Associations between living in localities with e-cigarette sales restrictions and e-cigarette use change among young adults in Los Angeles County.

Introduction: Local e-cigarette sales restrictions (ESRs) may impact e-cigarette use. This study examined the associations between living in localities with various ESR policies and changes in e-cigarette use among young adults in Los Angeles (LA) County, California, USA.

Methods: Data were from a cohort of LA County young adults (18-21 years; n=2100) who completed two waves of surveys (Fall 2018-Summer 2019 and Summer-Fall 2020). Local flavoured (n=9) and comprehensive (n=2) ESRs in LA County implemented between June 2019 and May 2020 were identified, coded and merged with the baseline data. Multivariable logistic regressions were used to examine the associations between living in ESR localities and e-cigarette use at follow-up, controlling for covariates and stratified by cigarette smoking at baseline.

Results: Overall, 20.9% and 14.3% of participants lived in localities with flavoured and comprehensive ESRs, respectively. Participants who were non-Hispanic, had higher socioeconomic statuses and were currently using e-cigarettes were generally more likely to live in ESR localities than their counterparts. The associations between living in ESR localities and e-cigarette use at follow-up were not found among baseline non-e-cigarette users regardless of their cigarette smoking status; a positive relationship was found among baseline e-cigarette users who also smoked cigarettes but not among non-smokers.

Discussion: Participants who lived in localities with various ESR policies were different in their baseline e-cigarette use and socioeconomic backgrounds. Future research examining the potential impact of ESRs on e-cigarette use change should consider the localities' overall sociodemographic and tobacco-using characteristics and individuals' cigarette smoking histories.