Prediction of cardiorrespiratory fitness by screen time in schoolchildrens / Predição de aptidão cardiorrespiratória por meio do tempo tela em escolares

ABSTRACT The time spent in front of the screens, results in accumulations of sedentary behavior, which is related to health damages to adolescents, such as a low cardiorespiratory fitness. In this sense, this study aimed to predict cardiorespiratory fitness through screen time in schoolchildren. Cross-sectional study, as a sample composed of 2.764, of which 1.370 boys and 1.394 girls between 10 and 18 years old were the public school system of Paranavaí, Paraná, Brazil The self-report questionnaire was used to estimate screen time (ST) and cardiorespiratory fitness (CF) was estimated using the 20-meter multi-stage test, and to verify the predictive power of the screen time in relation to CF, the Roc curve was used. The results showed that screen time was considered a good predictor of cardiorespiratory fitness in boys (weekdays, weekends and all week), and in general (boys and girls) only for weekdays (Monday to Friday). In the survey, the screen time cut-off for boys on weekdays was 137 minutes (CI: 65-43), at weekends of 165 minutes (58-51) and general of 156 minutes (64-45). For the general sample (girls and boys), the cut bridge on weekdays was 142 minytes (64-44). For the girls the screen time had no predictive power (CI> 0.50) and consequently the cut-off point was not verified. Thus, it can be concluded that the screen time in boys and in general (only weekdays) was able to predict cardiorespiratory fitness and that this variable of easy application can be an important tool to predict CF in the school environment.

RESUMO O tempo gasto em frente à telas, resulta em acúmulo de comportamento sedentário, o qual está relacionado com malefícios a saúde dos adolescentes, tais como uma baixa aptidão cardiorrespiratória. Nesse sentido esse estudo teve por objetico predizer a aptidão cardiorrespiratória por meio do tempo de tela em escolares. Estudo transversal, como amostra composta por 2.764, sendo 1.370 meninos e 1.394 meninas entre 10 e 18 anos rede pública de ensino de Paranavaí, Paraná. O questionário de autorrelato foi utilizados para estimar o de tempo de tela (TL), e a aptidão cardiorrespiratória (ACR) foi estimada por meio do teste de 20 metros multiestágios. Para verificar o poder preditivo do tempo de tela em relação a ACR, a Curva Roc foi utilizada. Os resultados mostraram que o tempo de tela foi considerado um bom preditor de aptidão cardiorrespiratória em meninos (dias de semana, fins de semana e semana toda), e de modo geral (meninos e meninas) apenas para os dias de semana. Na pesquisa, o ponte de corte de tempo de tela para meninos em dias de semana foi de 137 minutos (IC: 65-43), nos fins de semana de 165 minutos (58-51) e geral de 156 minutos (64-45). Já para a amostra geral (meninas e meninos) o ponte de corte nos dias de semana foi de 142 minutos (64-44). Para as meninas o tempo de tela não teve poder preditivo (IC > 0,50) e consequentemente não foi verificado o ponto de corte. Desse modo, conclui-se que o tempo de tela em meninos e de maneira geral (apenas nos dias de semana) foi capaz de predizer a aptidão cardiorrespiratória e que essa variável de fácil aplicação pode ser um instrumento importante para predizer a ACR no ambiente escolar.

Body mass index, waist circumference, and arterial hypertension in students.

OBJECTIVE: to investigate what is the best anthropometric predictor of arterial hypertension among private school students. METHOD: this was a cross-sectional study with 286 students between the ages of 10 and 14 from two private schools in the city of Paranavaí, Paraná, Brazil. The following variables were analyzed: body mass index, waist circumference and blood pressure. Statistical analysis was conducted with Pearson's partial correlation test and multivariate logistic regression, with p<0.05. RESULTS: both anthropometric indicators displayed weak correlation with systolic and diastolic levels, with coefficients (r) ranging from 0.27 to 0.36 (p < 0.001). Multivariate analysis showed that the only anthropometric indicator associated with arterial hypertension was waist circumference (OR= 2.3; 95% CI: 1.1-4.5), regardless of age or gender. CONCLUSION: this age group, waist circumference appeared to be a better predictor for arterial hypertension than body mass index.

