Effect of a multicomponent intervention on variables related to screen time in adolescents: a cluster-randomized controlled trial
The aim of this study was to evaluate the effect of an intervention on screen time and on psychosocial factors (Attitude, self-efficacy, support of family and school members) associated with reduced screen time in students. A cluster-randomized controlled trial was conducted in three schools in the intervention group (n = 548) and three in the control group (n = 537). The intervention focused on teacher training, opportunities for practicing physical activity at school and reducing screen time, as well as health education. The questionnaire (applied in July and December 2014) included questions about time using TV and computer / video game on weekdays and weekend days (Combined in full-screen time). The psychosocial factors were obtained through scales. The control variables were school and income. The analysis included binary logistic regression models and generalized linear models. The effect size was calculated with analyzes stratified by sex and age (p < 0.05). The intervention group reduced TV (boys: OR = 2.86; CI95%: 1.06-7.71) time and computer/video game (girls: OR = 3.34; CI95%: 1.14-9.84; 11 to 13 years: OR = 3.08; CI95%: 1.17-8.08) for < 2 hours / day (p < 0.05). Positive effects of the intervention were observed on attitude (among girls and adolescents of both age groups) and school support (all subgroups), with effect sizes ranging from 0.21 to 0.54. We concluded that the intervention caused improvements in certain components of the screen time, as well as attitude and school support. Interventions in the school context can help reduce screen time in the young population.