- One study found more emphysema in marijuana smokers compared to tobacco smokers of the same age.
- The study’s author told Insider that her research raises concerns that smoking marijuana is no safer than cigarettes.
- The results suggest that smoking both marijuana and cigarettes is more harmful than smoking tobacco alone.
A small study found more emphysema, a lung condition that causes shortness of breath, in marijuana smokers compared to age-matched tobacco smokers. The study also suggests that using marijuana and tobacco together may be more harmful than using tobacco alone.
Dr. Giselle Revah, a cardiothoracic radiologist at Ottawa Hospital and the study’s lead author, reviewed chest CT scans at Ottawa Hospital from 2005 to 2020 and identified 56 patients who reported using marijuana.
The majority of marijuana users – 50 of the 56 patients – said they also smoked cigarettes. She compared them to 33 tobacco-only smokers and 57 non-smokers.
The ages of the tobacco-only smokers increased because Revah collected these chest CT scans from patients at her hospital’s lung cancer screening event, which was open to patients over 50 who self-reported themselves as heavy smokers. Marijuana smokers in her sample tended to get a chest CT for reasons unrelated to emphysema.
When the radiologist matched tobacco-only smokers with age-matched marijuana smokers, marijuana smokers had more emphysema: 93% (28 out of 30) compared to 67% of age-matched tobacco smokers.
The radiologist found that marijuana users in general — including younger people who weren’t exposed to as much smoke — had significantly higher rates of paraseptal emphysema, a rare form of the condition that damages small ducts that connect the air sacs of the lungs.
The way marijuana smokers use the drug can damage air sacs. Marijuana users tend to take deep breaths and hold in the smoke longer, creating pressure changes that can irritate the air sacs of the lungs, Revah told Insider.
“The main message of the whole study is that there’s a public perception that marijuana is safe; people believe it’s safer than cigarettes,” Revah said. “And this study raises concerns that marijuana may not be as safe as everyone thinks, and suggests that we ultimately need more robust research before we can make any sweeping conclusions.”
The article sheds light on the under-researched health effects of marijuana. Literature on marijuana smokers’ chest CTs is scarce, Revah said, as Canada only legalized the drug in 2018. The US has not legalized cannabis nationally and obtaining funding for marijuana research involves cumbersome legal steps.
Pulmonologists told Insider that more research is needed on the health effects of marijuana use.
Dr. Philip Diaz, a lung disease physician at Ohio State University Wexner Medical Center who was not involved in the study, said that because most of the marijuana smokers in the study were cigarette smokers, it’s possible that both marijuana and cigarette smoking may increase the risk of lung damage. increases. But Diaz stressed that the results of the small study should not be exaggerated.
“You don’t want to downplay the fact that cigarette smoking is the problem,” Diaz told Insider. “I think all you could say is there could be an increased risk if you do both.”
Revah said she’s working on a prospective study asking patients how much marijuana they use, and she hopes a larger study will confirm her findings.
Dr. Albert Rizzo, the chief medical officer of the American Lung Association, told Insider scientists and physicians that longer, more in-depth research is needed on marijuana’s long-term health effects, especially as the drug quickly becomes legalized in states across the US.
“I think this study is a good one to try to show or support that marijuana use leads to respiratory problems, including emphysema,” Rizzo told Insider. “Smoking marijuana is not safe and we don’t really know the long-term effect of smoking marijuana.”