Impact of implementation of a smoking prevention intervention on vocational students’ smoking status

INTRODUCTION: Smoking prevalence is high in vocational education across Europe. School-based programs to reduce smoking among older adolescents and young adults are sparse. School tobacco policies are often used though the evidence for their effectiveness is inconclusive. The implementation process of far-reaching smoking prevention initiatives such as tobacco policies can be challenging due to, e.g., nicotine dependency and attitudes towards smoking. We investigated the association between implementation of a smoking prevention intervention and students’ smoking status. METHODS: The “Focus” intervention combined a comprehensive school tobacco policy with educational activities and access to smoking cessation support. It was tested in a cluster-randomized controlled trial in 14 Danish vocational schools. Based on a conceptual model, we calculated an individual level implementation score for all students in the intervention arm, including schools’ delivery (principal and teacher surveys) and students’ receipt (student surveys) of the intervention components at 4-5 month-follow-up. We compared odds for smoking daily or weekly (regular smoking) for students with low, medium, and high implementation with students in control schools using multilevel logistic regression models (N = 1112). RESULTS: Students with high implementation had significantly lower odds for smoking compared to the control group (OR: 0.37, 95% CI: 0.18-0.78) whereas students with medium (OR: 1.72, 95% CI: 0.95-3.12) and low (OR: 1.26, 95% CI: 0.68-2.34) implementation had higher odds, although insignificant. CONCLUSIONS: High implementation of the “Focus” intervention was associated with less smoking. Tendencies in the opposite direction for lower implementation may indicate a complex, non-linear relationship between implementation level and smoking behavior. This suggests that careful implementation efforts are needed to reduce smoking in older adolescent and young adult school settings. KEY MESSAGES: • Our study suggests that efforts to support implementation of smoking prevention interventions are needed to reduce smoking in vocational education and similar settings. • To capture the complexity of the implementation process, we use an individual level measure of implementation based on a conceptual model and multiple data sources.