Self-reported race/ethnicity was recoded into 5 groups: Whites, Blacks, Hispanics, Native Hawaiians or other Pacific Islanders (NH/PI) and American Indians or Alaskan Natives (AI/AN). Other socio-demographic factors included gender, age, urbanicity (urban vs. rural), nativity (US-born vs. foreign-born), level of education, individual and family income, marital status, and employment status. Early substance use onset (before age 14) and family history of SUDs (any alcohol or drug use disorder among first degree relatives) were also included as substance use-related covariates.
