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Medical New marijuana study on long term lung function

  1. Jan 10, 2012 #1
    Hot and fresh off the press! It claims 1-2 joints a week does not harm the lungs long term. If anything, I think this reaffirms the call for balance in life. A drink or smoke a week won't kill you, but don't binge with either. What are your thoughts on the studies results?

    Association Between Marijuana Exposure and Pulmonary Function Over 20 Years
    http://jama.ama-assn.org/content/307/2/173.short

    Marijuana doesn't harm lung function, study found
    http://news.yahoo.com/marijuana-doesnt-harm-lung-function-study-found-210146886.html
     
    Last edited: Jan 10, 2012
  2. jcsd
  3. Jan 10, 2012 #2

    Evo

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    But one or two cigarettes a week probably won't hurt either.
     
  4. Jan 10, 2012 #3
    Does anyone smoke just a cigarette a week?
     
  5. Jan 10, 2012 #4

    Evo

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    Probably as many as only smoke a joint a week. :smile:

    The study compared heavy cigarette smoking to occsional pot smoking, then says that heavier marijuana use could be worse
    JAMA

    And that the deeper breathing tested among marijuana users could just be the result of the deeper breathing by marijuana smokers. (yahoo)

     
  6. Jan 10, 2012 #5

    berkeman

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    Beyond the humorous aspect of the term from the JAMA abstract, shouldn't they have considered the differences associated with smoking the "bowls" from a bong or straight? Wouldn't the bong water help to filter out some of the substances that can hurt pulmonary function?

    The folks who I know who currently indulge (using Medical MJ RX Cards currently allowed [mostly] in California) use bongs to smoke their marijuana.
     
  7. Jan 10, 2012 #6

    turbo

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    Regardless of legality, if someone has access to high quality marijuana for medicinal use (or recreational) they are unlikely to smoke more than 1-2 joints/bowls per week. A couple of hits here and there would likely keep them happy. Snuff it and re-light another day.
     
  8. Jan 10, 2012 #7
    1-2 joints a week? :rofl:
     
  9. Jan 10, 2012 #8

    Evo

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    People I've known that smoke do it every chance they get.

    I'm not against legalizing it. The money we spend on law enforcement and prisons could be better spent elsewhere. But even inhaling smoke from fires like barbecues is bad for you. Smoke=bad. That's why our ancestor's suffered and died from diseases caused by smoke inhalation.
     
  10. Jan 10, 2012 #9

    Moonbear

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    I'll have to read the full article when in the office tomorrow, because I can't access it free from home while not logged in to the university servers. The thing I want to look into is how many people in their study smoked pot and not tobacco, since they were eliminating tobacco as a confounding variable. I just don't know of many people who would smoke pot but not tobacco, so I wonde how strong the data are if you remove all the tobacco smokers.
     
  11. Jan 10, 2012 #10

    PAllen

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    Actually, I think there is a lot of orthogonality. Among my circle in my youth who smoked MJ, none smoked tobacco at all; looked down on it. Agree with Evo that 1-2 a week is a joke. Not like chain tobacco smokers, but a couple 3-5 nights a week was a typical amount.
     
  12. Jan 10, 2012 #11

    berkeman

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    3-5 whats a night? No way that's sinsemilla joints. People would be passed out long before that. Maybe 3-5 hits a night?
     
  13. Jan 10, 2012 #12

    PAllen

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    I thought I said a couple of joints or bowls, 3-5 nights a week. For sensimilla that would be a few pinches a night. The issue is that, whatever, the measure, usage was more daily than weekly.
     
  14. Jan 10, 2012 #13

    Ygggdrasil

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    One major flaw with this study is that it takes a rather narrow view of lung health. The only metrics with which the authors measure lung health are forced expiratory volume in the first second of expiration (FEV1) and forced vital capacity (FVC). In contrast, when most people think of the health consequences of smoking they don't think about volumes of air that they can exhale; they think about lung cancer. Unfortunately, the authors do not address the issue of whether marijuana use is associated with lung cancer.

    So while their results suggest that marijuana smoke may somehow be less damaging to pulmonary function (as narrowly measured by FEV1 and FVC), this finding alone does not mean that marijuana use is harmless. Indeed, the authors cite prior studies that find consistent evidence of mucosal injury and inflammation and increased respiratory symptoms in marijuana smokers (refs 7-9 in the paper). These results alone call into question the conclusion that marijuana does not harm lung function. Furthermore, I would argue that any study of the long term effects of marijuana smoke is incomplete without an analysis of its effects on lung cancer rates.

    An important part of any scientific or medical study is choosing the right outcomes to measure. Unfortunately, the authors of this study do not examine all of the important outcomes to make any meaningful conclusion on the effect of marijuana use on long term lung health.
     
