The American Heart Association issued its first official policy recommendation on electronic cigarettes this week, saying they were a last-resort method of quitting traditional cigarettes.
The heart association also pointed to studies suggesting that e-cigarettes, which contain nicotine but no tobacco, could serve as a "gateway" drug to addict young people, who may go on to regular cigarettes or smokeless tobacco.
Despite growing in popularity, many questions remain over e-cigs and potential health risks. Here are answers to some common questions:
What are e-cigarettes?
E-cigarettes are battery operated inhalers that consist of a rechargeable battery, a cartridge called a cartomizer and an LED that lights up at the end when you puff on the device.
Are e-cigarettes currently regulated by the Food and Drug Administration?
No. An April proposal from the Food and Drug Administration would require most e-cigarettes to undergo an agency review. In its new statement, the heart association calls on the FDA to put the proposed rules — three years in the making — in place before the end of the year.
What is vaping?
Vaping is defined as the act of inhaling water vapor through a personal vaporizer or electronic cigarette. When users draw on the device, the battery heats the liquid, which is then atomized into an inhalable vapor.
How does vaping differ from traditional smoking?
E-cigarettes differ from traditional cigarettes in that they do not contain carcinogens such as arsenic and vinyl chloride. Additionally, there is no secondhand smoke associated with vaping.
How many e-cigarette products are on the market?
There are 466 brands and more than 7,700 flavors on the market, according to the policy report. There have been an average of 10 new brands entering the market every month for the last two years, a recent Internet survey found.
What are the biggest markets for the products?
Europe and North America. In April, U.S. regulators proposed treating e-cigarettes as tobacco products with rules including a ban on sales to people under 18 and the establishment of warning labels.
Do e-cigarettes contain nicotine?
Yes. They do not contain tobacco.
What is in the liquid inhaled?
The main components of a cartridge of "juice" are nicotine, propylene glycol, solvents and flavors.
What are the health risks of e-cigarettes?
Little is known about the health effects, which have been sold in the USA since 2007.
Thomas Glynn, the director of science and trends at the American Cancer Society, said there was a great likelihood that e-cigarettes would prove considerably less harmful than traditional cigarettes, at least in the short term.
Due to the relative newness in the popularity of vaping, the long-term effects of vaping have yet to be analyzed.
Michael Siegel, a tobacco control expert at the Boston University School of Public Health, said as long as e-cigs are primarily used to help quite smoking and not to spur kids to smoke, they will be a benefit to public health.