At a time when the number of smokers worldwide is at its highest, and antismoking policies are proliferating,1 the sector for alternative smoking products is in a froth of excitement about the potential to increase its market share and revenues. One of the most recent products in the market is the electronic cigarette (e-cigarette), which is intended, whether overtly stated or implied, to reduce concentrations of toxic compounds in mainstream and sidestream smoke and to help smokers give up. They are battery powered devices that simulate tobacco cigarettes by vaporising nicotine and other chemicals into an inhalable vapour. The scarce data available so far indicate that sales of e-cigarettes are rising,2 yet recently the US Food and Drug Administration (FDA) expressed serious concerns about their safety.3
To date, animal and human studies on the health effects of actively or passively smoking e-cigarettes are lacking, although three toxicological analyses have been released evaluating various brands of e-cigarettes for their nicotine content and other impurities. The three reports are from the FDA,3 a private enterprise called Health New Zealand (HNZ),4 and Demokritos, a publicly funded Greek research institute.5
The FDA’s analysis showed that similarly labelled cartridges emitted markedly different amounts of nicotine with each puff (between 26.8 and 43.2 micrograms of nicotine per 100 ml puff) and that nicotine was detected in all cartridges, including in samples identified as containing no nicotine. This is in contrast to HNZ’s findings that the labelling of different e-cigarettes reflected their actual nicotine content.
Propylene glycol, a generally safe antifreeze chemical constituent in various cosmetics and foods, was detected in all analyses. But the FDA also detected diethylene glycol, a highly toxic liquid involved in a number of prominent mass poisonings, in one cartridge at a content of about 1%; neither HNZ nor Demokritos analysed this constituent. Tobacco specific N-nitrosamines, powerful carcinogens that are chemically related to nicotine and other tobacco alkaloids,1 were found by the FDA and HNZ, while no relevant test was described in the Greek report. The existence of polycyclic aromatic hydrocarbons—potent, locally acting carcinogenic byproducts of the incomplete combustion of organic material1—was reported by HNZ but not by Demokritos, while the FDA did not describe relevant tests. Tobacco specific impurities suspected of being harmful to humans, including anabasine, myosmine, and β nicotyrine, were detected by FDA, but HNZ and Demokritos did not report such analyses.
Interestingly, although the results of the three reports are similar, their interpretations are partly conflicting. Overall the FDA carefully raises caution on the potential harmful effects of e-cigarettes, HNZ recommends e-cigarette use on the basis of a comparison with the health risks of normal tobacco products, while Demokritos maintains a neutral position and focuses mainly on delivery of results. This disparity may reflect the fact that FDA and Demokritos are government entities, whereas HNZ is a private enterprise. It should also be noted that HNZ’s toxicological analyses were funded by an e-cigarette manufacturer.
The limited information given in these three reports represents all the knowledge we currently have about e-cigarettes. This may be one reason why the battle in the United States between the FDA and e-cigarette manufacturers has been so heated. In the past year the FDA has detained or blocked numerous e-cigarette shipments at the US border because the devices have been classified as an unapproved drug or device, yet they remain available to consumers online and at shopping mall kiosks. The legal and political issues are thorny, and companies importing e-cigarettes have challenged the FDA’s basic jurisdiction to regulate e-cigarettes and are seeking a preliminary injunction requiring the FDA to allow their distribution. On the other hand, the companies have not submitted applications to the FDA for approval of their products, which would require data showing that e-cigarettes are safe and effective. To the best of our knowledge e-cigarettes are not regulated in the European Union, and the European Centre for Disease Prevention and Control has not released any germane reports.
Alternative smoking strategies aimed at reducing the threat to public health caused by the tobacco epidemic are always welcome.6 However, the design, implementation, and commercialisation of strategies must adhere to appropriate regulations to protect the health of consumers. To date, our knowledge about the acute and long term effects of e-cigarette use is, at best, very limited. The scarce evidence indicates the existence of various toxic and carcinogenic compounds, albeit in possibly much smaller concentrations than in traditional cigarettes.
However, the quality control processes used in the manufacture of e-cigarettes seem to be largely unsuitable given the variability in the concentrations of compounds even in e-cigarettes of the same label. Thus the reports from FDA, HNZ, and Demokritos cannot be used to draw any conclusions or inferences about potential effects on health. More rigorous chemical analyses are needed, followed by extensive research involving animal studies and, finally, clinical trials in humans. Until these crucial implementation stages are completed, physicians and other healthcare professionals must inform consumers of the probable fallaciousness of the claims of manufacturers of e-cigarettes.
