Maciej L. Goniewicz

Levels of selected carcinogens and toxicants in vapour from electronic cigarettes

Significance Electronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e–cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals. Materials and methods Vapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods. Results We found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9–450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product. Conclusions Our findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.)

Carbonyl Compounds in Electronic Cigarette Vapors—Effects of Nicotine Solvent and Battery Output Voltage

INTRODUCTION Glycerin (VG) and propylene glycol (PG) are the most common nicotine solvents used in e-cigarettes (ECs). It has been shown that at high temperatures both VG and PG undergo decomposition to low molecular carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. The aim of this study was to evaluate how various product characteristics, including nicotine solvent and battery output voltage, affect the levels of carbonyls in EC vapor. METHODS Twelve carbonyl compounds were measured in vapors from 10 commercially available nicotine solutions and from 3 control solutions composed of pure glycerin, pure propylene glycol, or a mixture of both solvents (50:50). EC battery output voltage was gradually modified from 3.2 to 4.8V. Carbonyl compounds were determined using the HPLC/DAD method. RESULTS Formaldehyde and acetaldehyde were found in 8 of 13 samples. The amounts of formaldehyde and acetaldehyde in vapors from lower voltage EC were on average 13- and 807-fold lower than in tobacco smoke, respectively. The highest levels of carbonyls were observed in vapors generated from PG-based solutions. Increasing voltage from 3.2 to 4.8V resulted in a 4 to more than 200 times increase in formaldehyde, acetaldehyde, and acetone levels. The levels of formaldehyde in vapors from high-voltage device were in the range of levels reported in tobacco smoke. CONCLUSIONS Vapors from EC contain toxic and carcinogenic carbonyl compounds. Both solvent and battery output voltage significantly affect levels of carbonyl compounds in EC vapors. High-voltage EC may expose users to high levels of carbonyl compounds.

Effects of Switching to Electronic Cigarettes with and without Concurrent Smoking on Exposure to Nicotine, Carbon Monoxide, and Acrolein

Concern has been raised about the presence of toxicants in electronic cigarette (EC) aerosol, particularly carbonyl compounds (e.g., acrolein) that can be produced by heating glycerol and glycols used in e-liquids. We investigated exposure to carbon monoxide (CO), nicotine (by measuring cotinine in urine), and to acrolein (by measuring its primary metabolite, S-(3-hydroxypropyl)mercapturic acid (3-HPMA) in urine) before and after 4 weeks of EC (green smoke, a “cig-a-like” EC, labeled 2.4% nicotine by volume) use, in 40 smokers. Thirty-three participants were using EC at 4 weeks after quitting, 16 (48%) were abstinent (CO-validated) from smoking during the previous week (EC only users), and 17 (52%) were “dual users.” A significant reduction in CO was observed in EC-only users [–12 ppm, 95% confidence interval (CI), –16 to –7, 80% decrease) and dual users (–12 ppm, 95%CI, –19 to –6, 52% decrease). Cotinine levels also declined, but to a lesser extent (EC-only users: –184 ng/mg creatinine; 95% CI, –733 to –365, 17% decrease; and dual users: –976 ng/mg creatinine; 95%CI, –1,682 to –270, 44% decrease). Mean 3-HPMA levels had decreased at 4 weeks by 1,280 ng/mg creatinine (95%CI, –1,699 to –861, 79% decrease) in EC-only users and by 1,474 ng/mg creatinine (95%CI, –2,101 to –847, 60% decrease) in dual users. In dual users, EC use significantly reduced exposure to CO and acrolein because of a reduction in smoke intake. EC may reduce harm even in smokers who continue to smoke, but long-term follow-up studies are needed to confirm this. Cancer Prev Res; 8(9); 873–8. ©2015 AACR.

Nicotine Levels in Electronic Cigarettes

INTRODUCTION The electronic cigarette (EC) is a plastic device that imitates conventional cigarettes and was developed to deliver nicotine in a toxin-free vapor. Nicotine in a solution is heated and vaporized when a person puffs through the device and is inhaled as a vapor into the mouth. The EC is a new product on the market and little is known about its safety and nicotine delivery efficacy. The aim of the study was to analyze nicotine levels in vapor generated from various EC brands and models. The study was designed to assess efficacy and consistency of various ECs in converting nicotine to vapor and to analyze dynamics of nicotine vaporization. METHODS Sixteen ECs were selected based on their popularity in the Polish, U.K. and U.S. markets. Vapors were generated using an automatic smoking machine modified to simulate puffing conditions of real EC users. Nicotine was absorbed in a set of washing bottles with methanol and analyzed with gas chromatography. RESULTS The total level of nicotine in vapor generated by 20 series of 15 puffs varied from 0.5 to 15.4 mg. Most of the analyzed ECs effectively delivered nicotine during the first 150-180 puffs. On an average, 50%-60% of nicotine from a cartridge was vaporized. CONCLUSIONS ECs generate vapor that contains nicotine, but EC brands and models differ in their efficacy and consistency of nicotine vaporization. In ECs, which vaporize nicotine effectively, the amount inhaled from 15 puffs is lower compared with smoking a conventional cigarette.

