Objective: To investigate determinants of physical inactivity among adolescents aged 15 to 19 years in the city of Recife, northeastern Brazil.Method: This case-control study involved 597 private school students aged 15 to 19 years selected by convenience sampling. Exclusion criteria were adolescents with diseases that interfered with or hindered anthropometric measurements, who were being treated with drugs or diet for excess weight or who had changed their physical activity over the past 30 days. The students were recruited according to physical activity, as determined by the International Physical Activity Questionnaire: cases -inactive (sedentary or insufficiently active); and controls -active (active and very active). The adolescents reported the number of hours per day of television watching and computer use to identify the number of sedentary hours/day. Anthropometry (weight and height) of the adolescents was measured by Gibson's technique and used to calculate the body mass index. Weight, height and educational level of mothers were self-reported. Data were analyzed by multiple logistic regression, using the SPSS software, version 11.5, in order to control for confounding variables.Results: Female adolescents were twice as likely to be inactive (odds ratio = 1.94; 95% confidence interval = 1.35-2.79) compared to male adolescents. Watching television for more than 1 hour/day showed increased risk for physical inactivity compared to less than 1 hour/day (odds ratio = 1.55; 95% confidence interval = 1.01-2.39).
Conclusion:Physical inactivity among adolescents was associated with females and longer time spent per day watching television.J Pediatr (Rio J). 2010;86(6):520-524: Physical activity, risk factors, overweight, television, case-control studies, adolescents.
ResumoObjetivo: Investigar fatores determinantes da inatividade física entre adolescentes de 15 a 19 anos na cidade do Recife (PE).
Método:O estudo foi caso-controle, envolvendo 597 adolescentes de 15 a 19 anos, estudantes de escolas particulares, selecionadas por conveniência. Os critérios de exclusão foram adolescentes com doenças que interferissem ou impossibilitassem a avaliação antropométrica, que estavam em tratamento medicamentoso ou dietético para sobrepeso ou que haviam modificado sua atividade física nos últimos 30 dias. Eles foram recrutados de acordo com a atividade física, determinada pelo International Physical Activity Questionnaire: casos -inativos (sedentários e insuficientemente ativos); e controles -ativos (ativos e muito ativos). Os adolescentes informaram quantas horas diárias assistiam televisão e usavam computador para identificar o número de horas sedentárias/dia. A antropometria (peso e estatura) dos adolescentes foi aferida pela técnica de Gibson; assim, foi calculado o índice de massa corporal. O peso, a estatura e a escolaridade das mães foram autorreferidos. Os dados foram analisados por análise múltipla de regressão logística, utilizando o programa SPSS, versão 11.5, objetivando controlar variáveis de confusão...