Marijuana Damages Lungs in Tobacco Smokers

A new study has clarified that tobacco smokers are more susceptible to damage to their lungs if they smoke marijuana.

Although there is a public perception that marijuana is safer than tobacco, the study, led by Dr. Giselle Revah, an assistant professor in the department of radiology at the University of Ottawa in Ontario, raises concern contrary to the wider assumption.

The study published in Radiology, a journal of the Radiological Society of North America, compared computed tomography (CT) chest scans of fifty-six people who smoked marijuana and tobacco with lung scans of thirty-three people who had been heavy cigarette smokers for over twenty-five years.

Scans from an additional fifty-seven non-smokers with no preexisting lung disease, chemotherapy, or other history of lung damage were used as controls.

According to findings, 75 percent of some of the people in the study who smoked marijuana and tobacco had emphysema, a disease of the small airways that causes damage to the air sacs in the lungs.

Dr. Revah said 67 percent of the tobacco-only smokers had emphysema while only 5 percent of the non-smokers had the disease.

“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,” Dr. Revah stated.

Percentage margin in marijuana is small but significant

According to research results, a difference of 8 percentage points between marijuana plus tobacco and tobacco-only smokers was identified, and although this may not seem like a huge difference, Dr. Revah stressed it was significant.

She said, “It suggests that marijuana has additional effects on the lungs than tobacco alone.”

“Is it the combination of the marijuana and tobacco that makes more holes in the lungs and airway inflammation or just the marijuana itself?” she inquired

She added that “these patients presumably had less lifetime exposure to smoke, except they’re even sicker than those who are heavy tobacco smokers and have been doing it longer.”

Dr. Revah further pointed out a concern regarding the age of marijuana smokers many of whom were much younger than fifty. She pointed out that “we just don’t know if it’s a synergistic effect between the marijuana and the tobacco versus the marijuana alone.”

Airway damage from smoke can be permanent

Based on her radiology experience, Dr. Revah noted that airway damage from smoking can quickly become permanent.

“Airway inflammation early on is reversible, [and] when I see mucus and thickening of the airways, if you stop the exposure that should improve,” she said. “But sometimes that can lead to dilatation of the airways and when it’s dilated, then it’s irreversible.”

However, she stated that the study had some limitations, stressing that it was small and there was little information on how much marijuana was smoked or how it was inhaled— bong, blunt, or joint.

There are several differences in how marijuana and tobacco are consumed that could provide clues for further investigation. Tobacco is typically smoked with a filter while marijuana is not, she said, adding that tobacco smokers quickly exhale while marijuana smokers often inhale and hold their breath to maximize the high.

She also said, “People usually have a longer breath hold and a higher puff volume, so they are holding in the larger volume of smoke for a longer period of time, [which] could lead to micro-trauma of those airspaces. These are all questions for future research.”

“If you’re smoking an unfiltered joint, let’s say, more particulates will reach the airways, get deposited and become irritants, which is why you see the mucus and the inflammation,” she added.

Marijuana versus tobacco study conducted earlier

Prior to this study, the effects of lung damage from inhaling marijuana was recently published in a June study. The study identified that cannabis users were 22 percent more likely than non-users to visit an emergency department or be hospitalized.

Although the main reason was physical injury, lung damage concerns were also given high priority, and a 2021 study found 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.

Carol Boyd, founding director of the Center for the Study of Drugs, Alcohol, Smoking & Health at the University of Michigan in Ann Arbor, said, “I often am approached by both parents and teens who believe vaping cannabis is ‘OK’ and better than smoking [a joint, blunt, doobie, etc.].”

“And so, they ask, ‘Vaping is safe — right?’” she explained. My response is that they are fooling themselves.

“We know that inhaling hot tobacco/cannabis smoke into your lungs is unhealthy and can cause bronchitis or life-threatening breathing problems,” she concluded.

Lastly, she emphasized that heating chemicals into a vapor, including carcinogens, and inhaling them is also an unhealthy behavior.