New preliminary research presented today at the annual conference of the Society for Research on Nicotine and Tobacco in Chicago, Ill., is sure to further stoke an ongoing debate on the actual harms of electronic cigarettes.

The study claims to have found that even the heavy use of e-cigarettes, roughly equivalent to 350 puffs a day, leaves little formaldehyde, a known carcinogen, behind. To further bolster their point, the authors compared their measured levels of daily formaldehyde exposure from three vaping products to several safety benchmarks, including one designed by the World Health Organization (WHO), finding they fell dramatically short. And when compared to a conventional tobacco cigarette, a readily available source of formaldehyde, they found the level of e-cigarette exposure was over 10 times less, again indicating their relative safety.    

“The results from this study show that even heavy use of these products still only results in daily formaldehyde exposure that is less than one-sixth of the exposure from breathing indoor air that complies with WHO air quality standards,” lead author Dr. Sandra Costigan said in a statement.


Despite these impressive results, the list of caveats that come attached with the study should be enough to make anyone cautiously skeptical.

For one, the study was funded and conducted by British American Tobacco (BAT), a company that in 2013 trumpeted its status as the “first international tobacco company to launch an e-cigarette, Vype, in the UK.” In 2014, it developed two additional e-cigarette products, the Vype eStick and Vype ePen, and 2015 saw the arrival of the Vype eTank (the study appears to have tested the Vype, Vype ePen, and Vype eTank). Costigan, in addition to being the lead author, is also BAT’s Principal Toxicologist for electronic cigarettes.

Without casting aspersions on BAT personally, it’s worth emphasizing the long history of tobacco industry-funded studies that concluded their “reduced risk” products, such as low-tar cigarettes, did just that, only to be eventually debunked by independent scientists afterwards. For one of many examples, while medium-tar, filtered cigarettes, the type most smokers use today, are safer than the high-tar cigarettes of the past, there doesn’t appear to be any difference in mortality when switching to low-tar cigarettes, namely because low-tar users simply take longer puffs or smoke more cigarettes to get the same nicotine high. 

Second, as mentioned, the study has yet to be published in a peer reviewed journal. Meanwhile, a study that was peer reviewed and published in the New England Journal of Medicine (NEJM) last year also sought to measure levels of formaldehyde from the heavy use of e-cigarettes and came to very different conclusions. Testing a device similar to the Vype eTank at a high voltage level, researchers estimated that the levels of formaldehyde they measured could, over the long term, amount to an “incremental lifetime cancer risk” five to 15 times higher than conventional cigarettes.

The "Dry Puff" Problem

Of course, the plot only thickens from here. As Costigan explains, how formaldehyde is produced differs between the two products. “In cigarette smoke, most formaldehyde is produced as the result of burning sugars naturally present in tobacco as well as added sugars and glycerol, whereas in vaping products, it is generally produced as a thermal breakdown product of glycerol and propylene glycol (PG).”

In the simplest terms, that means tobacco cigarettes produce a gaseous form of formaldehyde, whose effect on cancer risk we’ve studied extensively. However, vaping products produce formaldehyde-releasing agents, and as the NEJM authors admit, we don’t really know how these agents affect our body when inhaled.

That ambiguity aside, other researchers have criticized the NEJM study and those similar to it for cherry-picking their findings by choosing to focus on a high-voltage setting that few consumers would typically use, since it would purportedly create an unpleasant-tasting “dry puff.” Indeed, at lower voltages, the NEJM researchers found negligible amounts of formaldehyde production.

In a response, the authors acknowledged these criticisms, but also claimed there was “a lack of objective data with which to judge whether these devices are being used as safely as possible.” They further remarked that while some cigar smokers actively avoid inhaling cigar smoke, there are plenty who do, and that the same could be true for some e-cigarette users who enjoy the dry puff, especially if the vast variety of flavored vaping products successfully masks the taste.

In short, the fight over formaldehyde comes down to what we should consider typical heavy use, one that likely won’t be settled by any one study (the current study relied on “vaping robots” to produce vapor).

“We believe e-cigarettes hold great potential for reducing tobacco-related disease. For this reason, we continue to strive to better define and further reduce any residual risks that there may be, to as low a level as possible,” Costigan said.

Much of that touted potential is believed to come from the notion that tobacco users can and will switch over to less harmful e-cigarettes, and eventually wean themselves off nicotine completely. Unfortunately, as with formaldehyde, the evidence for that actually happening in the real world is decidedly mixed.

“It is true that cigarettes are known to contain many toxicants at relatively higher concentrations than electronic nicotine-delivery systems (ENDS),” the NEJM authors wrote at the end of their response. “What is unknown are the overall toxicologic effects of ENDS. It will probably take at least a decade for the public health consequences of long-term vaping to be even partially understood.”

In other words, buckle your seatbelts, folks. It’s going to be a long ride.

Source: Costigan S, Sommarstrom J. Formaldehyde from different format electronic cigarettes compared to the WHO air guideline. Annual Conference of the Society for Research on Nicotine and Tobacco. 2016.