Frequency of breakfast consumption and its associations with food consumption by degree of industrial processing and with indicators of overweight in Brazilian adolescents (EVA-JF Study).

OBJECTIVE: The aim of this study was to investigate the frequency of breakfast consumption and estimate its associations with the consumption of food at different degrees of industrial processing and with overweight indicators in Brazilian adolescents. METHODS: This cross-sectional study involved a probabilistic sample of 14- to 19-y-old adolescents enrolled in 29 public schools in the municipality of Juiz de Fora, MG, Southeast Brazil (n = 805). The frequency of breakfast consumption was evaluated via a questionnaire (classified into "do not consume", "sometimes consume", and "regularly consume"). The evaluation of food consumption involved two 24-h dietary recalls, the items of which were analyzed according to the NOVA classification system. Overweight indicators (waist circumference, body mass index for age (BMI-for-age), and body fat percentage) were evaluated according to a standard protocol. Linear regression models were performed, first without and then with adjustments for sociodemographic characteristics. RESULTS: We found that 20% of adolescents skipped breakfast, and ∼46% of the caloric intake came from ultra-processed foods. Breakfast omission was associated with a mean increase of 3.02% (95% confidence interval [CI], 0.52-5.53) in energy intake from ultra-processed foods, in addition to a mean increase of 0.28 z-score (95% CI, 0.05- 0.52) of BMI-for-age and of 1.64% (95% CI, 0.21-3.08) in body fat. CONCLUSIONS: We verified that the omission of breakfast was associated with higher consumption of ultra-processed foods, as well as a higher BMI-for-age and higher percentage of body fat, reinforcing the importance of actions to encourage the consumption of this meal and the adoption of healthy eating practices in adolescents.

Involvement of Brazilian adolescents in home cooking: An exploratory analysis (EVA-JF Study).

OBJECTIVE: The aim of this study was to investigate the involvement of Brazilian adolescents in home cooking, estimating its associations with sex and socioeconomic status. METHODS: This cross-sectional study involved a probabilistic sample of 14- to 19-y-olds enrolled in 29 public schools in the municipality of Juiz de Fora, MG, Southeast Brazil (n = 835). To assess involvement in home cooking, a 12-question questionnaire was used. The content was based on the Brazilian Food Guide, which encourages the acquisition, development, and sharing of culinary skills. Pearson's χ test and Poisson regression models were carried out, without and with adjustments. RESULTS: Most of the adolescents did not usually participate in meal planning (61%), and in the choice/purchase of food and culinary ingredients (67%). Boys were less likely to know how to cook "from scratch", positively self-evaluate their culinary skills, enjoy cooking, wish to learn more about cooking and meal preparation, and to participate frequently in the planning and preparation of meals. Belonging to a lower socioeconomic status represented a greater probability of preparing meals alone for the family. CONCLUSIONS: We verified an alarming prevalence of adolescents with behaviors unaligned with Brazilian Food Guide recommendations; that is, most of them, especially boys, were not involved in home cooking. Adolescence may present a window of opportunity for the development of culinary skills, resulting in long-term benefits for the population's diet quality. Furthermore, to change a historical pattern that overloads women's daily lives, it is necessary to encourage, from an early age, the presence of boys in the kitchen.

Eating contexts and their associations with socio-demographic factors in Brazilian adolescents (EVA-JF Study).

OBJECTIVE: To describe the eating contexts and estimate their associations with socio-demographic factors in a sample of Brazilian adolescents. DESIGN: Cross-sectional study. We used an exploratory questionnaire about eating contexts (encompassing regularity of meals, places where they occur and if they take place with attention and in company), which was submitted to cluster analysis. Subsequently, three clusters were identified: cluster 1, 'appropriate eating contexts at breakfast, lunch and dinner'; cluster 2, 'inappropriate eating context at breakfast' and cluster 3, 'inappropriate eating context at dinner'. Multinomial logistic regression models were performed, without and with adjustments, using cluster 1 as reference. SETTING: Twenty-nine public schools of Juiz de Fora, MG, Southeast Brazil. PARTICIPANTS: Adolescents, 14-19-year-olds (n 835). RESULTS: We observed relevant prevalence of adolescents omitting breakfast (52·9 %) and dinner (39·3 %), and who had the habit of eating sitting/lying on the couch/bed or standing/walking, and in front of screens. Breakfast usually occurred unaccompanied (70·8 %); around half (47·5 %) and little over a third (36·1 %) of the sample also would usually have lunch and dinner unaccompanied, respectively. Furthermore, through multivariate analysis, we found associations of eating contexts clusters with female sex (more likely in clusters 2 and 3), age range 14-15-year-olds (less likely in cluster 2) and higher mother's schooling (more likely in cluster 3). CONCLUSIONS: We verified an alarming prevalence of adolescents with eating contexts unaligned with healthy eating recommendations. Additionally, inappropriate eating contexts at breakfast and/or at dinner were associated with socio-demographic factors (sex, age range and mother's schooling).

