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If you're the parent of a teen and you've been reading the headlines lately, you might have heard about findings showing that teens are vaping at "record levels" because it "looks cool," even though "vape culture" can be dangerous to their health.

And this is probably worrisome, because you know that vaping leads to smoking, and smoking cigarettes leads to smoking marijuana, and marijuana leads to heroin, and heroin leads to nothing, because now you're dead. Vaping vigilance is warranted, the story goes, because the road to drug dependency is paved with"Blue Razzle Berry Vape Juice."

Right?

Well, maybe not so fast. A new study published this week in the journal Tobacco Control provides some clarity as to what, exactly, your teen is smoking when they puff away on Saturday Morning Cereal Vape Juice.

First, a word on what exactly vaping is and how it works. "Vaping" is the popular term for using electronic cigarettes or vaporizers — devices that heat up small quantities of liquid or oil until they produce an inhalable vapor. Vaporizer liquids -- "vape juice" to the cool kids — come in a variety of flavors. Some of these juices contain nicotine, others contain marijuana or its active ingredient, THC. Many juices contain no drugs at all, and retailers often allow users to customize the amount — or lack thereof — of nicotine in the juices they buy.

And as it turns out, the overwhelming majority of teens who experiment with vaping — about two-thirds of them — use only the flavored vaping juices that contain absolutely no nicotine, marijuana or other drugs. The findings "suggest that the recent rise in adolescent vaporiser use does not necessarily indicate a nicotine epidemic," the authors concluded.

The study was conducted by some heavy-hitters in the world of adolescent drug policy — the same team at the University of Michigan that conducts the federal Monitoring the Future (MTF) survey, one of the gold-standard annual assessments of teen substance use in the United States.

The researchers found that nicotine-based vaping was fairly uncommon among the teens surveyed in the most recent MTF — 13 percent of eighth-grade vapers and 20 percent of 10th- and 12th-grade vapers had opted for nicotine during their most recent vaping session. Only 6 percent of adolescent vapers across all three grades had used marijuana.

It's important to know all this, because vaping has rapidly become popular among high school students. In 2015, students in all grades were considerably more likely to have used an e-cigarette device than to have smoked an actual, physical cigarette. Whether this is, on balance, good news or bad news remains hotly contested among public health researchers.

On the one hand, a fair amount of evidence suggests that vaping is less harmful to individuals than smoking traditional cigarettes. E-cigarette users inhale vaporized liquid, not smoke, which is thought to contain fewer cancer-causing and otherwise harmful compounds. Some studies suggest that e-cigarettes might be a less harmful alternative to traditional cigarettes for users who are looking to quit or cut back their nicotine intake.

On the other hand, other researchers are concerned that vaping might be a gateway to more traditional and harmful ways of smoking. And while vaporized liquid is probably better for your lungs than hot smoke, vape juice typically still contains a number of chemicals and flavoring compounds whose long-term effects on the human body aren't really known yet.

Traditionally, public health groups have viewed rising rates of vaping among teens with alarm. "E-cigarette use among youth will begin kids on a lifelong addiction to nicotine and tobacco products," said the president of the American Lung Association in 2014.

But given the latest data from the Monitoring the Future survey, the University of Michigan researchers warn that this may be an overreaction. "These results challenge the common assumption that all vaporizer users inhale nicotine," the researchers wrote.

Earlier this year, the Food and Drug Administration announced it would begin regulating the use of vaporizers, putting them under a set of restrictions similar to those in use on traditional cigarettes. The FDA considers vaporizers to be "Electronic Nicotine Delivery Systems."

But the University of Michigan researchers said that designation isn't accurate, given that most teens, and an as-yet unknown percentage of adults, don't use nicotine products in their vaporizers. That term "seems inaccurate for the description of a device that the majority of youth do not use to vape nicotine," the researchers write.

This has important implications for policy measures that help keep children off of drugs. One who is already hooked on nicotine needs a different public health intervention than one who likes the way "Amaizeballs e-juice" tastes but who otherwise isn't interested in developing a nicotine dependency.

"In conclusion, the majority of US youth who use vaporizers and e-cigarettes do not vape nicotine," the researchers wrote. "This finding challenges many common assumptions and practices, and points to the need for vaporizer-specific research to assess and ultimately regulate the public health threat of vaporizers."