Smoking marijuana may lead to worse lung damage than smoking tobacco, according to a new study.
The Canadian research, published in the journal Radiology, raises a red flag amid increased use of the drug and more states legalizing it for recreational or medical use.
The researchers at the Ottawa Hospital Department of Radiology compared the CT scans of 56 marijuana smokers, 33 tobacco-only smokers and 57 nonsmokers.
They found higher rates of emphysema among marijuana smokers (42) that tobacco smokers (22) and nonsmokers (three).
The study showed more instances of airway inflammation among marijuana smokers compared to people who smoked cigarettes only or not at all.
The study also compared CT scans with age-matched subgroups. It found emphysema rates higher among pot smokers as well as rates of other lung damage, such as bronchial thickening, bronchiectasis and mucoid impaction.
Study limitations make it difficult to compare the risks of the two substances, scientists say.