*The following is excerpted from an online article posted on HealthDay.
E-cigarettes are fast becoming a clever way for American teens to use pot, with a new survey showing that nearly a third of high school e-cig users have vaped marijuana.
The survey involved nearly 20,700 middle and high school students from both public and private institutions. The goal was to gain fresh insight into vaping, which has been the most popular means for smoking among American youth since 2014.
One of every 11 students overall said he or she had ever used marijuana in an e-cigarette.
"That equates to more than 2 million youth who have ever used cannabis in an e-cigarette," noted lead investigator Katrina Trivers. She is a lead epidemiologist in the office on smoking and health with the U.S. National Center for Chronic Disease Prevention and Health Promotion at the U.S. Centers for Disease Control and Prevention.
Among those who said they have ever used an e-cigarette at all, 1 in 3 high schoolers and 1 in 4 middle schoolers said they had used pot by vaping it.
Trivers said the findings point to seemingly dramatic shifts underway in how and what teens smoke.
"Although we've seen considerable declines in the use of regular cigarettes among U.S. youth over the past several decades, the tobacco product landscape is evolving, and the use of other tobacco products has become increasingly popular," she said.
"This high rate of cannabis use in e-cigarettes is a public health concern, because any form of tobacco product use is unsafe among youth, irrespective of whether it's smoked, smokeless or electronic," she stressed.
On that front, Trivers pointed out that National Academies of Science has stated that pot use among youth "can adversely affect learning and memory, and may impair later academic achievement and education."
More broadly, she noted that the U.S. Surgeon General "has concluded that the aerosol emitted from e-cigarettes is not harmless," based on its nicotine and chemical compound content.
By simply adding hash oils, waxes and other liquids that contain pot's active ingredient directly into the e-liquid section, teens can turn an e-cig into a pot-delivery device.
Trivers noted that the survey found that pot vaping was "significantly higher" among boys. It was also more common among high schoolers.
"Use was also higher among those who had used e-cigarettes more recently and more frequently," she added, as well as among students who said they use other tobacco products and/or live with someone who uses tobacco products.
Regardless, the researchers concluded that the survey showed pot use in e-cigs is as popular -- or perhaps more popular -- than believed.
The findings were published online Sept. 17 as a letter to the editor in the journal JAMA Pediatrics.