(CNN) Teens are about twice as likely to report "wheezing or whistling" in the chest after vaping marijuana than after smoking cigarettes or using e-cigarettes, a new study has found.
"This surprised us, we thought we would find more negative respiratory symptoms in both cigarettes and e-cigarettes users," said study author Carol Boyd, co-director of the Center for the Study of Drugs, Alcohol, Smoking & Health at the University of Michigan in Ann Arbor.
"Without a doubt, cigarettes and e-cigarettes are unhealthy and not good for lungs. However, vaping marijuana appears even worse," she said.
"Since many teens who vape nicotine, also vape cannabis, I recommend parents treat all vaping as a risky behavior (just like alcohol or drug use)," Boyd said via email.
Vaping weed is associated with a dangerous, newly identified lung disease called EVALI, short for e-cigarette, or vaping, product use-associated lung injury.
The disease was first identified by the US Centers for Disease Control and Prevention in August 2019, when otherwise healthy young people began being hospitalized for severe, sometimes fatal, lung infections across the country.
A link between the deadly new condition and vaping was soon found, with a major role being played by vitamin E acetate, a sticky oil substance often added to vaping products to either thicken or dilute the oil in cartridges.
That was especially common in vaping products that contain THC, the main psychoactive compound in marijuana.
"According to the CDC, 84% of the EVALI cases were associated with cannabis-containing products," Boyd said.
As of February 2020, 68 deaths from EVALI have been confirmed in 29 states and the District of Columbia.
The new study, published Wednesday in the Journal of Adolescent Health, analyzed data collected over a two-year period by the Population Assessment of Tobacco and Health study. It's a national longitudinal study of the health impact of tobacco use administered by the National Institutes of Health and the US Food and Drug Administration.
A fourth wave of the PATH study asked nearly 15,000 teens between the ages of 12 and 17 to describe their last 30-day cigarette, e-cigarette and weed use, as well as the total time they had spent vaping marijuana over their "lifetime."
Each teen was also asked if they had any of these five symptoms over the last year: wheezing or whistling in the chest; disturbed sleep due to wheezing; limited speech due to wheezing; wheezing during or after exercise and experiencing a dry cough at night that was not due to a cold or chest infection.
After analyzing the data, Boyd and her team found "adolescents' lifetime cannabis vaping" use was associated with all five negative respiratory symptoms.
"This was not true for cigarette or e-cigarette use," Boyd said.
The study was limited by the original questions asked in the PATH study, which did not allow the researchers to fully explore vaping cannabis over time. A household survey, the longitudinal study also excluded adolescents residing in institutions who "may have higher rates of cannabis use," Boyd said.
Despite those limitations, "the current study had a large national sample and we found a robust association between lifetime cannabis use with ENDS (electronic nicotine delivery systems) and respiratory symptoms during a critical stage of development among youth," Boyd said.
Would these health concerns also apply to adults who vape weed? The study was not designed to test that, Boyd said, but "vaping THC/CBD is a relatively new behavior, and thus, not many individuals over the age of 25 years were vaping cannabis as teens. We have too few data to make an assessment."
That doesn't mean that vaping is a safe behavior, Boyd stressed.
"I often am approached by both parents and teens who believe vaping cannabis is 'OK' and better than smoking (a joint, blunt, dobie, etc.). And so, they ask, 'Vaping is safe—right?'
"My reaction: 'You are fooling yourself. We know that inhaling hot tobacco/cannabis smoke into your lungs is unhealthy and can cause bronchitis or life-threatening breathing problems.
"And yet, you seem to believe that heating chemicals (including carcinogens) into a vapor and inhaling them is healthy? My answer is, 'No, it is not a healthy behavior.' "