Factors associated with normal-weight obesity in adolescents.

A new phenotype of obesity has been studied: normal-weight obesity (NWO), which describes individuals with normal-weight by BMI and excess body fat. Despite normal-weight, individuals with NWO have a higher cardiometabolic risk. There is still a gap in the literature on the subject, especially in adolescents, as studies with this population are scarce. This study aims to investigate the sociodemographic factors, family history of chronic non-communicable diseases, body perception, lifestyle and food consumption associated with NWO in adolescents. This is a cross-sectional study, with 506 normal-weight adolescents aged 10­19 years, of both sexes. Weight and height were obtained, and BMI/age was calculated. Body fat analysis was performed using dual-energy X-ray absorptiometry. Sociodemographic data, level of physical activity, food consumption, body self-perception and lifestyle habits were also obtained. Logistic regression with hierarchical approach was used to analyse the associations. The odds of NWO are greater with age (OR = 1·14; 95 % CI = 1·04, 1·26), lower in male adolescents (OR = 0·21; 95 % CI = 0·11, 0·41) and higher in those with a history of familial dyslipidemia (OR = 1·81; 95 % CI = 1·01, 3·28). Adolescents satisfied with their body (OR = 0·30; 95 % CI 0·16, 0·56) and physically active (OR = 0·44; 95 % CI = 0·24, 0·81) have a lower odds of NWO, compared with the others. In addition, it was observed that the odds of NWO is greater among adolescents who use sweeteners (sugar substitutes) (OR = 3·84; 95 % CI = 1·70, 8·65). The factors associated with NWO were female sex, older age, positive family history of dyslipidemia, lower body satisfaction, lower level of physical activity and greater use of sweeteners.

Cardiometabolic risk in adolescents with normal weight obesity.

BACKGROUND: Normal weight obesity (NWO), which is defined by the excess of body fat in normal weight individuals, has been neglected among adolescents, due to their normal weight and young age. Few studies were carried out on the topic with adolescents. OBJECTIVE: To analyze whether the NWO is associated with cardiometabolic risk factors in adolescents. SUBJECTS/METHODS: Cross-sectional study, with 506 normal weight adolescents aged 10-19 years, selected in schools in Brazil. Weight, height, waist circumference (WC) and neck circumference were obtained and the body mass index (BMI) and waist/height ratio (WHR) were calculated. Body composition analysis was performed using dual-energy X-ray absorptiometry. The clinical evaluation included lipid and glycid profile, platelets, leukocytes, lymphocytes, monocytes, uric acid and blood pressure, as well as the presence of metabolic syndrome (MS) and its components. NWO was defined by the presence of normal weight, according to BMI for age, and excess body fat (≥25% and ≥30% in males and females, respectively). Logistic regression models were used to analyze associations between normal weight adolescents with and without the NWO phenotype. RESULTS: NWO associated positively with abdominal obesity, analyzed through WC (OR = 1.36;95%CI = 1.27-1.47), WHR (OR = 25.89;95%CI = 10.43-64.26) and android fat (OR = 1.49;95%CI = 1.36-1.63); insulin resistance (OR = 4.09;95%CI = 1.72-9.70), hyperinsulinemia (OR = 3.83;95%CI = 1.50-9.76) and the highest values of the triglycerides-glycemia index (OR = 4.28;95%CI = 1.21-15.08); uric acid (OR = 1.81;95%CI = 1.29-2.55), as well as the changes in LDL (OR = 3.39;95%CI = 1.47-7.81), total cholesterol (OR = 2.77;95%CI = 1.22-6.29), and in at least one (OR = 1.87;95%CI = 1.04-3.37) or two (OR = 6.61;95%CI = 1.45-30.19) components of MS. CONCLUSION: NWO is associated with the presence of cardiometabolic risk factors in adolescents.

