title: School and class environments are differently linked to future smoking among preadolescents.
abstract: BACKGROUND
  There are few observational studies of school and class risk factors for smoking behavior in preadolescence.
  
  
  METHODS
  A cohort study of 2,883 children recruited in the fifth grade with follow-up in sixth grade was undertaken. Information on school and class factors was collected from principals and teachers of 91 schools.
  
  
  RESULTS
  A decreased risk of smoking uptake was associated with exposure to short antitobacco education prior to the fifth grade (compared to no education). Problematic interpersonal relations in the class were associated with a relative risk of smoking initiation of 1.42 (confidence interval 1.05, 1.93) compared to positive interpersonal relations. This excess risk was not mediated by class smoking prevalence in the fifth grade. School policy and school characteristics were not significantly associated with preadolescents' smoking.
  
  
  CONCLUSIONS
  Class-related, rather than school-related, characteristics were associated with smoking initiation and progression. Changes in microenvironmental factors might be useful in smoking prevention among preadolescents.
authors.affiliation: Division of Epidemiology, Karolinska Institute, Sweden. ingvar.rosendahl@smd.sll.se
authors.forename: K Ingvar
authors.initials: KI
authors.lastname: Rosendahl
authors.forename: M Rosaria
authors.initials: MR
authors.lastname: Galanti
authors.forename: Hans
authors.initials: H
authors.lastname: Gilljam
authors.forename: Sven
authors.initials: S
authors.lastname: Bremberg
authors.forename: Anders
authors.initials: A
authors.lastname: Ahlbom
mesh_terms: D002648:Child; D015331:Cohort Studies; D006266:Health Education / Q000379:methods*; D006801:Humans; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D000074606:Smoking Prevention; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology