Determinantes do índice de massa corporal em adolescentes de escolas públicas de Piracicaba, São Paulo

Are Fat Mass and Lean Mass Associated with Grip Strength in Adolescents?

Background: The interaction between lean body mass (LBM) and fat mass index (FMI) with grip strength (GS) has not been explored in the same analysis model in adolescents. This study thus aims to analyze the association between FMI and LBM with GS. Methods: This cross-sectional study was conducted with data from the 2016 follow-up of the 1997/98 Birth Cohort of São Luís. Grip strength was assessed by the Jamar Plus + dynamometer. The LBM and FMI indexes were assessed [ratio of the mass (lean or fat-kg) to height (m2)]. The confounding variables identified for the relationship between FMI and LBM with GS in the same analysis model, by directed acyclic graph (DAG), were sex, age, race, work, alcohol consumption, smoking, physical activity, and consumption of ultra-processed foods and culinary preparations, used in the adjusted analysis. Results: A total of 2339 adolescents (52.5% girls) were analyzed. The boys have a higher GS than the girls. In the adjusted analysis, with each increase of 1 kg/m2 in the FMI, GS was reduced by 0.72 kgf for boys and 0.35 kgf for girls. At each increase of 1 kg/m2 in the LBM, GS increased by 2.18 kgf for boys and 1.26 kgf for girls. Conclusions: FMI was associated with lower GS regardless of the LBM. LBM was associated with higher GS regardless of the FMI.

Body phenotypes and sexual maturation in Brazilian and US adolescents: evidence for a change in BMI category

OBJECTIVE

Our study aimed to describe body phenotypes (BP) estimated by multivariate analysis and their association with body mass.

DESIGN

BP were defined based on demographic variables, anthropometric data (body mass, height, skinfolds and circumferences), body composition (phase angle measured by bioelectrical impedance analysis), biochemical parameters (TAG, glucose, total cholesterol ratio/LDL, Hb and sexual maturation (pubic hair and breasts or gonads). ANOVA was performed to verify the differences between skin colour and the stages of pubertal development, BP, body composition, anthropometric and biochemical variables.

SETTING

Cities of São Paulo-SP, Piracicaba-SP and Florianópolis-SC from Brazil and the United States.

PARTICIPANTS

9269 adolescents aged between 10 and 15 years old.

RESULTS

The composition of BP was similar in all surveys, which are: BP1 was composed by skinfolds, body mass and circumferences variables; BP2 by pubic hair, breast in girls or gonad in boys, height and age; BP3 by cholesterol, TAG and glucose; and BP4 by phase angle, Hb and glucose (negative loading). There was a strong correlation (r = 0·9, P < 0·001) between BP1 and BMI.

CONCLUSION

We highlighted independence observed between biochemical parameters, anthropometry, body composition and sexual maturation. BP may support the calculation of scores for diagnosis of obesity based on anthropometric variables and overcome ambiguity in the isolated use of BMI.

[Body phenotypes in adolescence and sexual maturation]

The study aims to describe body phenotypes estimated by multivariate technique for the assessment of nutritional status in adolescence during the process of sexual maturation. The sample consisted of 833 schoolchildren 10 to 15 years of age, selected by complex sampling in Piracicaba, São Paulo State, Brazil. Body phenotypes were defined by principal components analysis (PCA) based on anthropometric data (body mass, height, skinfolds, and waist circumference), body composition (phase angle measurement by bioelectric impedance), biochemical parameters (triglycerides, glucose, total/LDL cholesterol ratio, hemoglobin), and sexual maturation (self-classification of stages of pubic hair and breasts or genitals). Body phenotypes were: P1adiposity, characterized by a positive association with the variables skinfolds, body mass, and waist circumference; P2puberty, characterized by positive association with stages of pubic hair and breasts in girls or genitals in boys, height, and age; P3biochemical, characterized by positive association with cholesterol, triglycerides, and glucose; and P4muscular, characterized by positive association with phase angle and hemoglobin and negative association with glucose. Only P1adiposity showed a strong association with body mass index, and there was independence between P1adiposity and P2puberty. Our results highlight the independence between biochemical parameters, anthropometry, body composition, and sexual maturation. Body phenotypes can provide the basis for calculating scores on likelihood of obesity based on anthropometric variables and overcoming ambiguity with the use of body mass.

