Role of smoking intention in tobacco use reduction: A mediation analysis of an effective classroom-based prevention/cessation intervention for adolescents.

INTRODUCTION: Although some school-based tobacco cessation and prevention programs have been proven to be effective, there remains a lack of understanding of how these programs succeed.

METHODS: This longitudinal study aimed to test smoking intention as a mediator of Project EX's intervention efficacy to reduce tobacco use. Using a computerized random number generator, six high schools located in the Mediterranean coast were randomly selected to participate in the program condition (Spanish version of Project EX) or the waiting-list control group with baseline, immediate-posttest, and 12-month follow-up assessments. At baseline, 685 adolescents aged 14-20 years (mean age: 14.87; SD = 0.92; 47.4% were females) were evaluated using self-administered tests of tobacco, and smoking intention. A biomarker of smoke inhalation, a measurement of exhaled carbon monoxide (ECM), was used. Mediation analyses were conducted using the PROCESS v2.12 macro for Windows.

RESULTS: Project EX had a significant effect on smoking intention. Indirect effects indicated that Project EX reduced the ECM level, and number of cigarettes used.

CONCLUSIONS: This is the first Spanish study that explored intention as a mediator of the long-term efficacy of Project EX to reduce tobacco use in adolescents. Results suggested that interventions that reduce consumption intention at short-term are more likely to be successful in decreasing tobacco use in the long-term.