In a large national survey released yesterday, last year, 4.5 per cent of high school students said they had used e-cigarettes in the previous month. That's up from 1.5 per cent in 2011 and 2.8 per cent in 2012.
It's not known, though, how many were repeatedly using e-cigarettes and how many only tried it once during that month and didn't do it again.
E-cigarettes began to appear in the United States in late 2006, but marketing has exploded in recent years. The devices heat liquid nicotine into a vapour.
Dozens of states outlaw the sale of e-cigarettes to minors, and federal officials have proposed a nationwide ban on such sales.
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The e-cigarette findings from the federal Centers for Disease Control and Prevention are disheartening, said Dr Patrick T O'Gara, president of the American College of Cardiology.
Smoking rates has slowly been declining over the last several decades, but "we risk going backwards if a new generation of smokers becomes addicted to nicotine," O'Gara said in a statement.
The CDC survey also found 13 per cent of high school students recently smoked regular cigarettes, and that about 23 per cent used some form of tobacco product be it cigarettes, e-cigarettes, flavoured cigars, hookahs or something else.