Anthropometric and body composition parameters in adolescents with the metabolically obese normal-weight phenotype.

We aimed to investigate the anthropometric and body composition parameters associated with the metabolically obese normal-weight (MONW) phenotype. This cross-sectional study was conducted with 506 adolescents in Brazil (aged 10-19 y). The MONW phenotype was defined as normal-weight, according to BMI/age, and at least one metabolic alteration. Anthropometric measurements were obtained and the DEXA was used for body composition analysis. Crude and adjusted Poisson regression models with robust variance were used to estimate the associations. The phenotype was positively associated with waist circumference (male: prevalence ratio (PR) = 1·05; 95% CI 1·01, 1·09; female: PR = 1·06; 95% CI 1·02, 1·09), waist:height ratio (male: PR = 1·26; 95% CI 1·07, 1·49; female: PR = 1·29; 95% CI 1·07, 1·56) and android:gynoid fat ratio (male: PR = 1·25; 95% CI 1·03, 1·51; female: PR = 1·39; 95% CI 1·20, 1·62), in both sexes. Furthermore, there was a positive association of phenotype with waist:hip ratio (PR = 1·32; 95% CI 1·06, 1·65) and trunk:arm fat ratio (PR = 1·13; 95% CI 1·02, 1·24) only in males and with trunk:leg fat ratio (PR = 2·84; 95% CI 1·46, 5·53), BAIp (PR = 1·06; 95% CI 1·01, 1·12), fat mass index (PR = 1·24; 95% CI 1·10, 1·41) and regional indices of metabolic load and capacity (PR = 1·29; 95% CI 1·09, 1·53), in females. Anthropometric and body composition parameters indicative of central and total fat are associated with the MONW phenotype.

Static cut-points of hypertension and increased arterial stiffness in children and adolescents: The International Childhood Vascular Function Evaluation Consortium.

Pediatric elevated blood pressure (BP) and hypertension are usually defined using traditional BP tables at the 90th and 95th percentiles, respectively, based on sex, age, and height, which are cumbersome to use in clinical practice. The authors aimed to assess the performance of the static cut-points (120/80 mm Hg and 130/80 mm Hg for defining elevated BP and hypertension for adolescents, respectively; and 110/70 mm Hg and 120/80 mm Hg for children, respectively) in predicting increased arterial stiffness. Using data from five population-based cross-sectional studies conducted in Brazil, China, Korea, and New Zealand, a total of 2546 children and adolescents aged 6-17 years were included. Increased arterial stiffness was defined as pulse wave velocity ≥sex-specific, age-specific, and study population-specific 90th percentile. Compared to youth with normal BP, those with hypertension defined using the 2017 American Academy of Pediatrics guideline (hereafter referred to as "percentile-based cut-points") and the static cut-points were at similar risk of increased arterial stiffness, with odds ratios and 95% confidence intervals of 2.35 (1.74-3.17) and 3.07 (2.20-4.28), respectively. Area under the receiver operating characteristic curve and net reclassification improvement methods confirmed the similar performance of static cut-points and percentile-based cut-points (P for difference > .05). In conclusion, the static cut-points performed similarly well when compared with the percentile-based cut-points in predicting childhood increased arterial stiffness. Use of static cut-points to define hypertension in childhood might simplify identification of children with abnormal BP in clinical practice.

Ponderal index classifies obesity in children and adolescents more accurately than body mass index z-scores.

