The natural history of cigarette smoking: predicting young-adult smoking outcomes from adolescent smoking patterns.

Assessed the magnitude of risk that adolescent cigarette smoking carries for adult smoking. Using a longitudinal, prospective design, results indicate that even infrequent experimentation in adolescence significantly raises the risk for adult smoking and that regular (at least monthly) adolescent smoking raises the risk for adult smoking by a factor of 16 compared to nonsmoking adolescents. Relative risk was also increased by an early onset of smoking and by a stable, uninterrupted course from experimentation to regular smoking. Relative risk did not significantly vary by age or sex. The continuity of smoking behavior between adolescence and adulthood supports the importance of primary prevention programs directed at adolescent populations.