By Adam Cresswell
Cannabis smokers risk developing emphysema 20 years before it tends to strike tobacco smokers, Australian researchers have found.
Experts say the findings suggest the potentially serious lung condition could be more widespread in cannabis smokers than first thought. The higher temperature of cannabis smoke and different inhalation behaviour may explain the greater risk.
Emphysema reduces the normal elasticity of the lungs’ airways and air sacs. Air inside the lungs has to be forced out, putting pressure on the sacs and in some cases making them collapse. It tends to strike tobacco smokers at an average age of about 65.
Matthew Naughton, head of general respiratory and sleep medicine at Melbourne’s The Alfred hospital, said the research began after a 40-year-old patient came in with a severe chest infection and was found to have large cysts, or holes, throughout the lungs.
The patient was a heavy cannabis user who smoked through a waterpipe.
Mr Naughton said his team then decided to ask other patients whether they smoked cannabis. Over the following year, they found a further 10 similar cases among regular marijuana users, aged from 28 to 50.
In just under half the cases, standard breath tests were normal and 40 per cent also had a normal chest X-ray.
A more sophisticated technique, called a computed tomography or CT scan, picked up the problems in 90 per cent of the cases, but this test would not routinely be ordered to detect emphysema.
“The pattern we were seeing with marijuana smoking was different to that seen in tobacco smoking,” Mr Naughton said.
“A tobacco smoker generally has smaller holes in the top of the lungs. What we were seeing (in marijuana smokers) was larger holes in the top and mid-part of the chest.
“It’s occurring 20 years earlier and is more advanced.”
Factors accelerating the emphysema might include the “incredibly hot” smoke from cannabis, particularly when smoked through waterpipes, compared with the smoke from filtered cigarettes, he said.
Cannabis smokers also tended to inhale more deeply and hold the smoke for longer, and marijuana might also contain other chemicals that worsened the lung damage.
Author: Adam Cresswell
Source: The Australian