BACKGROUND: We aimed to compare the accuracy of the ponderal index (PI) vs. BMI-for-age z-scores transformed (BMIz) in estimating body fat levels and classifying obesity in children and adolescents from a Brazilian urban population. METHODS: This is a cross-sectional study with 1149 participants (53.2% male), aged 6 to 18 years. Body fat percent (BFP) was obtained by multi-frequency bioelectrical impedance. Non-linear regression analysis provided the accuracy of both BMIz and PI in estimating BFP. False positive rate was obtained from the proportion of individuals placed at or above the 95th percentile for BMIz or PI, whereas their BFP was discordantly below the 95th percentile. RESULTS: PI and BMIz appeared with similar stability from childhood to adolescence for both boys and girls. The portion of the variability in BFP explained by BMIz (R2 = 0.74 and R2 = 0.75) was close to the variability in BFP explained by PI (R2 = 0.73 and R2 = 0.75) for boys and girls, respectively. False positive rate was higher for BMIz compared with PI among boys (21.8% vs. 3.9%) and girls (28.5% vs. 17.5%). CONCLUSIONS: PI is a promising index for replacing BMIz in children and adolescents due to its potential to reduce false diagnosis of obesity.

Evaluation of lifestyle of female adolescents through latent class analysis approach.

BACKGROUND: Lack of regular physical activity, high sedentary behavior and presence of unbalanced alimentary practices are attitudes associated with an inadequate lifestyle among female adolescents. OBJECTIVE: to assess the lifestyle of female adolescents based on measurements of behavioral variables. METHODS: Cross-sectional study with 405 female adolescents between 14 and 19 years old, resident and attending public schools in Viçosa (state of Minas Gerais). Their lifestyle was analyzed by the Physical Activity Recall, number of steps, screen time (ST), cellphone time (CT), sitting time, food frequency questionnaire (FFQ), and alcohol and tobacco consumption. With multiple correspondence analysis it was possible to observe dispersion and approximation of the variables' categories. Latent class analysis (LCA) was used for modeling the "lifestyle" variable, having been conducted in the poLCA (Polychromous Variable Latent Class Analysis) package of the R statistical software. RESULTS: The mean age was 15.92 ± 1.27 years. Most of the adolescents were considered physically inactive (78%) and with low number of steps (82.57%); 41.45% reported not performing Moderate to Vigorous Physical Activities (MVPA) adequately. Sedentary behavior was found high when assessing ST (72.90%) and CT (65.31%). It was found the best fitted latent class model for the lifestyle (p-G2 = 0.055, p-χ2 = 0.066) featured three latent classes and one covariate (alcohol): Class 1, 'Inactive and Sedentary' (γ = 77.5%); Class 2, 'Inactive and Non-sedentary lifestyle (γ=16.31%); and Class 3, 'Active and sedentary' (γ=6.19%). Female adolescents that had 'never consumed alcohol' were 2.26 times as likely (log OR = 0.8174; p = 0.033) to belong to class 3 (Active & Sedentary lifestyle) than to class 1 (Inactive & Sedentary lifestyle). CONCLUSION: Latent class analysis model with five manifest variable (MVPA, number of steps, ST, sitting time and number of meals) and alcohol consumption like covariate showed itself to be an accurate and objective method in the assessment of female adolescents' lifestyle. Female adolescents that had 'never consumed alcohol' were more as likely to belong to class 'Active & Sedentary lifestyle' than to class Inactive & Sedentary lifestyle. An inactive and sedentary lifestyle is coupled to other unhealthy behaviors during adolescence, possibly carrying over into adult life.

Abundance of Gut Microbiota, Concentration of Short-Chain Fatty Acids, and Inflammatory Markers Associated with Elevated Body Fat, Overweight, and Obesity in Female Adolescents.

