Study: Long Term Cannabis Exposure “Not Associated With Significant Effects On Lung Function”

The inhalation of one marijuana cigarette per day over a 20-year period is not associated with adverse changes in lung health, according to data published online ahead of print in the journal Annals of the American Thoracic Society.

Investigators at Emory University in Atlanta assessed marijuana smoke exposure and lung health in a large representative sample of US adults age 18 to 59. Researchers reported that cannabis exposure was not associated with FEV1 (forced expiratory volume) decline or deleterious change in spirometric values of small airways disease.

Authors further reported that marijuana smoke exposure may even be associated with some protective lung effects among long-term smokers of tobacco. Investigators acknowledged, “[T]he pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.”

Researchers also acknowledged that habitual cannabis consumers were more likely to self-report increased symptoms of bronchitis, a finding that is consistent with previous literature. Separate studies indicate that subjects who vaporize cannabis report fewer adverse respiratory symptoms than do those who inhale combustive marijuana smoke.

Authors concluded, “[I]n a large representative sample of US adults, ongoing use of marijuana is associated with increased respiratory symptoms of bronchitis without a significant functional abnormality in spirometry, and cumulative marijuana use under 20 joint-years is not associated with significant effects on lung function.”

This study is the largest cross-sectional analysis to date examining the relationship between marijuana use and spirometric parameters of lung health.

A separate study published in 2012 in The Journal of the American Medical Association (JAMA) similarly reported that cumulative marijuana smoke exposure over a period of up to 7 joint-years (the equivalent of up to one marijuana cigarette per day for seven years) was not associated with adverse effects on pulmonary function.

A 2013 review also published in the Annals of the American Thoracic Society acknowledged that marijuana smoke exposure was not positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease. It concluded: “[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function. Findings 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.”

You may view an abstract of the study, “Effects of marijuana exposure on expiratory airflow: A study of adults who participated in the US National Health and Nutrition Examination Study,” here.

34 thoughts

  1. This study is a brand of murder placed on the authors and defenders of the C.S.Act, the drug czar, the ONDCP, and the DEA.
    And begs the question: What about vaporized marijuana? Can we measure the benefits of lung health in a professional study?

  2. I have smoked more than a joint of ganja a day for 30+ years, and am consistently healthy, and regionally ranked road runner for many of those years. My lungs feel great and doctors detect no abnormalities at all.
    Legalize it!

  3. “Authors further reported that marijuana smoke exposure may even be associated with some protective lung effects among long-term smokers of tobacco. Investigators acknowledged, “[T]he pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.””

    The last I heard smoking both weeds increased the risk of cancer. The carcinogenic effects of tobacco overwhelmed the anti-tumor effects of marijuana, I assumed. I wonder if vaporizing just the marijuana would help against the carcinogenic effects of tobacco. I would think anyone who vaporized one would also vaporize the other, though.

    I’m 65 and still run win sprints on occasion. I’m not going to make the US Olympic team, but it’s wonderful to still be able to run like a kid at my age.

  4. Cannabis is an adaptogen.

    Many herbs are adaptogens that help maintain or re-establish homeostasis in Humans.

    Ginseng is another well known adaptogen.

    Cannabis is an herbal health supplement.

    I demand my right to grow cannabis be legally recognized.

  5. Many years ago ,I trained alongside an Olympic Weight lifter who won a Bronze Medal at the Olympics…and who also consumed cannabis on a regular basis in order to help recuperate after training sessions.

    Believe you me when I tell you it takes quite a bit of lung power to throw 500+ pounds overhead!

  6. One of the arguments I loved from the haters was, “marijuana is dangerous because of the WAY you smoke it: you TOKE and HOLD it in. Yeah, because your laws make it black-market expensive….

  7. We need some regionally ranked road runner or untimid writer with a good grasp of medical jargon to persuade the American Thoracic Society to lay aside obsolete “one Joint a day” surveys and research the advantages of

    (A) vaporizers, which generally start at $40, and

    (B) a CHEAPLY MADE $1.29 DIY Flexdrawtube One-hitter which divides any typical 500-mg joint into twenty (20) rational 25-mg Single Vapetokes, which could be spread out over a week and still provide brilliant Creative Paranoia results (More Marley, Less Monoxide).

