Cox proportional hazards (PH) regression analyses were conducted to examine associations with a) initiation of alcohol use, b) transition from alcohol initiation to onset of AUD symptoms, and c) transition from alcohol initiation to onset of AUD diagnosis. Cox PH regression analyses allow for the possibility that participants who have not yet experienced a particular outcome may do so in the future. Age at first alcohol use was used as the entry point in the AUD symptom onset and AUD diagnosis analyses. As such, data up until the time of censoring (most recent interview) is used in the calculation of hazard ratios. In addition, the PH assumption that risk remains constant over time was tested with the Grambsch and Therneau test of the Schoenfeld residuals (Grambsch and Therneau, 1994). Trauma exposures, PTSD, MDD, tobacco and cannabis use were modeled as time-varying covariates coded as negative in each year prior to the age at first occurrence and positive for that year and each subsequent year, so that only behaviors that occurred prior to or at the same time as the outcomes
