Effects of cannabis on lung function: a population-based cohort study
The effects of cannabis on lung function remain unclear and may be different to tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n=1037). … Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity, and residual volume. Cannabis was also associated with higher airways resistance but not with forced expiratory volume in 1 second, forced expiratory ratio, or transfer factor. These findings were similar amongst those who did not smoke tobacco.
By contrast, tobacco use was associated with lower forced expiratory volume in 1 second, lower forced expiratory ratio, lower transfer factor, and higher static lung volumes, but not with airways resistance. Cannabis appears to have different effects on lung function to those of tobacco.