While marijuana legalization in some U.S. states and Canada may send a message that weed is harmless, that’s not necessarily so, according to a new study that found lung damage was more common in marijuana smokers than tobacco users.
Research into marijuana’s impact on the lungs is just getting started, because weed wasn’t legal in many places until recently, but early indications are that it could do some serious damage.
“The main message is that it may not be as safe as people think it is, and we need more information,” said study co-author Dr. Giselle Revah, a cardiothoracic radiologist and assistant professor at the University of Ottawa in Canada. “This is sort of just the opening. I want people to be aware that it may cause problems.”
Revah said it’s possible to see that someone is a heavy or longtime cigarette smoker just by looking at their CT scan. She wondered if marijuana, the second most commonly smoked substance after tobacco, would show similar results. She was surprised to find little information existed.
For this study, the researchers compared chest CT results from 56 marijuana smokers, including some who also used tobacco, with 33 who smoked only tobacco and 57 nonsmokers.
Roughly 75% of the weed smokers had emphysema compared to 67% of the…