Patterns of electronic cigarette use and user beliefs about their safety and benefits: an internet survey.

INTRODUCTION AND AIMS As the popularity of electronic cigarettes (e-cigarettes) increases, it is becoming important to find out more about the characteristics of e-cigarette users, why and how they use the product and whether e-cigarettes are used exclusively or in combination with conventional cigarettes. The objective of this study was to investigate patterns and effects of e-cigarette use and user beliefs about e-cigarette safety and benefits. DESIGN AND METHODS E-cigarette users in Poland were recruited online and asked to participate in a web-based survey. The participants provided information on their smoking history, patterns of e-cigarette use, beliefs and attitudes regarding the product and information on concurrent use of conventional cigarettes. RESULTS The survey was completed by 179 e-cigarette users. Almost all participants used e-cigarettes daily. E-cigarettes were primarily used to quit smoking or to reduce the harm associated with smoking (both 41%), and were successful in helping the surveyed users to achieve these goals with 66% not smoking conventional cigarettes at all and 25% smoking under five cigarettes a day. Most participants (82%) did not think that e-cigarettes were completely safe, but thought that they were less dangerous than conventional cigarettes. Sixty percent believed that e-cigarettes were addictive, but less so than conventional cigarettes. DISCUSSION AND CONCLUSIONS The participants primarily used e-cigarettes as a stop-smoking aid or as an alternative to conventional cigarettes, and the majority reported that they successfully stopped smoking. More data on e-cigarette safety and its efficacy in harm-reduction and smoking cessation are needed.

Secondhand Exposure to Vapors From Electronic Cigarettes

INTRODUCTION Electronic cigarettes (e-cigarettes) are designed to generate inhalable nicotine aerosol (vapor). When an e-cigarette user takes a puff, the nicotine solution is heated and the vapor is taken into lungs. Although no sidestream vapor is generated between puffs, some of the mainstream vapor is exhaled by e-cigarette user. The aim of this study was to evaluate the secondhand exposure to nicotine and other tobacco-related toxicants from e-cigarettes. MATERIALS AND METHODS We measured selected airborne markers of secondhand exposure: nicotine, aerosol particles (PM(2.5)), carbon monoxide, and volatile organic compounds (VOCs) in an exposure chamber. We generated e-cigarette vapor from 3 various brands of e-cigarette using a smoking machine and controlled exposure conditions. We also compared secondhand exposure with e-cigarette vapor and tobacco smoke generated by 5 dual users. RESULTS The study showed that e-cigarettes are a source of secondhand exposure to nicotine but not to combustion toxicants. The air concentrations of nicotine emitted by various brands of e-cigarettes ranged from 0.82 to 6.23 µg/m(3). The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes (31.60±6.91 vs. 3.32±2.49 µg/m(3), respectively; p = .0081). CONCLUSIONS Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions.

Electronic Cigarette Use Among Teenagers and Young Adults in Poland

BACKGROUND: Electronic cigarettes (e-cigarettes) are battery-powered devices developed with the goal of mimicking the action of smoking, including nicotine delivery, without the toxic effects of tobacco smoke. Little is known about the uptake of e-cigarettes among young people. METHODS: A survey was conducted with a cluster sample of 20 240 students enrolled at 176 nationally representative Polish high schools and universities between September 2010 and June 2011. We estimated national e-cigarette prevalence among various demographic groups by using population weights. Multiple logistic regression was used to evaluate which demographic factors were independent predictors of 2 outcomes: ever use of e-cigarettes and use in the previous 30 days. RESULTS: Among high school students, aged 15 to 19 years, 23.5% had ever used e-cigarettes and 8.2% had done so within the previous 30 days. Among those in universities, aged 20 to 24 years, 19.0% had ever used an e-cigarette and 5.9% had done so in the previous 30 days. In multivariate analyses that controlled for covariates, smoking cigarettes, male gender, living in an urban area, and having parents who smoke were associated with ever use of e-cigarettes. Overall, 3.2% of never smoking students reported ever use of e-cigarettes. CONCLUSIONS: About one-fifth of Polish youth have tried e-cigarettes; most of them had previously smoked cigarettes. It is unclear whether e-cigarettes are just a novelty that young people try only once or whether they have potential to compete in the marketplace with conventional cigarettes.

Nicotine content of electronic cigarettes, its release in vapour and its consistency across batches: regulatory implications.

