It's little wonder why e-cigarettes' popularity has exploded into a multi-billion pound industry over the last few years; the promise of safe, harmless nicotine delivery without all the carcinogenic byproducts of looseleaf combustion is a hard offer to pass up. But are these devices and the nicotinated fluids they atomise really that safe? Science says it's complicated.
E-cigarettes are quite the media darling these days appearing in everything. The CDC found that e-cig usage jumped from around 10 per cent in 2010 to more than 21 per cent in 2011 among US adults who already smoked conventional cigarettes. Similarly, 10 per cent of American high school seniors reported experimenting with e-cigarettes over the same period.
What exactly is an e-cigarette? US patent application No. 8,490,628 B2 defines an e-cigarette as "an electronic atomisation cigarette that functions as substitutes [sic] for quitting smoking and cigarette substitutes". They were first invented in 2002 by a Chinese pharmacist as smoking cessation devices, and China remains the primary manufacturer of e-cigarettes globally today. The devices atomise a nicotinated propylene glycol solution, known as e-liquid, that may be doctored with additional additives, such as flavourings and colourings or variable nicotine concentrations. They can also be modified to vaporise cannabis derived products.
Smoke and Mirrors
Much of the e-cigarette's meteoric rise has been thanks to aggressive marketing campaigns by their manufacturers, touting the health "benefits" of vaping over smoking. A 2014 survey conducted by a team of researchers from the Center for Tobacco Control Research and Education at UC San Francisco looked at nearly 60 e-cigarette manufacturers websites and found that more than 90 per cent of them cited e-cigs as healthier, cheaper, and cleaner than conventional cigarettes, 76 per cent of them said that e-cigs do not produce secondhand smoke, and a quarter of them even used paid doctor endorsements to drive home those points — suggesting that some e-cig companies are only paying lip service to the FDA's stringent requirements about labelling.
What these websites fail to mention is that e-cigarettes also deliver a fraction of the nicotine that cigarettes do; that's roughly 20 per cent (between 0 and 35 μg of nicotine per puff) of what a regular cigarette delivers. Which means the average vaper is more likely to be huffing on these devices longer and more often than conventional cigarettes. Or simply augmenting their current cigarette regimen with e-cigs (you know, for crowded bars and restaurants where smoking a real cigarette would get you thrown out for douchebaggery). It's the so-called "dual use effect".
"The e-cigarettes are rapidly penetrating the market, especially with kids. they're being heavily promoted largely by the cigarette companies that have purchased e-cigarette companies as a way to quit smoking, a way that's safe and doesn't pollute the air", Dr. Stanton Glantz, director of the Center for Tobacco Control Research and Education at UCSF, told me. "What the evidence to date shows is that while a puff on an e-cigarette isn't as dangerous as a puff on a regular cigarette, the main effect they seem to be having is to keep people smoking cigarettes," thanks again to the dual use effect. Sneaky, sneaky.
"You don't know what that is doing to your lungs," Ray Casciari, director of the thoracic oncology program and the chief medical officer at the OC's St. Joseph Hospital, told Forbes. "My experience over the past 35 years is that anything you put in the lungs has a chance of causing either lung damage or irritation."
Another recent practical study, published this year in the journal Reproductive Toxicology, similarly found that the vapors can damage the developing lungs of America's youth:
Bahl et al screened 41 e-cigarette refill fluids from four companies for cytotoxicity using three cell types: human pulmonary fibroblasts, human embryonic stem cells, and mouse neural stem cells. Cytotoxicity varied among products from highly toxic to low or no cytotoxicity.
The authors determined that nicotine did not cause cytotoxicity, that some products were noncytotoxic to pulmonary fibroblasts but cytotoxic to both types of stem cells, and that cytotoxicity was related to the concentration and number of flavourings used. The finding that the stem cells are more sensitive than the differentiated adult pulmonary fibroblasts cells suggests that adult lungs are probably not the most sensitive system to assess the effects of exposure to e-cigarette aerosol. These findings also raise concerns about pregnant women who use e-cigarettes or exposed to secondhand e-cigarette aerosol.
What's Really In Your Cig?
Another recent study published in the journal Toxicology and Applied Pharmacology showed that e-cigarette performance was virtually identical to that of regular cigarettes in terms of exhaled nitric oxide rates.
Nitric oxides cause the smooth muscles in the lungs and heart to relax, which can lead to reduced lung function and increased risk of heart attack. The more NO your body retains, the worse it is for you. And bear in mind, these are studies conducted using the products of top-shelf manufacturers. There's an entire other issue with harmful additives used by less scrupulous offshore firms that we're not even getting into.
What we do know is in e-cigs is not reassuring. Multiple studies have found chemicals like acetaldehyde, formaldehyde, and toluene, as well as heavy metals like cadmium, nickel, and lead, in both first and second-hand vapour. Again, these were present in concentrations a magnitude lower than conventional cigarettes but at high enough levels that they could arguably fall under California's Proposition 65 rules for mandatory labelling of their carcinogenic nature.
