The first study definitively linking vaping to cancer was published yesterday. Researchers at New York University found a link between e-cigarette nicotine vapour and lung and bladder cancer in mice.
During the study, which was funded by the National Institutes of Health and published in Proceedings of National Academy of Sciences (PNAS), researchers exposed 40 mice to e-cigarette smoke with nicotine over the course of 54 weeks, and 20 mice to e-cigarette smoke without nicotine over the course of four years. Nine of the 40 mice (or 22.5%) exposed to nicotine developed lung adenocarcinomas, and 23 (or 57.5%) developed pre-cancerous lesions on their bladders. None of the mice exposed to e-cig smoke without nicotine developed cancer.
“It’s foreseeable that if you smoke e-cigarettes, all kinds of disease comes out,” the study’s lead researcher, Moon-Shong Tang, PhD, of NYU School of Medicine, told CNBC. “Long term, some cancer will come out, probably. E-cigarettes are bad news.”
The study emerges amid reports of illnesses and deaths associated with vaping, which led the Centre for Disease Control and Prevention to issue a health warning, several states to ban e-cigarettes, and President Trump to announce plans for a national ban on flavoured e-cigarettes. However, critics of the ban say that the illnesses and deaths are tied to bootleg marijuana vaping products rather than people using e-cigarettes as intended.
The Vapour Technology Association disputed the findings of the new study, pointing to a 2015 study that found that e-cigarettes were 95% less harmful than cigarettes.
Dr. Tang admitted that there are limitations to the study — the mice were exposed to smoke outside their bodies instead of inhaling it like humans would, for example — and the results in mice can’t be directly compared to the results in humans. However, while he acknowledged that more research is needed, he said that the results are “statistically very significant” and indicate that it’s unlikely that e-cigarettes are safe for humans.
It'll take at least 10 more years before we fully understand the effects of vaping, Dr. Tang added to Gizmodo. “It takes two decades or more for a life-time smoker to develop lung cancer,” he said. “If tobacco smoke-induced lung carcinogenesis is a paradigm for e-cig carcinogenicity, then it will take at least another decade to have e-cig-related human lung cancer to show up.”
Next, the researchers plan to expand the study by including more mice, varying the exposure times, and investigating the genetic changes caused by e-cigarette smoke.