title: Boys and girls smoking within the Danish elementary school classes: a group-level analysis.
abstract: OBJECTIVE
  To quantify the correlation between male and female smoking prevalence in elementary school classes by group-level analysis.
  
  
  METHODS
  This study was the Danish contribution to the cross-national study Health Behaviour in School-Aged Children (HBSC) 1998. Ninety school classes at grade nine (1,515 students) from a random sample of schools in Denmark took part. The proportion of male and female "at all" smokers and daily smokers in the school class was calculated.
  
  
  RESULTS
  The mean "at all" smoking proportion in the school classes is 39% for girls and 32% for boys. The proportion of male and female smokers within school classes does not correlate. There is high variation in male and female smoking behaviour between school classes.
  
  
  CONCLUSIONS
  The influence of social classroom environment on the processes causing smoking behaviour may be different for boys and girls. This paper illustrates that group-level analysis provides valuable new knowledge.
authors.affiliation: Institute of Public Health, Department of Social Medicine, University of Copenhagen, Denmark. M.Rasmussen@socmed.ku.dk
authors.forename: Mette
authors.initials: M
authors.lastname: Rasmussen
authors.forename: Mogens T
authors.initials: MT
authors.lastname: Damsgaard
authors.forename: Pernille
authors.initials: P
authors.lastname: Due
authors.forename: Bjørn E
authors.initials: BE
authors.lastname: Holstein
mesh_terms: D002648:Child; D002652:Child Behavior / Q000523:psychology*; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D012309:Risk-Taking; D012574:Schools; D012907:Smoking / Q000453:epidemiology*; D013334:Students / Q000523:psychology* / Q000706:statistics & numerical data