Study: Marijuana Smoking Not Associated With Airway Cancers, COPD, Emphysema, Or Other Tobacco-Related Pulmonary Complications

Pulmonary complications associated with the regular smoking of cannabis are “relatively small” and far lower than those associated with tobacco smoking, according to a recent review published in the June edition of the scientific journal Annals of the American Thoracic Society.

The paper – authored by Donald P. Tashkin, MD, emeritus professor of medicine and medical director of the Pulmonary Function Laboratory at the David Geffen School of Medicine at University of California, Los Angeles – is “the most comprehensive and authoritative review of the subject ever published,” according to an accompanying commentary. Donald Tashkin conducted US-government sponsored studies of marijuana and lung function for over 30 years.

His review finds that although smoking cannabis may be associated with symptoms of chronic bronchitis, studies do not substantiate claims that it is positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease.

“[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function,” Tashkin writes. “[F]indings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use. … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

Writing in an accompanying commentary, McGill University’s Dr. Mark Ware concludes: “Cannabis smoking is not equivalent to tobacco smoking in terms of respiratory risk. … [C]annabis smoking does not seem to increase risk of chronic obstructive pulmonary disease (COPD) or airway cancers. In fact, there is even a suggestion that at low doses cannabis may be protective for both conditions. … This conclusion will affect the way health professionals interact with patients, parents with teenagers, and policy makers with their constituents. … Efforts to develop cleaner cannabinoid delivery systems can and should continue, but at least for now, [those] who smoke small amounts of cannabis for medical or recreational purposes can breathe a little bit easier.”

Full text of the study, “Effects of marijuana smoking on the lung,” appears in Annals of the American Thoracic Society.

35 thoughts

  1. Ignorance is a bliss. There are a lot of ignorant people, not stupid(although there are a lot of stupid people too), just ignorant. So it is our job to educated these people and hope to gain some followers for the legalization movement.

  2. Because they don’t know the real affects of cannabis… I know a few people in my school who think weed kills your brain cells.

  3. @Cat Cassie – I’ve noticed sometimes certain ideas just don’t ever seem to sink in with the general populace. For example, the difference between a scientific THEORY, which explains a widely diverse set of facts, and the word theory as used by the lay public, which is little more than a whimsical guess.

  4. might want to do a study on the marijuanna that is out in the real world, ie, hydro, chemically grown marijuanna, not bush weed grown naturally, and it might answer why people who have never smoked tobacco in their life but smoke pot, get cancer.. moron

  5. Great study and a good reason to smoke cannabis rather than tobacco. Has even more significance in Europe where many people still smoke cannabis mixed with tobacco yet think of the mixture as just cannabis. I think smoking is an outdated means of ‘cannabinoid delivery’ (as the article points out) but a move away from smoking will only really gather pace once legalisation has happened on a much wider scale.

  6. Money.
    The money it generates for the people to fight it. Both law enfacement and the money to the corporate prisons The money that drug companies and alcohol companies think they will lose. And I would not be surprised to find congressmen that vote against it also get some money from mexican cartels. Like most everything else its not for the good of the majority of people its for the pockets of the few.

  7. The findings published within this UCLA study should definitely be disseminated far and wide, as this is sure to calm the nerves of those concerned that they will be afflicted by the aforementioned medical conditions as a result of their medicinal usage.

  8. Anonymous says:
    July 10, 2013 at 7:37 am

    might want to do a study on the marijuanna that is out in the real world, ie, hydro, chemically grown marijuanna, not bush weed grown naturally, and it might answer why people who have never smoked tobacco in their life but smoke pot, get cancer.. moron


  9. Thanks, Owen, for that well worded, fact heavy, and thoroughly cited disposition. With that accomplished, I can only assume that you will be spending the rest of your day, in the woods smashing rocks together as your own personal particle collider disproves the research at CERN.

  10. Anyone who thinks pot is not bad for your lungs is nuts! I smoke several times a day and have developed smokers hack. I cough up that same brown crap that cig smokers do. Can’t be good for you. I’m all for legalizing, but come on, stop sticking your head inthe sand; it is unhealthy for lungs to be filled with anything but clean air. Pot smoke is no exception.

    [Editor’s note: No one at NORML claims that cannabis is harmless. That is not the question. The question is ‘should cannabis be illegal?’ When reform groups and activist post information about scientific studies about cannabis not having the same negative health consequences as tobacco smoke, why would that info not be shared with the public? The juxtaposition of cannabis to tobacco makes imminent sense, and in doing so, cannabis appears markedly less harmful to humans than tobacco. Which then begs the question again ‘should cannabis be illegal?’

