The researchers also exposed cultured human lung and bladder cells to nicotine, and found the same effects - DNA damage and suppressed DNA fix. On this, Tang is bullish: "Both tobacco smoke and E-cigarette smoke cause DNA damage, inhibit DNA fix and enhance mutations, and the degree of these effects are not much different between E-cig and tobacco". The study seems to reaffirm the basic premise that e-cigarettes aren't as risky as tobacco products, but it isn't the first to suggest they (not to mention the various flavours added to them) have their own set of risks. "The results may take years to come in because cancer is such a slow process", he said. Meanwhile cultured human cells reacted in a similar manner when exposed to nicotine and its derivatives.
"Our results suggest that e-cigarettes might be just as bad as cigarettes". E-cigarettes are marketed as a safer alternative to smoking tobacco.
Tang exposed mice to e-cigarette smoke for three hours a day, five days a week for three months. The popularity of e-cigarettes decreases with age and is used more by teenagers and young adults.
In the tests, mice breathing the e-cigarette vapour showed greater damage to their DNA in the heart, lungs and bladder, as well as being more likely to develop tumours compared to the control group of mice breathing filtered air. Mice exposed to ECS also had reduced DNA fix activity and lower levels of certain DNA fix proteins in the lungs relative to control mice.More news: Prez, PM hope for early Par approval of Triple Talaq bill
Tang went on to look at human lung and bladder cells and found that exposing the cells to nicotine and its breakdown products made the cells turn into tumour tissue more easily.
The study was published January 29 in the Proceedings of the National Academy of Sciences.
Last week a major United States report into the health effects of e-cigarettes found that vaping might be useful to help people quit smoking. The findings add to the already weighty body of evidence showing vaping to be far less hazardous than smoking.
Dr Mehmet Kesimer, who led the study said: "There is confusion about whether e-cigarettes are "safer" than cigarettes because the potential adverse effects of e-cigarettes are only beginning to be studied".