Marijuana smoke contains chemicals, as does cigarette smoke; but a landmark study reported in the Journal of the American Medical Association shows smoking cannabis may not harm lung function.

Laytonsville, MD 20882 Medical Cannabis

A long-term study of cardiovascular disease risks – called the Coronary Artery Risk Development in Young Adults study – tested lung function of more than 5,000 people ages 18 to 30. Some were cigarette smokers, some were marijuana smokers, and some used both.

The study found that those who smoked only cigarettes, or cigarettes and marijuana, saw their lung function drop over two decades. Meanwhile, cannabis-only smokers saw their lung function improve slightly over time.

It is important to note that most cannabis users in the study were light smokers; the average study subject lit up two to three times a month. However, the researchers also did not see evidence of breathing problems in more frequent cannabis smokers, either. The study did not account for other factors that might contribute to improved lung function, such as increased exercise.

Why Marijuana and Tobacco Affect the Lungs Differently 

The difference between marijuana and tobacco on lung function may be related to dose: cannabis smokers in the study used a few times a month, while the cigarette smokers lit up many times per day. Still, some experts say THC may protect lungs because it contains anti-inflammatory properties. It might prevent irritation from turning into a chronic pulmonary (lung) disease such as COPD. Cigarette smoke, on the other hand, is a major contributor to pulmonary disease. 

Heavy Marijuana Use Can Harm Breathing

Heavy cannabis smoking, on the other hand, appears to be detrimental to a number of health conditions, including pulmonary function. Studies of older subjects showed that those who smoked one joint a day for 40 years most days per month experienced decreased lung function. The number of heavy smokers in each study was small, however, and researchers agree more data are needed to draw a conclusion. 

Leading pulmonologists who reviewed the landmark study agree that the outcome should not be the sole reason for people to start lighting up. Genetics and other lifestyle factors also contribute to overall lung health. 

Weighing the Risks of Smoking Cannabis 

Mounting research suggests cannabis is beneficial for pain control, mood management, appetite, seizure disorders, insomnia, and more. Experts suggest that medical marijuana users who are concerned about lung health should stick to non-smokable forms like edibles, tinctures, and gummies. Others may benefit from light to moderate toking, as recommended by a healthcare provider. 

If you have questions about cannabis smoking and lung health, contact Dr. Sheila Brush, Laytonsville medical cannabis doctor and get a personalized treatment recommendation.