Inductive Characterization of ENDS-Associated Adverse Events Among California Young Adults

•Young adult E-cigarette users report more than 40 distinct adverse events.•E-cigarette‒related adverse event experiences vary greatly along multiple variables.•The most common E-cigarette‒related adverse events tend to cluster with each other. Previous studies have identified numerous adverse events experienced with the use of ENDS or E-cigarettes. However, much remains unknown about adverse event frequency, duration, and response experienced by users. The purpose of this study was to inductively characterize ENDS-attributed adverse events among young adults. Sixteen focus groups were held with 114 young adults (aged 18–29 years) who have reported lifetime ENDS use in April 2021. Discussion topics included current and previous tobacco, nicotine, and cannabis use; specific symptoms and frequency and duration of and response to symptoms of ENDS-attributed adverse events; and the impact of other conditions such as COVID-19 on ENDS use. Data were inductively analyzed using a team-based approach. More than 40 ENDS-attributed adverse events were reported in focus groups among approximately three quarters of all study participants, with headache, coughing, lightheadedness, nausea, dry or sore throat, and dizziness the most common. In general, adverse events were transient, with most resolving in a few hours, although some tended to last for longer. The frequency of adverse events varied most between every time ENDS were used and when someone vaped excessively. Finally, behavioral responses varied by adverse events, with difficulty in breathing, chest pain, and lung discomfort more likely to result in quitting permanently. Overall, the results of this study show that not only do adverse events vary greatly, but they also vary across multiple dimensions of user experience.