Electronic Nicotine Delivery Systems (ENDS)


The effect of menthol on ENDS users' dependence, respiratory, and toxicants emission outcomes (2022-2027)

The use of electronic nicotine delivery systems (ENDS; e-cigarettes) has reached epidemic levels among young people in the United States (US). ENDS heat and vaporize a nicotine-containing liquid to produce an inhalable aerosol mist. While generally considered less harmful than combustible cigarettes, ENDS use exposes users to dependence-producing nicotine and respiratory and cardiovascular toxicants such as aldehydes. Flavor is a major factor in getting young people to use ENDS, thus limiting flavors to menthol and tobacco for prefilled cartridge ENDS “pod mods” was the first major action taken by the FDA to reduce the spread of ENDS among young people. Menthol flavor, however, can present a potential risk given its increasing popularity among young people in the US, and its puffing and nicotine-enhancing properties. Yet, the extent of menthol’s ability to affect users’ experience and puffing patterns, and how these affect dependence, exposure to toxicants, and clinical outcomes continue to be understudied. Such evidence will be critical to the FDA’s ability to set further regulatory standards to reduce ENDS potential harm. Our team of experts in tobacco regulatory science will apply clinical and analytical laboratory methods to address this gap in evidence by conducting a 2×2 (pre-post x menthol vs. tobacco flavor) crossover clinical lab study. We will recruit current/past month ENDS users (n=200, 21-35 yrs), who will come to the lab for two sessions and use their ENDS once with menthol and once with tobacco flavors. While we apply standard and well-tested lab models suitable for regulatory-related research, we have supplemented these with cutting-edge puffing robot technology to detect ENDS-associated emissions of toxicants. The proposed studies will answer two key regulatory questions consistent with FDA’s focus on the role of flavor in tobacco products’ addiction and toxicity; 1) compared to tobacco flavor, does menthol carry additional risk by enhancing puffing, abuse liability, and toxicant exposure in ENDS users, and; 2) is this effect more pronounced among high dependence compared to other users. Other outcomes such as harm perception, satisfaction, clinical responses, intention to use or quit, and group comparisons such as according to race, and sex will allow the FDA a comprehensive assessment of the pros and cons of regulating mentholated ENDS for different segments of the society. Such evidence will help advance FDA regulatory policies with the potential to reduce ENDS harm.

Funding source: NIH 5R01DA055937

Assess the Influence of Nicotine Flux and Nicotine Form on Subjective Effects Related to Dependency (2022-2025)

Electronic nicotine delivery systems (ENDS) heat and vaporize a nicotine-containing liquid to produce an aerosol that can deliver nicotine to the blood and the brain. ENDS use has increased rapidly in the last decade, especially among youth: over 20% of US high school students are current ENDS users, and there is evidence of nicotine dependence in this population. Federal legislation has been proposed that would restrict ENDS liquid nicotine concentration to make ENDS “significantly less addictive and appealing to youth.” However, these and other efforts to curb addiction by limiting nicotine liquid concentration are unlikely to succeed because nicotine emissions from ENDS depend on multiple variables. To achieve the intended public health aims, regulations targeting addiction must focus on nicotine delivery, not nicotine concentration. While nicotine delivery cannot be regulated directly, the rate at which an ENDS emits nicotine, the “nicotine flux”, can be regulated and, importantly, predicted based on a few device design and operating variables. However, to date there is no empirical evidence demonstrating the relationship between flux and delivery, nor between flux and the subjective effects that support nicotine dependence. Closing this gap is essential for providing an effective framework for regulating ENDS. At the American University of Beirut, the investigators will assess the relationship between nicotine flux, form, and subjective effects. Participants will use ENDS devices with varying nicotine fluxes and forms. Dependency measures, such as urge to smoke, craving, and abstinence, will be assessed. The outcome will indicate the degree to which nicotine flux/form influence subjective effects related to dependency, puffing intensity, and exposure to toxicants. In summary, this project will provide the empirical evidence needed for public health agencies to use nicotine flux as an encompassing and convenient construct to regulate nicotine delivery from ENDS.

