Teens who see frequent ads for e-cigarettes are more likely to pick one up and start vaping, a new study has found. The US Centers for Disease Control and Prevention said today that middle and high school students exposed to e-cig ads — be it online, on TV, or printed in a store or magazine — were more likely to have vaped in the past 30 days than teens who weren't. The more ads they saw, the more likely they were to have vaped.

E-cigs have kept kept teen tobacco use from falling

The data comes from the CDC's 2014 National Youth Tobacco Survey, with results being self-reported by more than 22,000 students. The findings are being published today in the journal Pediatrics.

Teen vaping has dramatically risen over the past few years — so much so that it's surpassed cigarette smoking. Earlier this month, the CDC said that 3 million middle school and high school students were current e-cigarette users. That number rose 500,000 from the year prior. While smoking of traditional cigarettes is declining, the increase in vaping has kept teen tobacco use from declining since 2011. There's no consensus yet over just how harmful e-cigarettes are for their users, but the CDC notes that "any tobacco use by youth is dangerous to their health."

With these findings, the CDC is starting to push back against one of the classic factors of tobacco use. "The unrestricted marketing of e-cigarettes and dramatic increases in their use by youth could reverse decades of progress in preventing tobacco use among youth," Brian King, deputy director at the CDC's smoking division, says in a statement. King says today's e-cig ads "look eerily like the ads" that used to sell cigarettes, leaning on depictions of "sex, independence, and rebellion."

The CDC has no control over tobacco or e-cigarette advertising. But the Food and Drug Administration, which as long regulated tobacco, is now in the process of finalizing a rule that will give it some command over e-cigarettes. When it does, limitations may be placed on e-cig manufacturers and retailers meant to reduce sales to teens. Among other limitations, the FDA plans to prohibit e-cig sales in vending machines that teens and children have access to. That'll be a start, but it doesn't go quite as far as the CDC is recommending.

In a release accompanying the new findings, the CDC suggests limiting e-cig sales to stores that only admit adults, preventing e-cig sales from being offered close to schools, and making e-cigs harder to purchase online. Much of this may come down to state and local law, as it initially did with cigarettes. With the CDC's release today, regulators and lawmakers have some of the evidence they need to back those actions up.