PROJECT SUMMARY
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.