A new study found that teens who vape cannabis reported more symptoms of lung injury than those who smoked cigarettes, marijuana or e-cigarettes, though one expert cautions the study has some limitations.
The study conducted by researchers at University of Michigan, looked at self-reported symptoms such as wheezing and whistling in the chest and dry cough from a sample of almost 15,000 adolescents between the ages 12 and 17 from the Population Assessment of Tobacco and Health Study.
What they found were that adolescents who vape marijuana were at a greater risk for respiratory symptoms indicative of lung injury than teens who smoked cigarettes or weed, or vaped nicotine. However, it’s important to note that the research didn’t look at other types of lung injury such as cancer, emphysema, or other long-term lung issues associated with smoking.
The study looked in particular at five main symptoms of lung injury, including: 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.
According to the study, teens who reported vaping marijuana were about twice as likely to report “wheezing and whistling” in the chest than those who used e-cigarettes or smoked.
While smoking cigarettes, e-cigarettes and cannabis were all linked with some respiratory symptoms, such as dry cough, most of the associations weren’t significant after controlling for vaping cannabis – a result that goes against a lot of preconceived beliefs.
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“I thought that e-cigarettes (vaping nicotine) would be the nicotine product most strongly associated with worrisome respiratory symptoms,” said the study’s lead author Carol Boyd in a press release.
“Our data challenges the assumption that smoking cigarettes or vaping nicotine is the most harmful to the lungs. If we control for vaping cannabis in our analyses, we find there is a weaker relationship between e-cigarette or cigarette use and respiratory symptoms when compared to vaping cannabis.”
Matthew Stanbrook, a respirologist at Toronto Western Hospital, told Forbes he thought this study was helpful in dispelling the idea that smoking cannabis is safe.
“We really know almost nothing about vaping cannabis on health and there’s the perception that it’s safe but it’s not the truth,” he said.
However, despite the fact that the study does show that vaping cannabis might not be as safe as once thought, Stanbrook notes it is a bit misleading.
“The problem with this study is they’ve taken data from people at a single point in time [and] there’s a lot of potential for bias in that,” he told Forbes, explaining that the study asked about people’s symptoms from over a year ago making recall bias very likely.
Further, Stanbrook noted that while the study asked if participants had ever, in their life, vaped cannabis, it failed to ask about the participants if they’d ever smoked or used e-cigarettes.
“It’s an unfair comparison. You would see [the symptoms] with all these exposures,” he said, explaining that if the study had looked at lifetime use they likely would have found that all methods would be linked to lung injury symptoms just based on the previous research that’s out there.
Boyd is careful to point out that the findings don’t mean that vaping nicotine or smoking cigarettes or weed isn’t bad for you. All of the aforementioned have been linked to numerous respiratory problems and an increased risk of cancer.
“In short, it is all bad […] Without a doubt, cigarettes and e-cigarettes are unhealthy and not good for lungs,” she said in a statement.
Vaping devices have increasingly become a popular way to consume cannabis, and have been linked to a number of lung illnesses, including the new lung disease called EVALI, short for e-cigarette, or vaping, product use-associated lung injury.
The Centers for Disease Control and Prevention eventually found a link to vitamin E acetate, which has been used as a cutting agent in e-liquids containing THC.
As of February 2020, 68 deaths from EVALI have been confirmed in 29 states and the District of Columbia.