There have been several studies that suggests e-cigarettes are harmful, but many questioned whether smoking was still to blame since most vapers also smoke traditional cigarettes or have a prior history of smoking.
The study looked at 82 healthy adults split them into three categories — current vapers, people who only smoke cigarettes and a control group who had never smoked or vaped.
The research studied 37 current vapers, 22 current smokers and 23 non-smokers in Los Angeles.
E-cigarette users may be more likely to suffer a stroke in middle-age than traditional smokers, research suggests. .
While vaping is generally accepted as healthier than cigarettes, researchers warned exposure to the devices at a young age can still do irreparable damage. .
The study found 12 per cent of affected genes in vapers were in the mitochondria — the parts of cells that scientists say can help keep the immune system working effectively and prevent cancer and other diseases developing. .
The number of damaged genes in smokers was around 7.4 times higher than in vapers, researchers said.
This means they could then be licensed as a medical product and prescribed by doctors on a case-by-case basis to people who want to quit traditional cigarettes
The researchers said results may have been affected by the higher number of vapers than smokers studied — 37 and 22 respectively
But they said regulators should take note of the findings, especially with the number of vapers increasing all the time.