• Mayo Clinic Minute: Are e-cigarettes safe?

Most health officials will tell you they believe e-cigarettes are less harmful than a conventional tobacco cigarette. But there is still plenty of uncertainty regarding the damage that e-cigarette vapor can cause to a person's body over time.

A recent study published in the Proceedings of the National Academy of Sciences found that mice exposed to e-cigarette vapor experienced DNA damage to certain organs that could increase the risk of cancer and heart disease.

Because there are so many unknowns and there is no scientific evidence that vaping is safe, Mayo Clinic experts urge e-cigarette users to be cautious. Jason Howland has more in this Mayo Clinic Minute.

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The use of electronic cigarettes, also called vaping, has exploded in the last five years.

"There are probably 600 different kinds you can purchase on the internet," says Dr. J. Taylor Hays, director of the Mayo Clinic Nicotine Dependence Center. "There are 7-8,000 different solutions that you can purchase."

Dr. Hays says e-cigarette manufacturing is a relatively unregulated industry. And, while some people might think they are safe to vape, Dr. Hays says the harmful chemicals in that vapor are similar to tobacco smoke but at much lower levels.

"It's safer, but it's not safe," he says. "What we don't know are what long-term effects will these lower-level toxicants have."

Dr. Hays says some patients prefer to use e-cigarettes as an aid to stop smoking. He says, while vaping is less harmful than smoking cigarettes, there are safer and proven effective alternatives for people who want to quit smoking.

"And that's behavioral counseling — even brief counseling — and approved medications," says Dr. Hays.