Trends in screen time on week and weekend days in a representative sample of Southern Brazil students.

BACKGROUND: Economic and technological improvements can help increase screen time use among adolescents, but evidence in developing countries is scarce. The aim of this study was to examine changes in TV watching and computer/video game use patterns on week and weekend days after a decade (2001 and 2011), among students in Santa Catarina, southern Brazil. METHODS: A comparative analysis of two cross-sectional surveys that included 5 028 and 6 529 students in 2001 and 2011, respectively, aged 15-19 years. The screen time use indicators were self-reported. 95% Confidence intervals were used to compare the prevalence rates. All analyses were separated by gender. RESULTS: After a decade, there was a significant increase in computer/video game use. Inversely, a significant reduction in TV watching was observed, with a similar magnitude to the change in computer/video game use. The worst trends were identified on weekend days. CONCLUSIONS: The decrease in TV watching after a decade appears to be compensated by the increase in computer/video game use, both in boys and girls. Interventions are needed to reduce the negative impact of technological improvements in the lifestyles of young people, especially on weekend days.

Factors associated with active commuting to school and to work among Brazilian adolescents.

BACKGROUND: Active commuting has decreased substantially in recent decades and has been more frequent in specific demographic and socioeconomic profiles. The objective of this study was to describe the prevalence of active trips and the possible associations with demographic and socioeconomic variables. METHODS: A questionnaire on lifestyle and risk behavior was administered to a sample population of 5028 adolescents, ages 15 to 19 years, attending public high schools in the state of Santa Catarina, Brazil. Logistic regressions (odds ratio--OR; 95% confidence interval) were used to test associations. RESULTS: Active commuting to school was reported for 56.7% of students, and active commuting to work was reported for 70.0%. The likelihood of commuting passively was greater among girls (school: OR = 1.27; 1.10-1.45), older adolescents (school: OR = 1.17; 1.02-1.33; work: OR = 1.49; 1.22-1.82), those who lived in rural areas (school: OR = 12.1; 9.91-14.8), those who spent more time in commuting (school: OR = 2.33; 2.01-2.69; work: OR = 4.35; 3.52-5.38), and those from high-income families (school: OR = 1.40; 1.21-1.62; work: OR = 1.69; 1.37-2.08). CONCLUSIONS: The proportion of students taking active trips was higher when going to work than to school. All indicators were associated with the mode of commuting, except gender and place of residence for commuting to work.

Active commuting: prevalence, barriers, and associated variables.

BACKGROUND: Research has demonstrated that adolescents who actively commute have higher levels of physical activity (PA), which have declined precipitously over the past 30 years. The purpose of this study was to describe the prevalence of active commuting to school; and to identify barriers associated with active commuting. METHODS: A cross-sectional study was conducted with 1672 students (46.8% boys and 53.2% girls) from 11 to 17 years of age in Caxias do Sul/RS, Brazil. The students were asked to answer questionnaires about active transport, PA, and sedentary behaviors. They also completed a cardiovascular fitness test and body composition measurements. The study used a multivariate Poisson regression analysis. RESULTS: A total of 62.5% of students were observed to actively commute and the prevalence ratio (PR) of not actively commuting was associated with the type of school (Private: 2.41; 1.47, 3.95) and the time spent on commuting (>20 min: 1.93; 1.23, 3.03). The associated barriers to passive commuting were distance (3.02; 1.95, 4.71), crime/danger (2.65; 1.82, 3.85), and traffic (1.75; 1.19, 2.58). CONCLUSIONS: This study showed that environmental variables were strongly associated with active commuting. However, no alterations in body composition or other behavioral variables were observed after adjustment.

Determinação do estado nutricional de adolescentes por meio de medidas referidas de peso e estatura: um estudo de validação / Determination of the nutritional status of adolescents through self-reported weight and height: a validation study

