Have combustible cigarettes met their match? The nicotine delivery profiles and harmful constituent exposures of second-generation and third-generation electronic cigarette users

Introduction:
This text discusses a study that compares the nicotine delivery profile and exposure to harmful constituents of second-generation (G2) and third-generation (G3) electronic cigarettes (e-cigarettes) and their users with cigarette smokers. The study aims to understand the potential of e-cigarettes as a public health strategy to end smoking. The key points and main message of the study are summarized below.

Key Points:

* The study recruited 10 cigarette smokers, 9 G2 e-cigarette users, and 11 G3 e-cigarette users.
* Baseline measurements of exhaled carbon monoxide (eCO), saliva and urine samples were taken to assess the levels of harmful constituents.
* G2 and G3 users completed a 2-hour vaping session, during which blood samples, subjective effects, device characteristics and e-liquid consumption were assessed.
* Smokers had significantly higher levels of eCO and total 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) compared to G2 and G3 users.
* G3 devices delivered significantly higher power to the atomizer but G3 users vaped e-liquids with lower nicotine concentrations.
* G3 users achieved significantly higher plasma nicotine concentrations than G2 users following the first 10 puffs and at 25 and 40 minutes of ad libitum use.
* G3 users consumed significantly more e-liquid than G2 users.
* Vaping urges/withdrawal were reduced following 10 puffs, with no significant differences between device groups.

Main Message:
The main message of the study is that both G2 and G3 e-cigarettes deliver cigarette-like amounts of nicotine, but G3 devices match the amount and speed of nicotine delivery of a conventional cigarette. Compared to cigarettes, G2 and G3 e-cigarettes result in significantly lower levels of exposure to a potent lung carcinogen and cardiovascular toxicant. These findings have significant implications for understanding the addiction potential of these devices and their viability/suitability as aids to smoking cessation. However, the study also highlights the need for further research on the relationship between quantity and strength of e-liquid consumed and the uptake of harmful constituents.

Wagener, Theodore L, Evan L Floyd, Irina Stepanov, Leslie M Driskill, Summer G Frank, Ellen Meier, Eleanor L Leavens, Alayna P Tackett, Neil Molina, and Lurdes Queimado. “Have Combustible Cigarettes Met Their Match? The Nicotine Delivery Profiles and Harmful Constituent Exposures of Second-Generation and Third-Generation Electronic Cigarette Users.” Tobacco Control 26, no. e1 (March 2017): e23–28. https://doi.org/10.1136/tobaccocontrol-2016-053041.