Does Adding Modified Risk Statements to E-Cigarette Advertisements and Packages Change Risk Beliefs? A Systematic Review and Meta-Analysis

Introduction Modified risk statements (MRS), claiming e-cigarettes are less harmful than cigarettes, attempt to alter tobacco risk beliefs but may conflict with warning messages. Absolute risk beliefs reflect the perceived likelihood of harm from e-cigarettes, while relative risk beliefs reflect the likelihood of harm from e-cigarettes versus cigarettes. This systematic review and meta-analysis examined whether adding MRS to e-cigarette advertisements and packages containing warnings affects risk beliefs and intentions to vape. Methods We searched PubMed, Embase, Scopus, PsycInfo, and Business Source Premier, and supplemental sources, identifying 10 eligible experimental studies (N = 11,025). Studies compared e-cigarette advertisement or packages containing warnings with versus without MRS. Random-effects meta-analyses estimated effect sizes (d), heterogeneity, and three moderators. Databases were last searched in May 2025. Risk of bias was assessed using a modified JBI tool for randomized controlled trials. Results Compared with no MRS, advertisements and packages containing MRS reduced absolute risk beliefs of e-cigarettes (d = - 0.08, p = .003). No significant effects emerged for relative risk beliefs (d = - 0.05, p = .108) or intentions to vape (d = 0.03, p = .173). Smoking status moderated effects on relative risk beliefs (p = .03); MRS reduced relative risk beliefs that e-cigarettes are more harmful than cigarettes among non-smokers only (d = -0.12). Conclusions MRS lowered absolute risk beliefs, but the effect was very small and MRS did not affect overall relative risk beliefs or intentions to vape. Given the modest number of studies available for this review, additional work is needed on communicating about the continuum of tobacco product risk. Funding NIH/NIDA (R01DA049155) and NCI (R37CA222002). Registration OSF(https://osf.io/8t9hz)