title: School-based intervention on healthy behaviour among Ecuadorian adolescents: effect of a cluster-randomized controlled trial on screen-time.
abstract: BACKGROUND
  Effective interventions on screen-time behaviours (television, video games and computer time) are needed to prevent non-communicable diseases in low- and middle-income countries. The present manuscript investigates the effect of a school-based health promotion intervention on screen-time behaviour among 12- to 15-year-old adolescents. We report the effect of the trial on screen-time after two stages of implementation.
  
  
  METHODS
  We performed a cluster-randomised pair matched trial in urban schools in Cuenca-Ecuador. Participants were adolescents of grade eight and nine (mean age 12.8 ± 0.8 years, n = 1370, control group n = 684) from 20 schools (control group n = 10). The intervention included an individual and environmental component tailored to the local context and resources. The first intervention stage focused on diet, physical activity and screen-time behaviour, while the second stage focused only on diet and physical activity. Screen-time behaviours, primary outcome, were assessed at baseline, after the first (18 months) and second stage (28 months). Mixed linear models were used to analyse the data.
  
  
  RESULTS
  After the first stage (data from n = 1224 adolescents; control group n = 608), the intervention group had a lower increase in TV-time on a week day (β = -15.7 min; P = 0.003) and weekend day (β = -18.9 min; P = 0.005), in total screen-time on a weekday (β = -25.9 min; P = 0.03) and in the proportion of adolescents that did not meet the screen-time recommendation (β = -4 percentage point; P = 0.01), compared to the control group. After the second stage (data from n = 1078 adolescents; control group n = 531), the TV-time on a weekday (β = 13.1 min; P = 0.02), and total screen-time on a weekday (β = 21.4 min; P = 0.03) increased more in adolescents from the intervention group. No adverse effects were reported.
  
  
  CONCLUSIONS
  A multicomponent school-based intervention was only able to mitigate the increase in adolescents' television time and total screen-time after the first stage of the intervention or in other words, when the intervention included specific components or activities that focused on reducing screen-time. After the second stage of the intervention, which only included components and activities related to improve healthy diet and physical activity and not to decrease the screen-time, the adolescents increased their screen-time again. Our findings might imply that reducing screen-time is only possible when the intervention focuses specifically on reducing screen-time.
  
  
  BACKGROUND
  Clinicaltrials.gov identifier NCT01004367.
authors.affiliation: Food Nutrition and Health Programme, Universidad de Cuenca, Avenida 12 de Abril y, Loja, 010202, Cuenca, Ecuador. susana.andrade@ucuenca.edu.ec.|Department of Food Safety and Food Quality, Ghent University, Coupure links 653, 9000, Ghent, Belgium. susana.andrade@ucuenca.edu.ec.
authors.forename: Susana
authors.initials: S
authors.lastname: Andrade
authors.affiliation: Department of Movement and Sport Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium. maite.verloigne@ugent.be.
authors.forename: Maïté
authors.initials: M
authors.lastname: Verloigne
authors.affiliation: Department of Movement and Sport Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium. greet.cardon@ugent.be.
authors.forename: Greet
authors.initials: G
authors.lastname: Cardon
authors.affiliation: Department of Food Safety and Food Quality, Ghent University, Coupure links 653, 9000, Ghent, Belgium. pkolsteren@itg.be.|Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium. pkolsteren@itg.be.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kolsteren
authors.affiliation: Food Nutrition and Health Programme, Universidad de Cuenca, Avenida 12 de Abril y, Loja, 010202, Cuenca, Ecuador. angelica.ochoa@ucuenca.edu.ec.|Department of Food Safety and Food Quality, Ghent University, Coupure links 653, 9000, Ghent, Belgium. angelica.ochoa@ucuenca.edu.ec.
authors.forename: Angelica
authors.initials: A
authors.lastname: Ochoa-Avilés
authors.affiliation: Department of Food Safety and Food Quality, Ghent University, Coupure links 653, 9000, Ghent, Belgium. roosmarijn.verstraeten@ugent.be.|Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium. roosmarijn.verstraeten@ugent.be.
authors.forename: Roosmarijn
authors.initials: R
authors.lastname: Verstraeten
authors.affiliation: Food Nutrition and Health Programme, Universidad de Cuenca, Avenida 12 de Abril y, Loja, 010202, Cuenca, Ecuador. silvana.donosom@ucuenca.edu.ec.
authors.forename: Silvana
authors.initials: S
authors.lastname: Donoso
authors.affiliation: Department of Food Safety and Food Quality, Ghent University, Coupure links 653, 9000, Ghent, Belgium. carl.lachat@ugent.be.|Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium. carl.lachat@ugent.be.
authors.forename: Carl
authors.initials: C
authors.lastname: Lachat
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D003201:Computers / Q000706:statistics & numerical data*; D004032:Diet; D004484:Ecuador; D005247:Feeding Behavior; D005260:Female; D015438:Health Behavior; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D012572:School Health Services / Q000706:statistics & numerical data*; D057185:Sedentary Behavior; D013690:Television / Q000706:statistics & numerical data*; D018910:Video Games / Q000706:statistics & numerical data*