A poorly designed mouse study from the New York University School of Medicine in New York City is causing news outlets around the world to falsely report that the use of vapor products increases the risk of cancer and heart disease.
“In medical science, mouse studies are of very limited use in determining effects on humans,” said Bruce Nye, RN, Vice-President of CASAA. “We have cured cancer and other diseases many times in mice yet the results do not have the same effect on people. Mice are not men.”
The researchers say they found that mice exposed to e-cigarette vapor experienced DNA damage in the lungs, bladder, and heart and that such damage has been previously linked to an increase in the risk of cancer and heart disease. They also found similar damage in lab-grown human lung and bladder cells that had been exposed to liquified e-cigarette vapor, leading them to conclude that it is “possible that e-cigarette smoke may contribute to lung and bladder cancer, as well as heart disease, in humans.”
However, what the researchers considered “light use” exposure in mice might actually be far more than average exposure for humans. Ten mice were exposed to vapor containing 10 mg/mL of nicotine for 3 hours a day, 5 days a week, for 12 weeks. They exposed cell cultures directly to a liquid bath of vapor products, substantially differing from what happens in the real world. Because the study didn’t test real-world use or exposure, it cannot show that there would be any adverse effect on human health from vaping.
“The design of experiment matters,” explained Nye. “This design does not model real-world exposures. Instead the doses were concentrated hundreds of times and the exposures were continuous over 3 hours to ‘simulate’ the effect of vaping for longer periods. The problem with this is it violates the basics of toxicological research – the dose makes the poison and exposure makes the risk.
“Attempting to substitute short exposures at higher doses for small exposures at lower doses produces a false result which can not be duplicated in the real-world. This is the same as giving the entire adult daily dose of narcotics to an infant in a single dose – the infant will die. This is a basic mistake often made by those who are either not familiar with toxicology, or who have a specific goal of experiment in mind to support their pre-drawn conclusion.”
Curiously, the researchers hinge their conclusions about cancer risk from vaping on “nitrosamines that are derived from the nitrosation of nicotine.” Yet they showed no mechanism for the nitrosation of nicotine in such exposures. In fact, it has never been proven that nicotine exposure is a carcinogen in humans. More so, the FDA has strongly proclaimed nicotine as safe for long-term use and eliminated the required time limit recommendations on labeling for over-the-counter nicotine products. The most recent research still hasn’t shown a link between nicotine products and cancer, either.
Furthermore, the study didn’t compare damage from e-cigarette vapor to the damage caused by smoking. It is a gross oversight in any study of vapor products not to compare it to smoking, as the vast majority of vaping consumers would otherwise be exposed to smoke, rather than air. Every previous study that has compared vaping to smoking demonstrates that e-cigarette vapor is dramatically less harmful than smoke.
“Showing DNA damage that may increase the risk of cancer is not even close to the same as showing an actual increased risk,” Nye concluded. “DNA damage occurs regularly, it is a normal part of the biological process in every living thing.”