Frequent cannabis users have a significantly lower risk of developing sinus diseases compared to non-users, according to results from a first-of-its-kind study.
The research, published in the journal Laryngoscope Investigative Otolaryngology, compared 25,164 cannabis users with 113,418 non-users from the National Institutes of Health’s All of Us database. Researchers found that daily cannabis users were 36% less likely to develop chronic rhinosinusitis, whilst weekly users showed a 38% reduction in risk compared to those who had never used cannabis.
The inhalation of tobacco smoke has long been associated with an increase in sinonasal diseases such as chronic rhinosinusitis (CRS), allergic rhinitis (AR), and chronic rhinitis (CR), so researchers expected to see similar results with cannabis consumers.
“Given the known detrimental impact of tobacco smoking use on sinonasal tissue and inflammation, it was expected that patients who more regularly used cannabis would also be more likely to have sinonasal inflammatory diseases, especially in those who smoked cannabis. However, the present study results do not support this hypothesis,” study authors explained.
The protective effect appeared to increase with frequency of use. Daily users showed the strongest protection against chronic rhinosinusitis (36% lower risk), allergic rhinitis (36% lower risk), and chronic rhinitis (39% lower risk). Weekly and monthly users also demonstrated significant reductions in risk across all three conditions.
Importantly, the method of cannabis consumption – whether smoked or consumed as edibles – did not affect the outcomes, suggesting the protective effect may be related to the cannabis compounds themselves rather than the delivery method.
To establish an accurate comparison between cannabis users and non-users, researchers utilised case-control data from the All of Us database – a growing biomedical data resource that collects medical information from over 630,000 US residents.
A team from Houston’s Methodist Hospital Department of Otolaryngology conducted a retrospective analysis of the cohort’s medical data, including their electronic health record (EHR) data. Participants were also asked to answer questions about the frequency of their cannabis use.
After adjusting for demographics, health insurance status, healthcare visit frequency, and existing medical conditions, the protective effect of cannabis use remained significant.
“This study accounted for comorbidities, demographics, and usage frequency to specifically demonstrate lower risks of CRS, AR, and CR when compared to matched controls using a diversely representative national database,” the study said. “Route of consumption did not affect CRS incidence. To our knowledge, this is the first study to demonstrate this finding.”
Researchers noted that their study shows only an association, not causation, and cannot determine whether cannabis use directly prevents sinus disease or whether other factors may explain the relationship. Despite confidence in their data they warned that recreational cannabis use can have a negative impact on the user, specifically the inhalation of cannabis smoke.
“Although the study presents intriguing findings, caution remains warranted due to the well‐documented and significant adverse effects of recreational cannabis use and the caustic nature of inhaling combustion products,” study authors concluded.