    Of course the $igarette Empire Oligarchy has sneaky ways to deny funding to any marijuana researchers who don’t copy the old roll-up-papers script– “To children whose parents followed advice to keep them ignorant about cannabis, every Joint, every picture of a Joint and every mention of Joint in a scholarly publication is a $igarette adverti$ement.”

  8. I smoke far less medical grade cannabis than I do when I have to settle for what is available on the black market. Eating cannabis does wonders for my circulation and blood pressure.

  9. @Mexweed,
    I kinda knew you were going to jump all over the superior to health alternatives to smoking a joint, but with that said, I’m glad these studies focus on smoking so we can break the propaganda chain in the court room. Can you believe that in the 80’s the ONDCP said smoking marijuana was deadly because they put gas masks on monkeys and shot marijuana smoke through until they all asphyxiated? I’d like to say we’ve come a long way but from WHAT?

  10. I’ve known several long distance runners that would routinely smoke before the workout,for motivation and for the bronchodilator effects.
    This one person in particular would do 200 mile bike rides in the desert under 24 hours.He would always make sure that he was well supplied with buds, for his his journeys.He also had insanely low- blood pressure for a 200 pound person.So in this particular case,it contributed to “motivational syndrome” as opposed to anti-motivational syndrome'(remember that one from the 1970s?)or how about “inspirational syndrome”. yeah,thats even better!

  11. correction: The phrase used in the 1970s was called: “Amotivational syndrome” not ,anti-motivational syndrome.

  12. I have never heard of or read of anyone being harmed by the consumption of cannabis. When it is legalized and we are able to really study it without prejudice. That is when we will truly realize the many benefits of cannabis.

  13. “inspirational syndrome”. – Fed-up

    Great comment, Fed-up…Like you,I know many former athletes who were/are also cannabis consumers…

    Inspiration towards independent critical thought is exactly why cannabis remains illegal.

    The Mind/Heart numbing effect of alcohol is exactly why it’s legal and promoted by our Ruling Class Master’s…Propaganda works…but it works quicker with liquor!

    Cannabis = Adaptogen + Entheogen= Healthy

    Alcohol = Anesthetic + /Mind/Heart/Soul damage = Health Hazard

  14. I heard about this report before years ago. Weed doesn’t hurt you, unless you have asthma. I wonder if you smoke cigs a little and weed would that give you cancer? Not saying smoking cigs everyday, but here and there.I enjoy nicotine every now and then and when i’m stressed.

  15. Erick K Johnson,I hear what you are saying about alcohol.I guess it’s easy for the conservatives to understand moderation when imbibing with liqueur,to rationalize the difference with one or two drinks versus 8 drinks and the different consequences that come with those decisions.But when it comes to cannabis use,they have a hard time understanding the concept that, there can be distinctions as far as catching a mild buzz with one or two puffs and titrating you’re dosages to fit the level that you want to go to, and are comfortable with.They can understand that the wino passed out in the alley is drinking the same beverage that people are drinking at a UN. Convention,and they can rationalize that it comes down to individual responsibility as far as how much wine you want to drink in a certain time frame,the amount of food in you’re stomach,how much sleep you had the night before,medication interactions,and all the subtle factors going into making a responsible decision.But when it comes to an ancient herb that our ancestors have been using before recorded history,they pretend to be clueless and say stuff like;’you just want to get “high’ or “you’re trying to escape from reality” witch is a joke, because reality is subjective’re perception of reality can be altered by simple choices like, eating a sugar cereal and a donut and having a hypoglycemic crash an hour later, or choosing to eat some poached eggs on whole wheat toast and having sustained energy and concentration for hours.We don’t have food police monitoring our dietary decisions.However,there is a term now called “Nutraceutical’ that means food as a medicine. Can you imagine having to get a medical prescription for a certain food to treat an illness? how crazy is that! Oh well,sorry for this long winded post.But i agree with you’re definitions,cannabis in mild doses can be an adaptogen just like ginseng,and is FAR less toxic to the internal organs than alcohol.

    I wonder if there has ever been an isolated case of somebody flipping out on ginseng,because of anger issues,irritability because of higher testosterone levels? haha NO,and if there was, so what,Watch the media blow it up on the news,get the DEA involved…haha,stranger things have happened!

  16. SweetFantasy,

    Can you really do nicotine “every now and then” without getting hooked into “everyday”? I’ve never met the first person who could do that for longer than a year or two until they became addicted. Everyone I have known wound up either smoking (tobacco) daily or not at all. If you really could I’d say it is like infrequent pot smokers: not your thing in the first place.