A recent meta-study by Dr. Priscilla Callahan-Lyon of the FDA's Center for Tobacco Products examining data from 18 previous studies on e-cig vapour found that most contained at least trace amounts of the solvents used to dissolve the nicotine and flavourings. These solvents are potent lung irritants and, upon heating, can be converted to carcinogenic compounds known as carboxyls.
What's more, since the first generation of e-cigs didn't produce the same nicotine kick that regular smoking did, manufacturers began incorporating voltage controls allowing users to up the power and increase the device's operating temperature — thereby increasing not just the rate of nicotine vaporisation but that of carboxyl vaporisation as well. According to Maciej Goniewicz of the Roswell Park Cancer Institute in Buffalo, using a current generation variable voltage vape on maximum can produce the same amount of formaldehyde as a regular cigarette.
What's more, the atomisation process generates ultra-fine particles, which can instigate the same effects seen in tobacco smoke or industrial air pollution. A 2007 study published in Environmental Health Perspectives found that the size and chemical composition of these particles can vary greatly between products. This variability has a big effect on their individual cytotoxicities, but the study did conclude that their presence in the air has a similar effect to tobacco smoke in terms of your pulmonary health. Altogether, between 20 and 27 per cent of e-cigarette vapour's ultra-fine particles make their way into the circulatory system, compared to 25 to 35 per cent for regular cigarettes. A recent report from Science News points out that these nanoparticles can trigger inflammation in the mucus membrane and have been linked to chronic diseases like asthma, stroke, heart disease, and diabetes.
We're In Unknown Territory
Even the supposedly inert chemical substrate of e-liquid, propylene glycol, can have some pretty nasty effects on your body when heated and inhaled. Propylene glycol (PG) is a ubiquitous synthetic liquid added to a variety of foods, cosmetics, and medicines as a humidifying agent. For these functions, the FDA has rated PG as GRAS, or Generally Recognised As Safe, the agency's general seal of approval, effectively.
However, none of those functions involve madly huffing hot PG into your lungs. "We have little information about what happens to propylene glycol in the air," the federal Agency for Toxic Substances and Disease Registry website declares.
We do know that habitual inhalation of aerosolised PG in industrial settings can lead to issues with the central nervous system, personality and behaviour changes, and reduced spleen function. In fact, the Dow Chemical Company states that "inhalation exposure to [propylene glycol] mists should be avoided," and the American Chemistry Council has repeatedly issued warnings about inhaling theatre fog as it may contribute to eye and respiratory infections.
"Propylene Glycol is a pulmonary irritant—it's used for theatre fog," Glantz told me. "And if you look on the product packaging, there's a warning on there to avoid prolonged exposure. And there you're not even breathing it in hot."
Even better, when heated above a certain temperature, PG will convert to propylene oxide: a class 2B carcinogen as rated by the International Agency for Research.
We Need More Data
In response to the potential health threats that these devices may instigate, the FDA has begun asking for more research into their effects on pulmonary health. And despite the FDA's rumblings about regulating the e-cig market more strictly, scientists simply haven't had time understand the long-term effects of vaping on human physiology or its effectiveness as a cessation device. "Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking," Callahan-Lyon recently wrote.
"Certainly, as the cigarette companies take over the e-cigarette market, there's no incentive for them to promote e-cigarettes as an alternative to regular cigarettes because the tobacco companies make a lot more money off of cigarettes," Glantz explained. $83 billion more annually to be precise, and that's just in America. "The federal government and the FDA have to date been extremely flaccid in trying to deal with e-cigarettes," Glantz told me.
The solution is fairly simple, Glantz continued, only requiring more robust market regulation:
The first and, I think, most important thing to do is that e-cigarettes be included in existing clean indoor air laws which many, many cities are already doing. I believe there are already 150 to 200 cities around the country that have already done this including major cities like New York, Los Angeles, Chicago, and San Francisco.
Getting rid of the "smoke anywhere" claim and also protecting bystanders from breathing second-hand vapour, I think is very important. E-cigarettes should be subject to the exact same marketing restrictions as conventional cigarettes are—we shouldn't have them being advertised on television or the radio. The same kind of licensing requirements places have for selling cigarettes should be applied to stores selling e-cigarettes. And they should be prohibited from making these unsubstantiated claims that e-cigarettes are good for helping people quit smoking or that they are emitting only harmless water vapour.
So in the end, we still have more questions than answers when it comes to the long-term health effects of e-cigarettes. Sure, they're safer than conventional cigarettes (existing research bears that out) but they are far from truly "safe." They are not "harmless," and they do not generate "pure water vapour," or whatever Dorff was rambling on about in his e-cig advertising campaign. At the same time, there's an argument to be made that by even minimally reducing the harm caused by cigarettes is a positive thing.
Either way, the fact remains that e-cigs are synthetic chemical cocktails that we know precious little about. So maybe think twice before absentmindedly puffing away. [Science News - Forbes - Huffington Post - Scientific American - UCSF 1, 2 - BMJ]
Lead image: Marc Bruxelle