Association between tobacco-related social environment and e-cigarette use among young adults in northern Vietnam: A cross-sectional study with latent class analysis

INTRODUCTION: Tobacco and e-cigarette use among cohabitants and friends tends to cluster together, but data are scarce regarding the association between the clustering patterns and e-cigarette use. The objectives of this study are to identify clusters of the tobacco-related environment and assess the extent to which these clusters are associated with e-cigarette use among young adults in Vietnam. METHODS: We carried out a cross-sectional study among Vietnamese undergraduate students in the second year of study or higher at two universities in Hanoi between September and December 2024. We used latent class analysis to identify clusters in a tobacco-related social environment. We performed multivariable logistic regression to assess the association between these clusters and ever e-cigarette use. RESULTS: Among our participants (n=1448 students), three distinct clusters/classes emerged: 1) Low exposure - participants with a low level of exposure to tobacco use in the social environment; 2) Parent smokers - participants who had parents who currently smoked; and 3) Peer smokers and/or e-cigarette users - participants with friends who currently smoked cigarettes and/or used e-cigarettes (64.9%, 24.6% and 11.5% of all participants, respectively). Participants from the parent smokers class (adjusted odds ratio, AOR=2.15; 95% CI: 1.06-4.34) and the peer smokers and/or e-cigarette users class (AOR=6.33; 95% CI: 3.10-13.07) were significantly more likely to be e-cigarette ever users than those from the low exposure class. CONCLUSIONS: The most common smokers in the social environment were parents and peers, whilst the most typical e-cigarette users were peers. The influence of having peers who smoked cigarettes and/or used e-cigarettes was stronger than the influence of having parents who smoked. The study findings provide basic information that may be useful to stakeholders in designing tailored anti-e-cigarette use campaigns. Campaigns should consider focusing on norms and spaces where young people often socialize.