However, a large-scale national study suggests that even moderate use of marijuana is less harmful to users’ lungs than exposure to tobacco, even though the two substances contain at least some of the same components.
The study also offered up a nugget that likely will surprise many: Evidence points to slight increases in lung airflow rates and increases in lung volume from occasional marijuana use. Air flow is the amount of air someone can blow out of their lungs one second after taking the deepest breath possible. The volume measure is the total amount of air blown out once someone has taken the deepest breath possible.
This comprehensive study, led by UCSF and University of Alabama at Birmingham, and published in the Journal of American Medical Association (JAMA). Researchers collected data from more than 5,000 U.S. adults for more than 20 years, and analyzed the relationship between current and lifetime exposure to marijuana and pulmonary function. The Coronary Artery Risk Development in Young Adults (CARDIA) study collected medical data from 5,115 men and women in four U.S. cities from 1985 to 2006.