Children like adults are increasingly trying electronic cigarettes, according to the first large US study to gauge use by teenage students.
Health officials say the study suggests many kids are now getting a first taste of nicotine through e-cigarettes and moving on to regular tobacco products.
The devices began to appear in the United States in late 2006, but marketing has exploded in the last couple of years.
About 2% of students said they'd used an e-cigarette in the previous month, according to the survey done last year. That was up from 1% in 2011.
More kids still smoke traditional cigarettes than the new electronic ones, and it's not clear how dangerous e-cigarettes are. It's also not clear from the report how many children are using them on a daily or weekly basis.
Electronic cigarettes are battery-powered devices that provide users with aerosol puffs that typically contain nicotine, and sometimes flavourings like fruit, mint or chocolate. They've often been described as a less dangerous alternative to regular cigarettes.
Unlike regular cigarettes, the federal government does not regulate e-cigarettes, although about 20 states have banned store sales to minors.
More marijuana than tobacco
The new study released Thursday by the Centers for Disease Control and Prevention is based on a questionnaire filled out by nearly 19 000 students in 2011 and another 25 000 in 2012.
In 2011, about 3% said they'd tried an e-cigarette at least once. That rose to 7% last year and translates to nearly 1.8 million students.
In contrast, 6% of adults have tried e-cigarettes, according to a different CDC survey done in 2011.
Children still are more likely to light up regular cigarettes, though teen smoking rates have dropped in the past decade. More teens now smoke marijuana than tobacco, surveys have found.
Some makers of e-cigarettes said Thursday that they supported regulations that keep the devices out of kids' hands. But some are wary of steps that might affect adult buyers.
Future regulations shouldn't "stifle what may be the most significant harm reduction opportunity that has ever been made available to smokers," Murray Kessler, chief executive of Lorillard Inc., the nation's third-biggest tobacco company and owner of Blu Ecigs, said in a statement.