title: Are participant characteristics from ISCOLE study sites comparable to the rest of their country?
abstract: OBJECTIVE
  The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) provides robust, multi-national information on physical activity, diet and weight status in 9-11-year-old children around the world. The purpose of this analysis was to examine the similarities and differences between participant characteristics from ISCOLE sites and data from nationally representative surveys from ISCOLE countries (Australia, Brazil, Canada, China, Colombia, Finland, Kenya, India, Portugal, South Africa, the United Kingdom and the United States).
  
  
  METHODS
  Distributions of characteristics were assessed within each ISCOLE country-level database, and compared with published data from national or regional surveys, where available. Variables of comparison were identified a priori and included body mass index (BMI), physical activity (accelerometer-determined steps per day) and screen time (child-report).
  
  
  RESULTS
  Of 12 countries, data on weight status (BMI) were available in 8 countries, data on measured physical activity (steps per day) were available in 5 countries and data on self-reported screen time were available in 9 countries. The five ISCOLE countries that were part of the Health Behaviour in School-aged Children Survey (that is, Canada, Finland, Portugal, the United Kingdom (England) and the United States) also provided comparable data on self-reported physical activity. Available country-specific data often used different measurement tools or cut-points, making direct comparisons difficult. Where possible, ISCOLE data were re-analyzed to match country-level data, but this step limited between-country comparisons.
  
  
  CONCLUSIONS
  From the analyses performed, the ISCOLE data do not seem to be systematically biased; however, owing to limitations in data availability, data from ISCOLE should be used with appropriate caution when planning country-level population health interventions. This work highlights the need for harmonized measurement tools around the world while accounting for culturally specific characteristics, and the need for collaboration across study centers and research groups.
authors.affiliation: Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: A G
authors.initials: AG
authors.lastname: LeBlanc
authors.affiliation: Pennington Biomedical Research Center , Baton Rouge, LA, USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Katzmarzyk
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA, USA; University of Syracuse, Syracuse, New York, USA.
authors.forename: T V
authors.initials: TV
authors.lastname: Barreira
authors.affiliation: Pennington Biomedical Research Center , Baton Rouge, LA, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Broyles
authors.affiliation: Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: J-P
authors.initials: JP
authors.lastname: Chaput
authors.affiliation: Pennington Biomedical Research Center , Baton Rouge, LA, USA.
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authors.initials: TS
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authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki , Helsinki, Finland.
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authors.initials: M
authors.lastname: Fogelholm
authors.affiliation: University of Leicester , Leicester, UK.
authors.forename: D M
authors.initials: DM
authors.lastname: Harrington
authors.affiliation: Pennington Biomedical Research Center , Baton Rouge, LA, USA.
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authors.affiliation: St Johns Research Institute , Bangalore, India.
authors.forename: R
authors.initials: R
authors.lastname: Kuriyan
authors.affiliation: St Johns Research Institute , Bangalore, India.
authors.forename: A
authors.initials: A
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authors.affiliation: Department of Human Biology, Division of Exercise Science and Sports Medicine, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa.
authors.forename: E V
authors.initials: EV
authors.lastname: Lambert
authors.affiliation: Alliance for Research in Exercise Nutrition and Activity (ARENA), School of Health Sciences, University of South Australia , Adelaide, South Australia, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Maher
authors.affiliation: CIFI2D, Faculdade de Desporto, University of Porto , Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Maia
authors.affiliation: Centro de Estudos do Laboratório de Aptidão Física de São Caetano do Sul (CELAFISCS) , Sao Paulo, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Matsudo
authors.affiliation: Alliance for Research in Exercise Nutrition and Activity (ARENA), School of Health Sciences, University of South Australia , Adelaide, South Australia, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Olds
authors.affiliation: Department of Recreation Management and Exercise Science, Kenyatta University , Nairobi, Kenya.
authors.forename: V
authors.initials: V
authors.lastname: Onywera
authors.affiliation: School of Medicine, Universidad de los Andes , Bogota, Colombia.
authors.forename: O L
authors.initials: OL
authors.lastname: Sarmiento
authors.affiliation: Department for Health, University of Bath , Bath, UK.
authors.forename: M
authors.initials: M
authors.lastname: Standage
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA, USA; Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA, USA.
authors.forename: C
authors.initials: C
authors.lastname: Tudor-Locke
authors.affiliation: Department of Kinesiology, University of Massachusetts Amherst , Amherst, MA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute , Ottawa, Ontario, Canada.
authors.forename: M S
authors.initials: MS
authors.lastname: Tremblay