Table 1.

Key Research Gaps: Definitions and Methods

Definitions

• What should the devices be called: electronic nicotine delivery systems (ENDS, though some contain no nicotine), electronic cigarettes, e-cigarettes, aerosolized delivery system?

• What is the definition of ENDS and electronic cigarettes?

• How should the various types of e-cigarettes be classified?

• What terms should be used when surveying consumer use, such as e-hookah or hookah pen?

Methods, populations, moderating factors

• What standardized methods should be used to assess the function and effects of e-cigarettes?

–Machine-determined exposures (mimic human behaviors)

–Aerosol generation and constituent evaluation

–Pharmacokinetic and acute effects studies (control for volume, duration, naive vs. experienced users, etc.)

–Quantification of e-cigarette use—number of cartridges, tank refills, disposable products

–Quantification of dependence

–Clinical trial methods and outcome measures

–Animal models

• What tools could be developed to understand effects?

–Labeled nicotine tracer in e-cigarette liquid to assess delivery

–Placebo e-cigarettes with additive (e.g., capsaicin) to mimic nicotine harshness

• What are the intra- and inter-variation in user response to e-cigarettes?

• What factors within populations moderate the effects of e-cigarettes?

–Age

–Sex

–Race

–Pregnancy

–Vulnerable populations (low income, co-morbid mental illness or other disease, high-risk groups such as youth)

–History of e-cigarette use, e.g., naive and experienced users