Este estudo verificou a validade de medidas referidas de peso e estatura para a determina-ção do estado nutricional de adolescentes. Participaram do estudo 641 escolares do ensino médio da cidade de Londrina-PR que referiram suas medidas de peso e estatura, e, em seguida, foram pesados em uma balança digital e medidos em um estadiômetro. O índice de massa corporal (IMC) foi calculado e o estado nutricional foi determinado. Em média, o IMC obtido a partir das medidas referidas foi subestimado em ambos os sexos, sendo o grau de subestimação maior nas meninas comparadas aos meninos (0,44 e 0,24 kg/m2). Houve tendência de maior subestimação do IMC entre escolares com excesso de peso (P<0,001). Um terço das meninas com excesso de peso não foram classificadas como tal pelas medidas referidas. A prevalência de excesso de peso a partir das medidas referidas foi subestimada no sexo feminino em 2,5 pontos percentuais (10,9 vs 8,4; P<0,05). Conclui-se que medidas referidas de peso e estatura subestimam o IMC de adolescentes, podendo levar a um incorreto diagnóstico do estado nutricional, principalmente em adolescentes do sexo feminino e/ou com excesso de peso corporal.

This study verified the validity of self-reported weight and height to determine the nutritional status of adolescents. A total of 641 students from high schools of Londrina-PR self reported their weight and height and, thereafter, had these variables measured with a digital scale and a stadiometer. The body mass index (BMI) was calculated from both self reported and measured weight and height and the nutritional status was determined. On average, the IMC obtained from self-reported measures was underestimated in both sexes, with a higher degree of underestimation in girls compared with boys (0.44 and 0.24kg/m2). There was a trend for stronger underestimation of BMI among those at risk of overweight (P<0.001). One third of girls at risk of overweight were misclassified from the self reported measures. The prevalence of girls at risk of overweight was underestimated in 2.5 percentage points (10.9 versus 8.4; p< 0.05). It was concluded that self reported measures of weight and height underestimate the BMI of adolescents, and misclassification of nutritional status is a concern, mainly in female and/or those at risk of overweight.

Undernutrition and obesity associated with high blood pressure in children and adolescents from João Pessoa, Paraíba, Brazil.

The objective of this study was to describe the prevalence, correlation, and association of undernutrition and obesity with high blood pressure (HBP). One thousand five hundred seventy (1570) students (808 boys and 762 girls), aged 7-12 years, from João Pessoa, Paraíba (Northeastern Brazil) participated. Measurements of stature, body weight, skinfolds [triceps (TS) and subscapular (SS)], upper-arm circumference (UAC), upper-arm fat area (UAFE), total upper-arm area (TUAA), and BP were taken. Four criteria were adopted to classify undernutrition and obesity. HBP was defined as systolic BP (SBP) and/or diastolic BP (DBP) values >or=90th percentile. Analysis of covariance, Spearman's correlation, logistic regression, and multiple linear regression were used. In the logistic regression model, undernutrition was not associated with HBP; however, the chances of HBP increased when two or more obesity indicators were present [boys: odds ratio (OR) = 2.08, 95% confidence interval (CI 95%) = 1.26-3.41; girls: OR = 2.26, CI 95% = 1.44-3.55]. In the multiple regression, the BMI, SS, and UAFE explained 15% of the variance of high SBP (r (2) = 0.153) in boys, whereas the body mass index (BMI) and TUAA accounted for 16% of the variance of the SBP (r (2) = 0.166) in girls. The DBP was influenced by the SS in boys (r (2) = 0.022) and the TUAA (r ( 2 ) = 0.054) in girls. There was an association between obesity and HBP. The BMI, SS, and UAFE in boys and the BMI and TUAA in girls explained approximately 16% of elevated SBP.

Excess weight, arterial pressure and physical activity in commuting to school: correlations.

BACKGROUND: The prevalence of obesity and elevated arterial pressure (AP) has increased in children and adolescents, whereas physical activity has decreased. OBJECTIVE: To identify and correlate excess weight, body fat and elevated AP among active and passive students with the way they commute to school. METHODS: One thousand five hundred and seventy students aged 7 to 12 years participated in the study conducted in João Pessoa, state of Paraíba. Students completed a questionnaire about the way they commuted to school (active = walking/biking or passive = by car/motorcycle/bus) and the time spent traveling to school. Excess weight was determined by BMI > or =25 kg/m(2), excess body fat as > or =85th percentile for tricipital fold measurement, and high AP as > or =90th percentile. Chi-square test and Poisson's regression were used for the analysis. RESULTS: Active commuting was associated with a lower prevalence of excess weight and body fat as compared to passive commuting (p<0.05). The prevalence ratio (PR) of excess weight was associated with excess body fat (Male: PR= 6.45 95%CI= 4.55-9.14; Female: PR= 4.10 95%CI= 3.09-5.45), elevated SAP [Systolic Arterial Pressure] (Male: PR= 1.99 95%CI= 1.30-3.06; Female: PR= 2.09 95%CI= 1.45-3.01), and elevated DAP [Diastolic Arterial Pressure] in girls (PR = 1.96 95%CI= 1.41-2.75). No association with active commuting was observed (p>0.05) CONCLUSION: Passive commuting to school showed a correlation with excess weight and body fat but not with elevated AP. Excess weight was associated with excessive body fat and elevated AP. Excess weight should be prevented as a way to avoid fat accumulation and AP elevation.

