E-cigarette smoke has been found to damage DNA in the heart, lungs and bladder in mice, according to research from New York University's School of Medicine.
The study investigated whether e-cigarette smoke damages the organs of a mouse and whether it affects DNA repair activity. The researchers exposed mice to e-cigarette smoke for three hours a day, five days a week for three months.
The nicotine in the e-cigarette vapour affected both the mice’s DNA and human cells in a dish, as the vapour made the cells less able to repair the DNA damage. 'It is therefore possible that e-cigarette smoke may contribute to lung and bladder cancer, as well as heart disease, in humans,' the researchers wrote in the study, published in PNAS.
The study suggests that the nicotine used in e-cigarette vapour is not risk-free. However experimentation results on animals do not necessarily translate into the same risks for humans, the researchers note. To address this, research on human participants would be necessary.
'Studies like this are important for building up the evidence around vaping, and how e-cigarette vapour might damage cells in controlled conditions,' said Michael Walsh of Cancer Research UK.
However, it is premature to conclude that vaping causes cancer in humans. The study also did not compare e-cigarette vapour to smoke from traditional cigarettes. Many studies have shown that vaping is less harmful overall to human health than smoking tobacco.
Jasmine Just of Cancer Research UK told the Guardian: 'Research like this is important, but this lab study only looked at the effects of e-cigarette smoke on cells and on mice, which means it’s not possible to draw any conclusions from this about how e-cigarettes might affect people in real life.'
Cancer Research UK and other researchers not involved in the study have cautioned that exaggerating the findings of the study could have negative consequences. As many vapers are ex-smokers using e-cigarettes to quit smoking, it should be noted that people with nicotine addictions are still better off vaping than smoking, said Professor Peter Hajek, director of the Tobacco Dependence Research Unit at Queen Mary University of London.
Claims that vaping causes cancer, as some news sources have reported, are part of 'a long line of false alarms which may be putting people off the switch from smoking to vaping which would undoubtedly be of great benefit to them', Professor Hajek said.