Changes in Tobacco Dependence and Association With Onset and Progression of Use by Product Type From Waves 1 to 3 of the Population Assessment of Tobacco and Health (PATH) Study

IntroductionThis study examined trajectories of tobacco dependence (TD) in relationship to changes in tobacco product use, and explored the effects of product-specific adding, switching, or discontinued use on dependence over time.MethodsData were analyzed from the first three waves from the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal study of adults and youth in the United States (U.S.). Data included 9556 Wave 1 (2013/2014) adult current established tobacco users aged 18 or older who completed all three interviews and had established use at ≥2 assessments. Mutually exclusive groups included: users of cigarettes only, e-cigarettes only, cigars only, hookah only, any smokeless only, cigarette + e-cigarette dual users, and other multiple product users. A validated 16-item scale assessed TD across product users.ResultsPeople who used e-cigarettes exclusively at Wave 1 had small increases in TD through Wave 3. Wave 1 multiple product users' TD decreased across waves. TD for all other Wave 1 user groups remained about the same. For Wave 1 cigarette only smokers, switching to another product was associated with lower levels of TD than smokers whose use stayed the same. Movement to no established use of any tobacco product was consistently associated with lower TD for all product users.ConclusionsExcept for Wave 1 e-cigarette only users (who experienced small increases in TD), TD among U.S. tobacco product users was stable over time, with daily users less likely to vary from baseline.ImplicationsThe level of TD among most U.S. tobacco users was stable over the first three waves of the PATH Study and trends in levels of TD were predominantly unrelated to changes in patterns of continued product use. Stable levels of TD suggest a population at persistent risk of health impacts from tobacco. Wave 1 e-cigarette users experienced small increases in levels of TD over time, perhaps due to increases in quantity or frequency of their e-cigarette use or increasing efficiency of nicotine delivery over time.