Índice de massa corporal, circunferência da cintura e hipertensão arterial em estudantes / Índice de masa corporal, circunferencia de la cintura y hipertensión arterial en estudiantes / Body mass index, waist circumference, and arterial hypertension in students

RESUMO Objetivo: investigar qual o melhor preditor antropométrico de hipertensão arterial em alunos de escolas privadas. Método: estudo transversal, com amostra composta por 286 alunos com idade de 10 a 14 anos de duas escolas privadas de Paranavaí-Paraná. As variáveis analisadas foram: índice de massa corporal, circunferência de cintura e pressão arterial. Na análise estatística foram utilizados os testes de correlação parcial de Pearson e a regressão logística multivariada, considerando-se p<0,05. Resultados: os dois indicadores antropométricos demonstraram fracas correlações com os níveis sistólicos e diastólicos, com coeficientes (r) variando de 0,27 à 0,36 (p< 0,001). Na análise multivariada, o único indicador antropométrico associado ao risco de hipertensão arterial foi a circunferência de cintura (OR= 2,3; IC 95%: 1,1-4,5) independente da idade e gênero. Conclusão: nesta faixa etária, a circunferência de cintura parece ser melhor do que índice de massa corporal como preditor de hipertensão arterial. .

RESUMEN Objetivo: investigar cuál es el mejor predictor antropométrico de la hipertensión arterial en los alumnos de escuelas particulares. Métodos: estudio transversal con muestra compuestas por 286 alumnos con edad de 10 a 14 años de dos escuelas privadas de Paranavaí-Paraná. Las variables analizadas fueron: índice de masa corporal, circunferencia de la cintura y la presión arterial sistólica y diastólica. En el análisis de estadísticas fueron utilizadas las pruebas de correlación parcial de pearson y regresión logística multivariada considerándose p<0.05. Resultados: los dos indicadores antropométricos han mostrado débiles correlaciones con los niveles sistólicos y diastólicos, con Coeficientes (r) variando de 0,27 a 0,36 (p<0,001). En el análisis multivariado el único indicador antropométrico asociado al riesgo de hipertensión arterial fue la circunferencia de la cintura (OR=2,3; IC 95%: 1,1- 4,5) independiente de la edad y el género. Conclusión: en este grupo de edad, la circunferencia de la cintura parece ser mejor de que el índice de masa corporal como predictor de la hipertensión arterial. .

ABSTRACT Objective: to investigate what is the best anthropometric predictor of arterial hypertension among private school students. Method: this was a cross-sectional study with 286 students between the ages of 10 and 14 from two private schools in the city of Paranavaí, Paraná, Brazil. The following variables were analyzed: body mass index, waist circumference and blood pressure. Statistical analysis was conducted with Pearson’s partial correlation test and multivariate logistic regression, with p<0.05. Results: both anthropometric indicators displayed weak correlation with systolic and diastolic levels, with coeffi cients (r) ranging from 0.27 to 0.36 (p < 0.001). Multivariate analysis showed that the only anthropometric indicator associated with arterial hypertension was waist circumference (OR= 2.3; 95% CI: 1.1-4.5), regardless of age or gender. Conclusion: this age group, waist circumference appeared to be a better predictor for arterial hypertension than body mass index. .

Physical inactivity and anthropometric measures in schoolchildren from Paranavaí, Paraná, Brazil / Inatividade física e medidas antropométricas em escolares de Paranavaí, Paraná, Brasil

OBJECTIVE: To investigate the association between physical inactivity and anthropometric measures in schoolchildren from Paranavaí-Parana, Brazil. METHODS: Cross-sectional survey, carried out in July and August 2013. Sample of 566 students (287 boys and 279 girls) from 6th to 9th grade, aged 10 to 14 years, from public and private schools of Paranavaí - PR, Southern Brazil. The variables analyzed were: time of weekly physical activity through a questionnaire (physical inactivity <300 minutes/week), body mass index (BMI) and waist circumference (WC). In the statistical analysis, the U Mann-Whitney and Student's t tests were used for comparison between genders. To identify factors associated with insufficient levels of physical activity, univariate and multivariate logistic regression analysis was applied and expressed in Odds ratio (OR) and 95% confidence interval (95%CI). RESULTS: There was an association between physical inactivity and anthropometric measurements for BMI (p<0.001) and WC (p<0.001), with a prevalence rate of 56.1% and 52.7% of inactive adolescents, respectively. In the multivariate analysis, there was significant association of physical inactivity and overweight (OR 1.8, 95%CI: 1.1-3.0) and with increased waist circumference (OR 2.8, 95%CI: 1.4-3.8). CONCLUSIONS: Inadequate levels of physical activity is a determining factor for overweight and abdominal adiposity. Accordingly, preventive measures should be taken, especially in schools, emphasizing the importance of exercise for body composition control and weight reduction. .

