Associations of Objective and Perceived Neighborhood Ethnic Density on Hazardous Alcohol Use among Latinx Emerging Adults.

: Emerging adulthood is an important time where substance use often peaks. Neighborhood Latinx ethnic density could be protective against negative health behaviors. Most studies on neighborhood ethnic density have focused on census-level aggregate measures, however perception of the neighborhood ethnic density could differ from objectively measured neighborhood density. This study investigated the effects of neighborhood ethnic density, both perceived ethnic and objectively measured ethnic density, on hazardous alcohol use among Latinx emerging adults in Maricopa County Arizona and Miami-Dade County Florida by gender. : 200 Latinx emerging adults residing in Arizona and Florida completed a cross-sectional survey. Inclusion criteria were being age 18-25, self-identify as Latinx, and currently living in Maricopa County or Miami-Dade County. Data were analyzed using multivariate logistic regression and moderation analyses. : There was a statistically significant difference between perceived and objective ethnic density (Kappa = 0.353,  < 0.001). When ethnic density was measured objectively, alcohol use severity was statistically significantly lower for individuals living in highly ethnically dense neighborhoods (OR: 0.34, 95% CI: 0.12, 0.92). However, this association was only found for women in moderation analyses. There was no statistically significant association between perceived ethnic density and alcohol use severity. : The present study found a statistically significant decrease in alcohol use severity among Latinx emerging adults who live in highly ethnically dense neighborhoods after adjusting for covariates. Future research should investigate the potential mechanisms in which these neighborhoods protect against alcohol use severity among Latinx emerging adults.