Smoking marijuana can raise risk of lung disease: Study

Smoking marijuana could be more harmful than people realize, a new study suggests.

Chest scans show marijuana smokers may be more likely to develop inflamed airways and a certain type of emphysema than people who puff away on traditional cigarettes.

The analysis by Canadian researchers, published Tuesday in Radiology, compared the chest scans of marijuana smokers and tobacco-only smokers who were matched according to age. They found that twice as many of those who inhaled cannabinoids developed paraseptal emphysema as people who smoked cigarettes only.

Paraseptal emphysema is a disease of the small air sacs of the lungs that are responsible for taking in oxygen and removing carbon dioxide, said a study coauthor, Dr. Giselle Revah, a cardiothoracic radiologist at The Ottawa Hospital.

“When they are damaged, small holes are created in the lungs and gas exchange doesn’t work as well,” she said.

The higher rate of paraseptal emphysema among marijuana smokers could be due to two factors, Revah suspects. Unlike cigarettes, joints aren’t filtered, and marijuana smokers inhale more deeply and longer than cigarette smokers do.

While it isn’t as lethal as the most common type of emphysema linked with long-term heavy tobacco smoking, paraseptal emphysema can lead to a number of distressing symptoms, said a pulmonologist and longtime cannabis researcher, Dr. Donald Tashkin of the UCLA David Geffen School of Medicine.

Emphysema symptoms include:

Shortness of breath climbing stairs.

A sensation that a person can’t get enough air in the lungs.

Persistent cough and wheezing.

Coughing up mucus.

Fatigue.

Paraseptal emphysema can sometimes lead to a collapsed lung, which can be life-threatening, Tashkin said.

No form of emphysema is curable.

eople should understand “that all inhalation is bad for the lungs, whether it is tobacco smoke or marijuana smoke,” said Dr. Thomas McLaren, a cardiothoracic radiologist who is an assistant professor of radiology and cardiology at Vanderbilt University Medical Center.

If you’re going to use cannabis, “this is absolutely not the best way to do it, McLaren said, adding that edibles are what is suggested for cancer patients.

A previous UCLA study of people who smoke only marijuana found symptoms of chronic bronchitis and widespread pathological changes in the airways, Tashkin said.

“So smoking marijuana is doing some injury to the central airways,” he said.