New research says e-cigarette vapor causes lung cancer and possibly bladder cancer in mice. The study also shows vapor damaged the DNA of the mice.

The researchers concluded that vaping is “very harmful” to humans as well. Lead researcher Moon-Shong Tang said on CNBC.com: “Long term, some cancer will come out, probably. E-cigarettes are bad news.”

This research is the first direct link between vaping nicotine products and cancer.

Study links vaping and cancer

The researchers exposed 40 mice to nicotine-laden e-cigarette vapor and 20 mice to e-cigarette smoke without nicotine over the course of 54 weeks.

22.5 percent of the mice exposed to nicotine developed lung cancer, and 57.5 percent developed precancerous bladder lesions. In contrast, none of the 20 mice who were not exposed to nicotine developed cancer or precancerous lesions.

The e-cigarette vapor caused DNA damage in the bladder and lungs of the mice. That damage inhibited DNA repair of tissues.

This study might mean good news for cannabis vapers. Since the 20 mice who were not exposed to nicotine did not develop cancer, regulated cannabis may be safer.

Implications and limitations

The researchers estimated that the vapor exposure amount was similar to what a regular vaping human would inhale over approximately three to six years. However, that exposure took place over weeks, not years.

The study sample was small. Also, according to the researchers, the mice in the sample were more likely to develop cancer.

Research from Public Health England has found something different. There is no proof that vaping carries no elevated risk for lung cancer, cardiovascular disease, COPD, and other smoking-related illnesses. However, it certainly carries less risk than traditional combustible smoking.

Keep calm, decide whether to vape on

Although the sensational headlines attached to this study may feel upsetting, it’s important to keep this in perspective. The most important conclusion this study makes is that e-cigarette vapor demands more study. This is true.

However, a study like this is not directly analogous to human health. Compounds that could be carcinogenic might affect humans and people differently, so these results are suggestive for, but not directly applicable to, people.

Still, since nicotine is not a carcinogen, these results are notable. It is possible that other harmful compounds that could cause cancer may occur in some e-cigarettes. Or, the inhalation process itself along with the compounds may be involved.