Associations between ZIP code-level alcohol outlet density and binge drinking among people who inject drugs in 22 US Metropolitan Areas.

Background: Although alcohol outlet density (AOD) is associated with drinking behaviors in the general population, little evidence exists about this relationship among people who inject drugs (PWID). Establishing this connection is particularly important, as alcohol use exacerbates the risk of opioid overdose. This study investigated 1) the association between ZIP code-level AOD and binge drinking among PWID who use opioids, and 2) the potential moderating effect of race/ethnicity on the AOD-binge drinking relationship. Methods: This analysis linked 2018 National HIV Behavioral Surveillance (NHBS) data and 2016 ZIP code-level AOD data from the ZIP Code Business Pattern survey. Hierarchical generalized linear models quantified the association between AOD and binge drinking, overall and by race/ethnicity. Results: Of 9,660 PWID, 27% reported recent binge drinking. For Hispanic/Latinx and White PWID, increases in AOD were associated with a 1% and 3% increase in the odds of binge drinking, respectively (p < 0.05); AOD was unrelated to binge drinking among Black PWID. However, when AOD was set to the median, binge drinking probability was highest among Black PWID (PP: 0.28, 95% CI: 0.24-0.33). Conclusions: Reducing AOD may decrease binge drinking among White and Latinx PWID. Our results suggest, however, that this strategy alone may be not be effective among Black PWID. Holistic strategies targeting structural determinants of alcohol and opioid co-use among Black PWID are needed to address inequities in drug-related harms.