The number of American middle and high school students who’ve tried electronic cigarettes has surged, more than doubling between 2011 and last year, according to a new survey released Thursday by the Centers for Disease Control and Prevention.

The findings from the CDC’s National Tobacco Survey show that more than 1.78 million middle and high school students tried electronic cigarettes, or e-cigarettes, in 2012. Among high school students, the number who said they had ever tried an e-cigarette rose from 4.7 percent in 2011 to 10 percent in 2012. The number who had used an e-cigarette within the past 30 days increased from 1.5 to 2.8 percent.

Similar spikes were noted among middle school students. What’s more, the study found that more than three quarters of the students who used e-cigarettes within the past 30 days had also smoked regular cigarettes.

“This report raises the concern that e-cigarettes may be an entry point for youth to begin using more traditional tobacco products, including cigarettes,” said Nancy Brown, CEO of the American Heart Association. “It’s imperative that we keep the tobacco industry from addicting yet another generation of smokers.”

The AHA cites cigarette smoking as the most important preventable cause of premature death in the United States, accounting for more than 440,000 of the more than 2.4 million annual deaths from heart disease.

“Every day, each of the 1,200 Americans who die from tobacco-related diseases is replaced by two smokers under the age of 26,” said Brown. “If e-cigarettes are luring high school and middle school students into a lifetime of addiction, it represents a public health tragedy. We cannot sentence more young Americans to a lifetime of battling cardiovascular disease because of tobacco addiction.”

Unlike conventional tobacco cigarettes, e-cigarettes are battery-powered devices that deliver a vapor of nicotine and other additives. The CDC said they typically contain nicotine, an aerosol component such as propylene glycol or glycerol, and flavorings such as fruit, mint or chocolate. They may also contain irritants and other ingredients that can cause cancer in animals

But because the Food and Drug Administration does not yet regulate them, good information about the amounts and types of components and potentially harmful contents of e-cigarettes is unknown. The FDA has said it intends to start regulating e-cigarettes.

“The CDC reinforces the American Heart Association’s serious concerns about the potential public health effects of e-cigarettes,” said Brown. “We hope this new information will prompt swift action by the FDA to regulate this product before even more youngsters fall prey to tobacco use.”

The CDC’s National Youth Survey is a question­naire given to students in all 50 states in grades 6 through 12 to help understand the smoking habits and rates among students across the nation.

A different tobacco youth survey from the United Kingdom on Thursday found that graphic warnings on the back of cigarette packs had little impact on teenagers who buy them.

While garish pictures of tumors and smoke-stained teeth were slightly more effective than words, the images are often put on the back of packs making them less visible and less effective, according to a report in today’s Huffington Post UK edition.

You can read the AHA’s full statement on the CDC study about e-cigarettes here.