Impact of a multi-level intervention to prevent secondhand smoke exposure in schoolchildren: A randomized cluster community trial

Abstract Objective To assess the effectiveness of a multi-level (individual, family, and school) school-based intervention to prevent the exposure to secondhand smoke (SHS) in a population of schoolchildren (12–14 years old). Method This was a community trial with cluster randomization of schools to an intervention and comparison group (ClinicalTrials.Gov identifier NCT01881607). The intervention targeted schoolchildren in Terrassa (Catalonia, Spain). We assessed SHS exposure in different settings and tobacco consumption by means of a questionnaire before and one year after the intervention. Results We analyzed data from 1734 students with both baseline and follow-up data. The crude analysis showed that SHS exposure among students in the intervention group significantly decreased at school (− 14.0%), at home (− 19.9%), and on transportation (− 21.8%). In the comparison group, SHS exposure significantly decreased only at home (− 16.9%). After adjustment for potential confounders, the good accomplishment of the activities showed a possible trend towards a non-significant reduction in exposure at home, transportation, and leisure time. Conclusion While this school-based multi-level intervention had no overall effect in SHS exposure, the improvement of the activities focused on preventing SHS would be needed in order to achieve a significant decrease in the proportion of children exposed to SHS.