Marijuana and the Lungs

When reading through a lot of the blogs on our class website, I tend to see a lot of posts regarding the beneficial effects of smoking marijuana.  While I can’t say I read every argument defending the positive aspects of it and disproving all the negatives, there is one question that always pops up in my head: How is it so beneficial event though you’re still inhaling smoke?  I took to Google to find out and quickly found a meta-analysis published in Nature Partner Journals entitled Effect of Cannabis Smoking on Lung Function and Respiratory Symptoms: A Structured Literature Review that took a look into how marijuana smoking affected the respiratory system and pulmonary diseases.

Initially, the meta-analysis took 256 studies but narrowed it down to 19 studies based on specific criteria.  For all of these studies, it can be assumed that the null hypothesis was that smoking marijuana doesn’t affect the human respiratory system, and that the alternative hypothesis was that smoking marijuana does affect the human respiratory system.  While the ways in which each study conducted their experiment were not written in the article, the results did somewhat surprise me.  Out of the 19 studies, only 8 reported no change, 6 found a decrease in respiratory health, and the rest deemed the method in which they found their answers incompetent.  I looked at the studies Table 1, where all the results were listed, and again found a wide array of answers.  While these mixed revues were a good starting point, I was unsatisfied that I was unable to see the process in which they did their study, so I kept researching.

I found several other studies, which I will list below, that all had varying results as well leaving me unhappy with my findings.  It seems that the s635961444810294824-marijuanacience world is split when it comes combining the information of multiple studies into one answer.  Some studies published results stating no change, but when I looked at the site for the American Lung Association, they claimed that the toxins made from burning just about anything can affect the lungs.  The ALA also brought up the point that often, marijuana is inhaled and held in the body for longer amounts of time than cigarettes therefore the affect of tar is greater.

While the answers I found on the ALA site best matched the alternative hypothesis and my own prediction, I don’t want to only believe the information that follows my assumptions when other studies disagreed.  In my opinion, I believe that the marijuana debate will end up much like the debate on smoking in the 60s.  Since the issue of marijuana is a hot topic, and since some people may want the studies to result in certain ways, I believe that a lot of studies must be suffering from the file-drawer problem.  Not only that, I feel that it’d take a medical concern like another increase in lung cancer to occur in order for heavy research to be funded on this topic.  As of right now, a lesser functioning respiratory system is not enough especially since nothing worse has been found.

Maybe in a few decades, when chronic marijuana smokers are older and may have certain health issues related to smoking, larger scale studies may be run in order to find a mechanism.  Since so many small ones have been run that all vary in their methods, finding consistent results is difficult.  Until then, it can be assumed that while smoking marijuana is not as bad as smoking cigarettes, they probably do have a minor affect your lung health.

Initial study:

Other articles I looked into:

American Lung Association on marijuana:


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