BACKGROUND AND AIMS Electronic cigarettes (EC) may have a potential for public health benefit as a safer alternative to smoking, but questions have been raised about whether EC should be licensed as a medicine, with accurate labelling of nicotine content. This study determined the nicotine content of the cartridges of the most popular EC brands in the United Kingdom and the nicotine levels they deliver in the vapour, and estimated the safety and consistency of nicotine delivery across batches of the same product as a proxy for quality control for individual brands and within the industry. METHODS We studied five UK brands (six products) with high internet popularity. MEASUREMENTS Two samples of each brand were purchased 4 weeks apart, and analysed for nicotine content in the cartridges and nicotine delivery in vapour. RESULTS The nicotine content of cartridges within the same batch varied by up to 12% relative standard deviation (RSD) and the mean difference between different batches of the same brand ranged from 1% [95% confidence interval (CI) = -5 to 7%] to 20% (95% CI=14-25%) for five brands and 31% (95% CI=21-39%) for the sixth. The puffing schedule used in this study vaporized 10-81% of the nicotine present in the cartridges. The nicotine delivery from 300 puffs ranged from ∼2 mg to ∼15 mg and was not related significantly to the variation of nicotine content in e-liquid (r=0.06, P=0.92). None of the tested products allowed access to e-liquid or produced vapour nicotine concentrations as high as conventional cigarettes. CONCLUSIONS There is very little risk of nicotine toxicity from major electronic cigarette (EC) brands in the United Kingdom. Variation in nicotine concentration in the vapour from a given brand is low. Nicotine concentration in e-liquid is not well related to nicotine in vapour. Other EC brands may be of lower quality and consumer protection regulation needs to be implemented, but in terms of accuracy of labelling of nicotine content and risks of nicotine overdose, regulation over and above such safeguards seems unnecessary.

Tobacco-Product Use by Adults and Youths in the United States in 2013 and 2014.

Background Noncigarette tobacco products are evolving rapidly, with increasing popularity in the United States. Methods We present prevalence estimates for 12 types of tobacco products, using data from 45,971 adult and youth participants (≥12 years of age) from Wave 1 (September 2013 through December 2014) of the Population Assessment of Tobacco and Health (PATH) Study, a large, nationally representative, longitudinal study of tobacco use and health in the United States. Participants were asked about their use of cigarettes, e‐cigarettes, traditional cigars, cigarillos, filtered cigars, pipe tobacco, hookah, snus pouches, other smokeless tobacco, dissolvable tobacco, bidis, and kreteks. Estimates of the prevalence of use for each product were determined according to use category (e.g., current use or use in the previous 30 days) and demographic subgroup, and the prevalence of multiple‐product use was explored. Results More than a quarter (27.6%) of adults were current users of at least one type of tobacco product in 2013 and 2014, although the prevalence varied depending on use category. A total of 8.9% of youths had used a tobacco product in the previous 30 days; 1.6% of youths were daily users. Approximately 40% of tobacco users, adults and youths alike, used multiple tobacco products; cigarettes plus e‐cigarettes was the most common combination. Young adults (18 to 24 years of age), male adults and youths, members of racial minorities, and members of sexual minorities generally had higher use of tobacco than their counterparts. Conclusions During this study, 28% of U.S. adults were current users of tobacco, and 9% of youths had used tobacco in the previous 30 days. Use of multiple products was common among tobacco users. These findings will serve as baseline data to examine between‐person differences and within‐person changes over time in the use of tobacco products. (Funded by the National Institute on Drug Abuse and the Food and Drug Administration.)

Elimination kinetics of the tobacco-specific biomarker and lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is tobacco specific and has a longer half-life than other tobacco biomarkers studied thus far. An accurate measurement of the NNAL half-life is important for optimal use to assess exposure to tobacco smoke. We determined the half-life of NNAL in urine in eight daily smokers on a clinical research ward and in five occasional smokers in a real-life environment. Total NNAL in urine was monitored for 14 days in daily smokers after stopping smoking and for up to 60 days in occasional smokers. The average half-life for the terminal phase in the daily smoker group using a two-compartmental body model was 10.3 days (beta phase), and using a noncompartmental model, it was 9.1 days. In the occasional group, these values were 17.6 and 16.0 days, respectively. The alpha-phase half-lives were 14.3 and 27.8 hours for the two groups, respectively. The inter-subject coefficient of variation of the NNAL terminal half-life ranged from 14% to 30%, and the intra-subject coefficient of variation ranged from 3% to 18%. There was very good agreement between the plasma and urinary half-lives in two subjects with plasma analyses: 7.4 versus 7.9 days and 9.2 versus 10.7 days. Mean renal clearance of NNAL was 13 ± 2.3 mL/min. The terminal half-life of NNAL of 10 to 18 days indicates that this biomarker can be used to detect tobacco smoke exposure for 6 to 12 weeks after cessation of exposure and requires a similar time to assess the steady levels of NNAL after switching from one tobacco product to another. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3421–5)