Selya Arielle S
Behavioral Sciences Group, Sanford Research, 2301 East 60th Street North, Sioux Falls, SD, 57104, USA.
Department of Pediatrics, University of South Dakota Sanford School of Medicine, 1400 West 22nd St, Sioux Falls, SD, 57105, USA.
Harm Reduct J. 2021 Mar 20;18(1):36. doi: 10.1186/s12954-021-00484-6.
Electronic cigarettes ("e-cigarettes") have altered tobacco smoking trends, and their impacts are controversial. Given their lower risk relative to combustible tobacco, e-cigarettes have potential for harm reduction. This study presents a simulation-based analysis of an e-cigarette harm reduction policy set in the USA.
A system dynamics simulation model was constructed, with separate aging chains representing people in different stages of use (both of combustible cigarettes and e-cigarettes). These structures interact with a policy module to close the gap between actual (simulated) and goal numbers of individuals who smoke, chosen to reduce the tobacco-attributable death rate (i.e., mostly combustible cigarette-attributable, but conservatively allowing e-cigarette-attributable deaths) to that due to all accidents in the general population. The policy is two-fold, removing existing e-liquid flavor bans and providing an informational campaign promoting e-cigarettes as a lower-risk alternative. Realistic practical implementation challenges are modeled in the policy sector, including time delays, political resistance, and budgetary limitations. Effects of e-cigarettes on tobacco smoking occur through three mechanisms: (1) diversion from ever initiating smoking; (2) reducing progression to established smoking; and (3) increasing smoking cessation. An important unintended effect of possible death from e-cigarettes was conservatively included.
The base-case model replicated the historical exponential decline in smoking and the exponential increase in e-cigarette use since 2010. Simulations suggest tobacco smoking could be reduced to the goal level approximately 40 years after implementation. Implementation obstacles (time delays, political resistance, and budgetary constraints) could delay and weaken the effect of the policy by up to 62% in the worst case, relative to the ideal-case scenario; however, these discrepancies substantially decreased over time in dampened oscillations as negative feedback loops stabilize the system after the one-time "shock" introduced by policy changes.
The simulation suggests that the promotion of e-cigarettes as a harm-reduction policy is a viable strategy, given current evidence that e-cigarettes offset or divert from smoking. Given the strong effects of implementation challenges on policy effectiveness in the short term, accurately modeling such obstacles can usefully inform policy design. Ongoing research is needed, given continuing changes in e-cigarette use prevalence, new policies being enacted for e-cigarettes, and emerging evidence for substitution effects between combustible cigarettes and e-cigarettes.
电子烟已经改变了吸烟趋势，其影响存在争议。鉴于电子烟相对于可燃烟草风险较低，具有减少危害的潜力。本研究对美国一项电子烟减少危害政策进行了基于模拟的分析。
构建了一个系统动力学模拟模型，有独立的老化链代表处于不同使用阶段的人群（包括可燃香烟和电子烟使用者）。这些结构与一个政策模块相互作用，以缩小实际（模拟）吸烟人数与目标吸烟人数之间的差距，目标是将烟草归因死亡率（即主要是可燃香烟归因死亡率，但保守地考虑电子烟归因死亡率）降低到与普通人群中所有事故归因死亡率相当的水平。该政策有两方面，一是取消现有的电子烟液口味禁令，二是开展宣传活动，宣传电子烟是一种低风险替代品。在政策领域对现实的实际实施挑战进行了建模，包括时间延迟、政治阻力和预算限制。电子烟对吸烟的影响通过三种机制发生：（1）使人们不再开始吸烟；（2）减少发展为长期吸烟的情况；（3）增加戒烟率。保守地考虑了电子烟可能导致死亡这一重要的意外影响。
基础模型复制了自2010年以来吸烟人数的历史指数下降和电子烟使用人数的指数增长。模拟结果表明，实施该政策约40年后吸烟人数可降至目标水平。实施障碍（时间延迟、政治阻力和预算限制）在最坏情况下可能会使政策效果延迟并减弱高达62%，相对于理想情况而言；然而，随着负反馈回路在政策变化带来的一次性“冲击”后使系统稳定，这些差异会随着时间的推移在衰减振荡中大幅减小。
模拟表明，鉴于目前有证据表明电子烟可抵消或转移吸烟行为，将推广电子烟作为减少危害的政策是一项可行的策略。鉴于实施挑战在短期内对政策效果有很大影响，准确模拟这些障碍可为政策设计提供有益参考。鉴于电子烟使用流行率持续变化、针对电子烟颁布的新政策以及可燃香烟和电子烟之间替代效应的新证据不断出现，仍需开展持续研究。
