Electronic cigarettes: what are they and what do they do?

Abstract

Electronic cigarettes (ECIGs) use electricity to power a heating element that aerosolizes a liquid that often contains solvents, flavorants, and the dependence-producing drug nicotine for user inhalation. ECIGs have evolved rapidly in the past 8 years, and the changes in product design and liquid constituents affect the resulting toxicant yield in the aerosol and delivery to the user. This rapid evolution has been accompanied by dramatic increases in ECIG use prevalence in many countries, including among adults and especially adolescents in the United States. This increased prevalence of a novel product that has the potential to deliver nicotine and other toxicants to users’ lungs drives a rapidly growing research effort. This review highlights the most recent information regarding the design of ECIGs and liquid and aerosol constituents, the epidemiology of ECIG use among adolescents and adults (including correlates of ECIG use), and preclinical and clinical research regarding ECIG effects. The current literature suggests a strong rationale for an empirical regulatory approach toward ECIGs that balances any potential ECIG-mediated decreases in health risks for smokers who use them as substitutes for tobacco cigarettes and against any increased risks for nonsmokers who may be attracted to them.

Electronic cigarettes—A review of the physiological health effects

“…Sleiman et al (2016) identified two other potential carcinogens in EC vapour: propylene oxide and glycidol. Other articles showed similar results, with increasing levels of toxicants when higher-powered devices were used (Laugesen 2008;McAuley et al 2012;Goniewicz et al 2014b;Hutzler et al 2014;Kosmider et al 2014;Tayyarah and Long 2014;Geiss et al 2015;Herrington and Myers 2015; Zucchet and Schmaltz 'Connell et al 2015;El-Hellani et al 2016;Jo and Kim 2016;Leigh et al 2016;Sleiman et al 2016;Talih et al 2016). The amount and types of these degradation products vary substantially in different studies, making generalizations about the health effects of ECs difficult.…”

“…The high level of formaldehyde is especially concerning as this compound is a potent carcinogen and is toxic to the human reproductive system (Duong et al 2011). Formaldehyde and other carbonyls are also problematic because their concentrations can be high and correlated with the power of the device (El-Hellani et al 2016). This is of special concern with newer generation high-powered devices.…”

“…Vansickel and Eissenberg (2013) found that experienced vapers allowed to use their own device ad libitum for 1 h were able to generate blood nicotine concentrations of 16.3 ± 4.5 ng/mL, similar to CC use. Similarly, in two separate studies, EC users allowed to use an EC device for 15 puffs also produced levels of blood nicotine (and systemic retention times) comparable with or higher than CCs (El-Hellani et al 2016;St. Helen et al 2016).…”

“…Goniewicz et al (2013) found that 300 puffs from an EC generated a significant amount of nicotine in the vapour at approximately 0.5-15.4 mg of nicotine depending on the level of nicotine in the liquid. Inconsistencies in nicotine concentrations are of concern as there seems to be a positive correlation in most studies to date between EC liquid nicotine concentration and the amount of nicotine found in aerosols (Breland et al 2016). Other EC liquids contain toxicants not supposed to be found in such products (Goniewicz et al 2014a;Lisko et al 2015).…”

Prevalence of Use of Electronic Nicotine Delivery Systems (ENDS) to Vape Recreational Drugs by Club Patrons in South London

“…These are frequently marketed as having a role in smoking cessation. ENDS liquids contain nicotine, at least one solvent agent (usually propylene glycol and/or glycerin) as well as flavours [1]; however, they can contain any variety of compounds and may contain no nicotine. The make-up of the liquid, the power output of the device and the strength of user inhalation influence the yield of substance inhaled from a given ENDS aerosol [1].…”