Knowledge about chemicals in e-cigarette secondhand vapor and perceived harms of exposure among a national sample of U.S. adults

Abstract

Potentially harmful chemicals are detectable in e-cigarette secondhand vapor (hereafter SHV), contrary to advertising and marketing claims that it contains “only water vapor.” We assessed public knowledge about the presence of chemicals in SHV and associations between knowledge and perceived harms of exposure to SHV. We conducted an online survey of a nationally representative sample of 1449 U.S. adults (GfK's KnowledgePanel) from October-December 2013. Respondents were asked whether e-cigarette vapor contains only water vapor, contains tar, or contains formaldehyde (true/ false/ don't know). Responses to these three items were recoded (1=incorrect, 2=don't know, 3=correct) and averaged into a knowledge scale. They were also asked if they perceived breathing SHV to be harmful to one's health (two-item scale) and comparative harm of breathing SHV versus breathing secondhand smoke (SHS). Multiple regression analyses were weighted to the U.S. adult population and adjusted for potential confounders. Most respondents (58-75%) reported not knowing whether SHV contained only water vapor, if SHV contained tar, and if it contained formaldehyde. African-American respondents (versus white) and current smokers (versus non-smokers) had lower levels of knowledge about chemicals in SHV. Adjusting for covariates, correct knowledge about chemicals in SHV was associated with higher perceived harms about SHV for one's health and perceived comparative harm of SHV versus SHS. These findings suggest a need to provide accurate information about the presence of chemicals in SHV (e.g., using product ingredient labels or public education).