Psychosocial mediators and moderators of a school-based physical activity intervention among Brazilian adolescents.

School-based interventions are needed due to the low levels of physical activity (PA) in adolescents. The aim is to examine the mediation effects of psychosocial factors (attitude, self-efficacy, social support from parents, friends, general teachers, and PE teachers, and environment school perception) and moderation by sex, school grade, and socioeconomic level of a school-based PA intervention on the PA practice among adolescents. The Movimente Programme is a randomised controlled trial at schools in southern Brazil (n = 921 adolescents). Strategies included teacher training, educational actions, and environmental changes. Adolescents self-reported their weekly PA. Potential psychosocial mediators and moderators were investigated through validated questionnaires in a Brazilian sample. The product of the coefficients with percentile bootstrapping 95% confidence interval was performed. The Movimente Programme was related to positive changes in adolescents' perception of the school environment and social support from general and physical education teachers. Most psychosocial variables (attitude, self-efficacy, social support from friends, and social support from teachers) were associated with PA, but none mediated the impact of the Movimente Programme on PA. Results varied according to sex and school grade. The Movimente Programme increased the adolescents' perception of the school environment and social support from teachers, but no mediators were confirmed.

Relação entre somatório de dobras cutâneas e pressão arterial sistêmica em adolescentes / Relation between sum of skinfolds and systemic blood pressure in adolescents / Relación del total de pliegues cutáneos y presión arterial sistémica de adolescentes

Relacionar o somatório de dobras cutâneas com a pressão arterial sistêmica em adolescentes da rede pública. Métodos: Estudo transversal realizado com 543 adolescentes da rede pública de ensino de Curitiba-PR-Brasil, com idade entre 11 e 17 anos e independente do sexo, no período de agosto de 2010 a junho de 2011. Mediu-se peso corporal, estatura e dobras cutâneas (triciptal, subescapular, suprailiaca, abdominal e panturrilha). Mensurou-se a pressão arterial sistólica (PAS) e diastólica (PAD) através do método auscultatório, em duplicata. Realizou-se uma nova avaliação no dia posterior à primeira coleta nos adolescentes identificados com pré-hipertensão ou hipertensão. Utilizou-se a correlação parcial como medida de associação entre as variáveis, considerando estatura e idade como variáveis de controle. As análises foram estratificadas por sexo e o nível de significância foi de 5%. Resultados: Entre adolescentes do sexo masculino, o somatório de dobras cutâneas teve uma correlação com a PAS e a PAD de 0,18 (p<0,01) e 0,14 (p<0,05), respectivamente. Entre adolescentes do sexo feminino, a correlação do somatório de dobras cutâneas com a PAS e PAD foi de 0,15 (p<0,01) e 0,19 (p<0,01), respectivamente. Da amostra total, 9,2% (n=50) foram considerados pré-hipertensos e 7,6% (n=41) hipertensos. Conclusão: O somatório de dobras cutâneas apresentou relação direta com pressão arterial sistêmica nos adolescentes investigados...

To relate the sum of skinfolds to systemic blood pressure in adolescents attending public schools. Methods: Cross-sectional study conducted with 543 adolescents from public schools of Curitiba-PR-Brazil, aged between 11 and 17 years, regardless of sex, in the period from August 2010 to June 2011. Body weight, height and skinfolds (triceps, subscapular, suprailiac, abdominal and calf) were measured. Systolic (SBP) and diastolic (DBP) blood pressure were determined by duplicate auscultatory method. A new evaluation was performed the day after the first collection in adolescents identified with pre-hypertension or hypertension. Partial correlation was used as a measure of association between variables, considering height and age as control variables. Analyses were stratified by sex and the level of significance was set at 5%. Results: Among male adolescents, the sum of skinfolds presented a correlation to SBP and DBP of 0.18 (p<0.01) and 0.14 (p<0.05), respectively. Among female adolescents, the correlation of the sum of skinfolds to SBP and DBP was 0.15 (p <0.01) and 0.19 (p <0.01), respectively. Of the total sample, 9.2% (n=50) were prehypertensive and 7.6% (n=41) were hypertensive. Conclusion: the sum of skinfolds were directly related to the systemic blood pressure of the adolescents assessed...

Relacionar el total de pliegues cutáneos y la presión arterial sistémica de adolescentes de la red pública. Métodos: Estudio transversal realizado con 543 adolescentes de la red pública de enseñanza de Curitiba-PR-Brasil, con edad entre los 11 y 17 años y independiente del sexo en el período entre agosto de 2010 y junio de 2011. Se medio el peso corporal, la estatura y los pliegues cutáneos (triciptal, subescapular, suprailíaco, abdominal y pantorrilla). Se mensuro dos veces la presiónarterial sistólica (PAS) y diastólica (PAD) a través del método auscultatorio. Se realizó una nueva evaluación el día después de la primera en los adolescentes identificados con pre-hipertensión o hipertensión elevada. Se utilizó la correlación parcial como medida de asociación de variables, considerando estatura y edad como variables control. Los análisis fueron estratificados por sexo y el nivel de significación fue del 5%. Resultados: El total de pliegues cutáneos entre los adolescentes del sexo masculino se correlacionó con la PAS y la PAD en 0,18 (p<0,01) y 0,14 (p<0,05), respectivamente. La correlación del total de pliegues cutáneos com la PAS y PAD de los adolescentes del sexo femenino fue de 0,15 (p<0,01) e 0,19 (p<0,01), respectivamente. De toda la muestra, el 9,2% (n=50) fueron considerados pre-hipertensos y el 7,6% (n=41) hipertensos. Conclusión: El total de pliegues cutâneos presentó relación directa con la presión arterial sistémica de los adolescentes investigados...