Combined effect of physical activity and reduction of screen time for overweight prevention in adolescents

Abstract The main objective of this study was to identify the association between combined effect of physical activity, reduction of screen time and overweight in adolescents. The sample of this cross-sectional study consisted of 613 adolescents, aged 15-18 years living in a municipality in northeastern Brazil. Physical activity was measured using the short-version IPAQ (International Physical Activity Questionnaire), and screen time was verified through two questions about the time that, on average, interviewees watched television, played video games, used the cell phone or computer on a normal weekday and one weekend day. The predictive power and cutoff points of screen time and physical activity for the outcome of interest were identified using the Receiver Operating Characteristic (ROC) curves. Different logistic regression models were proposed, with excess weight as dependent variable. In all models, the combination of little physical activity and long screen time was used as reference. A 95% confidence interval (CI) was used. In boys, the combination of physical activity and short screen time on a weekend day was inversely associated with overweight (OR = 0.31; 0.12-0.85). The combined effect of physical activity and reduced time spent watching TV, computer screen and similar devices on a weekend day is inversely associated with overweight in boys.