Understanding patterns of electronic nicotine delivery systems use among young adults

Research is lacking on patterns of young adult current (i.e., past 30-day) ENDS use. The aim of this dissertation was to examine 1) latent classes of young adult current ENDS users and common characteristics of young adults in these classes, and 2) if latent class membership predicted subsequent ENDS use behaviors among a cohort of young adults in Texas. For Study 1, participants were 463 young adults aged 19-31 years, drawn from wave 4 (April-May 2016) of the Marketing and Promotions across Colleges in Texas project (Project M-PACT). Latent Class Analysis using six indicator variables was conducted to discern classes of young adult current ENDS users. For Study 2, participants were 424 young adults who participated in Study 1 and had complete data on wave 6 (April-May 2017). The Study 2 hypotheses tested if classification in the highest risk class predicted subsequent current ENDS use, ENDS nicotine dependence symptoms, and using ENDS more frequently one year later. Logistic and multiple regression analyses were used to test the Study 2 hypotheses. Findings from Study 1 identified three distinct classes of users, including non-nicotine dependent social ENDS users, high-risk poly-tobacco and substance users, and nicotine dependent ENDS users. Classes varied on sex, race/ethnicity, age, type of college attended, and current use of other tobacco products. Findings from Study 2 confirmed the hypothesis that membership in the highest risk class of high-risk poly-tobacco and substance users elevated risk for subsequent current ENDS use, ENDS nicotine dependence symptoms, and using ENDS more frequently one year later, compared to the lowest risk class of non-nicotine dependent social ENDS users, after accounting for covariates. Findings also confirmed the hypothesis that membership in the highest risk class of high-risk poly-tobacco and substance users also elevated risk for subsequent ENDS nicotine dependence symptoms and frequency of ENDS use one year later, compared to the nicotine dependent ENDS users, after accounting for covariates. Results underscore the heterogeneity among young adult current ENDS users and the need for development of distinct tobacco control messaging and intervention strategies tailored to different classes of young adult ENDS users.