BACKGROUND AND AIMS: Overweight is ever more prevalent in the pediatric population, and this cardiometabolic factor can be associated with inflammatory markers, gut microbiota composition, and short-chain fatty acid (SCFA) concentrations. The aim of this study is to evaluate to what extent the abundance of gut microbiota phyla, SCFA concentrations, and inflammatory markers are associated with elevated body fat percentage (BF%), overweight, and obesity in female adolescents. METHODS: An experimental and comparative study was conducted with 96 girls 14 to 19 years old. They were divided into 3 groups: G1-eutrophic (EUT) and adequate BF%; G2-EUT and high BF%; and G3-overweight (OW) or obese (OB) and high BF%. Waist circumference (WC), waist to height ratio (WtHR), and neck circumference (NC) were analyzed as indicators of central visceral adiposity. The BF% was evaluated by DEXA equipment. A food frequency questionnaire was used to evaluate the main types of food consumed in a week. The abundance of the Firmicutes, Bacteroidetes, and Proteobacteria phyla was measured by real-time polymerase chain reaction (RT-qPCR), and the SFCA concentrations (acetic, butyric, and propionic) were determined by high-performance liquid chromatography (HPLC). The inflammatory markers leptin, tumor necrosis factor-alpha, interleukin-6, and high-sensitivity C-reactive protein (hs-CRP) were assessed. RESULTS: Female adolescents in groups G2 and G3 had greater central visceral adiposity and leptin concentration than those in group G1. No association was found between gut microbiota phyla abundance and SFCA concentrations in any of the groups. WC and frequency of consumption of oily and fatty foods were associated with Firmicutes abundance and SFCA concentrations. Girls with high WC also had the greatest leptin (p < 0.001) and hs-CRP (p = 0.035) concentrations. CONCLUSIONS: Inflammatory markers showed association with increased BMI and high BF% in female adolescents. The abundance of Firmicutes was associated with WC and NC, but not with BMI classification or BF%. Specifically, WC and the consumption of oils and fats showed correlation with SCFA concentrations. Different anthropometric indicators, such as NC and WC, should be incorporated into the clinical evaluation of the nutritional status of individuals in the adolescent population.

Agreement of body adiposity index (BAI) and paediatric body adiposity index (BAIp) in determining body fat in Brazilian children and adolescents.

OBJECTIVE: To evaluate agreement of the body adiposity index (BAI) and paediatric body adiposity index (BAIp) in estimating body fat compared with dual-energy X-ray absorptiometry (DXA) and to propose cut-off points for these indices to classify excess adiposity in Brazilian children and adolescents. DESIGN: Cross-sectional study. Measures of weight, height, hip circumference, BMI and body fat percentage (%BF) assessed by DXA were taken, and BAI and BAIp were calculated. The Bland-Altman plot was used to estimate agreement between the methods, and the receiver-operating characteristic curve to determine the cut-off points for BAI and BAIp per age and sex in comparison with DXA. SETTING: Viçosa, Minas Gerais, Brazil. SUBJECTS: Children and adolescents aged 8-19 years (n 1049). RESULTS: Of the children and adolescents, 52·4 % were girls. BAI and BAIp had satisfactory performance by the receiver-operating characteristic curve, except for the 18-19 years age group, whose BAIp had better predictive capacity than BAI. The agreement analysis showed that BAI overestimated %BF by 2·64 %, on average, using DXA; while BAIp underestimated %BF by 3·37 %. CONCLUSIONS: BAI and BAIp showed low agreement with the body fat obtained by DXA, requiring caution when interpreting body composition data in children and adolescents.

CARDIOVASCULAR RISK AND ASSOCIATED FACTORS IN ADOLESCENTS.

BACKGROUND: changes in lifestyle are related to early exposure of adolescents to comorbidities associated with cardiovascular disease. These conditions may have consequences in adulthood. OBJECTIVE: to determine the prevalence of cardiovascular risk and its associated factors in the three phases of adolescence. METHODS: a cross-sectional study involving adolescents 10-19 years old in the city of Viçosa distributed in three stages. We evaluated laboratory tests, body mass index classified into Z-score according to gender and age, and the percentage of body fat classified by gender. We used the chi-square test, chi-square partition with Bonferroni correction and Poisson regression. The significance level was α < 0.05. The project was approved by the UFV Committee of Ethics and Research with Humans. RESULTS: overweight, excess body fat, lipid profile, sedentary behavior, and history of CVD in family were the most prevalent cardiovascular risk factors among adolescents. The adolescents had higher rates of overweight and excess fat. As for the stages, the first one showed a higher percentage of individuals with sedentary behavior, overweight, total cholesterol and LDL in comparison with other stages. Individuals with changes in nutritional status were more likely to develop hypertension, changes in total cholesterol, LDL, triglycerides, insulin, HOMA and low HDL when compared to healthy individuals. CONCLUSIONS: the cardiovascular risk factors have been observed in younger and younger individuals and are important factors to identify a population at risk.

