Tobacco control messages for individuals who use both cigarettes and e-cigarettes: a randomised trial comparing biomarker outcome with cessation experience narratives.

Background: Dual use of e-cigarettes and cigarettes is prevalent among US adults, increasing nicotine addiction and health risks. This study investigated what type of narrative messages would be more effective in encouraging individuals who use both e-cigarettes and cigarettes to quit both smoking and vaping.

Methods: We conducted an online between-subjects randomised experiment on individuals who currently use both e-cigarettes and cigarettes (n=489). The 'biomarker outcome' narrative group viewed a 'why-quit' message that highlighted a decrease in biomarkers of toxicant exposure on quitting smoking and vaping; the 'cessation experience' narrative group viewed a 'how-to-quit' message that highlighted strategies for quitting smoking and vaping. Multivariable regressions were conducted to evaluate message effects on motivation to quit smoking and vaping based on perceived importance, commitment and readiness (range: 0-10). Mediation analyses were performed to assess pathways from messages through emotional responses to motivation to quit.

Results: As compared with viewing the 'cessation experience' narrative, exposure to the 'biomarker outcome' narrative led to larger increases in the motivation to quit smoking (adjusted β (SE)=0.3 (0.1), p=0.02) and vaping (adjusted β (SE)=0.5 (0.1), p=0.003). Individuals who were exposed to the 'biomarker outcome' narrative reported higher negative emotions and lower positive emotions than those in the 'cessation experience' narrative group. The message effects on changes in motivation to quit smoking (β_{indirect effect}=0.06, p=0.002) and vaping (β_{indirect effect}=0.05, p=0.009) were significantly mediated by negative emotions, but not by positive emotions.

Conclusion: A biomarker outcome narrative message that highlights the efficacy of quitting smoking and vaping by presenting evidence-based, objective biomarkers of toxicant exposure may be a persuasive message format in anti-dual use messaging.