    Also consumption method appears to also play a role in health effects, i.e., smoking a rolled cigarette vs. water bong vs. vaporizers.]

  11. As time is given to the world of Marijuana, we will see changes good for all i pray. The best one for me is not having to look over my shoulder when I take my medicine, The Herb vaporized. Blessings Michael lr

  12. Hey, Mike have you ever heard of the herb Mullein? It can be smoked or made into a tea, I have used both methods. In minutes it clears any lung phlegm even makes my lungs feel like they opened big time. It really worked for me and others. goggle the herb and read for your self for sure
    Michael lr

  13. They kill dealers in Indonesia and south-east Asia. That’s not a good law. How many dumb laws have we had over the last 3500 years. Cannabis IS better for you than ALL other drugs. We should be “allowed” to smoke it. God invented it.

  14. “Anonymous says:
    July 10, 2013 at 7:37 am
    might want to do a study on the marijuanna that is out in the real world, ie, hydro, chemically grown marijuanna, not bush weed grown naturally, and it might answer why people who have never smoked tobacco in their life but smoke pot, get cancer.. moron”

    Yet you fail to clarify what kind of cancer, under what conditions, with any under lieing history, or family genetics. Your assumption that smoking cannabis equals cancer is null.

    Besides, as the editor’s note implies, no one stated that there couldn’t possably be any drawbacks. It’s a question of, IF alcohol and IF tobacco are both legal and more harmful, THEN would this be a bad idea to legalize as cannabis is easier for minors and adults to get than cigarettes or alcohol.

  15. no legalizing weed would make it harder to get because it would be regulated. the drug dealers don’t ask for identification, all they wanna see is your money. there would be penalties for selling to minors just like cigs and alcohol. the mexican cartels wont be able to sell their weed because legalization will decrease the price dramatically due to the low cost/maintenance to grow it. marijuana is a million dollar industry prohibiting it just fuels the black markets. lets instead use these profits for schools and parks.

  16. God created marijuana to get us to wonder why the endocannabinoid system exists. The endocannabinoid system exists to help our bodies recover from the insane amounts of damage we do to them every day. The herb has remarkable healing powers, but the government refuses to acknowledge the medical value with the policy hardline “marijuana has no valid or acceptable medical use within United States”.

    The reason for this is because it is also the sacrifice needed to petition God for deliverance from harsh and inescapable conditions. God does listen, and God does harsh things to people who think they’re doing their job but refuse to acknowledge the violations of their oaths to Him to, for example, protect and defend the constitution against attm

  17. Just say yes baby..!!!.. another study for me to pull out on a moment’s notice to shut down anti marijuana advocates..

  18. Keep up the good fight. We’re winning, we don’t need to convert the ones who’re fighting us we just need them to stop fighting and voting. If they see who they’re hurting they should quit. Unless they’re doing they’re thing out of hatred…

  19. I find it interesting that people will say, “well we just don’t know much about the effects of cannabis”. After 75 years, throwing millions of people into government cages, and destroying families, nobody decided to investigate? I think there’s a more sinister reason, and that’s now coming to light.

  20. Anonymous says:
    July 10, 2013 at 7:37 am
    might want to do a study on the marijuanna that is out in the real world, ie, hydro, chemically grown marijuanna, not bush weed grown naturally, and it might answer why people who have never smoked tobacco in their life but smoke pot, get cancer.. moron

    ACTUALLY, if people would research a topic before they start spouting about what they don’t know about, a lot less interesting new comers wouldn’t get the wrong idea.!!guess what, a lot of people who have never smoked cigarettes that get cancer, also NEVER smoked pot! the newer methods of growing, only one of which is hydro, are, when done correctly, mostly organic, and those that are not, there is a widely known process called”flushing” that is done a few times throughout, and usually thoroughly near the end of the grow cycle that actually get it almost as clean if not cleaner than what is grown naturally.if you truly want to know the pros AND cons, you must look at both sides of the debate.only then can you make a comment that is not at least 50% likely to sound “ignorant”!!

  21. This is great news since both the medical use of marijuana and legalized use in my state, WA is likely to significantly increase the already high rates of smoking marijuana.

