Hutchinson smoking prevention project: Long-term randomized trial in school-based tobacco use prevention - Results on smoking

Background: No long-term impact has yet been observed with the use of the s ocial-influences approach to school-based smoking prevention for youth. How ever, whether this lack of impact is due to methodologic problems with the studies or to the failure of the interventions is unclear. The Hutchinson S moking Prevention Project (HSPP), conducted from September 1984 through Aug ust 1999, aimed to attain the most rigorous randomized trial possible to de termine the long-term impact of a theory-based, social-influences, grade 3- 12 intervention on smoking prevalence among youth. Methods: Forty Washingto n school districts were randomly assigned to the intervention or to the con trol condition. Study participants were children enrolled in two consecutiv e 3(rd) grades in the 40 districts (n = 8388); they were followed to 2 year s after high school. The trial achieved high implementation fidelity and 94 % follow-up. Data were analyzed with the use of group-permutation methods, and all statistical tests were two-sided. Results: No significant differenc e in prevalence of daily smoking was found between students in the control and experimental districts, either at grade 12 (difference [Delta] = 0.2%, 95% confidence interval [CI] = -4.6% to 4.4%, and P = .91 for girls; Delta = 0.3%, 95% CI = -5.0% to 5.5%, and P = .89 for boys) or at 2 years after h igh school (Delta = -1.4%, 95% CI = -5.0% to 1.6%, and P = .38 for girls; D elta = 2.6%, 95% CI = -2.5% to 7.7%, and P = .30 for boys). Moreover, no in tervention impact was observed for other smoking outcomes, such as extent o f current smoking or cumulative amount smoked, or in subgroups that differ in n priori specified variables, such as family risk for smoking. Conclusio n: The rigor of the HSPP trial suggests high credence for the intervention impact results. Consistent with previous trials, there is no evidence from this trial that a school-based social-influences approach is effective in t he long-term deterrence of smoking among youth.