Examining Indirect Effects of Advertising Exposure on Young Adults' Cannabis and Nicotine Vaping

Objective: To examine longitudinal associations between exposure to two types of advertisements (medical/recreational cannabis and e-cigarette retailers [vape shops]) and young adults' cannabis and nicotine vaping behavior. Positive and negative expectancies for cannabis and vaping nicotine were examined as mediators of these associations. Method: Secondary analysis of observational data from a longitudinal cohort of young adults recruited from Southern California (Wave 13: N = 2,411, 56% female, M-age = 23.6). Participants completed web-based surveys annually, reporting on advertising exposure in 2018, expectancies in 2019, and cannabis and nicotine vaping in 2020. Two path models were specified: (a) of past-month cannabis vaping only, nicotine vaping only, and co-use (vs. no vaping) and (b) of single product vaping (vs. co-use). Path analyses modeled direct and indirect associations between variables. Results: Controlling for past-month cannabis and nicotine use and other covariates, there were no significant direct associations of advertising exposure with cannabis and/or nicotine vaping. However, the association between cannabis advertising exposure and vaping (cannabis only) was significantly mediated by positive cannabis expectancies (b = 0.02, SE = 0.01, p = .03). Among those who vaped cannabis and/or nicotine in the past month at Wave 13, expectancies did not significantly mediate associations between advertising exposure and single product use (vs. co-use). Conclusions: Although exposure to cannabis advertisements may not be directly associated with young adults' cannabis vaping 2 years later, the effects of advertising exposure may be exerted indirectly by increasing positive beliefs about cannabis. Implications for public health policy are discussed.