Chest CT Shows More Emphysema in Marijuana Smokers

Whitney J. Palmer

Images show greater rates of emphysema in individuals who smoke marijuana than in those who smoke tobacco-only cigarettes or non-smokers.

People who smoke marijuana face increased rates of emphysema compared to individuals who choose tobacco-only cigarettes.

In a scientific e-poster that will be presented during the 2021 ARRS Virtual Annual Meeting, researchers from Ottawa Hospital in Canada show that smoking marijuana not only elevates the emphysema rate overall, but the increase is even greater when patients are age-matched. In addition, the team saw greater rates of paraseptal emphysema.

To make this determination, the team, led by first author Luke Murtha, M.D., a diagnostic radiologist at Ottawa Hospital examined imaging reports from the facilities PACS system. They concentrated on three groups, matching them for age and sex: marijuana smokers (56 patients), non-smokers/non-marijuana users (57 patients), and tobacco-only smokers (33 patients).

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A review by two board-certified, fellowship-trained radiologists who were blinded to smoking or marijuana-use history, completed consensus reading of chest CTs for the study group.

Based on their analysis, they determined 75 percent of main-group marijuana smoking patients had greatly elevated rates of emphysema compared with 5 percent of main-group control patients. Rates were even higher among the age-matched subgroup where 93 percent of marijuana smokers and 66 percent of tobacco-only smokers experienced significant increases in emphysema.

The team also identified a much higher proportion of paraseptal emphysema – compared to other types – in marijuana smokers. Of those individuals, 53 percent demonstrated paraseptal emphysema, while only 24 percent of tobacco-only smokers and 7 percent of non-smokers experienced it.

In addition to these findings, Murtha said, marijuana use was also linked to other conditions.

“Marijuana smoking is also associated with airways disease, including bronchial wall thickening, bronchiectasis, and bronchiolar mucoid impaction, in comparison to both the control group and tobacco-only group,” he said.

These findings can be significant, the team said, because legalization of and use of marijuana is changing.

“Given that marijuana use is increasing, particularly within nations, such as Canada, that have legalized the substance, it is important for us, as radiologists, to define specific findings associated with its consumption,” the team concluded.