Does smoking marijuana increase the risk of chronic obstructive pulmonary disease?

As marijuana use continues to rise, so do concerns about its long-term effects on lung health—particularly its link to chronic obstructive pulmonary disease (COPD). While marijuana is the second most commonly smoked substance in the world after tobacco, its health risks remain less defined. Marijuana smoke shares many of the same harmful components as tobacco smoke, minus nicotine, and studies have shown that it can cause injury to large airways and produce respiratory symptoms such as cough and wheezing. However, the evidence connecting marijuana smoking alone to COPD remains inconsistent. Key studies show that marijuana users may experience airflow obstruction and lung hyperinflation, but most do not find the same degree of lung function decline or emphysema typically associated with tobacco. Interestingly, research suggests that combining marijuana and tobacco may amplify the risk of COPD more than tobacco alone, highlighting a possible additive effect.

Key Facts:

• Marijuana is the second most smoked substance globally, after tobacco.
• Marijuana and tobacco smoke are chemically similar, but only marijuana contains THC and only tobacco contains nicotine.
• Several studies have found modest respiratory symptoms and airway changes in marijuana-only smokers.
• No consistent evidence links marijuana alone to significant decline in lung function or COPD.
• The combination of marijuana and tobacco appears to increase the risk of COPD more than either substance alone.
• Studies are limited by small sample sizes, self-report bias, and focus on younger populations.

While more robust, long-term studies are needed—particularly among older adults—the current body of evidence suggests that marijuana smoke can harm the lungs but likely does not cause COPD on its own. However, using both marijuana and tobacco together may significantly raise the risk. As cannabis becomes more accessible, it’s important to stay informed and make lung-healthy choices that prioritize long-term respiratory wellness.

Reference: https://pmc.ncbi.nlm.nih.gov/articles/PMC2665954/