Excesso de peso, pressão arterial e atividade física no deslocamento à escola / Excess weight, arterial pressure and physical activity in commuting to school: correlations

FUNDAMENTO: A prevalência de obesidade e pressão arterial (PA) tem aumentado em crianças e adolescentes, enquanto os domínios da atividade física declinaram. OBJETIVO: Identificar e associar o excesso de peso, de gordura corporal e de PA elevada entre os estudantes ativos e passivos no deslocamento à escola. MÉTODOS: Participaram do estudo 1.570 escolares de 7 a 12 anos de idade, de João Pessoa, PB. Os estudantes responderam a um questionário sobre a forma de deslocamento à escola (ativo = caminhada/bicicleta ou passivo = carro/moto/ônibus) e o tempo despendido. O excesso de peso foi determinado no IMC > 25 kg/m², a gordura no percentil > 85 da dobra tricipital e a PA elevada no percentil > 90. Na análise, utilizaram-se o teste qui-quadrado e a regressão de Poisson. RESULTADOS: O deslocamento ativo associou-se à menor prevalência de excesso de peso e de gordura, em relação ao passivo (p < 0,05). A razão de prevalência (RP) para o excesso de peso associou-se à gordura (masculino: RP = 6,45, IC95 por cento = 4,55-9,14; feminino: RP = 4,10, IC95 por cento= 3,09-5,45), à PAS elevada (masculino: RP = 1,99, IC95 por cento= 1,30-3,06; feminino: RP = 2,09, IC95 por cento= 1,45-3,01) e à PAD elevada nas meninas (RP = 1,96, IC95 por cento = 1,41-2,75). Não houve associação com o deslocamento ativo (p > 0,05) CONCLUSÃO: O deslocamento passivo à escola associou-se ao excesso de peso e gordura, e dissociou-se da PA elevada. O excesso de peso associou-se ao excesso de gordura e à PA elevada. É preciso prevenir o excesso de peso, como meio de evitar o acúmulo de gordura e o aumento da PA.

BACKGROUND: The prevalence of obesity and elevated arterial pressure (AP) has increased in children and adolescents, whereas physical activity has decreased. OBJECTIVE: To identify and correlate excess weight, body fat and elevated AP among active and passive students with the way they commute to school. METHODS: One thousand five hundred and seventy students aged 7 to 12 years participated in the study conducted in João Pessoa, state of Paraíba. Students completed a questionnaire about the way they commuted to school (active = walking/biking or passive = by car/motorcycle/bus) and the time spent traveling to school. Excess weight was determined by BMI > 25 kg/m², excess body fat as > 85th percentile for tricipital fold measurement, and high AP as >90th percentile. Chi-square test and Poisson's regression were used for the analysis. RESULTS: Active commuting was associated with a lower prevalence of excess weight and body fat as compared to passive commuting (p<0.05). The prevalence ratio (PR) of excess weight was associated with excess body fat (Male: PR= 6.45 95 percentCI= 4.55-9.14; Female: PR= 4.10 95 percentCI= 3.09-5.45), elevated SAP [Systolic Arterial Pressure] (Male: PR= 1.99 95 percentCI= 1.30-3.06; Female: PR= 2.09 95 percentCI= 1.45-3.01), and elevated DAP [Diastolic Arterial Pressure] in girls (PR = 1.96 95 percentCI= 1.41-2.75). No association with active commuting was observed (p>0.05) CONCLUSION: Passive commuting to school showed a correlation with excess weight and body fat but not with elevated AP. Excess weight was associated with excessive body fat and elevated AP. Excess weight should be prevented as a way to avoid fat accumulation and AP elevation.