Cannabis can cause more damage to the lungs and airways than tobacco, according to a small Canadian study which was published on Tuesday.
Researchers from the University of Ottawa and Ottawa Hospital looked at chest X-rays of 56 cannabis smokers, 57 nonsmokers and 33 people who only smoked tobacco between 2005 and 2020. They found more airway inflammation and emphysema – a chronic lung disease – in regular cannabis smokers compared to regular tobacco smokers and non-smokers.
Cannabis vs Tobacco
"Marijuana smoking is on the rise and there is a public perception that marijuana is safe, or that it is safer than (tobacco) cigarettes," Giselle Revah, a radiologist at Ottawa Hospital, where the study was conducted, told AFP. "But this study raises concerns that this may not be true."
She said the higher rates of inflammation and disease in cannabis smokers versus tobacco may be related to the differences in how the drugs are typically consumed. “Marijuana is smoked unfiltered, unlike tobacco which is usually filtered,” she said. “When you smoke unfiltered marijuana, more particles reach your airways, get deposited there and irritate your airways.”
In addition, cannabis users take larger puffs and tend to hold the smoke longer, which could lead to more trauma to the airways.
Despite these possible explanations, the authors of the study, which was published in the journal Radiology, pointed out that some cannabis smokers also smoked tobacco and that some lung scans yielded inconclusive results.
As Revah pointed out, there has been very little research on the health effects of cannabis in general as it was banned in most countries. That has changed a lot in recent years. Canada, where the researchers are based, legalized the recreational use of cannabis in 2018.
It is also legal for recreational use in Uruguay and Mexico, among others, and in many US states, while several other countries and territories have recently decriminalized or approved possession of the drug for medicinal use.
Source: sciencealert.com (EN)