"No greater than the risk of getting cancer by chance" say British researchers
A recent study in mice showed a link between nicotine in e-cigarette vapor and lung cancer. However, the study is being criticized by several heavyweights in modern research with long experience in e-cigarettes and health issues.
The study from the US received stower attention in the US media when it was published. In particular, in the context of the lung damage initially linked to vejpning in the country (fall 2019). The study focuses on three groups of mice exposed to different types of vapor from e-cigarettes: nicotine-containing vapor, nicotine-free vapor and clean air. The mice in the nicotine group developed cancer at a higher rate than the clean air group. Surprisingly, the mice exposed to nicotine-free vapor developed the least cancer of all three groups.
Excessive amounts of nicotine
According to the research team, their study is a sign that nicotine in e-cigarettes can be a danger to the user in the long run. But that conclusion is now being criticized. Peter Hajek is Professor and Director at the Tobacco Dependence Research Unit at Queen Mary's University in London.
"The mice in the study were exposed to huge amounts and high concentrations of chemicals relative to their size. The conditions are not even close to what a regular e-cigarette user exposes themselves to," says Peter Hajek to the Science Media Center press service.
Minimal impact on cancer
Peter Hajek compares the current study with previous long-term studies involving active vejpers. The subject NNK, which is naturally present in nicotine, is carcinogenic in large quantities. It is this substance that the US researchers focused on. However, the British long-term study shows that the amount of carcinogenic substances in the body is significantly lower among vejp users than among smokers. Up to 450 times lower. Among these substances was also NNK.
"The exposure to NNK was negligible. The substance was present in concentrations that have minimal significance for the development of lung cancer," said Peter Hajek, to Science Media Center.
Chance is more important
Peter Hajek is supported by John Britton, Director of the UK Center for Tobacco and Alchohol studies. John Britton believes that the warning from the US researchers is greatly exaggerated. Especially in relation to the results presented by the researchers. And the fact that e-cigarettes increase the risk of cancer, albeit marginally, is not exactly news, he says.
"It is possible that vapor from e-cigarettes slightly increases the risk of cancer compared to breathing clean air, of course. But based on this study, it is the risk is no greater than what could happen by pure chance, says John Britton to the Science Media Center.
John Britton also argues that the study is far too small and that the comparisons between air, nicotine-free vapor and nicotine-containing vapor are not statistically significant. He also points out the apparent oddity that the mice exposed to nicotine-free vapor did better than those who breathed clean air.
"I suspect that these results are just scientific noise. This is nothing that should matter when it comes to warning the public" says John Britton.
Neither tar nor carbon monoxide
According to Public Health of England (PHE), e-cigarette vapor contains only 5% of the harmful substances found in regular cigarette smoke. According to the PHE's summary of hundreds of studies, there is no tar or carbon monoxide in e-cigarette vapor (if used correctly). The harmful substances that can be measured are at concentration levels between 9 and 450 times lower in tobacco smoke.
"It would be tragic if smokers, who could quit with the help of an e-cigarette, ignore it because of misinformation about the health risks" said John Newton, Head of PHE's Health Prevention Department to the Guardian newspaper in 2018.
Sources:
Study in mice links nicotine to cancer (Eureka Alert)
Long-term studies of carcinogens in e-cigarettes (Cancer Research UK)
