Interpersonal communication and perceived norms as social influence mechanisms of e-cigarette use among adults: a systematic review.

Background: Given the increasing popularity of e-cigarette use among adults and the ongoing debate about the benefits and the potential adverse health risks associated with e-cigarette use, it is critical to identify the correlates of e-cigarette use. Prior research has found associations between interpersonal communication, perceived norms, and adults' e-cigarette use, but the evidence has yet to be summarized and synthesized.Objectives: This paper reviewed empirical studies examining the relationship between interpersonal communication, perceived norms, and e-cigarette use among adults.Methods: Following PRISMA guidelines, articles were searched on DOAJ, EMBASE, Europe PubMed Central, Google Scholar, PsychINFO, PubMed, Web of Science, and the reference list of the retrieved studies for studies that examined social influence on e-cigarette use. Three reviewers independently screened 1,713 non-duplicate papers and further screened the full text of 195 articles for inclusion.Results: Thirty studies (30), consisting of quantitative (n = 25) and qualitative (n = 5) data, were included in this review. The twenty-five (25) quantitative studies consisted of both cross-sectional (n = 20) and longitudinal (n = 5) studies. Interpersonal communication portraying e-cigarettes as beneficial or harmful was found to increase e-cigarette use and quit attempts, respectively. Across study designs, greater perceptions of others' e-cigarette use or approval were related to more frequent e-cigarette use.Conclusions: The findings highlight that e-cigarette-related interpersonal communication and perceived norms are associated with e-cigarette use. These factors may be useful targets in brief interventions. However, most of the included studies were cross-sectional, limiting the ability to establish clear cause-and-effect relationships; therefore, more longitudinal studies are needed.