Clinical Laboratory Evaluation of Electronic Cigarettes/Electronic Nicotine Delivery Systems: Methodological Challenges

Abstract

Objective: Evaluating electronic cigarettes (ECIGs) in the clinical laboratory is critical to understanding their effects. However, laboratory evaluation of ECIGs can be challenging, as they are a novel, varied, and evolving class of products. The objective of this paper is to describe some methodological challenges to the clinical laboratory evaluation of ECIGs.

Methods: The authors gathered information about challenges involved in the laboratory evaluation of ECIGs. Challenges were categorized and solutions provided when possible.

Results: Methods used to study combustible cigarettes may need to be adapted to account for ECIG novelty and differences within the class. Challenges to ECIG evaluation can include issues related to 1) identification of ECIG devices and liquids, 2) determination of short -term ECIG abstinence, 3) measurement of use behavior, and 4) assessment of dependence. These challenges are discussed, and some suggestions to inform ECIG evaluation using clinical laboratory methods are provided.

Conclusions: Awareness of challenges and developing, validating, and reporting methods used to address them aids interpretation of results and replication efforts, thus enhancing the rigor of science used to protect public health through appropriate, empirically-based, ECIG regulation.

Keywords: clinical laboratory; electronic cigarette; electronic nicotine delivery system; evaluation; methods.

Figure 1

Mean plasma nicotine and CO levels (± SEM) for 33 daily cigarette smokers and 25 daily ECIG users, after ~12 hours of self-reported tobacco/nicotine abstinence (includes cigarettes and ECIGs; methods fully described in ^and and presented in . Asterisk indicates a significant group difference for plasma nicotine level, using an independent samples t-test (p< .05).