Cannabis use and associated longitudinal transitions in electronic nicotine delivery systems use among young adults in the United States

Objective: Cannabis is increasingly the first substance used by young people and research indicates that cannabis use may precede the onset of tobacco use. Little is known, however, about the role of cannabis use in stages of electronic nicotine delivery systems (ENDS) uptake and progression across young adulthood. This study examined the associations between past 30-day (P30D) cannabis use frequency and transitions in ENDS use among young adults. Methods: 5,018 18-29-year-olds (64.2% female) were recruited from 24 Texas colleges to participate in a multi-wave study across a 4.5-year period from 2014 to 2019. A continuous time, multi-state Markov model was used to assess associations between P30D cannabis use frequency and three ENDS use transitions, spanning at least six months 1) never to P30D use (initiation); 2) P30D to non-P30D use (desistance); and 3) nonP30D to P30D use (re-uptake). The model also included socio-demographic and time-varying intrapersonal (other tobacco use, alcohol use, sensation seeking, depressive symptoms) and interpersonal (peer ENDS use) confounding factors. Results: Past 30-day cannabis use frequency was associated with an increased probability of ENDS initiation and decreased probability of desistance in the model adjusted for socio-demographic and confounding factors. Past 30-day cannabis use frequency was not associated with an increased probability of ENDS re-uptake in the adjusted model. Conclusions: Cannabis use is associated with the uptake and continuation of ENDS use. Findings are concerning given that the most popular ENDS devices used by young adults contain high concentrations of nicotine that increase the risk for nicotine dependence and lifelong use.