In 2016, researchers surveyed more than 20,000 youth ages nine to 19, includingabout 5,200 children and teens who said they had vaped at least once.
Almost 9 percent of students surveyed in 2016 said they used an e-cigarette device with marijuana.
Vaping is generally considered less risky than smoking, because burning tobacco or marijuana generates chemicals that are harmful to lungs.
The researchers acknowledge in JAMA Pediatrics that the study wasn't a controlled experiment created to prove whether or how vaping on its own or using cannabis in e-cigarettes might directly cause health problems.
USA health regulators recently gave the five largest e-cigarette makers 60 days to produce plans to stop underage use of their products.
One in every 11 teens has used marijuana in electronic cigarettes, according to a research published Monday in JAMA Pediatrics, the pediatrics-focused peer-reviewed journal of the American Medical Association.
"Although using cannabis through an e-cigarette or in edibles does not have the same risks of smoking it, there are still health risks", Trivers said by email. "There are a variety of ways that cannabis or marijuana could be used in an e-cigarette, such as putting hash oils, waxes, and other THC liquids directly in the e-liquid section of an e-cigarette". It was the first time a question about marijuana vaping was asked on this particular survey. In that study, 8 percent of 10th graders said they vaped marijuana in the past year.
"The health risks of vaping reside not only in the vaping devices, but in the social environment that comes with it", said University of MI researcher Richard Miech. Kids who vape are more likely to become known as drug users and make friends with drug users, he said, adding that "hanging out with drug users is a substantial risk factor for future drug use".