Analysis of on-pack messages for e-liquids: a discrete choice study

Background Policymakers wishing to encourage smokers unable to quit to switch to using electronic nicotine delivery systems (ENDS) also need to consider how to deter ENDS use among non-smokers. We examined whether reduced-risk messages could increase ENDS' appeal among smokers and if increased-risk messages could decrease appeal among susceptible non-smokers, occasional and former smokers. Methodology An online discrete choice experiment tested three attributes: information message, nicotine content (0 mg or 3 mg) and flavour (tobacco, menthol or fruit). The sample comprised 352 current smokers, 118 occasional and former smokers, and 216 ENDS-susceptible never smokers. Smokers viewed reduced-risk messages that encouraged switching to ENDS, while other groups viewed increased-risk messages that discouraged ENDS use. All groups saw a typical addiction warning. We analysed the data by estimating multinomial logit regression and adjusted latent class analysis models. Results Relative to no message, reduced risk-messages increased the appeal of ENDS uptake among one class of smokers (33.5%) but decreased appeal among other smokers. However, among all smokers, reduced-risk messages increased preference more than a dissuasive addiction warning. By contrast, among occasional or former smokers, and susceptible non-smokers, all information messages discouraging ENDS use, including an addiction warning, decreased preference relative to no message. Conclusions On-pack relative-risk messages about ENDS could make transition more attractive to smokers while increased-risk messages could deter ENDS uptake among susceptible non-smokers, occasional and former smokers. Communicating diverse messages via discrete channels could recognise heterogeneity among and between smokers and non-smokers.