Cannabis Use Does Not Impair Lung Function: Study Finds

Written by Lydia Kariuki

Tobacco use has been found to impair lung function. But when it comes to smoking cannabis, the association is not clear-cut. And what happens when tobacco is combined with marijuana? A recent study discovered that smoking cannabis doesn’t worsen lung function and that the use of marijuana with tobacco does not hurt the lungs beyond the damage done by the tobacco.

Here are details of the study: A team of researchers from the University of Queensland conducted a longitudinal study to investigate whether tobacco and cannabis use and co-use can be used to predict lung function. Participants recruited were children of women who were pregnant between 1981-3. The participants completed questionnaires about cigarette smoking, cannabis use, and concomitant use of the two at 21 and 30-year follow-ups. The researchers measured lung function (FVC, FEV1, FEV1/FVC) at 30 years. Note that by the age of 30, chronic tobacco users already show signs of impaired lung function.

After examining the data, The researchers found no consistent association between cannabis use and measures of lung function. In addition, there was no additional impairment in lung function when cannabis was combined with tobacco, above that which was observed when tobacco was used alone. This led the researchers to conclude that cannabis use does not lead to an impairment of lung function, even after it is used for several years. On the other hand, cigarette smoking was associated with impaired lung function. The results of the study were published in Respiratory medicine in January 2023.


  1. Najman, J. M., Bell, S., Williams, G. M., Clavarino, A. M., Scott, J. G., McGee, T. R., & Mamun, A. A. (2023). Do tobacco and cannabis use and co-use predict lung function: A longitudinal study. Respiratory medicine, 208, 107124.

About the author

Lydia Kariuki