Changing patterns of cigarette and ENDS transitions in the US: a multistate transition analysis of youth and adults in the PATH Study in 2015-17 vs 2017-2019

Introduction: It is unknown how recent changes in the tobacco product marketplace have impacted transitions in cigarette and electronic nicotine delivery system (ENDS) use. Methods: A multistate transition model was applied to 24,242 adults and 12,067 youth in Waves 2-4 (2015-2017) and 28,061 adults and 12,538 youth in Waves 4-5 (2017-2019) of the Population Assessment of Tobacco and Health (PATH) Study. Hazards for initiation, cessation, and product transitions were estimated in multivariable models, accounting for gender, age group, race/ethnicity, and daily vs non-daily product use. Results: Changes in ENDS initiation/relapse rates from never, non-current, and cigarette-only use depended on age group, including among adults. Among youth never users, the 1-year probability of ENDS initiation increased after 2017 from 1.6% (95%CI: 1.4-1.8%) to 3.8% (95%CI: 3.4-4.2). Persistence of ENDS-only use (1-year probability of remaining an ENDS-only user) increased for youth from 40.7% (95%CI: 34.4-46.9%) to 65.7% (95%CI: 60.5-71.1%) and for adults from 57.8% (95%CI: 54.4-61.3%) to 78.2% (95%CI: 76.080.4%). Persistence of dual use similarly increased for youth from 48.3% (95%CI: 37.4-59.2%) to 60.9% (95%CI: 43.0-78.8%) and for adults from 40.1% (95%CI: 37.0-43.2%) to 63.8% (95%CI: 59.6-67.6%). Youth and young adult dual users became more likely to transition to ENDS-only use but middle-aged and older adults did not. Conclusions: ENDS and dual use have become more persistent. Middle-aged and older adult dual users have become less likely to transition to cigarette-only use but not more likely to discontinue cigarettes. Youth and young adults are more likely to transition to ENDS-only use.