Recall of Flavor at First E-cigarette Use and Its Association with E-cigarette Progression: The Mediating Effects of First Sensory Experience.

Objective: To test whether the association between flavor at first vape and continued use is mediated through subjective experience at first vape.

Study Design: In a 2020 cross-sectional survey, 955 young adult ever-vapers recalled their first flavor vaped, subjective experiences at first use, current vaping behavior, nicotine dependence, and quit attempts. A latent class model grouped first-use subjective experiences into classes. Two-part negative binomial hurdle models for each vaping behavior evaluated whether the association of first flavor used with vaping outcomes was mediated by positive experience.

Results: Four latent classes (positive, positive and negative, negative, and minimal experience) were further reduced to "any positive experience" (only positive, positive and negative) vs "no positive experience" (negative or minimal). Class membership mediated the association of first flavor used (mint/menthol/ice [ie, "cooling"] or sweet vs other) with each vaping outcome. For example, cooling flavor (vs. other) was associated with positive class membership (OR = 3.5; 95% CI: 1.5, 8.1), which was then associated with any past 30-day vaping (OR = 3.9; 95% CI: 2.7, 5.8) and greater number of vaping days among current vapers (RR = 1.9; 95% CI: 1.3, 2.7) in the two-part hurdle model. Similar results were observed for nicotine dependence and quit attempts, and for sweet (vs other) flavor for any dependence or quit attempts, but not number of dependence symptoms or quit attempts.

Conclusions: Use of a cooling or sweet flavor at first use was associated with having a positive first vaping sensory experience, and then greater likelihood as a young adult of reporting past 30-day vaping, more vaping days, and greater risk for nicotine dependence, suggesting a key mediating role of first use experience.