Dec. 18 (UPI) -- More than one in 10 high school seniors in the United States use e-cigarettes containing marijuana, a new analysis has revealed.
And, in all, the percentage of adolescents and teens who have tried e-cigarettes with marijuana was nearly 15 percent in 2018, up from just over 11 percent the previous year, according to two separate studies published Wednesday in the Journal of the American Medical Association.
"As the number of adolescents who vape marijuana increases, so too does the scope and effect of any associated health consequences, which may include lung injury when using black market formulations," researchers at the University of Michigan and University of Minnesota wrote in a research letter, which was based on data from the Monitoring Your Future project.
The researchers analyzed survey responses from nationally representative samples of 8th, 10th, and 12th graders totaling nearly 60,000 students over a three-year period. And their findings were surprising, given all the recent headlines regarding vaping-related illness.
In 2019, for example, 3.9 percent of 8th graders, 12.6 percent of 10th graders, and 14 percent of 12th graders said they had vaped with marijuana in the past 30 days. Notably, reported past 30-day use rates increased from 2018 to 2019, from 1.3 percent, 5.6 percent, and 6.5 percent in 8th, 10th and 12th graders.
In addition, near daily marijuana vaping was reported by 0.8 percent, 3 percent and 3.5 percent of 8th, 10th and 12th graders in 2019.
The other study, which was based on responses to the Centers for Disease Control and Prevention's National Tobacco Youth Survey, yielded similar results.
Hongying Dai, an associate professor in the College of Public Health at the University of Nebraska Medical Center, reports in a research letter that the largest increases in e-cigarette marijuana use in teens from 2017 to 2018 was observed among current users of a tobacco product -- from just over 33 percent to nearly 41 percent -- and among those who lived with a household member who vapes -- from nearly 23 percent to nearly 30 percent.
"The increase in marijuana use in e-cigarettes could be attributable to the increase of sales of pod-mod-style e-cigarette products, access to marijuana through informal sources and reduced perception among adolescents of the harms of marijuana," Dai wrote in the new letter.
In a study published Monday, Dai also reported that three-quarters of teens who use e-cigarettes vape nicotine, marijuana or both.
E-cigarette use has been linked with severe respiratory diseases, including 2,290 confirmed vaping-related lung injuries, and 47 deaths, reported through the end of November. More than three-quarters of these incidents involved use of marijuana-containing vaping products.