Transitions in cigarette and ENDS use in the PATH Study: a multistate transition model analysis of adults in 2021-2022 compared to previous years

IntroductionElectronic nicotine delivery systems (ENDS) products continue to evolve, and so ongoing analysis of transition rates over time is important for tracking real-world associations between ENDS and cigarette use and for providing the information necessary to project future public health outcomes. MethodsUsing the Population Assessment of Tobacco and Health (PATH) Study Waves 6-7 (2021-2022), we applied a Markov multistate transition model to estimate transition rates for initiation and cessation of each product. We estimated one-year transition probabilities for each transition. These results were compared to estimated rates and probabilities in Waves 1-6 (2014- 2021). ResultsThe fraction adopting ENDS use in 2021-22 among those who had never previously established tobacco product use, those not currently using tobacco products, and those currently smoking cigarettes increased to 0.5% (95% confidence intervals [CI]: 0.4, 0.6%), 2.7% (95% CI: 2.3, 3.2%), and 6.8% (95% CI: 6.1, 7.6%), respectively. These increases were driven by young adults (ages 18-24), with respective transition fractions of 2.7% (95% CI: 2.3, 3.2%), 23.6% (95% CI: 20.2, 27.0%), and 19.2% (95% CI: 14.0, 24.5%). The fraction of adults who transitioned from dual cigarette and ENDS use to cigarette-only use remained around 25% (26.2% [95% CI: 21.7, 30.7%]), while the fraction who transitioned to ENDS-only use increased to 24.2% (95%CI: 20.5, 27.9%). The increase in the dual to ENDS-only use transition was also driven by young adults (34.4% [95% CI: 26.2, 42.6%]) and adults ages 25-34 (29.4% [95% CI: 23.1, 35.7%]). ConclusionPublic health efforts are needed to promote cigarette cessation among older adults, specifically. What this paper addsO_ST_ABSWhat is already known on this topicC_ST_ABSO_LITransitions in cigarette and ENDS use have been changing over time. Young adults have been early adopters of ENDS, with older adults less likely to try ENDS or to completely switch from cigarettes to ENDS. C_LIO_LIFrequency of product use likely impacts the likelihood of product quitting or switching. C_LI What this study addsO_LIWe found increasing adoption of ENDS among adults who have never smoked, those not currently using cigarettes or ENDS, and those using cigarettes only. These patterns were driven by young adults, with little cigarette cessation or switching to ENDS among older adults. C_LIO_LIDaily (vs non-daily) use of ENDS facilitated cigarette cessation among those using cigarettes and ENDS, but it was a barrier to ENDS cessation among those using ENDS only. C_LI How this study might affect research, practice, or policyO_LIPublic health efforts are needed to promote cigarette cessation among older adults who smoke, many of whom may already be experiencing the health effects of tobacco use. C_LIO_LIStudies are needed to develop strategies for leveraging ENDS to maximize smoking cessation while also helping those who successfully quit smoking to avoid long-term ENDS use. C_LI