title: Screen Time Weight-loss Intervention Targeting Children at Home (SWITCH): process evaluation of a randomised controlled trial intervention.
abstract: The Screen Time Weight-loss Intervention Targeting Children at Home (SWITCH) trial tested a family intervention to reduce screen-based sedentary behaviour in overweight children. The trial found no significant effect of the intervention on children's screen-based sedentary behaviour. To explore these null findings, we conducted a pre-planned process evaluation, focussing on intervention delivery and uptake.
  
  
  
  SWITCH was a randomised controlled trial of a 6-month family intervention to reduce screen time in overweight children aged 9-12 years (n = 251). Community workers met with each child's primary caregiver to deliver the intervention content. Community workers underwent standard training and were monitored once by a member of the research team to assess intervention delivery. The primary caregiver implemented the intervention with their child, and self-reported intervention use at 3 and 6 months. An exploratory analysis determined whether child outcomes at 6 months varied by primary caregiver use of the intervention.
  
  
  
  Monitoring indicated that community workers delivered all core intervention components to primary caregivers. However, two thirds of primary caregivers reported using any intervention component "sometimes" or less frequently at both time points, suggesting that intervention uptake was poor. Additionally, analyses indicated no effect of primary caregiver intervention use on child outcomes at 6 months, suggesting the intervention itself lacked efficacy.
  
  
  
  Poor uptake, and the efficacy of the intervention itself, may have played a role in the null findings of the SWITCH trial on health behaviour and body composition.
  
  
  
  The trial was registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12611000164998 ); registration date: 10/02/2011.
authors.affiliation: MRC Epidemiology Unit and UKCRC Centre for Diet and Activity Research (CEDAR), University of Cambridge School of Clinical Medicine, Box 285, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. lf354@medschl.cam.ac.uk.|National Institute for Health Innovation, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand. lf354@medschl.cam.ac.uk.
authors.forename: Louise
authors.initials: L
authors.lastname: Foley
authors.affiliation: National Institute for Health Innovation, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand.
authors.forename: Cliona
authors.initials: C
authors.lastname: Ni Mhurchu
authors.affiliation: National Institute for Health Innovation, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand.
authors.forename: Samantha
authors.initials: S
authors.lastname: Marsh
authors.affiliation: Departments of Pediatrics, Community Health and Health Behavior and Social and Preventive Medicine, University at Buffalo School of Medicine and Biomedical Sciences, 3435 Main Street, G56 Farber Hall, Buffalo, NY, 14214, USA.
authors.forename: Leonard H
authors.initials: LH
authors.lastname: Epstein
authors.affiliation: Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, City East Campus, Frome Road, GPO Box 2471, Adelaide, SA, 5001, Australia.
authors.forename: Tim
authors.initials: T
authors.lastname: Olds
authors.affiliation: Pacific Health, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand.
authors.forename: Ofa
authors.initials: O
authors.lastname: Dewes
authors.affiliation: Heke Consulting, Auckland, 1142, New Zealand.
authors.forename: Ihirangi
authors.initials: I
authors.lastname: Heke
authors.affiliation: National Institute for Health Innovation, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand.
authors.forename: Yannan
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: National Institute for Health Innovation, School of Population Health, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland, 1142, New Zealand.
authors.forename: Ralph
authors.initials: R
authors.lastname: Maddison
mesh_terms: D001823:Body Composition; D002648:Child; D002662:Child Health Services; D005190:Family; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D009520:New Zealand; D010353:Patient Education as Topic; D063766:Pediatric Obesity / Q000517:prevention & control*; D017064:Process Assessment, Health Care; D013690:Television; D016896:Treatment Outcome; D018910:Video Games