OBJETIVO: Investigar a associação entre a inatividade física e medidas antropométricas em escolares de Paranavaí, Paraná, Brasil. MÉTODOS: Pesquisa com delineamento transversal, feita em julho e agosto de 2013. Amostra composta por 566 escolares (287 meninos e 278 meninas), de 10 a 14 anos, do 6° ao 9° ano da rede pública e privada de Paranavaí (PR). As variáveis analisadas foram: tempo de atividade física semanal, por meio de questionário (inatividade física: < 300 min/semanal), índice de massa corporal (IMC) e circunferência de cintura (CC). Na análise estatística foram usados os testes U de Mann-Whitney e t de Student para comparar os sexos. Para verificar os fatores associados ao nível insuficiente de atividade física aplicou-se o modelo de regressão logística binária univariada e multivariada, expressa em odds ratio (OR), e intervalo de confiança de 95% (IC95%). RESULTADOS: Houve associação entre inatividade física e as medidas antropométricas para IMC (p<0,001) e CC (p<0,001), com prevalências de 56,1% e 52,7% de inativos, respectivamente. Na análise multivariada, foram observadas associações significativas de inatividade física nos alunos que apresentaram excesso de peso (OR 1,8; IC95%: 1,1-3,0) e circunferência de cintura aumentada (OR 2,2; IC95%: 1,4-3,8). CONCLUSÕES: Nível inadequado de atividade física é fator determinante no excesso de peso e na adiposidade abdominal. Nesse sentido, medidas preventivas devem ser tomadas, principalmente nas escolas, e enfatizar-se a importância do exercício físico no controle da composição corporal e redução do pesoe. .

[Physical inactivity and anthropometric measures in school children from Paranavaí, Paraná, Brazil]. / Inatividade física e medidas antropométricas em escolares de Paranavaí, Paraná, Brasil.

OBJECTIVE: To investigate the association between physical inactivity and anthropometric measurements in school children from Paranavaí-Paraná, Brazil. METHODS: Cross-sectional survey, conducted in July and August 2013. Sample of 566 students (287 boys and 278 girls) from 6th to 9th grade aged 10 to 14 years of public and private schools from Paranavaí-PR, Southern Brazil. The variables analyzed were: time of weekly physical activity by a questionnaire (physical inactivity <300 minutes/week), body mass index (BMI) and waist circumference (WC). In the statistical analysis the U Mann-Whitney and Student t test were used for comparison between genders. To identify factors associated with insufficient levels of physical activity, univariate and multivariate logistic regression analysis was applied and expressed in Odds ratio (OR) and 95% confidence interval (CI). RESULTS: There was an association between physical inactivity and anthropometric measurements for BMI (p<0.001) and WC (p<0.001), with a prevalence rate of 56.1% and 52.7% of inactive adolescents, respectively. In the multivariate analysis, there was significant association of physical inactivity and overweight (OR 1.8, 95%CI: 1.1-3.0) and with increased waist circumference (OR 2.8, 95%CI: 1.4-3.8). CONCLUSIONS: Inadequate levels of physical activity is a determining factor for overweight and abdominal adiposity. Accordingly, preventive measures should be taken, especially in schools, emphasizing the importance of exercise in the control of body composition and reduction of weight.

Hypertriglyceridemic waist and metabolic abnormalities in Brazilian schoolchildren.

OBJECTIVE: To identify the prevalence of hypertriglyceridemic waist (HTW) phenotype and its association with metabolic abnormalities in schoolchildren. METHODS: A cross-sectional study, with a sample of 241 students aged 10 to 14 years from public schools (4 schools) and private (2 schools) from Paranavai town, in Parana State, Brazil. Anthropometric variables (weight, height, waist circumference) and levels of triglycerides, total cholesterol, HDL-C, non-HDL and LDL-C were analyzed. In statistical tests of Pearson partial correlation and multivariate logistic regression, considering p<0,05. RESULTS: The prevalence of HTW was 20,7% among schoolchildren, 14,1% in males and 6,6% among females with higher proportions aged 10-12 years old. Multivariate analysis indicated that the students who attended private schools were nearly three times more likely (95% CI: 1,2-5,6), to be diagnosed with HTW compared with those who attended public schools (p = 0,006), and LDL-C was the only metabolic variable positively associated with the outcome (p = 0,001), where the students categorized with elevated serum levels had odds 4,2 times (95% CI: 1,6-10,9) having the HTW compared to students in appropriate levels. CONCLUSION: This study showed higher prevalence of hypertriglyceridemic waist phenotype in students when compared to prospective studies in Brazil and worldwide. It also showed that the only metabolic alteration associated with HTW phenotype was LDL-C (low density lipoprotein).