How do consumers perceive differences in risk across nicotine products? A review of relative risk perceptions across smokeless tobacco, e-cigarettes, nicotine replacement therapy and combustible cigarettes

Objective To systematically review the literature regarding relative risk perceptions (RRPs) across noncombustible nicotine products. Data sources MEDLINE and PsycINFO databases were searched for articles published up to October 2014. Study selection Of the 5266 records identified, articles not published in English that did not quantitatively assess RRPs across categories of non-combustible nicotine products were excluded, yielding 55 records. Data extraction One reviewer extracted measures and findings of RRPs for product comparisons of smokeless tobacco (SLT), e-cigarettes (ECs) and nicotine replacement therapy (NRT) to one another, and to combustible cigarettes (CCs). Data synthesis A total of 157 samples from 54 studies were included in the analyses. The accuracy of RRPs differed based on the products being compared: although the accuracy of RRPs was variable across studies, substantial proportions of respondents reported inaccurate beliefs about the relative harmfulness of SLT versus CCs, as well as of ECs versus NRT. In addition, in most studies, respondents did not know the relative harmfulness of SLT versus NRT. In contrast, respondents in many studies correctly perceived NRT and ECs as less harmful than CCs. Cigarette smokers and users of noncombustible nicotine products tended to correctly perceive the relative harmfulness of products more often than non-users. Measures used to assess RRPs varied across studies, with different approaches characterised by certain strengths and limitations. Conclusions The highly variable and context-specific nature of non-combustible nicotine product RRPs have direct implications for researchers and present several challenges for policymakers working with modified risk products, including issues of measurement, health risk communication and behaviour change.