PROJECT SUMMARY/ABSTRACT
Electronic cigarette (EC) use is projected to exceed cigarette smoking within two years. Nicotine salt-based
ECs have raised concerns due to their high concentrations of nicotine, potentially contributing to their rapidly
increasing popularity. The US Food and Drug Administration (FDA) has regulatory authority over ECs and has
shown interest in exploring a product standard to limit the allowable level of nicotine in EC e-liquids. While the
proposed product standard has merit, emerging research suggests that it could lead to a product that is just as
addictive but more harmful, particularly to African American (AA) smokers. AA smokers bear a disproportionate
burden of smoking-related diseases and represent an understudied population with a propensity to use
products in a way that is different compared to the majority population. AA smokers take larger puffs and inhale
more intensely on cigarettes than whites. While AA smoke fewer cigarettes per day than whites, AA extract
30% more nicotine per cigarette and higher levels of non-nicotine toxicants per cigarette. As more AA smokers
switch to ECs, it is not known how they will use these products. No studies have investigated how rates of
compensatory puffing when using ECs differ as a function of nicotine concentration among AA and white
smokers or how the nicotine concentration of e-liquids could influence their rates of compensation, substitution,
and EC-related toxicant exposure. The proposed study will provide this scientific evidence to inform regulation
and to maximize public health benefit and limit potential harm to diverse users. Adults smokers (24 AA, 24 W)
will complete two study phases. In Phase 1, participants will complete two standardized, 10-puff vaping bouts
followed by a 60-minute ad libitum vaping session, using two e-liquids that differ only by nicotine concentration
(5% vs. 1.8%). Phase 1 will provide objective data regarding rates of compensation as a function of nicotine
concentration. In Phase 2, the same participants will be randomized to 5% or 1.8% nicotine e-liquid and
instructed to switch to them completely for 6 weeks. The randomized trial will allow us to understand the
comparative efficacy of 1.8% vs. 5% nicotine e-liquid on substitution rates and adverse health outcomes,
including exposure to non-nicotine constituents, in the short-term under real-world use conditions. If reduced
nicotine ECs were to result in greater e-liquid consumption via compensation, reduced substitution rates,
and/or greater exposure to toxicants, then this would suggest that a nicotine product standard placing a limit on
allowable levels of nicotine in e-liquid would lead to a product that is just as addictive but possibly more
harmful. This innovative study will provide the scientific foundation needed to establish effective regulatory
strategies for nicotine product standards that optimize public health. The project will serve as an incredibly
valuable training experience and will establish the K01 candidate, Dr. Eleanor Leavens, as an independent
tobacco regulatory scientist and launch Dr. Leavens’ career in substantial and measurable ways.
