Abstract
BACKGROUND: A supportive youth cigarette social environment, for example, friends' approval of use, leads to cigarette use initiation, and cigarette users develop a more supportive social environment. Whether there is a bidirectional relationship of electronic cigarette (e-cigarette) social environment with e-cigarette use has not been studied. METHODS: Prospective data were collected from 1441 Children's Health Study participants in 2014 (median age = 17.3 years) and at follow-up 1.5 years later. Associations were examined of (1) supportive e-cigarette social environment with subsequent e-cigarette use initiation and (2) baseline e-cigarette use with supportive e-cigarette social environment at follow-up (among those with a nonsupportive baseline social environment). RESULTS: Participants with three to four friends using e-cigarettes at baseline (vs. no friends) had an odds ratio (OR) of 4.08 of subsequent initiation (95% confidence interval [CI] = 1.96 to 8.49); those with best friends who would have a very friendly (vs. unfriendly) reaction to e-cigarette use had an OR of 2.54 of initiation (95% CI = 1.57 to 4.10); and those with someone in the home using e-cigarettes had an OR of 1.94 of initiation (95% CI = 1.19 to 3.15). Participants who had ever used e-cigarettes at baseline developed a supportive social environment at follow-up (OR of 2.06 of having any friends who used e-cigarettes [95% CI = 1.29 to 3.30] and OR of 2.33 of having friends who were friendly toward use [95% CI = 1.32 to 4.11]). Similar bidirectional associations were observed between ever cigarette use and a supportive cigarette social environment. CONCLUSIONS: The bidirectional relationship between a supportive e-cigarette social environment and ever use of e-cigarettes was similar to that previously observed between cigarette social environment and cigarette use. IMPLICATIONS: Disrupting the social acceptability of youth e-cigarette use merits consideration as a strategy for preventing initiation of e-cigarette use, just as the social denormalization of cigarette use has proven to be effective in preventing cigarette initiation.