Oral Nicotine Product Use and E-Cigarette Use Persistence in Adolescents and Young Adults: An Analysis Using Augmented Inverse Probability Weighting.

The impact of oral nicotine product (ONP) use on e-cigarette use persistence among adolescents and young adults (AYA) remains unclear. We applied augmented inverse probability weighting (AIPW) with machine learning (ML) to reduce bias from model misspecification and improve precision of treatment effect estimates. We combined data from two Southern California cohorts of adolescents (n=269; M[SD]=16.3[0.6] years) and young adults (n=449; age M[SD]=23.4[0.4] years) who reported past 6-month e-cigarette use at baseline in 2022 and were re-assessed an average of 8 months later in 2023. We examined the effects of baseline ONP use on e-cigarette use persistence using AIPW with ML, with analyses stratified by age group. Among 718 AYAs (53.1% female; 58.4% Hispanic), 14.2% reported ONP use at baseline and 64.3% reported persistent e-cigarette use at follow-up. Adolescents who used ONPs had a lower risk of e-cigarette persistence compared with non-users (risk difference=-0.18, 95% CI=-0.31, -0.04; risk ratio=0.70, 95% CI=0.52, 0.95), whereas no association was observed among young adults. Findings suggest ONPs may serve as a partial substitute for e-cigarettes among adolescents, but not young adults. Regulatory policies should balance potential harm-reduction benefits with age-specific risks and address dual e-cigarette and ONP among young adults.