Changes of Harm Perception and Effect of Health Warnings on Electronic Cigarette Use in US Youth

This dissertation 1) assessed the influence of electronic nicotine delivery systems (ENDS) harm perception on ENDS initiation over time among US youth and young adults; 2) tracked the changes in harm perception of ENDS use and examined their predictors among US youth; 3) conducted a pilot study to address the effectiveness of graphic health warning labels (GHWLs) on important outcomes among US young adult ENDS users. Data from 2013-2018 of the Population Assessment of Tobacco and Health (PATH) study were used for aims 1 & 2. Primary data with 26 participants that were collected from university campus during the year 2019 were used for aim 3. In the first study, 17.1% of adolescents and 25.5% of young adults who never used ENDS at Wave 1, initiated ENDS use in subsequent waves. Perceiving ENDS as lower relative harm predicted ENDS initiation among adolescents (HR=2.33; 95%CI: 1.98-2.74) and young adults (HR=2.01; 95%CI: 1.72-2.36). Perceiving ENDS as lower absolute harm (HR=2.22; 95%CI: 1.87-2.63) predicted ENDS initiation among adolescents. In the second study, adolescents who perceived ENDS as lower relative and absolute harm significantly decreased between Wave 1 and Wave 4 (P’s The final study evaluated the effect of placing GHWLs on the ENDS devices on users’ experience. Compared to the control sessions, using JUUL with GHWLs on the device was significantly associated with reduced positive experience such as pleasure, and product liking (P’s This study highlighted the importance of harm perception for ENDS initiation and the central role of risk communication strategies that need to target young people at risk of unwarranted ENDS use. Additionally, this proposal emphasized the demand for more effective tobacco regulatory policies to deter the ENDS epidemic among young people.