Regulated electronic cigarettes and nicotine vapes may be safer than smoking tobacco. However, a new study has shown, for the first time, that vaping nicotine could potentially cause lung or bladder cancer.
The study, funded by the National Institutes of Health and led by researchers at New York University School of Medicine, was published this week in the Proceedings of the National Academy of Sciences, one of the nation’s most prestigious scientific journals. Researchers found that when 40 otherwise healthy mice were administered nicotine vapes, 9 mice (22 percent) developed lung adenocarcinoma, a type of lung cancer.
Additionally, 23 out of 40 mice (57.5 percent) developed bladder hyperplasia, where DNA in the bladder cells began mutating. Bladder hyperplasia can develop into bladder cancer if left unchecked.
"Tobacco smoke is among the most dangerous environmental agents to which humans are routinely exposed, but the potential of e-cig smoke as a threat to human health is not yet fully understood," said Moon-shong Tang, PhD, a professor at NYU’s Departments of Environmental Medicine, and Pathology, and one of the lead authors on the study. "Our study results in mice were not meant to be compared to human disease, but instead argue that e-cig smoke must be more thoroughly studied before it is deemed safe or marketed that way."
There are some caveats regarding this study. First, the mice weren’t exposed to comparable levels of nicotine vape that a human would consume in a single sitting. Rather, the mice got the equivalent of three-months’ worth of human-sized vaping at a time. So, the study doesn’t prove that vaping nicotine causes cancer, but rather it simply shows that vaping could cause cancer.
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Second, mice are not humans. Although the experiment tried to replicate human behavior patterns of vaping, as well as shortening the study’s time span to account for the mouse’s shorter life span compared to a human’s, it can’t ideally replicate a real-world environment. Furthermore, mice are incredibly sensitive to inhaling anything that isn’t pure air, which is why mouse studies with weed rarely expose the mice to weed smoke.
Third, there’s good news for weed vapes: Vapes without nicotine did not lead to cancer in the 17 controlled mice. This suggests that marijuana vapes, which contain THC and/or CBD and cannabis terpenes could be relatively safe — at least when compared to vaping nicotine. However, one of the mice dosed on a nicotine-less vape did develop hyperplasia. Whether the vape caused the hyperplasia or the mouse just developed it on its own was not determined.
Scientists have known for a long time that nicotine alone is not carcinogenic. Although nicotine can disrupt normal immune function that eradicates pre-cancerous cells, nicotine doesn’t appear to damage DNA directly. Cigarettes and other tobacco products are carcinogenic because the plant material is treated with chemicals that cause nitrosation, a reaction that bonds nitrogen atoms to the nicotine molecule. Nitrosation converts nicotine into nitrosamines, which are incredibly carcinogenic. But vape users’ blood have much lower levels of nitrosamines, by about 95 percent less, than tobacco smokers, which is why vape companies market their products as a safer alternative to smoking tobacco.
So, what could be causing the DNA damage in the mice if nicotine doesn’t cause cancer? The researchers found that the murine cells naturally produced their own nitrosation compounds, which caused the nicotine from the vapes to convert into nitrosamines, ultimately screwing up the DNA of the mice.
What’s the takeaway here? E-cigs may be safer to consume than tobacco smoke, but they still carry risks. If you’re going to vape anything, vaping pure, uncut weed oils may be the safest bet (though, to be fair, there are practically no clinical studies on vaping weed oil). Vaping anything produces toxic free radicals, and vaping artificially flavored products produces more free radicals than hitting non-flavored vapes. Ultimately, though, vaping produces much fewer free radicals than smoking chemically-treated tobacco, especially when the cartridge is heated at its lowest possible setting.
There’s also a lung illness epidemic sweeping the nation that appears to be caused by unregulated, black market vapes, though authorities are still looking into legal, regulated vapes as a potential cause of the epidemic, too. Over 1,000 people have been hospitalized, and at least 19 people have died from the illness. As of now, the lung illness does not appear to be related to nicotine damage.
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