Background: Adolescents' intentions to smoke are generally regarded as a valid and reliable predictor of subsequent smoking. This association is largely based on research with adults and needs a more detailed analysis for adolescents.
Methods: Data on intentions and smoking status were collected as part of a longitudinal, birth-cohort study when the study members were 9, 11, 13, 15, 18, and 21 years of age.
Results: The results showed that intention to smoke only had an important predictive power in the subgroup of previous nonsmokers. Among those already smoking (on a monthly basis or greater), previous level of smoking was a more important predictor of future behavior than intention to smoke. In addition, the effect of positive intention to smoke was nonlinear over age and had the greatest effect at age 15.
Conclusion: The results indicated that in adolescence, measurement of intentions to smoke or not smoke cannot be assumed to be a general predictor of behavior at a later age for all groups of adolescents.