Are the apparent adverse effects of heavy cannabis use on bone just due to users being skinnier?
Effects of Marijuana on Weight Gain and Bone Density
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
There’s been a recognition that cigarette smoking can have a major effect on bone health for decades––increasing the lifetime risk of hip fracture by about half. It also appears to impair bone healing––so much so that surgeons ask if they should be discriminating against smokers, because the bone and wound healing complication rates are so high. But what about smoking marijuana?
There is accumulating evidence to suggest that cannabis compounds play important roles regulating bone mass and bone loss. Yeah, but are they friend or foe? “Results from research on [cannabis compounds] and bone mineral density in rodent models have been inconsistent. Some studies show increased bone formation, others [show increased] bone loss, and…others [show] no association” at all. This variation in results may be due in part to differences in the mouse strain used. But if you can’t even extrapolate from one mouse to another, how can you extrapolate to human beings?
So, what if you just measure cannabis use and bone mineral density in people? Thousands of adults were tested and asked about their cannabis use, and there did not appear to be any link between the two; that’s a relief. Though in this study, “heavy” cannabis use was defined as just five days or more of use in the last month. They didn’t ask beyond that. So, theoretically, someone who’s just smoked five joints in their entire life could be categorized as a “heavy user.”
How about cannabis use on five thousand separate occasions over a lifetime? Now that’s a heavy user, decades of regular use. And in that case, heavy use was associated with both low bone mineral density and an increased risk of bone fractures. About double the fracture rate––presumably due to lower bone density in the hip and spine, though heavy cannabis users were also skinnier on average, and skinnier people have lighter bones.
Hip fracture risk goes down as your weight goes up; nearly half of underweight women have osteoporosis. But less than 1% of obese women do, which makes total sense. Being obese forces your body to make your bones stronger to carry around all that extra weight. That’s why weight-bearing exercise is so important to constantly put stress on your skeleton: it’s use it or lose it. That’s why astronauts can lose a percent of their bone mass every month. Their bodies aren’t stupid; why waste all that energy making a strong skeleton if you’re not going to put any weight on it?
So, maybe that’s the only reason heavy cannabis users have frailer bones––is because they tend to be about 15 pounds lighter? Wait a second, users are slimmer? What about the munchies? The lower BMI of heavy cannabis users may seem counterintuitive, given the appetite stimulation, but this isn’t the first time this has been noted.
Pop culture “depicts marijuana users as a sluggish, lethargic,…unproductive subculture of compulsive snackers.” And it’s true that marijuana has been found to increase food intake; a single hit can increase appetite. And so, you’d expect obesity rates to rise in states that legalized it. But, if anything, the rise in obesity appeared to slow after medical marijuana laws were passed, whereas it appeared to just keep rising in other states.
The reason pot smokers may be slimmer is because of the effect of smoked marijuana on metabolism. We’ve known for nearly 40 years that within 15 minutes of lighting up, your metabolic rate goes up by about 25%, and stays there for at least an hour. So, that may be playing a role.
So is that why heavy cannabis use is associated with lower bone mineral density and increased risk of fractures? They’re just not as overweight? No. Even taking BMI into account, heavy cannabis use appears to be an independent predictor of weaker bones.
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- Law MR, Hackshaw AK. A meta-analysis of cigarette smoking, bone mineral density and risk of hip fracture: recognition of a major effect. BMJ. 1997;315(7112):841-846.
- Patel RA, Wilson RF, Patel PA, Palmer RM. The effect of smoking on bone healing: A systematic review. Bone Joint Res. 2013;2(6):102-111.
- Kim JH, Patel S. Is it worth discriminating against patients who smoke? a systematic literature review on the effects of tobacco use in foot and ankle surgery. J Foot Ankle Surg. 2017;56(3):594-599.
- Bourne D, Plinke W, Hooker ER, Nielson CM. Cannabis use and bone mineral density: NHANES 2007-2010. Arch Osteoporos. 2017;12(1):29.
- Idris AI, Ralston SH. Cannabinoids and bone: friend or foe? Calcif Tissue Int. 2010;87(4):285-297.