NÍVEIS DE ATIVIDADE FÍSICA: UM ESTUDO COMPARATIVO ENTRE ADOLESCENTES SURDOS E OUVINTES

RESUMO Introdução: A Organização Mundial da Saúde tem alertado para o crescente quadro de sedentarismo e suas consequências entre as populações. A inatividade física passou a ser o quarto principal fator de risco de saúde, tornando-se um dos maiores problemas de saúde pública na atualidade. Populações como adolescentes surdos brasileiros têm sido negligenciadas com ausência de inquéritos de saúde voltados à investigação dessa variável e proposições de estratégias que garantam equiparação de oportunidades. Objetivo: Assim, este estudo teve por objetivo verificar o nível de atividade física entre adolescentes surdos comparados a adolescentes ouvintes. Métodos: O grupo de adolescentes ouvintes mostrou-se significativamente mais ativo que os adolescentes surdos (61,29% para 29,03% com p &lt; 0,05). Resultados: O resultado da presente pesquisa evidencia que há necessidade de investigações sobre as realidades em que se desenvolvem os programas e ações voltados ao esporte para adolescentes surdos. Conclusões: É imprescindível buscar as causas e propor soluções junto a órgãos gestores e secretarias ligadas ao esporte, saúde e educação para a diminuição do índice encontrado, proporcionando equiparação de oportunidades entre surdos e ouvintes.

[Arterial hypertension among adolescents in Rio de Janeiro: prevalence and association with physical activity and obesity]

The scope of this study was to identify the prevalence of systemic arterial hypertension among adolescent students (aged 17-19 years) in the third and final year of high school in state schools in the municipality of Rio de Janeiro, and to investigate associations between systemic arterial hypertension and obesity and physical activity levels. Data on arterial pressure, body mass index and physical activity were gathered. The analysis included 854 individuals. Descriptive statistical analysis was applied to the sample, along with a Poisson regression model to determine the impact of the variables on the prevalence of systemic arterial hypertension. The prevalence of systemic arterial hypertension was 19.4%. Male sex, overweight and obesity presented significant positive associations with systemic arterial hypertension (p < 0.05), while physical activity was not shown to be significantly associated with systemic arterial hypertension (p > 0.05). The nature of these relationships should be interpreted in the light of reflection and not of passive labeling based on hegemonic concepts.

[Blood pressure and its association with physical activity and obesity in adolescents: a systematic review]

In the light of the importance of the impacts that obesity and physical activity may have on blood pressure (BP) among adolescents, and the suggestion that abnormal pressure levels at young ages are maintained into more mature stages of these individuals' lives, the scope of this study is to conduct a systematic review of the associations between obesity and BP and between physical activity and BP among adolescents. The PubMed database was consulted to search for scientific articles relating to this topic and, after applying the appropriate inclusion and exclusion criteria, 30 articles were selected and analyzed. To assess the quality of articles Strengthening the Reporting of Observational Studies in Epidemiology was applied. The results suggest that despite the existence of hegemonic thinking to guide these relationships, BP and physical activity do not always have negative associations, and BP and obesity do not always have positive associations. The conclusion reached is that this situation illustrates the need for more in-depth reflection on these relationships before pre-established paradigms are passively accepted.

Epidemiology of physical inactivity, sedentary behaviors, and unhealthy eating habits among brazilian adolescents

This systematic review analyzed the prevalence of physical inactivity, sedentary behaviors and unhealthy eating habits among Brazilian adolescents. Searches were conducted in five databases (Lilacs, SciELO, Medline, Web of Science, and Google Scholar) and in the references cited in the articles retrieved. The literature search yielded 5,872 potentially relevant titles and a total of 69 studies met all the inclusion criteria. The risk behavior most often evaluated was physical inactivity (48/69; 69.6%), and its prevalence rate ranged from 2.3% to 93.5%. Twenty-eight studies estimated the prevalence of physical inactivity at over 50%. Most studies observed the prevalence of greater physical inactivity among girls. The prevalence of sedentary behaviors (lengthy screen time or TV use) was also frequently over 50%. Several variables were used to identify unhealthy eating habits, and some criteria/studies have indicated unhealthy eating habit estimates at close to 100% among adolescents. In conclusion, the estimates of these risk behaviors among Brazilians adolescents were very close to or even greater than those found in developed countries in several studies analyzed in this review.

