New marijuana study on long term lung function

  • #1
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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
 
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  • #2
Evo
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Hot a 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
But one or two cigarettes a week probably won't hurt either.
 
  • #4
Evo
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Does anyone smoke just a cigarette a week?
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
but at higher levels of exposure, these associations leveled or even reversed.
JAMA

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

Study co-author Dr. Stefan Kertesz said there are other aspects of marijuana that may help explain the results.

Unlike cigarette smokers, marijuana users tend to breathe in deeply when they inhale a joint, which some researchers think might strengthen lung tissue. But the common lung function tests used in the study require the same kind of deep breathing that marijuana smokers are used to, so their good test results might partly reflect lots of practice, said Kertesz, a drug abuse researcher and preventive medicine specialist at the Alabama university.
 
  • #5
berkeman
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Association Between Marijuana Exposure and Pulmonary Function Over 20 Years
http://jama.ama-assn.org/content/307/2/173.short
Lifetime exposure to marijuana joints was expressed in joint-years, with 1 joint-year of exposure equivalent to smoking 365 joints or filled pipe bowls.
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.
 
  • #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.
 
  • #7
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1-2 joints a week? :rofl:
 
  • #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.
 
  • #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.
 
  • #10
PAllen
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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.
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.
 
  • #11
berkeman
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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.
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?
 
  • #12
PAllen
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3-5 whats a night? No way that's sensimilla joints. People would be passed out long before that. Maybe 3-5 hits a night?
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.
 
  • #13
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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.
 
  • #14
atyy
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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.
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.
 
  • #15
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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.
 
  • #16
DrDu
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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.
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
 
  • #17
Ygggdrasil
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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.
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.
 
  • #18
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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
 
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  • #19
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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?
 
  • #20
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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?
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?
 
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  • #21
Monique
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  • #22
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Yes, just look at the statistics of cannabis users.

First-year statistics: 43% use less than once a week, 7% has daily use.
Past-year statistics: 32% use less than once a week, 10% has daily use.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448346/bin/011536.A1.jpg
From: Am J Public Health. 2004 May; 94(5): 836–842.
I can't speak to the survey you're citing, but in general surveys of this type tend to underestimate actual usage, at least in countries where marijuana is illegal.

http://alcoholism.about.com/od/news/a/blndri060306.htm
http://heinonline.org/HOL/LandingPa...handle=hein.journals/cjccj17&div=46&id=&page=

The real issue is that the risks of marijuana use are still poorly understood and there is some evidence that marijuana use is not as benign as some believe. The utility of well documented case reports should not be underestimated. Many of the good ones document have dechallenge and rechallenge data. When it can be safely done, a positive dechallenge followed by a positive rechallenge is fairly strong evidence of a causal relationship. This would be related to acute inflammation in bullous lung disease.

In the case of bullous lung disease, there is a known relationship with tobacco use. Cocaine has also been associated with this disease.Other known causes are relatively rare and in any case can be excluded by history or tests. A well documented case report of this condition in someone who uses marijuana with little or no tobacco is an important finding. It's quite likely that very low doses are safe, but the effects of long term use even at low doses is not at all well understood.

http://www.ctsnet.org/sections/clinicalresources/clinicalcases/article-1.html [Broken]
 
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  • #23
Monique
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I can't speak to the survey you're citing, but in general surveys of this type tend to underestimate actual usage, at least in countries where marijuana is illegal.

http://alcoholism.about.com/od/news/a/blndri060306.htm
http://heinonline.org/HOL/LandingPa...handle=hein.journals/cjccj17&div=46&id=&page=
The statistics that I cited is for condoned cannabis use in Amsterdam, statistics for San Francisco are very similar (see graph). The percentages match my personal observations, although I agree that self-reported observations are not as reliable as actual measurements.
 
  • #24
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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.
I smoke pot on a daily basis but wouldn't touch a tobacco product. There's one data point FWIW.
 
  • #25
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I thought I would attach a PDF that is probably the most comprehensive look at the pharmcokinetic/dynamic properties of cannabinoids. This even cites research associated with distribution (pharmacokinetics) of cannabinoids in a fetus and breast milk.
 

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