Vaping nicotine linked to lung cancer

Using e-cigarettes or vaping has become immensely popular over the last decade, especially among teens. However, over the past few months, health experts warned the public against e-cigarette use due to the emergence of severe lung disease cases.

Now, for the first time, a new study links e-cigarette use or vaping to lung cancer. A team of researchers at New York University (NYU) School of Medicine has found that exposure to e-cigarette smoke caused mice to develop lung adenocarcinoma (lung cancer) and bladder urothelial hyperplasia in mice.

Published in the journal Proceedings of the National Academy of Sciences (PNAS), the study reveals that electronic-cigarette smoke (ECS)-exposed mice developed lung adenocarcinoma, a type of lung cancer, indicating that the vapor or smoke is a lung carcinogen and a potential bladder carcinogen in mice models.

“While it is well established that tobacco smoke poses a huge threat to human health, the threat ECS poses to humans is not yet known and warrants in-depth investigation,” the researchers wrote in the paper.

Mice developed abnormal tissue growth

To arrive at their findings, the researchers found that out of 40 mice in the laboratory exposed to e-cigarette smoke with nicotine for 54 weeks, 9 or 22.5 percent developed lung cancer. On the other hand, none of the 20 mice in the control group exposed to the same e-cigarette smoke without nicotine developed cancer.

Further, the researchers discovered that of the 40 mice, 57.5 percent or 23 mice exposed to the e-cigarette smoke with nicotine developed bladder hyperplasia, which can lead to abnormal tissue growth and cancer.

Tobacco smoke is the conventional way of delivering nicotine, a chemical stimulant of the nervous system that gives smokers with instant gratification, in turn, causing long-term addiction. Tobacco smoke also contains other chemicals, which have been unveiled as carcinogens. Over the past decades, cigarette smoking has been dubbed as the cause of human cancers, accounting for 85 percent of lung cancers, and 50 percent of bladder cancers.

Over the past decade, e-cigarettes showed promise as an alternative to cigarettes, delivering nicotine in aerosols through controlled heating of an organic solution. It doesn’t produce smoke, and there’s no burning involved, providing a safe replacement for tobacco smoke.

However, with the immense popularity of e-cigarettes, even those who aren’t smoking are now using the device. Teens and young adults, for instance, are fond of using vapes or e-cigarettes. The study is just one of the many that provide an idea of the adverse effects of e-cigarettes on health.

“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. 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,” Moon-shong Tang, a professor in the Departments of Environmental Medicine, Medicine, and Pathology, said.

Exposure to e-cigarette smoke effects

The researchers reiterate the need for further research about the link between vaping and cancer in humans. Because the vaping market is still young, it might take longer or even decades before its impact on humans will be understood.

The amount of smoke the mice in the laboratory were exposed to was quite similar to what humans would inhale if they used an e-cigarette regularly for about three to six years. Aside from vaping, the researchers said that secondhand smoke from vape fumes may also put other people at risk.

“It takes two decades or more for a life-time smoker to develop lung cancer. 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,” Tang added.

Journal reference:

Tang, M.S., Wu, X.R., Lee, H.W., Xia, Y., Deng, F.M., Moreira, A., Chen, L., Huang, W., and Lepor, H. (2019). Electronic-cigarette smoke induces lung adenocarcinoma and bladder urothelial hyperplasia in mice. Proceedings of the National Academy of Sciences (PNAS). https://www.pnas.org/content/early/2019/10/01/1911321116