- Sophocleous A, Robertson R, Ferreira NB, Mckenzie J, Fraser WD, Ralston SH. Heavy cannabis use is associated with low bone mineral density and an increased risk of fractures. Am J Med. 2017;130(2):214-221.
- Iwaniec UT, Turner RT. Influence of body weight on bone mass, architecture and turnover. J Endocrinol. 2016;230(3):R115-R130.
- Lang T, LeBlanc A, Evans H, Lu Y, Genant H, Yu A. Cortical and trabecular bone mineral loss from the spine and hip in long-duration spaceflight. J Bone Miner Res. 2004;19(6):1006-1012.
- Beulaygue IC, French MT. Got munchies? Estimating the relationship between marijuana use and body mass index. J Ment Health Policy Econ. 2016;19(3):123-140.
- Mohs ME, Watson RR, Leonard-Green T. Nutritional effects of marijuana, heroin, cocaine, and nicotine. J Am Diet Assoc. 1990;90(9):1261-1267.
- Sabia JJ, Swigert J, Young T. The effect of medical marijuana laws on body weight. Health Econ. 2017;26(1):6-34.
- Zwillich CW, Doekel R, Hammill S, Weil JV. The effects of smoked marijuana on metabolism and respiratory control. Am Rev Respir Dis. 1978;118(5):885-891.
Image credit: Pxhere. Image has been modified.
Motion graphics by Avocado Video.
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
There’s been a recognition that cigarette smoking can have a major effect on bone health for decades––increasing the lifetime risk of hip fracture by about half. It also appears to impair bone healing––so much so that surgeons ask if they should be discriminating against smokers, because the bone and wound healing complication rates are so high. But what about smoking marijuana?
There is accumulating evidence to suggest that cannabis compounds play important roles regulating bone mass and bone loss. Yeah, but are they friend or foe? “Results from research on [cannabis compounds] and bone mineral density in rodent models have been inconsistent. Some studies show increased bone formation, others [show increased] bone loss, and…others [show] no association” at all. This variation in results may be due in part to differences in the mouse strain used. But if you can’t even extrapolate from one mouse to another, how can you extrapolate to human beings?
So, what if you just measure cannabis use and bone mineral density in people? Thousands of adults were tested and asked about their cannabis use, and there did not appear to be any link between the two; that’s a relief. Though in this study, “heavy” cannabis use was defined as just five days or more of use in the last month. They didn’t ask beyond that. So, theoretically, someone who’s just smoked five joints in their entire life could be categorized as a “heavy user.”
How about cannabis use on five thousand separate occasions over a lifetime? Now that’s a heavy user, decades of regular use. And in that case, heavy use was associated with both low bone mineral density and an increased risk of bone fractures. About double the fracture rate––presumably due to lower bone density in the hip and spine, though heavy cannabis users were also skinnier on average, and skinnier people have lighter bones.
Hip fracture risk goes down as your weight goes up; nearly half of underweight women have osteoporosis. But less than 1% of obese women do, which makes total sense. Being obese forces your body to make your bones stronger to carry around all that extra weight. That’s why weight-bearing exercise is so important to constantly put stress on your skeleton: it’s use it or lose it. That’s why astronauts can lose a percent of their bone mass every month. Their bodies aren’t stupid; why waste all that energy making a strong skeleton if you’re not going to put any weight on it?
So, maybe that’s the only reason heavy cannabis users have frailer bones––is because they tend to be about 15 pounds lighter? Wait a second, users are slimmer? What about the munchies? The lower BMI of heavy cannabis users may seem counterintuitive, given the appetite stimulation, but this isn’t the first time this has been noted.
Pop culture “depicts marijuana users as a sluggish, lethargic,…unproductive subculture of compulsive snackers.” And it’s true that marijuana has been found to increase food intake; a single hit can increase appetite. And so, you’d expect obesity rates to rise in states that legalized it. But, if anything, the rise in obesity appeared to slow after medical marijuana laws were passed, whereas it appeared to just keep rising in other states.
The reason pot smokers may be slimmer is because of the effect of smoked marijuana on metabolism. We’ve known for nearly 40 years that within 15 minutes of lighting up, your metabolic rate goes up by about 25%, and stays there for at least an hour. So, that may be playing a role.
