related behaviours. Awareness of overweight and body dissatisfaction may be detrimental to the adoption of healthy weight-control behaviours. Interventions with overweight adolescents should encourage body satisfaction, rather than promoting awareness of overweight.

Excess body fat negatively affects bone mass in adolescents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Macronutrient intake is correlated with dyslipidemia and low-grade inflammation in childhood obesity but mostly in male obese

Condition of hypoxia caused by hypertrophy of adipose cells in obesity triggers macrophages recruitment and production of cytokines. Additionally, high consumption of saturated fatty acids (SFA) and high glycemic index meals may contribute to oxidative stress and chronic low-grade inflammation by increases NF-kB activation. Thus, the aim of the study was to analyze the contribution of the macronutrients intake in the metabolic and inflammatory profile, by levels of lipoproteins, insulin resistance, anti and pro inflammatory cytokines, in obese adolescents according the gender. sample was composed by 37 adolescents, both genders, identified as obese by body mass index (BMI). Body composition was assessed by Dual-energy X-ray absorptiometry (DEXA) and measures of intra-abdominal adiposity (IAAT) and subcutaneous adiposity tissue (SAT) were done by ultrasound. Biochemical analyses were done and the measurement of cytokines; fatty acids and insulin were performed by the technique of immunoassay ELISA. The estimation of macronutrients consumption was made by 3 day food register regarding food intake. Statistical significance was set at p-value < 5% and the statistical software SPSS version 17.0 (SPSS Inc, Chicago, IL) performed all analyses. BMI (p = 0.316), FM (p = 0.416), IAAT (p = 0.505) and SAT (p = 0.935) presented similarities between genders. Cytokines and metabolic variables values were similar between the groups. Only in the male group, metabolic variables and cytokines were significant correlated with the consumption of total lipids or its fractions. Was observed that insulin concentration had significant interaction with MUFA(g) (= -18.4; p = 0.004) and adiponectin with CHO(g) (= -58.2; p = 0.032) in the group male and female, respectively. macronutrients intake is associated with low-grade inflammation in obesity, by production of inflammatory cytokines and alteration of the lipid profile, especially male obese adolescents which seem to be more responsive of this consumption when compared with female obese adolescents.

Efeito dos exercícios resistidos sobre a função endotelial, parâmetros hemodinâmicos e metabólicos, modulação autonômica, biomarcadores inflamatórios, composição corporal e condicionamento físico de adolescentes obesos

