BACKGROUND: Cannabis may cause chronic pulmonary disease. Prior studies have been limited by low cannabis exposure, lack of data on tobacco cigarettes, and/or limited numbers of those without tobacco cigarette use.

OBJECTIVE: To examine whether inhaled cannabis associated with asthma and chronic obstructive pulmonary disease, independent of tobacco cigarettes.

DESIGN: Cross-sectional analysis of population-based, nationally representative survey data. Participants were adults 18-74 years who participated in the 2016-2020 Behavioral Risk Factor Surveillance System surveys.

MAIN MEASURES: The exposure was past-30-day cannabis use, from 0 (0/30 days) to 1 (30/30 days). Outcomes were self-reported diagnoses by a medical professional of asthma or chronic obstructive pulmonary disease. We used multivariable logistic regression to test whether inhaled cannabis was associated with odds of disease, adjusted for sociodemographics and tobacco cigarette use (current/former/never). Pre-specified analyses restricted to those with no lifetime tobacco cigarette use.

KEY RESULTS: Among n = 379,049, n = 23,035 reported inhaled cannabis use. Inhaled cannabis was associated with asthma overall (adjusted odds ratio (aOR) 1.44, 95% CI 1.26-1.63 for daily use) and among n = 221,767 with no lifetime tobacco cigarette use (aOR 1.51 for daily use, 95% CI 1.18-1.93). Inhaled cannabis was associated with chronic obstructive pulmonary disease overall (aOR 1.27 for daily use, 95% CI 1.10-1.46), with a non-significant elevated odds of disease among those with no lifetime tobacco cigarette use (aOR 1.54 for daily use, 95% CI 0.92-2.57).

CONCLUSIONS: Inhaled cannabis was associated with asthma and chronic obstructive pulmonary disease after adjusting for tobacco cigarette use. Among those with no lifetime tobacco cigarette use, the association with asthma persisted. Cannabis may be a potential modifiable risk factor for asthma and chronic obstructive pulmonary disease.