Cannabis link to brittle bones: Heavy users found to be at a higher risk of osteoporosis and have more fragile spines and hips
- Heavy cannabis users have more fragile spines and hips according to University of Edinburgh study
- They suffer more broken bones, because of lower bone density
- Drug previously linked with psychosis, schizophrenia and memory loss.
By Victoria Allen
Science Correspondent For The Daily Mail
Published: 18:36 EST, 12 October 2016
Updated: 10:56 EST, 13 October 2016
People who regularly smoke cannabis are damaging their bones and could get osteoporosis in later life.
Heavy cannabis users, who smoke several times a day, have more fragile spines and hips, a study by the University of Edinburgh found.
They suffer more broken bones, because of lower bone density, understood to be caused by the drug.
The first study of bone health in cannabis smokers is just the latest evidence of its harmful effects. Although many young people see it as a 'soft drug', it has been previously linked with psychosis, schizophrenia and memory loss.
Those who smoke it heavily are more at risk of bone-thinning disease osteoporosis for two reasons, scientists believe. Tetrahydrocannabinol, or THC, the ingredient which gets people high, has been shown in mice to stimulate the body to reabsorb bone faster than it can be regenerated.
Also, while a joint smoked by an occasional users can cause the 'munchies', those who use cannabis over a long period of time see their appetite suppressed. It means heavy cannabis smokers weigh less for their height, which in turn reduces their bone density.
Lead researcher Professor Stuart Ralston, of the University of Edinburgh's Centre for Genomic and Experimental Medicine, said: 'We have known for a while that the components of cannabis can affect bone cell function, but we had no idea up until now of what this might mean to people who use cannabis on a regular basis.
'Our research has shown that heavy users of cannabis have quite a large reduction in bone density compared with non-users and there is a real concern that this may put them at increased risk of developing osteoporosis and fractures later in life.'
Lucy Dawe, from the charity Cannabis Skunk Sense, said: 'The impact on bones is just another thing people do not know about. Cannabis is seen as a benign substance and people still think those who smoke it are happy and relaxed with no problems.
'The truth is that cannabis has not just mental effects but physical effects.'
Scientists looked at 170 cannabis smokers recruited from primary care, such as doctors' appointments, within UK inner cities between 2011 and 2014. Heavy cannabis used was defined as having taken the drug on more than 5,000 occasions over a lifetime. Researchers said this would include those smoking six or seven times a day.
Compared with 114 people who did not smoke cannabis, the heavy users had lower bone density in their hips and spines when X-rayed using a specialised technique. The density was about five per cent lower than cigarette smokers who did not take the drug.
They also suffered fractures more often, as broken bones occur more frequently when the bones are thinner.
The study follows research showing that cannabinoid receptors within the body, which react to the drug, affect bone mass and the way in which bone cells function.
It states: 'While further research will be required to investigate the mechanisms underlying the association, we observed the findings reported here have important clinical implications in identifying heavy cannabis use as potential cause of low bone mineral density, increased bone turnover and predisposition to fractures.'
This matters because heavy cannabis users are also at greater risk of getting osteoporosis in later life. The debilitating bone-thinning condition, which affects an estimated three million people in Britain, sees half a million admitted to hospital having suffered fractures every year.
The research, funded by Arthritis Research UK is published in the American Journal of Medicine.
