Law Enforcement and Gun Shops: A Spatial Analysis Approach to Firearm Homicide Victimization

Background: Firearm homicide is a significant public health issue, that is not evenly distributed, disproportionately affecting minoritized populations and urban communities. Limited research has examined these spatial relationships using population-based data across these groups. We study law enforcement locations and federal firearm licensees (FFL), the entities that shape firearm acquisition across neighborhoods. This dissertation examines how residential proximity to law enforcement locations and FFLs is associated with the risk of firearm homicide across different geographic and social contexts.Methods: We employed a case–control design, spatially analyzing firearm homicide decedents and controls in North Carolina (2014–2023). Our analytic dataset included 5,758 firearm homicide decedents and 22,582 frequency-matched controls (1:4) on age, sex, and year. Using generalized additive models, we estimated nonlinear associations between residential proximity to the nearest law enforcement location (Aim 1) or FFL (Aim 2). This yielded the log odds of firearm homicide for each exposure, adjusting for neighborhood disadvantage, sex, year, and spatial location.Results: Closer residential proximity to law enforcement location was associated with higher firearm homicide risk, with predicted rates of approximately 8 per 100,000 person-years within 1 kilometer (km). Black non-Hispanic individuals experienced the highest predicted rates (36 per 100,000 person-years at less than 1 km), nearly six times higher than that of the general population. Closer residential proximity to FFLs was consistently associated with elevated risk across all demographic subgroups, 90% lower odds at 15+ km compared to <1 km. Combined proximity to both entities produced synergistic effects (RERI = 0.14) in that joint exposure produced excess risk beyond individual effects, with the strongest synergy experienced by individuals living in suburban and rural areas (RERI = 1.54).Conclusions: Residential proximity to both law enforcement and FFLs creates amplified risk environments for firearm homicide victimization rather than protective zones. The substantial racial disparities observed indicate that these spatial exposures operate through fundamentally racialized pathways. This research has the potential to inform violence prevention research and practice, implications for zoning laws, urban planning, firearm policies and understanding how race and ethnicity and geography impact health disparities.