Introdução - O exercício aeróbio é considerado uma ferramenta eficaz na redução de fatores de risco cardiometabólico e na melhora da qualidade de vida em adolescentes obesos. No entanto, os benefícios de um programa exclusivo com exercícios resistidos (ER) ainda não foram estabelecidos nesta população. Objetivo - Avaliar o efeito de um programa exclusivo com ER sobre a função endotelial, parâmetros hemodinâmicos e metabólicos, modulação autonômica, biomarcadores inflamatórios, composição corporal e condicionamento físico de adolescentes obesos. Materiais e Métodos - Quarenta adolescentes participaram do estudo e foram divididos em dois grupos de acordo com o nível de adiposidade: grupo controle (C, n = 20; 13 meninos e 7 meninas) e grupo obeso (Ob; n=24; 7 meninos e 17 meninas). O grupo Ob foi submetido a um programa de ER, três vezes por semana, durante três meses. A função endotelial, o perfil metabólico e hemodinâmico, a modulação autonômica, os biomarcadores inflamatórios, a composição corporal e o condicionamento físico foram avaliados antes e ao final da intervenção. Na investigação de nossa hipótese utilizamos: laser-Doppler fluxometria, análises bioquímicas e de células endoteliais circulantes, monitorização da pressão arterial ambulatorial, variabilidade da frequência cardíaca (Polar), densitometria com dupla emissão de raios X, análise de força muscular em aparelho isocinético e teste cardiopulmonar de exercício submáximo em cicloergômetro. Resultados - Após três meses de intervenção exclusiva com ER observamos uma melhora na vasodilatação endotélio-dependente (P<0,05) e uma redução na pressão arterial sistólica (P<0,01), diastólica (P<0,01) e média (P<0,01), independentes de alterações no peso corporal. Adicionalmente, também observamos redução na frequência cardíaca (FC) de repouso (P<0,01), aumento na variabilidade da FC (P<0,01) e na atividade parasimpática (P<0,05). Observamos também redução na circunferência da cintura (P<0,001), na relação cintura/quadril (P<0,001), no percentual de gordura total (P<0,01), troncular (P<0,01) e de distribuição andróide (P<0,01). Os níveis de fibrinogênio (P<0,05), endotelina-1(P<0,05) e de insulina (P<0,01), e o índice HOMA-IR (P<0,05) foram menores após intervenção. Após a intervenção proposta houve redução na incidência de síndrome metabólica (16,6 vs. 0%) nos adolescentes obesos. Além disso, os estes adolescentes aumentaram a força muscular (P<0,05) e reduziram o consumo de oxigênio, a produção de gás carbônico, a ventilação e o dispêndio energético (P <0,01) durante o teste cardiopulmonar de exercício submáximo. Conclusões - Um treinamento exclusivo com ER resultou em benefícios cardiovasculares, metabólicos e na composição corporal e condicionamento físico de adolescentes obesos, independente de alterações no peso corporal. Nossos resultados sugerem que a prática de ER foi capaz de reduzir fatores de risco cardiovascular em adolescentes com obesidade.

O impacto do excesso de gordura corporal sobre a remodelação óssea de adolescentes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparação e implementação de um programa de intervenção nos hábitos sedentários e na composição corporal de adolescentes obesos

RESUMO: O estágio contemplou a preparação e implementação de um programa, programa de Tratamento da Obesidade Pediátrica (TOP), direcionado para a redução da obesidade dos adolescentes. Foi desenvolvido num contexto clínico e teve o envolvimento de uma equipa multidisciplinar. Existiu um trabalho inicial ao nível da consulta de obesidade, no Hospital de Santa Maria, onde se procedeu ao recrutamento dos participantes. Seguidamente, foram dinamizadas sessões interativas, com exercício físico, com os adolescentes participantes, na Faculdade, no âmbito de um projeto de intervenção, que teve uma duração de seis meses, tendo tido início em janeiro de 2011 e terminado em junho de 2011. A componente científica esteve presente no estágio através da avaliação objetiva do impacte da implementação do programa TOP. No presente estudo, foi avaliado o impacte nos hábitos sedentários dos adolescentes e como objetivo secundário, pretendeu-se analisar a associação entre as atividades sedentárias e a composição corporal. Os resultados do estudo indicam uma descida significativa do peso e de todos os perímetros corporais dos participantes na amostra, bem como do tempo sedentário avaliado por acelerometria, do início para o final da intervenção. Não existiram correlações entre as alterações da composição corporal e as modificações do comportamento sedentário. ABSTRACT: The training incorporated the preparation and the implementation of an exercise program — program Tratamento da Obesidade Pediátrica (TOP) — focused on the decreasing of adolescence obesity. It was developed in a clinic context and it had the involvement of a multidisciplinary team. The work began in Hospital de Santa Maria with the obesity appointment where the participants were recruited. After, the intervention was developed in the Faculty with exercise sessions. The intervention had duration of six months. It began on January and finished on June, in year 2011. The training had a scientific character through the objetive evaluation of the implementation’s impact of the program TOP. This study analysed the impact on sedentary behavior in obese adolescents. Its secondary goal was to analyse the association between the sedentary activities and the body composition. This study’s results demonstrate that the weight and all the circumferences decreased significantly in sample’s participants, as well the sedentary time estimated by accelerometry, in response to the exercise program. There were not correlations between the alterations of the body composition and the modifications of the sedentary behavior.