Dunedid, New Zealand: Inhaling cannabis has contrasting effects on lung function compared to smoking tobacco, according to the results of a population-based study published online in the European Respiratory Journal.
Investigators at the University of Otago in New Zealand compared the effects of cannabis and tobacco smoke on lung function in over 1,000 adults.
Researchers reported, “Cumulative cannabis use was associated with higher forced vital capacity [the volume of air that can forcibly be blown out after full inspiration], total lung capacity, functional residual capacity [the volume of air present in the lungs at the end of passive expiration], and residual volume. Cannabis was also associated with higher airways resistance but not with forced expiratory volume in 1 second [the maximum volume of air that can be forcibly blown out in the first second during the FVC test], forced expiratory ratio, or transfer factor. These findings were similar amongst those who did not smoke tobacco.”
Authors further reported, “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.”
They concluded, “Cannabis appears to have different effects on lung function to those of tobacco.”
A previous study conducted by the University of California at Los Angeles and published in the American Journal of Respiratory & Critical Care Medicine reported that long-term, habitual marijuana use was not associated with a decline in lung function compared to non-smokers.
Most recently, investigators at the University of British Columbia reported in April in the journal of the Canadian Medical Association that marijuana inhalation “was not associated with an increased risk of respiratory symptoms or COPD (chronic obstructive pulmonary disease).”
In 2007, a meta-analysis published by researchers at Yale University reported that the smoking of cannabis, even long-term, was not associated with a decline in pulmonary function.
For more information, please contact Paul Armentano, NORML Deputy Director, at: email@example.com. Full text of the study, “Effects of cannabis on lung function: a population-based cohort study,” will appear in the European Respiratory Journal.