title: Availability of data assessing the prevalence and trends of overweight and obesity among European adolescents.
abstract: OBJECTIVE
  To review recent data on objectively measured overweight/obesity in national representative samples of European adolescents (aged 10-18 years), as well as availability of studies assessing trends in overweight/obesity in this target group. Attention was paid to the ability of the data to describe the obesity epidemic, especially in sociodemographic subgroups.
  
  
  METHODS
  Data on prevalence and trends in overweight/obesity among adolescents in the twenty-seven European Community member states, Iceland, Norway and Switzerland, available as scientific publications as well as reports or unpublished data by the end of 2009, were retrieved. Reports on the most recent objectively measured data from national representative samples were selected and described with regard to the years of data collection, sample sizes, response rates, age ranges included, trends by age, type of measures of overweight/obesity, sociodemographic variables and the sources of information.
  
  
  RESULTS
  Objectively measured data on national representative samples were identified for only half of the countries, and the trend studies were mainly conducted applying subnational samples. Most studies used the criteria from the International Obesity Task Force (IOTF) to define overweight/obesity, but the age ranges studied and the years of data collection varied, and information on sample sizes and response rates were often not presented. Data on trends of overweight/obesity over time are increasing, and the most recent studies indicate that the prevalence rate of overweight/obesity has stabilized. Few studies reported data by sociodemographic subgroups other than gender and age.
  
  
  CONCLUSIONS
  Objectively measured data on national representative samples of adolescents appear scattered, and there is a large heterogeneity with respect to the quality and comparability of available data. Increasing use of the IOTF criteria for overweight/obesity contributes to improved comparability across studies. Data by sociodemographic subgroups, and in particular by socio-economic status, are scarce.
authors.affiliation: Faculty of Medicine, Department of Nutrition, Institute for Basic Medical Sciences, University of Oslo, PO Box 1046 Blindern, N-0316 Oslo, Norway. nanna.lien@medisin.uio.no
authors.forename: Nanna
authors.initials: N
authors.lastname: Lien
authors.forename: Hege B
authors.initials: HB
authors.lastname: Henriksen
authors.forename: Lena L
authors.initials: LL
authors.lastname: Nymoen
authors.forename: Marianne
authors.initials: M
authors.lastname: Wind
authors.forename: Knut-Inge
authors.initials: KI
authors.lastname: Klepp
mesh_terms: D000293:Adolescent; D002648:Child; D058872:Epidemics; D005060:Europe / Q000453:epidemiology; D006801:Humans; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology*; D015995:Prevalence