Smoking marijuana in combination with cigarettes may do more damage to lungs than cigarettes alone, a new study suggests.
A study published Tuesday in the peer-reviewed journal Radiology showed that marijuana use may be linked to an increased risk of emphysema versus smoking only tobacco. The trend is made more worrisome by the fact that cannabis users were younger on average — most were under 50 — than cigarette smokers.
Emphysema develops over time as lung tissue is damaged and causes air sacs to rupture and trap air in the damaged tissue and prevent oxygen from moving through the bloodstream. It can cause shortness of breath, coughing with mucus, wheezing and chest tightness, and is irreversible once it develops.
Over 3 million people in the United States have been diagnosed with the potentially deadly disease despite it being one of the most preventable respiratory illnesses, according to the American Lung Association.
Researchers from the Department of Radiology at Ottawa Hospital found that 75% of the people in the study who smoked marijuana, potentially alongside tobacco, had developed emphysema, while just 67% of the tobacco-only smokers showed signs of the disease. Only 5% of complete nonsmokers were diagnosed.
Furthermore, they saw that paraseptal emphysema, a specific subtype of the disease that affects the outermost parts of the lung, was more common among marijuana smokers compared to those who only smoke tobacco.
The study reviewed chest scans of 56 marijuana smokers — 50 of whom were also current or former tobacco users — 33 tobacco-only smokers and 57 nonsmokers, taken between 2005 to 2020.
But the small-scale study of 150 participants based in Canada had limitations. Researchers did not gather sufficient data on how subjects consumed cannabis, how often they smoked it or for how long they’ve kept up the habit. The method by which cannabis users inhale the substance makes a difference: Blunts, for example, contain tobacco in the wrap.
Tobacco-only smokers in the study were noted to have consumed at least one pack — 20 cigarettes — per day for the past 25 years.
Researchers also did not account for other previous health conditions.
“There’s a public perception that marijuana is safe, or that it’s safer than cigarettes. But this study raises concerns that this may not be true,” said lead study author Dr. Giselle Revah, assistant professor of radiology at the University of Ottawa, in a statement to Agence France-Presse.
“The American Lung Association says the only thing that should go into your lungs is clean air, so if you’re inhaling anything, it could potentially be toxic to your lungs,” Revah said in a CNN report.
“There’s definitely a concern that we’re going to see another generation of lung disease related to these behaviors,” Dr. Albert Rizzo, chief medical officer of the American Lung Association, told USA Today.
Researchers point out that marijuana and tobacco are smoked differently, with marijuana smokers usually inhaling deeper and longer, while tobacco is commonly smoked with quick exhalations. Conventionally manufactured cigarettes also have a filter, which may catch certain harmful toxins.
Due to the limitations, experts admit that the study cannot fully compare the safety of marijuana and tobacco, but agreed that the findings suggest more research should be done as use of the drug is on the rise. E-cigarettes, too, are increasingly popular and should be factored into future research.