The impact of flavors, health risks, secondhand smoke and prices on young adults' cigarette and e-cigarette choices: a discrete choice experiment.

Aims: To estimate young adults' preferences for cigarettes and e-cigarettes, and how preferences vary by policy-relevant factors. A related aim was to provide information on potential substitution/complementarity across cigarettes and e-cigarettes ahead of policy selection.

Design: An online discrete choice experiment (DCE) in which respondents chose their preferred option among cigarettes, two types of e-cigarettes (disposable/reusable) and 'none'. Each cigarette-type was characterized by policy-relevant attributes: flavors, short-term health risks to self, secondhand smoke risks and price. A latent class model identified smoking types that respond differently to these.

Setting: US tobacco market.

Participants: A total of 2003 young adults (aged 18-22 years) who ever tried either cigarettes or e-cigarettes, recruited via the survey platform Qualtrics, matched to the 2015 National Health Interview Survey by age, gender, education and census region.

Measurements: Respondents' DCE choices.

Findings: Young adults fell into two broad categories. One latent group, termed 'prefer smoking group', preferred cigarettes and another, 'prefer vaping group', preferred e-cigarettes. The 'prefer smoking group' preferred lower prices and lower health harms more than other attributes. The 'prefer vaping group' valued these, although price less intensely, and valued health and fruit/candy flavors more.

Conclusion: Banning all flavors in cigarettes and e-cigarettes might improve the health of young adults who ever tried either cigarettes or e-cigarettes. Young adult ever-triers might be deterred from smoking by increasing cigarette prices and encouraged to switch to e-cigarettes by reducing the health harms of e-cigarettes. Reducing health harms of e-cigarettes could also make the 'prefer vaping group' less likely to quit, resulting in increased health harm.