[Smoking initiation in students: cross-sectional and longitudinal study of predictive factors].

Background: This study examines the evolution of tobacco use among schoolchildren in sixth and seventh grades in Barcelona (11-13 years) and identifies smoking risk factors through cross-sectional and follow-up analysis. POBLATION AND METHODS: The cohort consists of 1,003 students attending 13 schools who served as control units for a study assessing the effects of a school-based addictive substances prevention program. Participants answered the same questionnaire in 1990 and 1991. Risk factors for the experimentation and for regular smoking are studied through cross-sectional and prospective studies.
Result: In a year, smokers increase from 9.7% to 18.9% and regular smokers rise from 1.1% to 5.5%. The initial cross-sectional analysis finds stronger associations than the follow-up one. Some variables loose their significance in the longitudinal analysis. Among non-smokers, the strongest predictors to emerge are intention to smoke, the belief that smoking is fun, peers, siblings and mother consumption, and being male; however girls appear to consolidate the consumption more than boys among the cohort of triers.
Conclusions: Tobacco use prevalences are consistent with other studies developed in our city. Social environment emerges as an important predictor; friends, siblings and mothers tobacco use and gender are the main risk factors.