So is that why heavy cannabis use is associated with lower bone mineral density and increased risk of fractures? They’re just not as overweight? No. Even taking BMI into account, heavy cannabis use appears to be an independent predictor of weaker bones.
Please consider volunteering to help out on the site.
- Law MR, Hackshaw AK. A meta-analysis of cigarette smoking, bone mineral density and risk of hip fracture: recognition of a major effect. BMJ. 1997;315(7112):841-846.
- Patel RA, Wilson RF, Patel PA, Palmer RM. The effect of smoking on bone healing: A systematic review. Bone Joint Res. 2013;2(6):102-111.
- Kim JH, Patel S. Is it worth discriminating against patients who smoke? a systematic literature review on the effects of tobacco use in foot and ankle surgery. J Foot Ankle Surg. 2017;56(3):594-599.
- Bourne D, Plinke W, Hooker ER, Nielson CM. Cannabis use and bone mineral density: NHANES 2007-2010. Arch Osteoporos. 2017;12(1):29.
- Idris AI, Ralston SH. Cannabinoids and bone: friend or foe? Calcif Tissue Int. 2010;87(4):285-297.
- Sophocleous A, Robertson R, Ferreira NB, Mckenzie J, Fraser WD, Ralston SH. Heavy cannabis use is associated with low bone mineral density and an increased risk of fractures. Am J Med. 2017;130(2):214-221.
- Iwaniec UT, Turner RT. Influence of body weight on bone mass, architecture and turnover. J Endocrinol. 2016;230(3):R115-R130.
- Lang T, LeBlanc A, Evans H, Lu Y, Genant H, Yu A. Cortical and trabecular bone mineral loss from the spine and hip in long-duration spaceflight. J Bone Miner Res. 2004;19(6):1006-1012.
- Beulaygue IC, French MT. Got munchies? Estimating the relationship between marijuana use and body mass index. J Ment Health Policy Econ. 2016;19(3):123-140.
- Mohs ME, Watson RR, Leonard-Green T. Nutritional effects of marijuana, heroin, cocaine, and nicotine. J Am Diet Assoc. 1990;90(9):1261-1267.
- Sabia JJ, Swigert J, Young T. The effect of medical marijuana laws on body weight. Health Econ. 2017;26(1):6-34.
- Zwillich CW, Doekel R, Hammill S, Weil JV. The effects of smoked marijuana on metabolism and respiratory control. Am Rev Respir Dis. 1978;118(5):885-891.
Image credit: Pxhere. Image has been modified.
Motion graphics by Avocado Video.
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Effects of Marijuana on Weight Gain and Bone Density
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Content URLDoctor's Note
I originally released a series of marijuana videos in a webinar and downloadable digital DVD. There are still a few coming out over the next year, but if you missed any of the published ones, here they are:
- The Institute of Medicine Report on the Health Effects of Marijuana
- Researching the Health Effects of Marijuana
- Is Marijuana Addictive?
- Does Marijuana Cause Health Problems?
- Does Marijuana Cause Permanent Brain Damage in Teens?
- Does Marijuana Cause Permanent Brain Damage in Adults?
- Will Cannabis Turn into Big Tobacco?
- Marijuana Legalization & the Opioid Epidemic
- Effects of Smoking Marijuana on the Lungs
- Smoking Marijuana vs. Using a Cannabis Vaporizer
- Does Marijuana Cause Lung Cancer?
- Can Cannabis Cure Cancer?
- Are Cannabis Edibles Safe?
- Pesticides in Marijuana
- The Effects of Marijuana on Fertility & Pregnancy
- Does Marijuana Cause Schizophrenia?
For more on bone health, see:
- Phytates for the Prevention of Osteoporosis
- Is Milk Good for Our Bones?
- Are Calcium Supplements Safe?
- Are Calcium Supplements Effective?
- Almonds for Osteoporosis
- Prunes for Osteoporosis
- Keto Diets: Muscle Growth & Bone Density
If you haven’t yet, you can subscribe to my videos for free by clicking here. Read our important information about translations here.