BACKGROUND AND AIMS: This study examined how substance use patterns influence gambling behaviors across racial/ethnic groups, amid expanding legalization of both substances and gambling in the US. METHODS: A nationally representative survey of 6543 US adults was conducted from December 2023 to January 2024. Participants reported on alcohol, cannabis, opioid, and stimulant use, along with gambling activities. Multivariate logistic regression models analyzed substance-gambling associations, incorporating race-substance use interaction terms and demographic controls. RESULTS: Substance use showed robust associations with gambling behaviors, with stimulant use demonstrating the strongest relationships (online gambling OR=4.694, 95 % CI: 1.876-11.745
casino gaming OR=3.055, 95 % CI: 1.318-7.084). These associations varied markedly by race/ethnicity: Hispanic adults showed the strongest substance-gambling patterns, with cannabis use associated with substantial increases in online gambling (22.6 %, p =0.003), casino table games (19.1 %, p =0.037), and machine gaming (19.2 %, p =0.044). Non-Hispanic Black adults demonstrated high baseline gambling odds independent of substance use but showed specific cannabis-sports gambling associations (15.0 %, p =0.011). Non-Hispanic White adults exhibited moderate substance-associated increases, particularly in online gambling (6.7 %, p =0.001) and casino gaming (5.6 %, p =0.010). Any past-year drug use was significantly associated with multiple gambling types (OR range: 1.376-2.330, p <
0.05). CONCLUSION: Race and ethnicity significantly moderate substance-gambling associations, suggesting distinct addiction vulnerability pathways across populations. The concurrent expansion of substance access and novel gambling modalities, particularly mobile platforms, presents emerging public health challenges that require longitudinal investigation of causal mechanisms and development of culturally-informed prevention strategies.