    I don’t mean this offensively, but it seems you must be rather young; if so, I’d steer clear of all nicotine while you can…

    Moreover, I hope you are aware cancer represents less than 1/3 of the hazards about which you should be concerned: don’t forget your cardio, respiratory, immune, neuro, etc., etc. systems and unlike cancer, it never misses those.

  17. Tell me something I have not already figured out for myself. Marijuana goes a long ways toward overcoming the negative effects of tobacco use.
    Spring 2002:I was just laying on the bed not feeling well my breathing was heavy, and my chest was tight. Surprise! a visitor arrived, a friend of a friend. She had weed and offered to get me high. At first I thought better of this then gave in, I enjoy female company. Afterward I felt completely better, my breathing had eased and the tightness in my chest 100% gone. I”m sure the government knows all about this and does not like it one bit! As for me I like my tobacco, however these days I use an e- cigarette most of the time. And of course prohibition throws a twit fit about those also, go figure.

  18. I started smoking “Dope” (that’s what it was called in those days), in 1969. I have smoked Cannabis from 1969 to the present day. I estimate, I smoked two grams a day of “Dope” for up to 15 years at a time +.

    When I see a physician they report, “Thank you Mr. ** Lab Rat for taking so good care of your health.” I also have had a CAT scan of my brain and the physicians said, “Your brain looks completely normal and healthy.” Plus an EKG that reported a healthy heart.

    Now, if Marijuana was poisonous and caused bodily injury, I would have been dead long ago. Now contrast that with all the Tobacco smokers and drunks and boozers I have known and they all all Dead but one or two.

    My question is: Where are all the bodies of people poisoned by Marijuana? From what “the Government” reports about Marijuana you would think there were rotting corpus
    from “Marijuana Poisoning” in every side street.

    The “Government” needs to stop its witch hunt and hounding of Marijuana smokers. The American Public is beginning to get fed up with their sandbagging and out right lies on the issue.

  19. I personally used to be a tobacco smoker for 24 years. I been a non tobacco smoker for almost 3 years now. But I have continued to smoke cannabis. I have been to the doc and they say my lungs are nice n healthy now. I know I can breathe 100 times better. I know from personal experience cannabis does harm me. I know here in Missouri we have big battle going on between 2 legalization sides. SMC side which is completely crazy with all its laws and does nothing to actually stop the drug war. Then we have the Cannabis Protection Act that actually is for the people instead of big biz. Its time we the people take our power back by supporting bills like Cannabis Protection Act. If you would like to learn more feel free to join Missouri Cannabis Reform group on facebook.

  20. I’m all for legalizing marijuana im 21 year’s old and I had a clapped lung last month they say marijuana make a bleb on your lung which is like a blister and that blister on my lung popped and it put me in the hospital for a week had part of my lung removed so I just what people have experienced like me to see what up they say I have already started to smoke again and I feel great I mean I healing still so coughing not the best for me but if that the only negative thing Marijuana does fuck it the cig do a way lost worse just at a older age and dr cant do cut open a 70 year old and take a piece of there lung so dr should tell people this then legalize it

  21. Ever since I started smoking weed I have made some big gains at the gym. And my school work just its easy because I can focus.legalize it

  22. as a long time consumer [32 yrs] I always felt good. maybe because my mind felt good! these last 5 yrs that my employer has been drug testing me have literally been the worst five yrs of my life.i find more health problems and I feel it is because my mind has become unhealthy!…cannabis so needs legalized!!

  23. Please share link to website:

    Nebraska is considering approving Medical Marijuana under LB 643. Sign the petition to show your support:

    [Paul Armentano responds: Better yet, Nebraskans should be directly contacting their state elected officials and urging them to consider this legislation and enact it. NORML has posted a legislative alert in favor of this measure here: By entering your zip code, you will automatically be able to direct your elected officials to support this measure.]

  24. I get it. BUT the website designers need to get the correct view of the chest X-ray correct.


  25. I have to fully agree that medical cannabis CANNOT harm you in any way. Here is a story about my Grandma. She was diagnosed with cancer but after 12 months of Cannabis Oil Treatment and smoking of the herb she has fully recovered and now she even competes in over 60 triathlons in Dublin, Ireland. Can’t believe stuff is still illegal in Europe and the UK. Happy for the USA folks.

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