Is Smoking Marijuana Bad for Your Bones?

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As more and more states are legalizing the use of marijuana, both for medicinal and recreational uses, more research is being performed to investigate the possible benefits, and the possible side effects, of this drug. In the medical world, many proponents of legalization tout the pain relieving effects of marijuana, especially given the challenges with narcotic pain medication usage in so many parts of the country.

While these and other potential benefits are clear, there are concerns that possible side effects of marijuana are not as well understood.

Bone Density

Bone density is the measure of how much mineral is in your bone, and can be used to asses your bone strength and bone health. People with a low bone density have a higher chance of sustaining bone fractures, injuries that have potentially serious consequences including possible surgery and possible declines in overall health and function.

There are many reasons why people may be at risk for having a low bone density. Some of these risk factors for low bone density are things we cannot control--for example female gender, caucasian, or advanced age. However, there are some other risk factors that can be controlled--such as tobacco use, medications, and weight bearing exercise. There is concern that marijuana use may also contribute to problems with bone density.

Cannabis Use

While marijuana use may have potential benefits for patients, there can also be consequences. One of these risks of heavy marijuana use seems to be an impact on bone density. Researchers have found that in patients who smoke marijuana regularly, bone density is on average about 5% lower than a similar group of non-marijuana smokers.

The precise reason why smoking marijuana may lower bone density is not entirely clear, and needs further investigation. However, there has been previous research that has shown that smoking marijuana can affect blood flow, an issue that can lead to problems with bone health and bone density. Furthermore, people who regularly smoke marijuana tend to have a lower BMI, also a risk that can lead to lower bone density. 

Again, it's too soon to know exactly how and why marijuana may lower bone density, but it does seem that people who are heavy marijuana users may be at risk for a lower bone density and therefore have a higher risk of fractures. For this reason, people who are already at risk for fractures should be cautious with any medicinal, or recreational, use of marijuana. In addition, regular monitoring of bone mineral density with a DEXA scan test can help to ensure your bones remain healthy.

One fact we cannot ignore that is related: smoking tobacco is well-known to be very detrimental to bone health.

In fact, the use of tobacco is not only linked to lower bone density and increased likelihood of fracture, but also to poor bone healing and high risk of nonunions of fractures. One of the reasons tobacco use is so harmful to bones is the contribution of nicotine in cigarette smoke. Nicotine causes vascular constriction, limiting the blood flow to bone, leading to some of these problems. Because there is no nicotine in marijuana, the mechanism of impact on bone health is different.

Bottom Line: Is Marijuana Bad for Bones?

Like any drug, recreational or medicinal, marijuana has possible risks associated with its use. These risks seem to be magnified by heavy use. One of the risks of using high doses of marijuana is lowering of the bone density and an increased risk of fractures. With over half of all states having legalized the use of marijuana (either for recreational or medicinal purposes) this may become a more common concern. If you are using marijuana, you should discuss with your doctor your bone density and if you need assessment or treatment to ensure your bones remain healthy and not prone to fracture.

Sources:

Sophocleous A. "Heavy Cannabis Use Is Associated With Low Bone Mineral Density and an Increased Risk of Fractures" Am J Med. 2016 Sep 2.

Wang X, et al. "One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function" J Am Heart Assoc. 2016 Jul 27;5(8).

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