title: Predictability of smoking in adolescence: between optimism and pessimism.
abstract: OBJECTIVE
  The present study aimed to assess how far associations between possible explanatory variables and smoking onset depend on the use of cross-sectional versus prospective designs.
  
  
  METHODS
  Data were analysed from a three-wave 5-year longitudinal survey among 1063 secondary schoolchildren (12-18-year-olds) in The Netherlands.
  
  
  METHODS
  The survey questionnaire contained items on smoking history, smoking-specific beliefs and attitudes, social influence variables and socio-demographic variables in each wave.
  
  
  CONCLUSIONS
  The cross-sectional analyses showed strong associations between explanatory variables and smoking behaviour (R2 varied from 0.50 to 0.71). However, only 8% of the variance in change of smoking status from non-smoking to regular smoking over a period of 5 years and 14% of the variance over a period of 3 years could be predicted by the model variables. Factors believed to lead to smoking may result from smoking or they may change quickly in ways that make them of low predictive value even though they may be important aetiologically.
authors.affiliation: Maastricht University, The Netherlands.
authors.forename: R C
authors.initials: RC
authors.lastname: Engels
authors.forename: R A
authors.initials: RA
authors.lastname: Knibbe
authors.forename: M J
authors.initials: MJ
authors.lastname: Drop
mesh_terms: D000293:Adolescent; D001294:Attitude to Health; D002648:Child; D003430:Cross-Sectional Studies; D003625:Data Collection; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012107:Research Design; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology* / Q000523:psychology; D000074606:Smoking Prevention