Excesso de peso e consumo alimentar em adolescentes de escolas públicas no norte de Minas Gerais, Brasil

Este estudo objetivou identificar a prevalência excesso de peso e o consumo alimentar entre adolescentes de rede pública de ensino ao norte de Minas Gerais. Desenvolveu-se estudo transversal com amostra aleatória e representativa de adolescentes. Foram coletadas informações demográficas e econômicas. O consumo alimentar foi avaliado pela aplicação de questionário semiquantitativo. Aferiu-se peso e altura para avaliação do estado nutricional com base no Índice de Massa Corporal (IMC) por Idade. A comparação entre os gêneros foi conduzida por meio do teste t de Student (médias) ou qui-quadrado (proporções), assumindo-se um nível de significância de p < 0,05. Foram avaliados 535 adolescentes e registrada uma prevalência de excesso de peso para 18,5%. Houve diferença significativa entre os gêneros para o IMC (p = 0,001), maior entre as meninas. O consumo médio de energia foi de 3.096,30kcal/dia. Observou-se consumo insuficiente de fibras em 35% dos adolescentes, de cálcio e vitamina A em 80% e gorduras insaturadas em 100%. Carboidratos e colesterol eram consumidos em excesso por 20,6% e 48%, respectivamente. A prevalência do excesso de peso e o consumo alimentar inadequado mostrou-se preocupante para a população estudada e demandam adequada intervenção nutricional.

Meta-analysis of the prevalence of physical inactivity among Brazilian adolescents

A systematic review and meta-analysis were carried out to investigate the prevalence of physical inactivity among adolescents in Brazil. We identified articles that had been published up to August 2010 and the search was conducted using six electronic databases. We did not enforce any search limitations. Forest plot-type graphs were generated using the prevalence of physical inactivity stratified by region and sex. Meta-regression models were fitted to identify possible sources of heterogeneity in the prevalence estimates. Of the 1,496 articles initially identified, 37 were deemed appropriate for the systematic review. Prevalence rates ranged from 2% to 80% for male and from 14% to 91% for female subgroups. The lowest prevalence rates of physical inactivity were found to be for the Southern region, whereas the highest rates were observed in the North-Northeast. The methods employed to evaluate physical inactivity in Brazilian adolescents also differed among the studies. This variation demonstrates the need for standardised and validated methods of measuring physical activity in epidemiological investigation.

Impacto de variáveis antropométricas sobre a insatisfação corporal e o comportamento alimentar em jovens atletas

OBJETIVO: Identificar a influência de variáveis antropométricas sobre a insatisfação corporal (IC) e o comportamento alimentar inadequado (CAI) em atletas adolescentes competitivos. MÉTODOS: Participaram 580 jovens (464 meninos e 116 meninas) com idades entre 10 e 19 anos, de ambos os sexos. Aplicou-se o Body Shape Questionnaire para mensurar a IC. Utilizou-se o Eating Attitudes Test para avaliar CAI. Foram aferidas dobras cutâneas para estimar o percentual de gordura (%G). Mensuraram-se peso e estatura para calcular o IMC. RESULTADOS: Os resultados evidenciaram que a IC no sexo feminino foi modulada apenas pelo %G, ao contrário do sexo masculino, em que IMC e %G, juntos, explicaram parte de sua variância (p < 0,05). O CAI no sexo masculino foi pouco influenciado pelo %G. CONCLUSÃO: Pode-se concluir que o %G foi a única variável que influenciou a IC em ambos os sexos. Ademais, os CAI em jovens atletas parecem não ser influenciados pelas características antropométricas mensuradas neste estudo.