Since 2014, e-cigarettes have become the most-used tobacco product among youth in the United States (Park-Lee et al., 2022). The alarming rates of adoption among youth elicited calls for curbing youth use of e-cigarettes (U.S. Department of Health and Human Services, 2016). The adverse health effects of using e-cigarettes have been widely documented. Notable health risks include negative influences on respiratory systems, nicotine exposure, ultrafine particles, and toxicant exposure, and increased risk for cardiovascular diseases (e.g., Glantz and Bareham, 2018, Gotts et al., 2019, Layden et al., 2020, Lin et al., 2022, Academies and of Sciences, Engineering, and Medicine, , 2018, Siegel et al., 2019). Over the years, a growing consensus has emerged among health authorities, highlighting the needs to address predatory promotions and reduce initiation of e-cigarette use among youth non-users (e.g., Gaiha and Halpern-Felsher, 2020, Herbst et al., 2022). Further research is necessary to investigate the factors leading to youth e-cigarette vulnerability.

One important contributor to youth initiation of e-cigarette usage concerns exposure to e-cigarette content on social media (Lee et al., 2023, Pokhrel et al., 2021, Shan and Azagba, 2021, Stanton et al., 2022, Zheng et al., 2021). Social media have become increasingly important for youth’s daily communications. A 2023 Pew Research Center survey conducted in the United States found that over 95% of youth used at least one social media platform (Anderson et al., 2023). Furthermore, marketers used various social media platforms to promote e-cigarettes, which has contributed to the popularity of e-cigarettes among middle and high schoolers (see Lee et al., 2023, O'Brien et al., 2020). A burgeoning line of research has shown that social media usage is associated with e-cigarette initiation and use among youth (e.g., Cho et al., 2019, Clendennen et al., 2020, Lin et al., 2021, Massey et al., 2021). However, previous research has predominately focused on the impact of e-cigarette advertising and general content on social media; rarely has research examined the impact of user-generated content on youth e-cigarette vulnerability.

User-generated content refers to social media content created and shared by individual users including real life friends, online friends, and celebrities and influencers. Examining user-generated content is critical for developing a thorough understanding of how social media platforms shape e-cigarette-related behaviors among youth. This is because social media possess a distinctive capability, unlike traditional marketing avenues such as print ads; it enables the convergence of personalized messaging with expansive reach, a phenomenon termed as “masspersonal communication” by social media researchers (O’Sullivan & Carr, 2018). Messages from social media users and influencers exemplify masspersonal communication—they are personalized and intimate in tone, yet accessible and visible to a large group of audiences (Abidin, 2015). Research suggests that user-generated content facilitates word-of-mouth dissemination and increases social influence (e.g., Amin et al., 2020; Lee, Suttiratana et al., 2023). For this reason, user-generated content on social media has the potential to influence e-cigarette use behaviors.

Although significant, the impact of user-generated content on youth e-cigarette behaviors remains understudied. To contribute to this area, our study investigates the influence of exposure to user-generated e-cigarette content on vulnerabilities to e-cigarette use among youth who have never used them before.

Marketers have capitalized on the power of user-generated content on social media to promote e-cigarettes. For example, celebrity and influencer marketing, building pro-vape communities, and encouraging friend tagging are marketing strategies widely used by e-cigarette companies (Lee, Suttiratana, et al., 2023). Previous studies have identified a highly connected network of e-cigarette influencers on Instagram, with a large portion of followers being youth (Vassey et al., 2023). Additionally, social media posts created and shared by non-influencer/celebrity individuals is another important source of e-cigarette content. Previous studies revealed that online discussions about e-cigarettes tend to be positive (e.g., Martinez et al., 2018, Zhan et al., 2017). Users shared novel experiences of vaping on various social media platforms, such as novel flavors and new ways of using e-cigarettes (e.g., Wang et al., 2015, Zhan et al., 2017). Youth participants also revealed that social media e-cigarette content usually involves others documenting usage in their daily lives or showing off (Vogel et al., 2023). Therefore, both friends and influencers are important sources of e-cigarette content for youth on social media.

Exposure to e-cigarette content posted by influencers/celebrities and other individuals including real-life friends and online-only friends can increase youth non-users’ vulnerabilities toward e-cigarette use. In our study, vulnerabilities are defined as factors associated with increased likelihood of initiating e-cigarette use. Specifically, exposure to such content can be associated with a range of vulnerability factors, including perceived norms, perceived risk, and e-cigarette susceptibility, all of which are associated with e-cigarette use and initiation (e.g., Bold et al., 2017, Buu et al., 2022, Stanton et al., 2022, Zheng and Lin, 2023). First, exposure to those content can increase perceived norms of using e-cigarettes—the perception that vaping is prevalent and socially acceptable (Vogel et al., 2023). Previous research has demonstrated that people can infer descriptive norm (i.e., the prevalence) of e-cigarette use from the content shared within one’s online social networks (Liu & Shi, 2019). User-posted content with positive sentiment can also contribute to perceived injunctive norm (i.e., approval) of e-cigarette use (e.g., Cho et al., 2019). Second, exposure to social media e-cigarette content posted by individuals may reduce perceived harm of e-cigarettes. Posts with positive sentiment about e-cigarette use, such as content highlighting flavor and health benefits of e-cigarettes, could lower youth’s risk expectancies of using e-cigarettes (Krishen et al., 2021, Wagoner et al., 2022).

Exposure to e-cigarette content posted by influencers/celebrities, real-life friends and online-only friends can increase susceptibility to future e-cigarette use (susceptibility thereafter) among youth non-users. For example, celebrity and influencer endorsed social media messages were found to increase perceived pleasure and benefits toward e-cigarettes (Phua et al., 2018), enhancing susceptibility among non-users (see Kwon et al., 2018, Pokhrel et al., 2019). Exposure to social media posts featuring vaping behaviors was found to be associated with susceptibility to use e-cigarettes (Hébert et al., 2017). Research has also found that exposure to user generated e-cigarette content can elicit curiosity, a core component of susceptibility, among youth non-users (Vogel et al., 2023).

Taken together, the current study tried to fill the literature gap by examining the associations between user-generated e-cigarette content on social media and vulnerability to e-cigarette use among youth non-users. We hypothesize that exposure to user-generated e-cigarette content on social media (specifically from real-life and online-only friends, celebrities or influencers) heightens the vulnerability of youth to e-cigarette usage. Specifically, this exposure is posited to correlate with a range of vulnerability factors, including stronger perceived norms, a diminished perception of risk, and a heightened susceptibility to e-cigarette use.