The effect of conflicting public health guidance on smokers' and vapers’ e-cigarette harm perceptions

Background: E-cigarettes are increasingly being viewed, incorrectly, as more harmful than cigarettes. This may discourage smokers from switching to e-cigarettes. One potential explanation for these increasingly harmful attitudes is conflicting information presented in the media, online and from public health bodies.

Methods: In a prospectively registered online study, daily UK smokers who do not vape (n=334) and daily UK vapers (n=368) were randomised to receive either: 1) a consistent harm reduction statement from two different public health bodies (Harm Reduction); 2) a consistent negative statement about e-cigarette harms from two different public health bodies (Negative); 3) a harm reduction statement from one public health body and a negative statement from another (Conflict); 4) a statement of the risks of smoking followed by a harm reduction statement from one public health body and a negative statement from another (Smoking Risk + Conflict). Participants then answered questions regarding their perceptions of e-cigarette harm.

Results: The Negative condition had the highest e-cigarette harm perceptions, significantly higher than the Smoking Risk + Conflict condition (MD=5.4, SE=1.8, p<.016, d=0.3 [CI 0.73 to 10.04]), which did not differ from the Conflict condition (MD=1.5, SE=1.8, p=.836, d=0.1 [CI -3.14 to 6.17]). The Conflict condition differed from the Harm Reduction condition, where harm perceptions were lowest (MD=5.4, SE=1.8, p=.016, d=0.3 [CI 0.74 to 10.07]).

Conclusions: These findings are the first to demonstrate that, compared to harm reduction information, conflicting information increases e-cigarette harm perceptions amongst vapers, and smokers who do not vape.