This retrospective cohort study used a globally federated health research network that provided access to consistently updated deidentified electronic medical records (TriNetX).²⁷ We used the US Collaborative network, which provided access to data from 64 health care organizations that accounted for greater than 90 million individuals. The cohort consisted of tertiary care centers within the US. The database complies with the Health Insurance Portability and Accountability Act, as information is supplied only in aggregated counts of 10 or greater with deidentified information only.

Two cohorts were created to compare relative risk of various HNCs. Cohort 1 (cannabis-related disorder group) included individuals who received a diagnosis of cannabis-related disorder (International Statistical Classification of Diseases, Tenth Revision, Clinical Modification [ICD-10-CM] F12) and had a recorded outpatient hospital clinic visit (Healthcare Common Procedure Coding System: G0463) with no prior history of HNC. Cannabis-related disorders are defined by the excessive use of cannabis with associated psychosocial symptoms, such as impaired social and/or occupational functioning.¹⁹ Cohort 2 (no cannabis-related disorder group) included individuals who had a recorded outpatient hospital clinic visit, never received a diagnosis of cannabis use disorder, and did not have a history of HNC. Each group was defined by diagnosis or hospital visit from April 19, 2004, to April 19, 2024. Similar groups were created, with stratification by age (younger than 60 years or 60 years or older, as per previous research).²⁶ The analysis was completed on April 19, 2024. The ICD-10 and Healthcare Common Procedure Coding System codes used are documented in the eTable in Supplement 1.