  15. Jan 10, 2012 #14

    atyy

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    http://lungcancer.about.com/od/causesoflungcance1/f/marijuana.htm supports your concern. It's surprising to me. I'd long bought the line that marijuana is no more dangerous than alcohol. At any rate, there's no ban on cigarette smoking, and I'd guess cigarettes are more harmful because of nicotine's addictiveness.
     
  16. Jan 10, 2012 #15

    Moonbear

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    FEV1 and FVC are the standard and accepted measures of lung function. If they're using those measures and drawing conclusions only about lung function, that's not a flaw. Cancer, asthma and emphysema all negatively impact those measures of lung function, which is why they make sense as a starting point. They don't seem to be making claims about cancer, just lung function. I'm more concerned with the apples to oranges comparison of light pot use with heavy smoking. I'll read the full article tomorrow to look at methods and results in detail.
     
  17. Jan 11, 2012 #16

    DrDu

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    Yes, smoke from fires for cooking are a big health problem in developing countries and it is probably of much greater public impact than some people having a joint every now and then:

    http://www.fic.nih.gov/News/Publica...ajor-environmental-cause-of-dealth-110211.pdf
     
  18. Jan 11, 2012 #17

    Ygggdrasil

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    I agree that the authors do a good job of not overstating their results and speaking solely in terms of lung function. The study is a good starting point toward investigating the long term health effects of marijuana smoking. However, the very narrow definition of pulmonary function in the medical literature is somewhat different from how laypeople would interpret the term. Thus, several posters, as well as the popular press, have taken the study to mean that smoking marijuana "does not harm the lungs long term" (to quote Greg from the opening post). I would not be ready to make that conclusion without first looking at data examining the effect of marijuana smoke on cancer.
     
  19. Jan 12, 2012 #18
    The following published case series of bullous lung disease (a severe form of emphysema) in chronic users of marijuana provides some reason to be cautious in interpreting the results of the JAMA study (MJ Pletcher et al). As Ygggdrasil says, this study focused on a limited number of parameters. To be sure, this case series consisting of just ten patients is small and is not a controlled study. It is insufficient by itself to draw conclusions. However, it suggests a need for caution and further investigation.

    http://www.ncbi.nlm.nih.gov/pubmed/18197922

    Here's another case series of marijuana users with "small exposure" to tobacco.

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1745720/pdf/v055p00340.pdf
     
    Last edited: Jan 12, 2012
  20. Jan 12, 2012 #19
    I don't know if anyone is thinking the same thing as me, but I gave a quick look to the pdf file and this can't be compared at all with the previous study that was posted by Mr.Bernhardt.

    Out of the four cases brought to attention, 3 are not casual smokers but heavy Marijuana smokers. Several pipe per day and 2-3 joints per day is huge!

    I'd like to know if anyone is else is thinking that this research proves pretty much nothing since there are so many factors to take into account and that the research was done with people who mix tabacco and marijuana and who intake massive amounts of marijuana per year... and not to mention this was taken from FOUR cases only...

    Any thoughts?
     
  21. Jan 12, 2012 #20
    Reputable journals do publish well documented case reports and they do so for a reason. In addition, government agencies such as the US FDA rely heavily on case reports to make regulatory decisions regarding drug safety. It's effectively impossible to do large, expensive studies to verify every safety issue that might arise with drug and environmental exposures. Safety issues are treated differently than efficacy issues. If potential safety problems were not reported, than the public might be justified in asking why such information was not made available. In the US, such omissions have led to successful lawsuits.

    I think I made it quite clear that case reports have limited value and conclusions cannot be drawn in a rigorous way. On the other hand, would you favor suppressing such information until some "definitive" study can be done? In that case, many such issues might never come to public attention.

    Finally, as Ygggdrasil, said, this study only addressed lung function tests. If you read the reports, you would have seen that some patients with bullous lung disease had normal lung function tests. That doesn't mean they didn't have serious lung disease. The accumulation of such reports is usually the basis for funding large controlled studies. Even this falls short of the standard required for demonstrating efficacy where randomized controlled clinical trials are necessary. Obviously there are ethical issues for doing such studies where there may be a safety problem with one of the interventions.

    EDIT: It's also quite easy to document other risk factors in individual cases. In fact, how could a sound treatment plan be developed for an illness if the treating physician couldn't rely on such important historical information and have a reasonable theory of causation for clinical findings? If a patient presented with bullous lung disease, and had a history of marijuana use (with or without tobacco use) would you advise the patient to continue the marijuana use because of the lack of a "definitive" study regarding marijuana and bullous lung disease?
     
    Last edited: Jan 12, 2012
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