Funding source: NIH R01DA052565

Assessing the effect of nicotine reduction on ENDS user's addiction and exposures (2021-2024)

The use of electronic nicotine delivery systems (ENDS or e-cigarettes) has reached epidemic levels among young people in the United States (US). ENDS emit toxic substances, including nicotine that irreversibly affects the developing brain and leads to dependence and increased risk of cigarette smoking initiation. Evidence indicates that young people using ENDS are likely to accelerate use and become nicotine dependent. Some of the most popular ENDS among youth (e.g. JUUL with 5% nicotine liquid) deliver in one cartridge a nicotine dose equal to an entire pack of cigarettes, and many users are unaware of this substantial exposure and the related risk of addiction. On the other hand, nicotine reduction (NR) has been considered by the US Food and Drug Administration (FDA) as an important strategy to limit the addictiveness and use of tobacco products. Now that the FDA regulates ENDS under the “deeming rule”, such a strategy can be considered for these emerging tobacco products. However, we still lack evidence on the expected effects of a range of NR levels on ENDS users at different stages of use trajectory. Using clinical and analytical lab methods we plan to compare among 5% nicotine ENDS users the effect of partial (3%) or total (nicotine-free, 0%) NR on users’ dependence, satisfaction, clinical (e.g. BP, oximetry, lung functions, symptoms), puffing behavior, and exposure to toxicants. We will recruit current ENDS users (n=120; 21-35 yrs), for a 3X2X2 within-between subject crossover lab study. Because the effect of NR on ENDS users will likely vary by frequency and stage of ENDS use, we will study NR effects in high vs. low-frequency users (use on ≥ 20 vs. < 20 days/past month). Therefore, the 3 nicotine conditions (5%, 3%, 0%) x 2 times (pre-post) are the within-subject factors, while the frequency of use is the between-subject factor. We hypothesize that NR will be associated with less satisfaction, withdrawal suppression, and intention to use and that such an effect will be more pronounced in total compared to partial NR and among high compared to low-frequency users. The proposed studies aim to answer 3 main regulatory questions: 1) is NR a promising regulatory option to reduce ENDS addictiveness and use; 2) what is the effect of partial vs. total NR on compensatory puffing and exposure to nicotine and respiratory toxicants, and 3) what is the effect of NR on ENDS users at different stages of their use. Combined, these studies will give direct and standardized evidence on the potential of NR regulations to limit the addictiveness and use of ENDS, and to help predict any potential side effects of NR on ENDS users’ exposure to harmful toxicants.

Funding source: NIH 5R01DA053587


Project 1: Using toxicity testing data to test hypotheses about advanced-generation ECIGs and generate population-level predictions regarding potential regulatory action (2018-2023)

