Myth: Alternative nicotine products are a gateway to smoking

Explaining the Gateway Hypothesis

Papers

2024: The “Gateway” hypothesis: evaluation of evidence and alternative explanations

• Conclusion: "Evidence offered in support of the gateway hypothesis does not establish that ENDS use causes youth to also smoke cigarettes. Instead, this evidence is better interpreted as resulting from a common liability to use both ENDS and cigarettes. Population-level trends are inconsistent with the gateway hypothesis, and instead are consistent with (but do not prove) ENDS displacing cigarettes. Policies based on misinterpreting a causal gateway effect may be ineffective at best, and risk the negative unintended consequence of increased cigarette smoking."
  • Citation: Selya, A. The “Gateway” hypothesis: evaluation of evidence and alternative explanations. Harm Reduct J 21, 113 (2024). https://doi.org/10.1186/s12954-024-01034-6
    • Acknowledgment: The author thanks Joe Gitchell, Sooyong Kim, and Saul Shiffman, all of Pinney Associates, Inc. for their feedback on an early draft of this manuscript, and Floe Foxon and Sooyong Kim for assistance with manuscript formatting. Through Pinney Associates, Inc., AS provides consulting services on tobacco harm reduction to Juul Labs, Inc. (JLI). JLI partially supported the preparation of this manuscript, and reviewed and commented on a near-final version. After the initial submission of this manuscript, AS also began individually providing consulting services on behavioral science to the Center of Excellence for the Acceleration of Harm Reduction (CoEHAR) through ECLAT Srl, which received funding from the Foundation for a Smoke-Free World (FSFW). Neither CoEHAR nor FSFW had any role in, or oversight of, this commentary.

Vaping Up < - > Smoking Down

Papers

2024: Increased e-cigarette use prevalence is associated with decreased smoking prevalence among US adults

• Nationally representative population-level data on tobacco product use by US adults continue to support the existence of an association between increasing prevalence of e-cigarette use and decreasing prevalence of cigarette smoking, i.e., possible substitution between cigarettes and e-cigarettes.
  • Citation: Foxon F, Selya A, Gitchell J, Shiffman S. Increased e-cigarette use prevalence is associated with decreased smoking prevalence among US adults. Harm Reduct J. 2024 Jul 18;21(1):136. doi: 10.1186/s12954-024-01056-0. PMID: 39026245; PMCID: PMC11256395.
    • Acknowledgment: Through PinneyAssociates, FF, AS, JG, and SS provide consulting services on tobacco harm reduction on an exclusive basis to Juul Labs Inc. The preparation of the previously-published version of this manuscript was funded by JLI, who reviewed and provided comments on a draft manuscript of the previously-published version. The present, updated version did not receive any funding or review from JLI, and was self-funded by PinneyAssociates. The content and the decision to publish are the responsibility of the authors. JG and SS also own interest in a novel nicotine gum that has neither been developed nor commercialized.

Critiques of Papers Claiming Gateway

2024: Comments RE: Association between e-cigarette use and susceptibility to tobacco product use: findings from the 2019 China National Youth Tobacco Survey

• "Causation vs. association. While the authors are careful in most places to avoid claiming that this association is causal, the authors seem to ultimately conclude in favor of a (causal) gateway hypothesis, which is inappropriate given unmeasured confounding by other “common liability” factors, and the cross-sectional nature of the data." (Selya)
• Referring to: Li S, Zeng X, Di X, Liu S. Association between e-cigarette use and susceptibility to tobacco product use: findings from the 2019 China National Youth Tobacco Survey. Front Public Health. 2024 Jan 15;11:1272680. PMID: 38288432; PMCID: PMC10823011 doi: 10.3389/fpubh.2023.1272680

2022: Comments RE: Impact of the e-cigarette era on cigarette smoking among youth in the United States: A population-level study

• "The present re-analysis shows that the report of a gateway effect in the NYTS data by Harrell et al. is not supported by these data when appropriate statistical methodology is applied." (Foxon)
• Referring to: Harrell MB, Mantey DS, Chen B, Kelder SH, Barrington-Trimis J. Impact of the e-cigarette era on cigarette smoking among youth in the United States: A population-level study. Prev Med. 2022 Nov;164:107265. Epub 2022 Sep 22. PMID: 36152819; PMCID: PMC10381788. doi: 10.1016/j.ypmed.2022.107265