title: Ethnic differences in body mass index and associated factors of adolescents from minorities in Oslo, Norway: a cross-sectional study.
abstract: OBJECTIVE
  To examine ethnic differences in body mass index (BMI), food habits and physical activity, and determine the factors contributing to differences in BMI.
  
  
  METHODS
  In 2000-2001, 7343 (response rate 88%) 15- and 16-year-old students, enrolled in lower secondary schools in Oslo, participated in the cross-sectional Oslo Health Study. Of these participants, 1719 were defined as ethnic minorities.
  
  
  RESULTS
  Significant gender and ethnic differences in mean BMI were observed. Of the ethnic minority adolescents, 5.8% were underweight (<5th percentile of the US Centers for Disease Control and Prevention (CDC)/National Center for Health Statistics (NCHS) reference distribution) and 9.1% were overweight (>85th percentile of the US CDC/NCHS reference distribution). BMI was not significantly associated with either socio-economic factors or physical activity. Food habits and physical activity differed with ethnicity but not with socio-economic factors. An ordinal regression showed that girls from East Asia (odds ratio (OR) 0.4) and boys from sub-Saharan Africa (OR 0.4) had lower BMI than the Western group. Among girls, higher BMI was associated with less frequent consumption of chocolates and sweets, full-fat milk and breakfast (OR 2.4, 1.7 and 1.7, respectively). Higher BMI, for both boys and girls, was associated with current and past dieting (OR 3.7 and 4.2, respectively).
  
  
  CONCLUSIONS
  Adolescent food habits and physical activity varied by gender and ethnicity but not with socio-economic factors. BMI was associated with ethnicity, gender and food habits, but no significant relationship was observed with socio-economic factors or physical activity. Ethnicity, in addition to gender, should be taken into consideration when studying BMI and associated factors among adolescents.
authors.affiliation: Section of Preventive Medicine and Epidemiology, Department Group for Community Medicine and General Practice, University of Oslo, Norway. bernadette.kumar@medisin.uio.no
authors.forename: B N
authors.initials: BN
authors.lastname: Kumar
authors.forename: G
authors.initials: G
authors.lastname: Holmboe-Ottesen
authors.forename: N
authors.initials: N
authors.lastname: Lien
authors.forename: M
authors.initials: M
authors.lastname: Wandel
mesh_terms: D000293:Adolescent; D017954:Africa South of the Sahara / Q000208:ethnology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005202:Asia, Eastern / Q000208:ethnology; D005247:Feeding Behavior / Q000208:ethnology*; D005260:Female; D006801:Humans; D008297:Male; D008913:Minority Groups; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology / Q000208:ethnology*; D012737:Sex Factors; D012959:Socioeconomic Factors