The Center for the Study of Tobacco Products (CSTP) has developed a model for evaluating novel tobacco products using, as exemplars, electronic cigarettes (ECIGs) that heat a liquid that often contains nicotine, forming an aerosol that users inhale. Now, CSTP leverages its methodological and ECIG expertise to pivot from product evaluation to an integrative theme of impact analysis. Specifically, the CSTP proposes methods with which FDA can generate predictions regarding a potential regulation?s effects, and then whether or not the predicted effects occur in the population can be tested. The CSTP?s model assesses how potential regulation might influence product toxicity (Project 1), user behavior (Project 2), and product addiction/abuse liability (Project 3). In this context, Project 1 will generate new data regarding the toxicants emitted by advanced-generation ECIGs and contribute to hypotheses about population-level regulatory impact (with Projects 2 and 3): Project 4 will test those population-level hypotheses. FDA regulations are designed to promote health, but may also have unintended consequences. For example, limiting ECIG liquids to <20 mg/ml nicotine, as in the European Union (EU), can drive use of higher power ECIGs that aerosolize more liquid/puff, leading users to inhale more nicotine and other toxicants. Unintended consequences may also occur from other action, like constraining ECIG nicotine flux (amount of emitted nicotine/unit time), or reducing flavor availability. The consequences of these and other potential regulatory actions may be predicted using aerosol research methods that allow rigorous control of key parameters, such as device power, liquid constituents, and puff topography (e.g., puff volume/duration). Outcome measures include amount of aerosol produced, mathematically-predicted nicotine delivery, actual nicotine yield, and aerosol toxicant profile. Results can inform testable population-level hypotheses regarding device/liquid preferences and dual ECIG/tobacco cigarette use. Thus, Project 1 specific aims are to use established aerosol research methods to examine how ECIG emissions are influenced by three potential regulatory actions: (1) limits on nicotine, (2) constraints on nicotine flux, and (3) reduction in flavor availability. Project 1 is informed by the Contextual Knowledge Core that will refine Aim 2 device/liquid choices and provide Aim 3 DIY methods. Project 1 provides new data regarding the role of nicotine concentration, flux, and liquid availability on ECIG toxicity, while informing predictions regarding the consequences of potential regulatory action. Project 4 examines these predictions at the population level. Thus, Project 1 is part of an integrative theme of impact analysis and draws on the team’s aerosol research expertise to provide FDA tools that can be used to guide regulation development so that, by the time a regulation goes into effect, methods predictive of population-level phenomena have tested it, refined it, and generated data that show that its health-promoting effects are maximized and unintended consequences are minimized.

Funding source: NIH P50/U54DA036105 

Project 1: Analytical Lab Methods for MRTP Evaluation - Center for the Study of Tobacco Products (2013-2018)

The U.S. tobacco marketplace is changing fast, and regulatory science lags far behind. The FDA can alter this dynamic, but needs the tools to do so. One necessary tool is a model for evaluating all types of modified risk tobacco products (MRTPs): novel tobacco products marketed with the claim that they reduce harm or risk associated with conventional products. There are few demonstrated models for predicting tobacco product harm or risk, which demands an understanding of MRTP constituents using analytic lab methods, toxicant exposure and abuse liability using human lab methods, longer-term effects using randomized control trial (RCT) methods, and attitudes, beliefs, and perceived effects using quantitative and qualitative methods. The overarching goal of the Center for the Study of Tobacco Products is to demonstrate empirically an integrated, iterative MRTP evaluation model that uses all of these methods to inform tobacco product regulation across all product types (combustible, oral, or vapor). The Center unites NIH-funded scientist/educators from multiple disciplines to demonstrate the transdisciplinary MRTP evaluation model. We begin with an evaluation of electronic cigarettes (EClGs), novel tobacco products that are marketed now and increasingly popular. EClGs offer an opportunity to demonstrate how the model we propose can inform regulatory policy. To meet the Center’s overarching goal we describe four integrated, multi-year projects that aim to: 1) Examine factors that influence MRTP nicotine and toxicant yield; 2) Compare short-term effects of MRTPs to other products in the human lab; 3) Characterize effects of real-world MRTP use in the natural environment using RCT methods; and 4) Study the influence MRTP use and misuse on user attitudes, beliefs, and perceived effects using qualitative and quantitative methods. An Administrative Core will facilitate financia and managerial processes, provide data management and biostatistical support, co-ordinate communication within and across centers, and interface with scientists and policymakers. A Training and Education Core will develop a course on transdisciplinary methods for evaluating products and will support up to 4 pre-doctoral and 4 postdoctoral appointees. Finally, a pilot research program will solicit and fund innovative projects from our Virginia-wide network of scientists and respond to emerging products of any type. The Center is thus structured to address FDA needs and operate collaboratively. Overall, this Center will provide the expertise, innovation, infrastructure, and information necessary for the sustained success of FDA’s mandate to regulate novel tobacco products, including MRTPs.

Funding source: NIH 5P50DA036105