A latent transition analysis of a Danish smoking reduction intervention trial

BACKGROUND: Distinct use patterns of tobacco and nicotine products are evolving among young people, notably after the market expansion of today's products. This study aims to identify and characterize subgroups of distinct tobacco and nicotine use patterns and to determine how a smoking reduction intervention and sociodemographic factors affected the transition patterns. METHODS: Data were from a Danish smoking reduction intervention targeting vocational school students. A latent transition analysis (LTA) was applied to identify patterns in latent classes of tobacco and nicotine use (use of cigarettes, smokeless tobacco, e-cigarettes, and hookah) from baseline to follow-up and to evaluate intervention effects on these patterns. RESULTS: A total of 2,158 students completed baseline and/or follow-up (FU) surveys (mean age = 20.8 years, 49.5% female). Three classes were identified: non-users (baseline: 31.3%, FU:33.9%), cigarette users (baseline: 36.0%, FU: 38.2%), and poly-users (baseline:33.7%, FU:27.9%). Students at intervention schools had 36% lower odds of transitioning from cigarette use at baseline to poly-use at follow-up (OR = 0.64; 0.41-0.99, p = 0.047) than control school students. Male and younger students were more likely to transition from cigarette use to poly-use. In contrast, students with origins other than Danish were more likely to transition from poly-use to non-use. CONCLUSIONS: Intervention efforts must address tobacco and nicotine use progression towards high-risk use patterns, targeting those at greater risk of these progressions, such as males and younger students. Future research could benefit from using the LTA approach when evaluating intervention effects. KEY MESSAGES: • Three distinct latent nicotine and tobacco use classes emerged among Danish young adults attending vocational schools: non-use, mainly smoking, and poly-use. • Students at intervention schools had lower odds of transitioning from cigarette use at baseline to poly-use at follow-up than control school students.