Regular cannabis use, with and without tobacco co-use, is associated with respiratory disease

Background: Cannabis use is a potential risk factor for respiratory disease but its role apart from tobacco use is unclear. We evaluated the association between regular cannabis use, with and without tobacco co-use, and onset of asthma, chronic obstructive pulmonary disease (COPD), and pneumonia.

Methods: Analysis of a limited data set obtained through IBM Watson Health Explorys, an electronic-health-record-integration platform. Matched controls using Mahalanobis distance within propensity score calipers were defined for: 1) cannabis-using patients (n = 8932); and subgroups of cannabis-using patients: 2) with an encounter diagnosis for tobacco use disorder (TUD; n = 4678); and 3) without a TUD diagnosis (non-TUD; n = 4254). Patients had at least: one recorded blood pressure measurement and one blood chemistry lab result in the MetroHealth System (Cleveland, Ohio). Cannabis-using patients had an encounter diagnosis of cannabis abuse/dependence and/or ≥2 cannabis-positive urine drug screens (UDSs). Control patients, not having cannabis-related diagnoses or cannabis-positive UDSs, were matched to the cannabis-using patients on demographics, residential zip code median income, body mass index, and, for the total sample, TUD-status.

Results: Regular cannabis use was significantly associated with greater risk for asthma (odds ratio (OR) = 1.44; adjusted odds ratio (aOR) = 1.50; OR = 1.32), COPD (OR = 1.56; aOR = 1.44; OR = 2.17), and pneumonia (OR = 1.80; OR = 1.84; OR = 2.13) in the total sample and TUD and non-TUD subgroups, respectively. TUD-patients had the greatest prevalence of respiratory disease, regardless of cannabis-use indication.

Conclusions: Regular cannabis use is associated with significantly greater risk of respiratory disease regardless of TUD status. Future research to understand the impact of cannabis use on respiratory health is warranted.