Niloufar Ghodsian

Project title: Health effects of exposure to cannabis in workers in an indoor growing facility

Degree: MS (Thesis) | Program: Exposure Science (ES) | Project type: Thesis/Dissertation
Completed in: 2019 | Faculty advisor: Christopher D. Simpson


Background: Legalization of recreational cannabis in multiple states, including Washington, has scaled up cultivation of this plant. This rise in cultivation also raises health and safety concerns for workers in this emerging industry. Limited research on occupational health hazards of working with cannabis has shown potential occupational exposures to volatile organic compounds, plant proteins, and microbial contaminants. Sensitization to different members of the Cannabaceae family like hemp and hops have been reported previously. Few reports are available about sensitization to cannabis in particular, but by evolving the legalization of cannabis, it is likely that this problem will increase in the future. Methods: First, using a baseline questionnaire, our study characterized the prevalence of work-related allergic and irritant symptoms and their association with exposure in workers in an indoor cannabis growing facility (n=31). Second, for two weeks, lung function and airway inflammation were measured in a subset of workers with work-related symptoms to characterize acute and chronic changes in these two measures (n=10). Third, in the same subset of workers, a skin prick test was used to characterize the prevalence of cannabis sensitization. Results: Among work-related symptoms, the prevalence of respiratory symptoms was the highest (65%), followed by ocular (39%), nasal (32%), and dermal symptoms (26%). Our findings suggested that workers with higher exposure to cannabis may have increased odds of having work-related symptoms, although none of the associations were statistically significant. Results of our analyses provided evidence for chronic decrease in pulmonary function and chronic increase in airway inflammation, but not strong evidence for acute changes in these two measures. Finally, 50% of participants in our sub-cohort of 10 workers with work-related symptoms were sensitized to cannabis. Conclusion: The high prevalence of work-related symptoms, cannabis sensitization and impaired lung function observed in our study, raises the possibility that occupational exposures to cannabis are harmful to workers in this industry. Preventive measures are recommended to reduce worker exposure to cannabis, especially in areas with high concentration of dust.