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 vapor. 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 labeling 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 vapor found that most contained at least trace amounts of the solvents used to dissolve the nicotine and flavorings. 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 vaporization but that of carboxyl vaporization 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. That's not good.
What's more, the atomization process generates ultrafine 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 percent of e-cigarette vapor's ultrafine particles make their way into the circulatory system, compared to 25 to 35 percent 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 Recognized As Safe, the agency's general seal of approval basically.
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 aerosolized PG in industrial settings can lead to issues with the central nervous system, personality and behavior 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 theater fog as it may contribute to eye and respiratory infections.
"Propylene Glycol is a pulmonary irritant—it's used for theater 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 more strictly regulating the e-cig market, 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 dollars 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 vapor, 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 vapor.
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 vapor," or whatever Dorf was rambling on about. 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.
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