Introducción: los cambios en el estilo de vida están relacionados con la exposición temprana de los adolescentes a las comorbilidades asociadas a la enfermedad cardiovascular. Estas condiciones pueden tener consecuencias en la edad adulta. Objetivo: determinar la prevalencia de riesgo cardiovascular y factores asociados en las tres fases de la adolescencia. Métodos: estudio transversal que incluye a adolescentes de 10-19 años en la ciudad de Viçosa, distribuidos en tres fases. Se evaluaron las pruebas de laboratorio, el índice de masa corporal clasificadas en Z-score, según el sexo y la edad, y el porcentaje de grasa corporal, clasificados por sexo. Se utilizó la prueba de chi-cuadrado, la partición de chi-cuadrado con corrección de Bonferroni y la regresión de Poisson. El nivel de significación fue < 0,05. El proyecto fue aprobado por el Comité de Ética en Investigación de la UFV en humanos. Resultados: el sobrepeso, la grasa corporal, el perfil lipídico, el comportamiento sedentario y la historia de enfermedades cardiovasculares en la familia fueron los factores de riesgo cardiovascular más prevalentes entre los adolescentes. Los adolescentes tenían tasas más altas de sobrepeso y grasa. En cuanto a las etapas, la inicial mostró un mayor porcentaje de individuos con comportamiento sedentario, sobrepeso y colesterol total y LDL en comparación con otras fases. Los individuos con cambios en el estado nutricional eran más propensos a desarrollar hipertensión, cambios en el colesterol total, LDL, triglicéridos, insulina, HOMA y HDL bajo, en comparación con los individuos sanos. Conclusiones: los factores de riesgo cardiovascular se han observado en personas cada vez más jóvenes y son factores importantes para identificar una población en riesgo.

[Nutritional status, metabolic changes and white blood cells in adolescents]. / Estado nutricional, alterações metabólicas e células brancas na adolescência.

OBJECTIVE: To analyze the relationship between the peripheral blood white cells, metabolic changes, and nutritional status of adolescents with and without excess weight and body fat. METHODS: This cross-sectional study evaluated the body mass index (BMI) and percentage body fat (%BF) in 362 adolescents from 15 to 19 years of age, of both sexes. White blood cell count, platelet count, uric acid, fasting glucose, insulin, and lipid profile were measured. The inclusion criteria were agreement to participate in the study and signature of the informed consent. Exclusion criteria were: presence of chronic or infectious disease; use of medications that could cause changes in biochemical tests; pregnancy; participation in weight reduction and weight control programs; use of diuretics and laxatives; or the presence of a pacemaker. The following statistical tests were applied: Kolmogorov-Smirnov test, Student's t or Mann-Whitney test, Pearson or Spearman correlation tests, and chi-squared test, considering p<0.05. RESULTS: Overweight was observed in 20.7% of adolescents. The total cholesterol (TC) had a higher percentage of inadequacy (52.2%), followed by high-density lipoprotein (HDL) (38.4%). There was a positive correlation between white cells and serum lipids, insulin, body fat, and BMI. Monocytes were negatively correlated with BMI, and rods with BMI, body fat, and insulin. CONCLUSIONS: Nutritional status is related to an inflammatory process, and adolescents with excess weight or body fat presented higher amounts of white blood cells.

Prediction of body fat in a dolescents: comparison of two electric bioimpedance devices with dual-energy X-ray absorptiometry.

INTRODUCTION: An accurate estimate of body composition is important in assessing and monitoring the nutritional status of adolescents. OBJECTIVES: To compare the accuracy of 2 electrical bioimpedance devices with that of dual-energy X-ray absorptiometry (DXA) to predict body fat in Brazilian adolescents. METHODS: We evaluated 500 adolescents aged between 10 and 19 years, stratified by sex and divided into overweight and non-overweight groups. The percentage of body fat (%BF) was estimated using 2 types of electrical bioimpedance devices: BIA1 (horizontal tetrapolar bioimpedance equipment) and BIA2 (vertical 8-electrode bioimpedance equipment), as well as by DXA. A Bland- Altman plot was used to calculate the total errors and standard errors of estimate. RESULTS: Considering BMI for age, 19.4% were overweight and 47.4% as assessed by %BF of DXA were overweight. The %BF estimated by BIA2 correlated well (p < 0.05) with the %BF predicted by DXA, and only the total errors for BIA2 in the overweight group were acceptable (≤2.5%). The standard errors of estimate was <3.5%, with the lowest values observed for BIA2. Both BIA1 and BIA2 underestimated the %BF in overweight adolescents, while overestimating the %BF in male adolescents of normal weight. CONCLUSIONS: The BIA2 was found to be more effective in the evaluation of body fat. Regardless of the method used, the results should be carefully interpreted when assessing the body composition of adolescents.

