No, a study did not show that E-Cigarette vapor causes lung cancer in mice

The study linked nicotine to mice lung cancer, not the vapor.

Aaron J. Alford
3 min readOct 8, 2019

I am no medical researcher, but I do know how to look at a study and read what is there. The headlines which are being posted about E-cigarettes causing cancer are absolutely not what the study they claim to quote is about. Simply reading the study will show you that the news is misleading the public yet again.

Okay, so a study just came out from the NYU School of Medicine on October 7, 2019. The study was published in Proceedings of National Academy of Sciences. The press are already coming out with misleading headlines such as “E-cigarette smoke caused lung cancer in mice” or “E-Cigarettes definitely linked to cancer.” These headlines are irresponsible and speak to an ignorance about the content of the study.

Due to the way that studies are reported on and the fact that people don’t read the studies they hear about, we are likely going to see a misconception develop that says that E-cigarettes are as bad as normal smoking and cause cancer.

Let me set the record straight here and now, the author of the study Dr. Moon-shong Tang clearly states that his study is not meant to compare mice to humans. Further, if you read the specifics of the study it found that 22.5% of mice who were exposed to nicotine developed lung cancer, but 0% of the mice exposed to E-cigarette vapor without nicotine developed cancer.

That means that the controlling factor in this study was not E-cig smoke, but instead was the nicotine, which is a known dangerous substance.

A more correct headline might read “study finds that nicotine may be linked to lung cancer” but the media never misses an opportunity to lie about public health issues for profit, now do they?

This study also had a lot limitations which won’t be reported by the media. Humans don’t go into a steam room of nicotine filled smoke and soak their bodies in it to get their nicotine, they inhale it for a few moments at a time.

The study exposed mice to high levels of nicotine for 4 hours a day, 5 days a week, for 54 weeks through “whole-body exposure” which is certainly different than direct inhalation. Additionally, it was a relatively small number of mice (roughly 85 mice in total) and, according to the study, mice are already predisposed to developing cancer over their lifetime.

Finally, these results are in conflict with other studies which examined whether E cigarette nicotine was carcinogenic in rats. A review of the literature surrounding the carcinogenicity of nicotine broadly leave the issue is ambiguity and inconclusive results. That isn’t to say nicotine isn’t dangerous, it absolutely is dangerous, but this study doesn’t really introduce much new information until more work can be done.

News outlets are going to report this as a study proving that “e cigarettes cause cancer in mice” but the truth it they have shown that tobacco can cause cancer in mice, something that has been examined before. The study also clearly states that the public should not equate the risk of E-cigarette smoke with that of cigarette smoke. Vaping has still been endorsed by many researchers as high as 95% safer than traditional tobacco.

This study is important, and speaks to how new technology is further our understanding of carcinogens broadly. E-cigarettes helped researchers remove thousands of toxic chemicals found in tobacco smoke, allowing scientists to examine more closely how nicotine itself contributes to various health problems in mice. Just don’t mistake the findings of this study to mean that E-cigarettes have been proven to cause cancer. We do not know the exact long term effects of E-cigarette usage and this study doesn’t claim to know either.

Finally, remember to read the source material that new outlets cover. You will often find that the news media shows a stunning lack of knowledge on the stories they report. Many study results can be misleading if you don’t examine closely the method, limitations, and actual conclusions of researchers. Do your own research and don’t believe everything you hear.



Aaron J. Alford

Media critique and memes. Writing about rhetoric and society. MA in Communication