I recently came across this article from EurkeaAlert!, a science news website. The article discusses the findings of a recent study that came out the University of Edinburgh in Scotland, whose findings conclude that those who smoke marijuana are more at risk for bone conditions such as low bone density and increased risk for fracture. The study gained the attention of many after it was published in the American Journal of Medicine, a well respected scientific journal. Here is the link to the study, which was lead by Professor Stuart Ralston. A quick Google search also lead my to many other articles which all revolved around the very same study, with headlines reading “Marijuana linked to bone fractures” or “Marijuana decreases bone health” or other such statements. However, upon reading the articles and looking into the study, I am a bit dubious as to whether or not it is a legitimate claim.
To start, there isn’t much of a clear consensus among scientists as to the effect that marijuana has on your bones. Running a quick Google search of “marijuana effect on bones” yields a wide array of different scientific articles citing a wide array of scientific studies. Some claim that smoking marijuana leads to decreased bone density and increased rate of fractures, some claim that marijuana has no effect on your skeleton at all, some even claim that marijuana increases bone strength and makes for healthier bones! An article on Live Science analyzes a study which claims that CBD (cannabidiol, a non-psychoactive cannabinoid found in marijuana) helps in creating stronger collagen which leads to stronger and faster fracture healing. Although there is not much consensus in this area more research seems to steer towards marijuana having a positive effect on bone healing rather than the opposite. But the biggest issues that I have with this study does not lie with its comparison to other studies, but rather with how it was performed.
The way that these test subjects were put into the experiment, from retrieval to segmentation, was problematic. The source of these test subjects is already questionable: they were all regular patients of routine appointments for general practice surgery, meaning they were already in doctor’s offices very frequently. Why were these pot smokers and non pot smokers taken from a healthy group of people? Why were they not randomly taken from a phone book or another, better, more random method? The variable measured were good, from smoking habits to other drug use to general demographics, etc. However the two groups had something odd in common. You notice earlier I stated the groups were split into pot smokers and non pot smokers, however, all test subjects were smokers of some sort. The test groups comprised of 56 “moderate” pot smokers, 144 “heavy” pot smokers, and a “control” group (and I place heavy emphasis on the quotes around control) of 114 cigarette smokers. So this begs the question: why did they not take any data from non-smokers? After all, there is a more than significant portion of the population which doesn’t smoke any substances at all. Why were they not accounted for in the study?
My other big issue concerns their classification of pot smoking habits. They completely ignore having a “light” marijuana smoking group, ignoring those that get high once in a blue moon or once in a while. It would be interesting to see the effects that marijuana has on them, and it would be more informative to the scientific community, but they are ignored. The way that they classify “moderate” and “heavy” also is a big concern of mine. Level of smoking is measured purely by the amount of times that a user has smoked ever, rating it by the number of estimated times they’ve smoked pot. So there’s no way to tell the difference between a 20 year old who’s smoked every day since turning 18 or a 30 year old who’s only smoked once a week since the same age. This is inherently problematic as it doesn’t get a true sense for who smokes weed at a more frequent rate. The researchers also mislead quite a bit when defining and analyzing their “heavy” marijuana smoker group. They define “heavy” as having smoked weed 5,000 times or more, which again, cannot truly get a sense for frequency of smoking. But even though they define “heavy” as 5,000 times or more, their “heavy” pot smokers group averaged at having taken the drug more than 47,000 times. That is A LOT of weed. Willie Nelson quantities of weed. If you wanted to smoke marijuana 47,000 times by doing it once a day, it would take you over 128 years to do so! Clearly, this study doesn’t exactly have a good grip on what it means to be a “heavy” smoker and instead collected data from what seems like an “extreme” smoker group.
So does this mean that the study is total nonsense and you should keep smoking weed like a chimney? Not really. There is good variable measurement to show that it is quite plausible for heavy weed use to deteriorate bone structure, particularly in those with lower BMI’s. They believe that the mechanism for more bone fractures and weaker bones comes from the fact that pot smokers tend to have lower BMI’s than non pot smokers. The skinnier and frailer you are the more likely you are to have bone issues, and the more you smoke pot the more likely you are to be skinnier (which I find odd considering how easy it can be for stoned Penn State students to vacuum up a container of Wings Over). So this study may sway you to cut back on smoking weed in order to save your skeletal structure. But should this incentivize you to put the bong down immediately and never touch the devil’s lettuce again? Probably not.