title: [Factors associated with smoking onset: 3-year cohort study of schoolchildren].
abstract: OBJECTIVE
  To analyze the predictors of smoking onset among schoolchildren.
  
  
  METHODS
  A cohort study of 1056 children starting in first year secondary school at 44 schools in Barcelona was carried out. Participating children were invited to answer a lifestyle questionnaire every year for 4 years. Each questionnaire carried a personal code to allow the 4 questionnaires to be matched. Matching questionnaires were found for 729 children, 70% of the initial sample.
  
  
  RESULTS
  Over the study period, the prevalence of regular smokers increased from 1.7% to 22% among boys and from 1.6% to 38.2% among girls. The predictors of smoking onset among boys were scoring high on the pro-smoking attitudes index (odds ratio [OR]=1.2; 95% confidence interval [CI], 1.1-1.3), intention to smoke in the future (OR=2.2; 95% CI, 1.0-4.9), low self-efficacy in resisting pressures to smoke (OR=0.98; 95% CI, 0.96-0.99), having siblings that smoke (OR=2.5; 95% CI, 1.2-5.4), and spending some free time in bars (OR=2.4; CI, 1.1-4.9). Among girls, the predictors were having low self-esteem (OR=0.94; 95% CI, 0.88-0.99), scoring low on the anti-tobacco attitudes index (OR=0.92; 95% CI, 0.88-0.97), having siblings who smoke (OR=2.5; 95% CI, 1.2-5.5), spending some free time in discotheques (OR=4.5; 95% CI, 1.9-11.8), and living in high socioeconomic-status neighborhoods (OR=3.1; 95% CI, 1.4-10.9).
  
  
  CONCLUSIONS
  The results show the importance of cognitive variables as well as a variety of environmental variables, particularly the pattern of free time use and the influence of sibling models. Prevention programs must take into account smoking onset risk factors as a whole.
authors.affiliation: Agencia de Salud Pública de Barcelona, Barcelona, Spain. mnebot@imsb.bcn.es
authors.forename: M
authors.initials: M
authors.lastname: Nebot
authors.forename: Z
authors.initials: Z
authors.lastname: Tomás
authors.forename: C
authors.initials: C
authors.lastname: Ariza
authors.forename: S
authors.initials: S
authors.lastname: Valmayor
authors.forename: M J
authors.initials: MJ
authors.lastname: López
authors.forename: O
authors.initials: O
authors.lastname: Juárez
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D015331:Cohort Studies; D005260:Female; D006293:Health Promotion; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012649:Self Concept; D012907:Smoking / Q000453:epidemiology*; D000074606:Smoking Prevention; D012931:Social Environment; D013334:Students; D011795:Surveys and Questionnaires