Associations between Interpersonal Communication, Perceived Norms, and E-Cigarette Use: The Moderating Role of Social Network Size.

Background: Prior studies have found that e-cigarette-related interpersonal communication and perceived norms are associated with young adults' e-cigarette use. However, it is unclear whether social network size moderates these relationships. This study examined the relationship between interpersonal discussions, perceived norms, and e-cigarette use outcomes (i.e., daily vaping episodes and vaping days per week) and further examined whether network size moderates these relationships. Methods: The sample consisted of 670 college students (81% female, 82.8% white; M Results: There was a significant and positive association between e-cigarette-related interpersonal communication, daily vaping episodes, and vaping days per week, but not for perceived norms. In addition, we found a significant interaction between interpersonal communication and network size. Follow-up Johnson-Neyman analyses revealed that the association between the frequency of e-cigarette discussions and vaping days per week was significant and positive when network size was low to medium; however, this relationship changes and becomes non-significant when network size was high. Conclusions: The results highlight that young adults who are in smaller social networks and frequently discuss e-cigarettes may be susceptible to vaping multiple times per day and days per week. Therefore, interventions to reduce e-cigarette use among young adults may be particularly effective when implemented within smaller social networks.