Researchers looked for cancer-causing substances in saliva taken from five vapers before and after a 15-minute session.
They also assessed DNA damage in the cells of the volunteers’ mouths.
They identified three DNA-damaging compounds, formaldehyde, acrolein and methylglyoxal, whose levels increased after vaping.
Four of the five e-cigarette users showed greater DNA damage related to acrolein exposure.
Cancer could develop if the cells do not repair the damage, boffins from the University of Minnesota warn.
The findings come after MPs on the Commons Science Committee last week called for rules on vaping to be relaxed.
Their report said e-cigs should be prescribed on the NHS and people should be allowed to use them in public places.
Public Health England has previously claimed that e-cig are “95 per cent safer” than smoking and could help people quit.
But critics warn vaping may be a gateway to smoking for youngsters and research has linked the habit to lung diseases.
Dr Silvia Balbo, who led the latest study, said: It’s clear that more carcinogens arise from the combustion of tobacco in regular cigarettes than from the vapour of e-cigarettes.
“However, we don't really know the impact of inhaling the combination of compounds produced by this device.
“Just because the threats are different doesn't mean that e-cigarettes are completely safe.
“We still don't know exactly what these e-cig devices are doing and what kinds of effects they may have on health, but our findings suggest that a closer look is warranted.”
Dr Romel Dator, who also worked on the study, said: “E-cigarettes are a popular trend, but the long-term health effects are unknown.
“We want to characterise the chemicals that vapers are exposed to, as well as any DNA damage they may cause.”
They researchers plan to follow up this preliminary study with a larger one involving more e-cigarette users and non-users.
They also want to see how the level of DNA damage differs between e-cigarette users and regular cigarette smokers.
Some 7.4million Brits smoke and 2.8million use e-cigs, Office for National Statistics figures show.
The findings were presented at the annual meeting of the American Chemical Society in Boston.
Source: Read Full Article