Effectiveness of a complex intervention on smoking in adolescents: A cluster-randomized controlled trial.

Tobacco smoking is a major preventable cause of death, and a significant public health problem worldwide. Most smokers begin in adolescence, age at which they are more susceptible to nicotine addiction. The prevalence of smoking in adolescence is considerable. Therefore, it would be convenient to incorporate smoking prevention programs in the school environment. It is necessary to provide evidence of its effectiveness. The primary objective of the study was to evaluate the effectiveness of a teacher-delivered school-based intervention on the initiation of smoking in adolescents (ITACA smoking prevention education program). A multi-center cluster randomized trial was designed. Twenty-two secondary schools from Spain were enrolled in 2 successive cohorts, from 2010 to 2011. The intervention consisted in the application of the ITACA smoking prevention education program. A 4-year cognitive-behavioral intervention that is based on the social-influences model and is integrated into schools' regular curricular activities. A total of 1055 students were surveyed before the intervention (age: 12-13 years-old), and at the third year of the intervention (age: 14-15 years-old) of a 4-year education program. The outcome measures were daily and weekly use of cigarettes, and initiation of smoking. There was no evidence that the intervention impacted the incidence of regular smoking (OR = 1.08; 95% CI: 0.50-2.33) or the initiation of smoking (OR = 1.09; 95% CI: 0.56-1.72). This trial provides evidence supporting the non-effectiveness of a complex educational smoking prevention program at 3 years after the intervention.

TRIAL REGISTRATION NUMBER: Current Controlled Trials: NCT01602796.