BackgroundLack of regular physical activity, high sedentary behavior and presence of unbalanced alimentary practices are attitudes associated with an inadequate lifestyle among female adolescents.Objectiveto assess the lifestyle of female adolescents based on measurements of behavioral variables.MethodsCross-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.ResultsThe 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).ConclusionLatent 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.

SummaryBackground: Analysis of metabolic alterations and body composition in adolescents.

OBJECTIVE: To verify whether neck circumference can predict cardiovascular risk factors and excess body fat in adolescents. METHODS: This cross-sectional study included male and female adolescents aged 10 to 14 years from Viçosa, Minas Gerais. The following data were collected: anthropometric measurements, blood pressure, percentage of body fat according to dual energy X-ray absorptiometry, and levels of fasting glucose, fasting insulin, triglycerides, total cholesterol, high-density lipoprotein, and low-density lipoprotein. The anthropometric measurements were used for calculating indices and assessing nutritional status. The receiver operating characteristic curve tested whether neck circumference could predict cardiovascular risk. We also investigated how neck circumference related to the study parameters. The significance level was set at 5% (p<0.05). RESULTS: A total of 260 adolescents were assessed of which 50.4% (n=131) were females, 20.4% (n=53) had excess body weight according to the body mass index-for-age index, and 42.7% (n=111) had excess body fat. Blood pressure (3.9%, n=10) and all biochemical parameters were affected, varying from 1.9% (n=5) for glucose to 65% (n=169) for total cholesterol. Neck circumference correlated with body fat, waist circumference, hip circumference, weight, height, body mass index, waist-to-height ratio, homeostasis model of assessment - insulin resistance, fasting insulin, blood pressure, and high-density lipoprotein (<0.05). It predicted excess body fat and changes in fasting insulin and blood pressure in both sexes, blood glucose and high-density lipoprotein in females, and triglycerides in males (area under the curve >0.5; p<0.05, varying from 0.610 for high-density lipoprotein to 0.817 for blood pressure). CONCLUSION: Neck circumference was capable of predicting excess fat and cardiovascular risk factors in adolescents.

Objective: To investigate the association between body image disorders and the lifestyle and body composition of female adolescents. Design: Cross-sectional study. Setting: The Body Shape Questionnaire (BSQ) and Silhouette Scale and Sociocultural Attitudes Towards Appearance Questionnaire-3 were used to evaluate the participants’ body image. Body composition was evaluated by a Dual-Energy X-ray Absorptiometry equipment, and lifestyles were identified by latent class analysis (LCA) using the poLCA package for R. Participants: Female adolescents aged 14–19 years old, in the city of Viçosa-MG, Brazil. Results: In total, 405 girls participated in the study. Almost half of the participants were dissatisfied with their current physical appearance (51·4 %), presented body perception distortions (52·9 %). 47·3 % of the adolescents were dissatisfied with their body according to the BSQ, and another 8 % severely so. Subjects with an ‘Inactive and Sedentary’ latent lifestyle were 1·71 times as likely to feel dissatisfied as those with active and sedentary or inactive and non-sedentary lifestyles (95 % CI 1·08, 2·90, P = 0·047). Body image disorders showed an association with decreased amounts of moderate and vigorous physical activity, high screen time, increased alcohol consumption and excess body fat. Conclusions: Particular patterns of lifestyle and body composition seem to be associated in female adolescents with dissatisfaction with, distortion of and excessive concern about appearance. Specifically, physical inactivity, sedentary behaviour, alcohol consumption and high body fat percentage may be strongly linked to body image disorders.

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.

This study concluded that female adolescents with higher cell phone time also present higher body dissatisfaction, as well as the most physically active ones. All body composition measurements were associated with body dissatisfaction, mainly body mass index, waist circumference, and waist-to-height ratio.

RESUMOObjetivo: Analisar a influência dos componentes da síndrome metabólica na resistência à insulina, por sexo e fase da adolescência. Sujeitos e métodos: Avaliaram-se dados bioquímicos, clínico, de estilo de vida e composição corporal de 800 adolescentes de 10 a 19 anos, de ambos os sexos, de Viçosa-MG/Brasil, divididos em fases: inicial (10 a 13 anos), intermediária (14 a 16 anos) e final (17 a 19 anos). Resultados: 10,3 e 3,4% apresentavam, respectivamente, resistência à insulina e síndrome metabólica. Na fase inicial, observaram-se maior prevalência de dislipidemia e na intermediária, de hiperuricemia e excesso de gordura corporal. O sexo feminino apresentou maior prevalência de dislipidemia, excesso de gordura corporal e resistência à insulina e o masculino, maior prevalência de HDL baixo, hiperuricemia e pressão arterial alterada. Os da fase inicial apresentaram maiores valores de colesterol total, LDL, HDL, triglicerídeos, glicemia de jejum e relação cintura/quadril, ficaram menos tempo sentados e realizavam maior número de refeições (p < 0,05) em relação às outras fases. O modelo final, ajustado por sexo, foi diferente para cada fase da adolescência. Conclusões: A resistência à insulina está associada à inadequação na composição corporal, nos níveis bioquímicos e no estilo de vida, sendo os fatores associados diferentes em cada fase da adolescência. Arq Bras Endocrinol Metab. 2014;58(6):610-8 Descritores Resistência à insulina; composição corporal; adolescente; síndrome X metabólica ABSTRACT Objective: To analyze the influence of metabolic syndrome components in insulin resistance, by gender and adolescence phase. Subjects and methods: We evaluated biochemical, clinical, lifestyle and body composition data of 800 adolescents from 10 to 19 years old, from both genders, from Viçosa, MG/Brasil, and there was the division by stage: early (10 to 13 years), intermediate (14 to 16 years) and late (17 to 19 years). Results: 10.3 and 3.4% had, respectively, insulin resistance and metabolic syndrome. In the initial phase there was a higher prevalence of dyslipidemia and intermediate hyperuricemia and excess body fat. Females had a higher prevalence of dyslipidemia, excess body fat and insulin resistance and higher male prevalence of low HDL, hyperuricemia and blood pressure changes. Those from the initial phase had higher levels of total cholesterol, LDL, HDL, triglycerides, fasting glucose and waist/hip ratio, stayed less time sitting and had more meals (p < 0.05) in relation to other phases. The final model, adjusted for gender, was different for each phase of adolescence. Conclusions: Insulin resistance is associated with inadequate body composition, in biochemical levels and lifestyle, being the factors associated different in each phase of adolescence. Arq Bras Endocrinol Metab. 2014;58(6):610-8

BACKGROUND: We aimed to compare the accuracy of the ponderal index (PI) vs. BMI-forage 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 95 th percentile for BMIz or PI, whereas their BFP was discordantly below the 95 th 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 (R 2 = 0.74 and R 2 = 0.75) was close to the variability in BFP explained by PI (R 2 = 0.73 and R 2 = 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.