BackgroundThe prevalence of overweight/obesity has become a major concern for public health in developing countries. Risk factors need to be well documented so that these countries develop public policies to fight the problem. Thus, the objective of this study is to determine the prevalence of excess fat among adolescents of a South Brazilian State Capital associated with risk factors and their consequences.MethodsThis study was conducted between 2014 and 2016 with adolescents aged 11–18 years. The following body composition measurements were collected: body mass, height, waist circumference, fat mass and bone mineral density (this latter through dual energy X-ray absorptiometry). Biochemical data as glucose, total cholesterol, and triglycerides were also collected. Finally, socioeconomic questionnaires were applied, as well as questionnaires regarding: the education level of guardians, active transportation, time spent with sedentary activities and physical activities. Odds ratios and chi-square test were applied in statistical analysis.ResultsData from 675 adolescents, from which 70% were males, were analyzed. The mean age was 14.7 ± 1.8 years. The prevalence of excess fat was 18.2% in boys and 92.1% in girls. As for sedentary lifestyle and physical inactivity, having one of these factors increased the risk of being overweight by 7.9 times for boys and 3.0 times for girls. In boys, there was a significant association between excess fat and waist circumference (p = 0.000; OR = 13.5; CI = 7.0–25.9), physical activity level (p = 0.000; OR = 4.0; CI = 2.5–6.5), triglycerides (p = 0.019; OR = 2.2; CI = 1.1–4.2) and total cholesterol (p = 0.000; OR = 2.6; CI = 1.6–4.5). In girls, there was an association between having excess fat and an increase in total cholesterol (p = 0.000; OR = 8.0; CI = 2.6–24.4).ConclusionsThe high prevalence of excess fat was greater than what was described by some studies conducted in developed countries. This reality demonstrates the need to implement public policies that can directly promote the reduction of sedentary habits and reinforce the importance of adopting an active lifestyle.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5216-0) contains supplementary material, which is available to authorized users.

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Percentile indicators, aided in its development by biomedical engineering, relative to body fat distribution in adolescents are able to help health professionals in better diagnosing overweight and obesity. The aim of this study was to calculate percentile values to body fat in adolescents aged between 12 and 17 years from the Curitiba-PR and its metropolitan region composed of 29 municipalities, having as reference method the dual energy x-ray absorptiometry (DXA) technology. After applying inclusion criteria for the adolescents, anthropometric measures of body fat and stature were taken, as well as evaluation of the body composition through DXA. The statistical analysis was grounded in the presentation of percentilic values developed by Cole and Green's LMS method, where L stands for the skewness curve, M for the mean curve and S for the variance curve. In total, 390 boys were evaluated. The fat percentage values tend to show a decrease between the ages of 12 (22.8±5.1%) and 16 years (17.9±2.9%). Moreover, for the superior percentiles: 90 th and 97 th re-start to increase at the age of 17 after showing a decrease in the previous years. The L, M and S parameters, altogether with the percentiles created to evaluate body fat are interesting tools to tendency and evolution analyses, as well as to enable inferences to be made about the body composition of adolescents.Resumo -Indicadores percentílicos referentes a distribuição da gordura corporal em adolescentes auxiliam profissionais da saúde em um melhor diagnóstico de sobrepeso e obesidade. O objetivo deste estudo foi calcular valores percentílicos para a gordura corporal de adolescentes com idades entre 12-17 anos de Curitiba-PR e região metropolitana formada ao todo por 29 municípios, tendo como método de referência a tecnologia de absorciometria de raios-X de dupla energia (DXA). Após a aplicação dos critérios de inclusão os adolescentes foram coletadas medidas antropométricas de massa corporal e estatura, além da avaliação da composição corporal com auxílio da DXA. A análise estatística teve como base a apresentação de valores percentílicos a partir do método LMS de Cole e Green, onde L representa a curva de assimetria, M a curva da média e S a curva da variação. Foram avaliados 390 meninos. Os valores de percentual de gordura tendem a apresentar um decréscimo entre as idades de 12 (22.8±5.1%) e 16 anos (17.9±2.9%). Além disso, para os percentis superiores: 90 th e 97 th voltam a crescer na faixa de 17 anos após redução nas idades anteriores. Os parâmetros L, M e S e os percentis criados para percentual de gordura são ferramentas interessantes para análises de tendência e evolução, bem como para que se façam inferências sobre a composição corporal de adolescentes.