LAUSR

INTRODUCTION Youth who carry firearms-and peers that surround them-are at increased risk for violent injuries. Because firearm carriage behaviors can change over time within an individual, it is important to identify individual and social-contextual determinants that explain this within-person variability in carriage. METHODS The authors identified individual and social-contextual determinants of firearm carriage in the past 6 months using multilevel logistic models on 5 waves of panel data from the Flint Youth Injury Study (n=597; ages 14-24 years), collected in 2009-2011 and analyzed in 2019. RESULTS Regarding within-person effects, when an individual had more positive peer affiliations than their average, their odds of carrying a firearm decreased (OR=0.88; 95% CI=0.81, 0.96). Conversely, an individual's odds of carrying a firearm increased when they had more negative peer affiliations (OR=1.08, 95% CI=1.02, 1.14), experienced more victimization (OR=1.03, 95% CI=1.01, 1.05), perceived greater community violence (OR=1.12, 95% CI=1.05, 1.21), or exhibited greater retaliatory attitudes (OR=1.10, 95% CI=1.01, 1.19) than their average. CONCLUSIONS Peer affiliations, victimization, community violence perceptions, and retaliatory attitudes explain within-person variability in firearm carriage. Strategies for reducing carriage among youth should consider individual- and environmental-level interventions to address these individual and social-contextual determinants.