Smoking in early adolescence: evidence from the 1993 Pelotas (Brazil) Birth Cohort Study

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.

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.

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.

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.