Background
initiation of smoking
SECONDARY
Despite well-documented detrimental health hazards of cigarette smoking, along with decades of efforts to reduce the prevalence and uptake of smoking globally, smoking continues to be an important public health issue [At the upper-secondary school level, some school types comprise a high proportion of students with low SES. In Denmark, young people who have finished compulsory education can choose between high school or vocational education and training (VET). Meanwhile, preparatory basic education (PBE) is offered to youth below 25 years who have completed compulsory school and need professional or personal upgrading to enter a youth education (e.g., VET) [Within the last decades, a host of smoking preventive initiatives have been initiated on a global scale, both on a political and community-based level, as a response to the alarming trends in smoking among the general population and especially among youth [The primary aim of this study was to examine the effect of a school-based multi-component smoking intervention ‘Focus’ on average daily cigarette consumption among students in VET and PBE schools using a cluster randomized controlled trial. As predefined in the trial registration, we hypothesized that students would reduce the average daily number of cigarettes by 1) reduced levels of cigarette consumption among daily smokers and 2) reduced initiation of smoking and progression to daily smoking among non-smokers and occasional smokers. A secondary aim was to examine the intervention effects on a range of pre-defined secondary outcomes at the individual, interpersonal, and environmental level, e.g., individual beliefs about smoking, support from other students and class community, and visibility of smoking at school, all of which were determinants expected to impact students’ smoking decisions, identified through the program theory [