vaping e-cigarette
© Hannah Mckay / Reuters
Vaping damages DNA, putting users at a higher risk of cancer and heart disease according to a new study which examined the effects of e-cigarette smoke on mice.

Researchers at New York University found that through damaging DNA and inhibiting DNA repair, e-cigarette smoke may contribute to human lung and bladder cancer as well as heart disease. The team noted, however, that further studies are needed to substantiate this claim.

E-cigarette smoke delivers nicotine through aerosols without burning tobacco. Nicotine inhaled from e-cigarettes could be converted into chemicals that damage DNA in the heart, lungs and bladder, according to the study.

As part of their tests, mice were exposed to e-cigarette smoke (ECS) for three months at a dose and duration equivalent to light e-cigarette smoking for 10 years in humans. The exposure led to DNA damage in the animals' lungs, bladders and hearts. It also retarded DNA repair functions and proteins in the lungs.

There are 18 million e-cigarette smokers in the United States - 16% of these are high school students according to the research. "Understanding the carcinogenicity of [this] is an urgent public health issue," the research published in PNAS stated. It adds that tests are limited to animal models and cell culture models as it takes decades for carcinogen exposure to induce cancer in humans.

Researchers acknowledged that carcinogens found in body fluids of e-cigarette users are 97 percent lower than in cigarette smokers but noted this is still "significantly higher than in nonsmokers."

The study brings into question the general punting of e-cigarettes as safe. It also comes just days after the Food and Drug Administration rejected a proposal from tobacco giant Philip Morris to market its new smokeless device as safer than smoking. The FDA panel concluded there wasn't enough proof to state that the device was a safer way to ingest tobacco and nicotine.

In 2016, the FDA finalized a rule extending its regulatory authority to all tobacco products, including e-cigarettes, cigars, as well as hookah and pipe tobacco, as part of its goal to improve public health.

Cancer research groups, however, were quick to warn against fearmongering and point to previous research indicating that e-cigarettes are far less harmful than smoking.

"E-cigs are a relatively new technology and so we can't be certain about any long-term effects the devices might cause to health - they haven't been around long enough for this to be completely worked out. But compared to smoking, the evidence so far shows they are less harmful," it said in statement.

Previous research indicated that e-cigarettes are safer than smoking. A study last year looked at the effects of e-cigarettes in what they defined as 'long-term users' (around 17 months). They found remarkable differences in levels of potentially toxic chemicals among e-cigarette users and smokers. One chemical known to cause lung cancer was 97% lower in e-cigarette users.