title: Smoking in early adolescence: evidence from the 1993 Pelotas (Brazil) Birth Cohort Study.
abstract: OBJECTIVE
  To evaluate the prevalence of tobacco use, and factors associated with it, in early adolescent (aged 10-12 years) participants of the 1993 Pelotas (Brazil) Birth Cohort Study.
  
  
  METHODS
  Children born in 1993 in Pelotas, Brazil were included in a prospective health study. In 2004-2005, all cohort members were sought. Adolescents and mothers were interviewed. A confidential questionnaire was applied to adolescents, including a section on smoking. Smoking experience was defined as having tried at least one cigarette in life.
  
  
  RESULTS
  Follow-up rate was 87.5%; 4452 adolescents were interviewed. Mean age was 11.3 years. Only 58 adolescents did not answer the question on smoking experience. Out of the 4394 respondents, 162 (3.7%; 95% confidence interval [CI] 3.1-4.2) had tried smoking. Of these, approximately half smoked the first cigarette before 10 years of age. Seventy-three cohort members reported smoking daily. In multivariable analysis, variables positively associated with smoking experience were: male gender, maternal smoking during pregnancy, living without the biological father, poor relationship with the mother, being beaten by the parents, family conflict, maternal smoking in 2004-2005, bad influences on the adolescent, participation in fights, history of attempting to run away from home, and experience with alcoholic beverages. The association was negative for socioeconomic level.
  
  
  CONCLUSIONS
  Family-related variables and habits of the adolescent were strongly associated with smoking in early adolescence. Because experimentation with tobacco in adolescence is related to a marked increase in the risk of tobacco addiction in adulthood, early interventions are warranted.
authors.affiliation: Federal University of Pelotas, Pelotas, Brazil. anamene@terra.com.br
authors.forename: Ana M B
authors.initials: AM
authors.lastname: Menezes
authors.forename: Helen
authors.initials: H
authors.lastname: Gonçalves
authors.forename: Luciana
authors.initials: L
authors.lastname: Anselmi
authors.forename: Pedro C
authors.initials: PC
authors.lastname: Hallal
authors.forename: Cora L P
authors.initials: CL
authors.lastname: Araújo
mesh_terms: D001938:Brazil / Q000453:epidemiology; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008425:Maternal Behavior; D015995:Prevalence; D012907:Smoking / Q000453:epidemiology*; D012923:Social Class; D011795:Surveys and Questionnaires