A new, large study has found that inhaling cannabis may increase the risk of developing asthma and chronic obstructive pulmonary disease (COPD), even among people who have never smoked tobacco.
The study, “Inhaled Cannabis, Asthma and Chronic Obstructive Pulmonary Disease: A Population-Based Cross-Sectional Study of n=379,049,” was recently published in the Journal of General Internal Medicine. In it, researchers analyzed data from 379,049 U.S. adults between 2016 and 2020. It is one of the largest studies to date examining cannabis and lung health.
Researchers discovered that daily cannabis users were significantly more likely to report an asthma diagnosis compared to nonusers. The link held true even in the subgroup of 221,767 participants who had never smoked cigarettes, suggesting cannabis alone may contribute to respiratory disease.
For COPD, cannabis use was also associated with a higher risk of the condition, although results were less conclusive for those without a tobacco history. Younger adults under age 50 who used cannabis appeared more vulnerable.
Researchers noted that the risk of asthma corresponded with increasing frequency of cannabis use in a dose–response manner, raising concerns that today’s younger generations (who are likely using cannabis at higher rates) may face worsening lung health as they age.
The study’s findings echo earlier evidence that cannabis smoke causes airway inflammation and changes in lung function, much like tobacco. Researchers stress more long-term studies are needed to confirm causation.
Still, researchers concluded that cannabis should be considered a potential modifiable risk factor for both asthma and COPD. They urged clinicians to screen patients with chronic lung disease for cannabis use and counsel them on the risks.
With nearly four million Americans starting cannabis use each year, researchers said the results highlight an urgent need for public health messaging on the respiratory consequences of smoking cannabis.