Introducción: Una estimación precisa de la composición corporal es importante para evaluar y monitorear el estado nutricional de los adolescentes. Objetivos: Comparar la exactitud de 2 dispositivos de bioimpedancia eléctrica con la absortometria de rayos X de doble energía (AXD) para predecir la grasa corporal en adolescentes brasileños. Métodos: Se evaluaron 500 adolescentes entre 10 y 19 años, estratificados por sexo y divididos en grupos con sobrepeso y sin sobrepeso. El porcentaje de grasa corporal (%GC) se estimó utilizando 2 tipos de bioimpedancia eléctrica: BIA1 (equipo de bioimpedancia tetrapolar horizontal) y BIA2 (vertical equipo de bioimpedancia 8 electrodos), así como por AXD. Un gráfico de Bland-Altman se utilizó para calcular los errores totales y errores estándar de estimación. Resultados: Teniendo en cuenta el IMC para la edad, el 19,4% tenían sobrepeso y el 47,4% según la evaluación de %GC de DXA tenían sobrepeso. El %GC estimado por BIA2 buena correlación (p.

Body composition and risk for metabolic alterations in female adolescents.

OBJECTIVE: To study anthropometrical and body composition variables as predictors of risk for metabolic alterations and metabolic syndrome in female adolescents. METHODS: Biochemical, clinical and corporal composition data of 100 adolescents from 14 to 17 years old, who attended public schools in Viçosa, Southeastern Brazil, were collected. RESULTS: Regarding nutritional status, 83, 11 and 6% showed eutrophia, overweight/obesity and low weight, respectively, and 61% presented high body fat percent. Total cholesterol presented the highest percentage of inadequacy (57%), followed by high-density lipoprotein (HDL - 50%), low-density lipoprotein (LDL - 47%) and triacylglycerol (22%). Inadequacy was observed in 11, 9, 3 and 4% in relation to insulin resistance, fasting insulin, blood pressure and glycemia, respectively. The highest values of the fasting insulin and the Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) were verified at the highest quartiles of body mass index (BMI), waist perimeter, waist-to-height ratio and body fat percent. Body mass index, waist perimeter, and waist-to-height ratio were the better predictors for high levels of HOMA-IR, blood glucose and fasting insulin. Waist-to-hip ratio was associated to arterial hypertension diagnosis. All body composition variables were effective in metabolic syndrome diagnosis. CONCLUSIONS: Waist perimeter, BMI and waist-to-height ratio showed to be good predictors for metabolic alterations in female adolescents and then should be used together for the nutritional assessment in this age range.

Somatic maturation and body composition in female healthy adolescents with or without adjustment for body fat.

OBJECTIVE: To evaluate the relationship between the stages of somatic maturation and body composition in eutrophic female adolescents with or without excessive body fat. METHODS: Cross-sectional study of 118 female adolescents, from 14 to 19 years-old, in Viçosa, Minas Gerais, Southeast Brazil. The adolescents were divided in two groups: Group 1 (G1), eutrophic with adequate body fat percentage, and Group 2 (G2), eutrophic with high body fat percentage. The somatic maturation was assessed by the formula for estimating the Peak Height Velocity (PHV). results: The PHV had higher average score in G1 adolescents compared to G2 (0.26 versus 0.05; p=0.032). There was an association between G1, G2 and the somatic maturation (p=0.049). The female adolescents before and during PHV presented higher values of fat body BMI (p=0.034) and percentage of central fat (p=0.039) compared to the adolescents after PHV. There was a correspondence between before PHV stage and the excess of body fat (α=0.751). CONCLUSIONS: There was an association between somatic maturation and body composition in eutrophic female adolescents. Length, BMI and fat percentage were different among the somatic maturation stages. It is relevant to evaluate the somatic maturation and the changes occurring in the body composition during adolescence in order to better evaluate and manage the nutritional status and the body fat excess.