Perceptions about levels of harmful chemicals in e-cigarettes relative to cigarettes, and associations with relative e-cigarette harm perceptions, e-cigarette use and interest.

BACKGROUND AND AIMS: Exposure to chemicals contributes to harm from nicotine products, and e-cigarette communications often refer to chemicals. However, while e-cigarette studies commonly measure perceived harmfulness of e-cigarettes relative to cigarettes, few have assessed comparative perceptions about chemicals. This study measured perceived levels of harmful chemicals in e-cigarettes compared with cigarettes and associations with e-cigarette/cigarette relative harm perceptions, e-cigarette use and interest. DESIGN, SETTING AND PARTICIPANTS: This was an on-line cross-sectional survey of adults/young adults from a nationally representative research panel in the United States conducted in January 2021. Participants were independent samples of 1018 adults who smoked cigarettes and 1051 young adult non-smokers (aged 18-29 years). MEASUREMENTS: Participants were asked their perceptions of the level of harmful chemicals in e-cigarettes versus cigarettes (fewer/about the same/more/do not know), perceived harmfulness of using e-cigarette versus cigarettes (less/about the same/more/do not know) and their current e-cigarette use and use interest. FINDINGS: Approximately 20% of all participants (18.1% of adult smokers, and 21.0% of young adult non-smokers) believed e-cigarettes contain fewer harmful chemicals than cigarettes, while 35.6% of adult smokers and 24.9% of young adult non-smokers responded 'do not know'. Participants more frequently reported 'do not know' to the chemicals item than the harm item. Approximately half (51.0-55.7%) of those who believed e-cigarettes contain fewer harmful chemicals also believed e-cigarettes are less harmful than cigarettes. Both beliefs were associated with higher odds of interest in using e-cigarettes [less harmful belief, odds ratio (OR) = 5.53, 95% confidence interval (CI = 2.93-10.43); fewer chemicals belief, OR = 2.45, 95% CI = 1.40-4.29] and past 30-day e-cigarette use (less harmful belief, OR = 2.53, 95% CI = 1.17-5.44; fewer chemicals belief, OR = 5.09, 95% CI = 2.31-11.19) for adults who smoke, but not young adult non-smokers. CONCLUSIONS: In the United States, most adults who smoke cigarettes and young adult non-smokers do not appear to think that e-cigarettes have fewer harmful chemicals than cigarettes, and many are uncertain about how these levels compare.