E-cigarette marketing reaches more than two-thirds of middle and high school students in the United States, according to a report yesterday - a development that some public health officials argue is prompting more teens to use the devices and threatening decades of progress in combating youth tobacco use.
"It's the Wild West out there when it comes to e-cigarette advertising," said Tom Frieden, director of the Centres for Disease Control and Prevention, which released the data.
"It's no coincidence that as the advertising has skyrocketed, the use of e-cigarettes has skyrocketed."
CDC's findings were drawn from the 2014 National Youth Tobacco Survey, which included a representative sample of more than 22,000 middle and high school students.
Nearly 70 per cent - an estimated 18.3 million students - reported having seen e-cigarette marketing in at least one setting that year, mostly in retail stores, followed by the internet, television, movies, newspapers and magazines.
Anti-smoking advocates and public health officials say advertising for conventional tobacco products such as cigarettes triggers increased experimentation among young people, leading to more smokers.
They worry the same scenario is playing out with e-cigarettes, which currently don't face the advertising restrictions that apply to traditional cigarettes.
That's bad news, they say, because of evidence that nicotine use can negatively affect the developing brains of teenagers, because so much remains unknown about the long-term effects of e-cigarettes and because of the potential that young people who try them could wind up as regular smokers.
E-cigarette sales in the US hit an estimated US$2.5 billion ($3.76 billion) last year. Researchers say e-cigarette advertising has grown along with the market, from an estimated US$6.4 million in 2011 to an estimated US$115 million in 2014.
While manufacturers insist their products are aimed solely at adults - in many cases, smokers looking for a way to satisfy their nicotine cravings while avoiding the well-documented harm of tobacco - the devices have become increasingly popular among young people.
CDC reported last year that the number of middle and high school students using e-cigarettes tripled from 2013 to 2014, eclipsing their use of traditional cigarettes.
Matthew Myers, president of the Campaign for Tobacco-Free Kids, said companies "are getting to them [kids] early, long before they become teenagers". "It was the case with cigarettes 25 years ago.
They are using the same themes and the same images but the penetration in the modern media era is as strong as anything we've ever seen."