The use of electronic cigarettes, or e-cigarettes, is increasing among adult smokers and former smokers, and these products remain unregulated by the Food and Drug Administration (FDA), except when they're sold for therapeutic reasons. The battery-powered devices deliver doses of nicotine and other additives via a vapor, and although the exact components vary by brand, e-cigarette cartridges may contain nicotine, a component to produce the vapor (an atomizer that heats up, turning a liquid, such as propylene glycol or glycerol, into vapor), and flavorings. In most states, there are no restrictions on sales to minors, but according to the Centers for Disease Control and Prevention (CDC), the devices seem to be growing in popularity among school-age children and teens (go to http://1.usa.gov/1hsHZWK for the entire report).

According to the CDC, the use of e-cigarettes doubled among U.S. middle and high school students from 2011 to 2012; extrapolation from the percentages suggests that there may be as many as 1.78 million student users. Additionally, an estimated 160,000 students who said they'd used e-cigarettes had never smoked conventional cigarettes.

The public health impact of e-cigarette use remains uncertain. "There have been reports of exploding cartons and possible harmful ingredients in the product and in the vapor," says Stella Bialous, president of Tobacco Policy International. Because they're unregulated, she says, whether these products are safe isn't yet known.

There are also no data confirming the efficacy of e-cigarettes as a cessation device, says Bialous, although a study in the Lancet (November 16, 2013) found that e-cigarettes were "modestly effective" in helping smokers quit. The level of abstinence from tobacco was similar to that observed with nicotine patches, and the study authors suggest that there may be potential for e-cigarettes in that context. E-cigarettes appeared to have no adverse effects, have a greater reach, and be more acceptable than nicotine patches, at least as observed in this study.

The FDA had tried to block the importation of e-cigarettes from China until their safety, as well as their efficacy as a cessation device, had been demonstrated in clinical trials, but a federal judge overruled the agency in January. The FDA's efforts were backed by several groups, including the American Cancer Society, the American Heart Association, Action on Smoking and Health, and the Campaign for Tobacco-Free Kids. The FDA has submitted a proposal to extend its authority over tobacco products to include e-cigarettes.-Roxanne Nelson