Electronic cigarettes are the most popular tobacco product among U.S. teens, but tobacco isn’t the only thing they’re vaping. A new report from researchers at the Centers for Disease Control and Prevention says that more than 2 million middle and high school students have used an e-cigarette to vape marijuana.

That figure is based on survey results from the 2016 National Youth Tobacco Survey, which polls a representative sample of American students in grades 6 through 12. Among the questions the 20,675 participants were asked in 2016 was, “Have you ever used an e-cigarette device with a substance besides nicotine?”

One of the possible answers was this: “Yes, I have used an e-cigarette device with marijuana, THC or hash oil, or THC wax.” (THC, short for tetrahydrocannabinol, is the mind-altering chemical that produces marijuana’s high.)

Altogether, 8.9% of the students — or nearly 1 in 11 — selected this response. That included 12.4% of students in grades 9 through 12 and 4.5% of students in grades 6 through 8.


Extrapolating those figures across the country, the researchers calculated that 1.7 million high school students and 425,000 middle school students have vaped marijuana at least once.

Next, the CDC team focused on the 5,217 students — that’s one-quarter of the total sample — who said they had used an e-cigarette at least once in their lives. In this group, 30.6% said they had vaped marijuana, including 33.3% of the high schoolers and 23.1% of the middle schoolers.

Certain groups of students were more likely to put a marijuana product in an e-cigarette, the survey revealed:

• 10.6% of all boys had done it, compared with 7.2% of girls.


• 10.8% of all Latino students had tried it, compared with 8.5% of white students and 8.4% of black students.

• 39.5% of current e-cigarette users (that is, those who had vaped within the past 30 days) said they had vaped marijuana at least once, compared with 6.1% of their fellow students who had never vaped or had not vaped recently.

• 38.5% of students who were current users of other tobacco products said they had vaped marijuana, compared with 5.3% of students who did not use other tobacco products.

• 13% of students who lived with a tobacco user had done it, as did 6% of those who did not live with a tobacco user.


• Among those who had ever used an e-cigarette, 63.7% of heavy users (defined as those who had vaped on at least 20 of the past 30 days) had vaped marijuana. That compares with 33.5% of those who vaped on one to five of the past 30 days and 39.8% of those who vaped on 6 to 19 of the past 30 days.

The findings were published Monday in the journal JAMA Pediatrics.

The report comes less than a week after the U.S. Food and Drug Administration announced a crackdown on companies that produce and sell e-cigarettes in response to their failure to keep the devices out of the hands of minors. The 2017 Monitoring the Future survey from the University of Michigan reported that more than 2 million middle and high school students called themselves current users of vaping products, and FDA Commissioner Scott Gottlieb called it an “epidemic of nicotine addiction” among American youth.

Since 2016 was the first time the National Youth Tobacco Survey asked students about mixing e-cigarette devices and marijuana, there isn’t enough data for researchers to gauge whether the practice is more popular now than it was two years ago, said study leader Katrina Trivers, lead epidemiologist in the CDC’s Office on Smoking and Health. But as more states liberalize their marijuana laws and new kinds of vaping products come on the market, she said, it’s certainly possible that the picture could change.


In the study, Trivers and her coauthors noted that marijuana poses particular health risks for adolescents.

“The National Academies of Sciences has found cannabis use among youth can adversely affect learning and memory and may impair later academic achievement and education,” they wrote. “Strategies to reduce cannabis use in e-cigarettes are critical for protecting young people from these potential health risks.”

karen.kaplan@latimes.com

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UPDATES:

12:15 p.m.: This story has been updated to include estimates of the number of students who have vaped marijuana in the U.S.

This story was originally published at 11:30 a.m.