title: An experimental study of the effects of electronic cigarette warnings on young adult nonsmokers' perceptions and behavioral intentions.
abstract: BACKGROUND
  Electronic cigarette ("e-cigarette") manufacturers use warning labels on their advertising that vary widely in content and the U.S. Food and Drug Administration has issued a warning label requirement for e-cigarettes. There is limited data on the effects of these warnings on e-cigarette perceptions and other potential predictors of future tobacco use behavior in populations of interest to inform future regulatory requirements. This study examined the effects of e-cigarette warnings on perceptions of e-cigarettes and cigarettes and other cognitive precursors to tobacco use among young adult non-smokers.
  
  
  METHODS
  Non-smoking young adults ages 18 to 30 years (n = 436) were recruited through an internet-based crowdsourcing platform for an online experiment. Participants completed pre-exposure measures of demographics, tobacco use, and other relevant constructs and were randomized to view 1 of 9 e-cigarette stimuli in a 3 (Ad/Warning condition: Ad Only, Ad with Warning, Warning Only) x 3 (E-cigarette brand: Blu, MarkTen, Vuse) design. After viewing e-cigarette stimuli, participants reported perceptions of e-cigarettes and behavioral intentions to use e-cigarettes. Participants in the Ad Only and Ad with Warning conditions also completed a heat-mapping task assessing aspects of the ads that captured their attention. Then, participants were randomized to view cigarette ads from 1 of 3 major cigarette brands and reported perceptions of cigarettes and intentions to smoke cigarettes.
  
  
  RESULTS
  Participants in the Warning Only condition reported significantly greater perceived harm and addictiveness of e-cigarettes and thoughts about not using e-cigarettes than the Ad Only and Ad with Warning conditions (p's < .05). The Ad Only and Ad with Warning conditions did not differ on these outcomes. Participants in the Warning Only condition also reported the harms of e-cigarettes were closer to those of cigarettes than the Ad Only condition (p < .05), but neither differed from the Ad with Warning condition. Visual inspection of heat-mapping task data indicate warnings drew few participants' attention. There were no significant differences across study conditions on perceptions of cigarettes or intentions to smoke.
  
  
  CONCLUSIONS
  Text-based warning messages influenced young non-smokers' perceptions in a way that may dissuade e-cigarette use, but warnings appearing on advertisements had little impact.
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, 3300 Whitehaven St NW Suite 4100, Washington DC, 20007 USA.
authors.forename: Darren
authors.initials: D
authors.lastname: Mays
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, 3300 Whitehaven St NW Suite 4100, Washington DC, 20007 USA.
authors.forename: Clayton
authors.initials: C
authors.lastname: Smith
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, 3300 Whitehaven St NW Suite 4100, Washington DC, 20007 USA.
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Johnson
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, 3300 Whitehaven St NW Suite 4100, Washington DC, 20007 USA.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Tercyak
authors.affiliation: Schroeder Institute for Tobacco Research & Policy Studies, Truth Initiative, 900 G Street NW, Washington DC, 20001 USA.
authors.forename: Raymond S
authors.initials: RS
authors.lastname: Niaura
keywords: Electronic cigarettes; Non-smokers; Warning labels; Young adults