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

Abstract

Introduction Electronic cigarettes’ (e-cigarettes) viability as a public health strategy to end smoking will likely be determined by their ability to mimic the pharmacokinetic profile of a cigarette while also exposing users to significantly lower levels of harmful/potentially harmful constituents (HPHCs). The present study examined the nicotine delivery profile of third- (G3) versus second-generation (G2) e-cigarette devices and their users’ exposure to nicotine and select HPHCs compared with cigarette smokers. Methods 30 participants (10 smokers, 9 G2 and 11 G3 users) completed baseline questionnaires and provided exhaled carbon monoxide (eCO), saliva and urine samples. Following a 12-hour nicotine abstinence, G2 and G3 users completed a 2-hour vaping session (ie, 5 min, 10-puff bout followed by ad libitum puffing for 115 min). Blood samples, subjective effects, device characteristics and e-liquid consumption were assessed. Results Smokers, G2 and G3 users had similar baseline levels of cotinine, but smokers had 4 and 7 times higher levels of eCO (p<0.0001) and total 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (i.e., NNAL, p<0.01), respectively, than G2 or G3 users. Compared with G2s, G3 devices delivered significantly higher power to the atomiser, but G3 users vaped e-cigarette liquids with significantly lower nicotine concentrations. During the vaping session, G3 users achieved significantly higher plasma nicotine concentrations than G2 users following the first 10 puffs (17.5 vs 7.3 ng/mL, respectively) and at 25 and 40 min 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. Discussion Under normal use conditions, both G2 and G3 devices deliver cigarette-like amounts of nicotine, but G3 devices matched the amount and speed of nicotine delivery of a conventional cigarette. Compared with cigarettes, G2 and G3 e-cigarettes resulted 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.

Electronic Cigarettes in Germany: Patterns of Use and Perceived Health Improvement

“…It may depend on how they reduce the quantity of their smoking [38,52]. Studies reported that dual users often use first-generation cig-alikes, but the use of second- or third-generation devices, which deliver nicotine more efficiently, could increase the number of users who switch completely [4,63,64,65]. Nearly all of our participants used e-cigarettes with refillable tanks and started with these devices.…”

“…The devices are divided into first-, second-, or third-generation models. Research suggests that users of second- or third-generation models are more successful in smoking reduction and cessation and more satisfied with their e-cigarettes than users of first-generation models, possibly due to the better device-related availability of nicotine [2,3,4]. In January 2014, an Internet search identified 466 brands and 7,764 unique flavors [5].…”

Conflicts and controversies in contemporary tobacco control

“…States and nations are taking widely divergent approaches to this question; no consensus has yet emerged about use in public places. However, in terms of toxicants, Wagener et al 6 suggest that later-generation e-cigarette devices, as compared with cigarettes, deliver less of at least some harmful constituents while matching the nicotine delivery profile of conventional, more harmful combustible cigarettes. This would add to the argument that perhaps these later devices should not be subject to more onerous regulatory approval regimes, while the most deadly combustible products are ‘grandfathered’ under US Food and Drug Administration authority.…”

Electronic cigarettes—A review of the physiological health effects

“…These devices can look like common household items such as pens or have a completely unique design and have a much higher voltage and (or) resistance and, therefore, power than the first-generation devices (Farsalinos et al 2014b). This higher power allows the user to generate more aerosols per puff than the first-generation devices, again exposing users to more of the vapour chemicals like nicotine (Wagener et al 2017). These factors (experience of the subjects, individual habits, and type of device and liquid) can explain some of the discrepancies in the literature and can cause different blood nicotine levels even if the exact same product is in use (Dawkins and Corcoran 2014).…”