Research Shows Emphysema More Common in Marijuana Smokers Than Cigarette Smokers

Chest X-Ray Smoker Lungs Emphysema

A new study has revealed that marijuana smokers have a higher rate of emphysema and airway diseases compared to cigarette smokers.

Researchers have found marijuana smokers have a higher rate of emphysema and airway diseases compared to cigarette smokers. The findings, from the University of Ottawa and The Ottawa Hospital, will be published today (November 15) in the journal Radiology.

In the study, the chest CT examinations of 56 marijuana smokers, 57 non-smokers, and 33 tobacco-only smokers between 2005 and 2020 were analyzed. The investigators determined higher rates of paraseptal emphysema (PSE) and airway inflammatory changes, such as bronchiectasis, bronchial wall thickening, and mucoid impaction, in the marijuana smokers.

Airway Changes in Marijuana and Tobacco Smoker

Airway changes in a 66-year-old male marijuana and tobacco smoker. Contrast-enhanced (A) axial and (B) coronal CT images show cylindrical bronchiectasis and bronchial wall thickening (arrowheads) in multiple lung lobes bilaterally in a background of paraseptal (arrows) and centrilobular emphysema. Credit: Radiological Society of North America

Giselle Revah is a radiologist and Assistant Professor in the Faculty of Medicine who was searching for answers on the effect of marijuana on the lungs and its health implications. This was especially important, as there was little information available in the current literature since marijuana only became legal in Canada in 2018.

“I can tell if someone is a heavy or a long-time cigarette smoker when I look at a CT scan. With marijuana being the second most inhaled substance after tobacco, I started wondering: What does marijuana inhalation look like on a CT scan? Would I be able to tell if someone was a marijuana smoker, is it different from cigarette smoke?” says Revah, a radiologist at The Ottawa Hospital, where the research was conducted.

Pulmonary Emphysema in Marijuana and Tobacco Smokers

Pulmonary emphysema in (A, B) marijuana and (C, D) tobacco smokers. (A) Axial and (B) coronal CT images in a 44-year-old male marijuana smoker show paraseptal emphysema (arrowheads) in bilateral upper lobes. (C) Axial and (D) coronal CT images in a 66-year-old female tobacco smoker with centrilobular emphysema represented by areas of centrilobular lucency (arrowheads). Credit: Radiological Society of North America

“What’s unique about this study is that it there hasn’t been anything comparing the imaging findings in tobacco smokers to marijuana smokers before. In fact, there is a lack of imaging research in marijuana, probably because it’s still illegal in many parts of the world, and in many U.S. states, which is why I think we were the first to do a project like this.”

Despite the small sample size, Revah’s findings suggest that marijuana smokers saw additional effects on the lungs above tobacco alone, including more instances of large and small airway diseases.

“We’ve identified an association between marijuana smoking and damage to both the small and the large airways,” she said. “We still need more research before we can affect policy change. We need larger, more robust prospective studies with more patients to confirm it.”

Reference: “Chest CT Findings in Marijuana Smokers” by Luke Murtha, Paul Sathiadoss, Jean-Paul Salameh, Matthew D. F. Mcinnes and Giselle Revah, 15 November 2022, Radiology.
DOI: 10.1148/radiol.212611

11 Comments on "Research Shows Emphysema More Common in Marijuana Smokers Than Cigarette Smokers"

  1. Smoking how? Water pipe, bong, hashish, smoking ditch-weed? There’s a lot missing here.

  2. VERY small sample, LOT of confounding variables, but interesting nonetheless to clinicians such as myself who have noticed for DECADES how many of our marijuana-smoking patients have “asthma,” “chronic bronchitis,” to “COPD/emphysema.”

    It’s a start.

    It’s one of those (for those of us who believe in evidence-based medicine as well as “anecdotal” office/clinical-based observation and actually deal with the direct physical, psychological, sociological and economic harm from the use of such substances) proverbial elephants in the room hardly anyone discusses.

    True believers (in lambs bread, ganja, the blessed sacrament of the global church), all KNOW that ALL data which runs counter to their beliefs in marijuana safety/efficacy is suspect, that ALL suggestions of harm are driven only by political extremists who have been co-opted by BIG PHARMA, that ONLY tobacco and alcohol are dangerous but weed is safe as houses or mothers’ milk. For them, NO data will be believed, nor acted upon, ‘cause “dope good, dude.”

    • I don’t doubt your observation, your anecdotal evidence, but you doubt mine. At 66, smoking pot since 15 years of age, I don’t think of MJ as a panacea. I don’t dispute that inhaled combustion products are not healthful.
      But… the study does not distinguish between emphysema and other “airway diseases”. Your own recounting does not distinguish between all-day everyday users and those who practice moderation, nor do you break down the difference between those who have a bit of bronchial trouble that clears up with abstinence and those who are permanently damaged. I could go on about sample size, and information as to how participants were selected, and whether they were heavy users, but the crux of my reply is that, anecdotally, I have known a multitude of MJ users , and it is other things that ruin their lungs, not MJ.
      I have the sense you will lump me in with the “dope good, dude” crowd, just as I think you are likely more interested in fitting data to your biases. “Not as bad as EtOH” may be a lame justification, but so is an opinion that ignores amount and type of usage, aggravating factors, and the cost/benefit discussion used to discuss any medical treatment. I haven’t even gotten to vaping at low temps, edibles, the ratio of THC to CBD, or any of the myriad details that go along with a non-kneejerk reaction. And yes, Doc, many of us do believe that “big pharma” is driven purely by the profit motive.

  3. George D. Bussey | November 16, 2022 at 3:21 pm | Reply

    Not surprising, but absent pack-year equivalent assessment it is hard to know exactly how much worse a joint is compared to a Marlboro.

    • A joint is not more harmful than a cigarette dumbass. There are no carcinoma in marijuana. It’s natural, cigarettes are not. You are beyond ignorant.

  4. Not true check the 30 year Harvard study of Pot smokers increased lung capacity…..your study is small and anecdotal.

  5. If you read the actual study it classifies the groups into three: non smokers, ONLY tobacco smokers, and marijuana smokers. I have a sneaking suspicion that that’s not ONLY marijuana smokers, but you can’t tell from the data or the write-ups and the way the person interviewed is talking about it they did not separate people who smoke marijuana and other substances from people who only smoke marijuana so of course the damage would be compounded… I emailed the study contact but haven’t heard anything back yet…

  6. It compares Marijuana smokers to tobacco-only smokers but are the marijuana smokers smoking tobacco as well? How much are each group smoking?

  7. This study was done in Canada where there iq is significantly lower. This study has zero credibility what so ever.

  8. This comment is for Greg. Even though cannabis does help with cancer, so far there’s no concrete proof that it doesn’t also cause it when inhaled, like cigarettes. Also, calling people names, like dumbass, doesn’t make you look smart or help you get your point across better. It merely helps to point out to the rest of the world that a Neanderthal is walking in their midst. Politeness goes a long way in a civilized society.

  9. Newsflash. You don’t need to smoke marijuana. You can make edibles, they work better and aren’t harmful to your lungs.

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