A new study published in the journal of the Radiological Society of North America shows marijuana smoke may be more harmful to lungs than cigarette smoke.

Researchers from Ottawa Hospital General in Canada examined some 150 lung scans from marijuana smokers, tobacco-only smokers, and nonsmokers.

The study found marijuana smokers faced higher rates of airway inflammation and emphysema than tobacco-only smokers and nonsmokers.

Seventy-five percent of marijuana smokers had emphysema — compared with only 5% of nonsmokers and 67% of tobacco smokers.

While the dangers of tobacco smoke have been well publicized for many years, the dangers of marijuana smoke are not as widely known.

The CDC reports that secondhand marijuana smoke contains THC, the psychoactive ingredient in marijuana, and that people who breathe secondhand marijuana smoke can be exposed to THC as a result.

A study published in the Canadian Medical Association Journal found adults under age 45 who frequently use marijuana are roughly twice as likely to suffer from a heart attack as adults who do not use marijuana.

A 2019 study found that regular marijuana use increased the risk of heart problems for young people, and a 2017 study reported marijuana smokers were three times as likely to die of hypertension.

All of this underscores what we have said for years: Marijuana may be many things, but “harmless” simply is not one of them.

Articles appearing on this website are written with the aid of Family Council’s researchers and writers.