  22. Haha omw the world and its human made up lies…well let me give you a piece of my mind* we’ll… Weed is the world best medicine wanna know why?? We’ll I know a man.. He is 82 years old and have been smoking marijuana for 66 years now and he is the most wisest
    clever and truthful man I know… And its because of the weed that woke him up… Really short term memory?? That’s the most pathetic thing I have ever heard… Its all bullshit of weed people simply make up these harsh accusations to make it more illegal why I don’t know but what I know is that weed is not a sin in God eyes because God made everything on this earth for mankind to discover and enjoy why make weed illigal??alcohol isint legal oh know its fine to drink go ahead sin against God he hates alcohol weed doesn’t make you drunk or makes you crazy mixing alcohol and crack and all that shit sort of works against weed because. Weed the moment you smoke it it goes to the places where your brain is stupid in and wakes it up but then you get the dumbass idiots who are fast asleep and full of nonsense that thinks you know everything well… This man I know when he is high he reads bible and when you read bible high you understand yhe word of God more clearly and see what’s right and wahts wrong.. All people do is try to find something bad against weed instead of looking what this wonder of God really does… God gave us plants and fruit to grow and be healthy HALLO idiots ..use your brain… What do you think people used in the olden days…I’m talkin bout thousand of years ago know..?? What kept them healthy?? Weed ofcousre..but oh no weed is just simply horrible well shut the hell up smoke some weed for a while and tell me straight that I’m talking bullshit… Challenge the scientists … Smoke weed and read the bible… Haha well talk soon… Idiots

  23. Reverend KyEl I like you man!!* your awesome smoking cigarettes screws your body smokinh marijuana does the exact opposite…it heals the mind soul and body*

  24. I’m a 45 year old male and my personal experience is that smoking cannabis eliminated my asthma when I was a teenager and it has never come back. It makes sens to me e because cannabis seems to dilate the broncheal passage ways and acts as an expectorant so it would tend to facilitate breathing and removal of buildup in the passageways. Thanks for this study to validate what I’ve thought for years in spite of the medical industry’s claims.

  25. Nothing other than clean air is good for a person’s lungs. There is no study needed for this fact. Any smoke or a substance that is burned, is going to coat the lung.

    I also have to very much doubt the comment made by Ed, regarding smoking cannabis removing his asthma as a teenager and claiming it never came back. Asthma does not have a known cure, period. It (along with other parts of what is commonly known as COPD) only progressively becomes worse.

    What perhaps may happen with some individuals, the smoking of Marijuana would help “deaden” nerve endings which then may create a sense of less felt congestion and after the initial irritation and coughing from use of smoking some Marijuana which would clear some of the mucus out of the lungs, there would not be any real long term or “healing” as per what some would tend to think of use of Marijuana in regards to the lungs and it’s affects on them.

    There may be some real truth to the line of thought that Marijuana is less harmful than a tobacco product on the lungs, but to think it is not harmful would be a false conclusion.

    I do also somewhat support the use of MEDICAL Marijuana, period.

  26. Daniel, so I guess all inhalants prescribed by doctors of medicine hurt their patients as this is for sure not clean air. Medicine comes in more ways than you obviously have studied. Yes some medicines even come in smoke form. Of course so much of mmj is consumed other ways. Please study the subject before you quote what you read or heard from some ignorant writer or speaker. Ignorance means not knowing. Ignorance with stigma or political agenda, even over zealous religious judgement, causes many unnecessary problems for the patients, doctors, and society as a whole.

    Michael lr

  27. The truth is sometimes difficult for people to comprehend. ANY smoke, vapor, oil or other irritant will cause some level of emphysema. EVERYONE has some level of emphysema. The studies indicate that the high levels of macro-emphysema seen in tobacco users are not seen in mj users.

    And of course, ingestion (other than smoking) will not impact lungs at all!

  28. I didn’t read the paper, just the abstract by following the link.

    This is bad news, not good news, for people who smoke marijuana. Large airway inflammation, for example, is not good.

    Note the lost of cilia in smokers. I autopsied a young marijuana smoker who died of the swine flu complicated by bacterial pneumonia. Coincidence? Maybe. Bullous changes from smoking marijuana are well known. My autopsy patient had a h/o pneunothorax. He was in his early 20’s.

    Why people think you can inhale a hot, carcinogenic smoke (marijuana burns hotter than tobacco) and not damage your lungs is beyond me.

    What seems to protect marijuana users thus far is that the drug is illegal (death from cirrhosis dropped during prohibition) and mind altering, so you don’t can’t smoke a pack per day. But, give it time. It takes about 30 years of smoking a pack per day to start seeing clinical lung damage. In the 1970’s the lung cancer rate was so low among smoking women that many serious people doubted tobacco caused lung cancer, or that the ladies didn’t inhale, or only Camels caused lung cancer. The rates finally sky-rocketed in the 1980’s. Lag time.

    I haven’t seen any studies on smoking marijuana and alpha-1-antitrypsin deficiency. This is a not uncommon problem. You might want to get tested before you smoke anything.

    Anyhow, enjoy your little vice, but don’t tell people it is harmless.

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