Chicago homicides and non-fatal shootings: census tract-level analysis of firearm victimisation data and SDoH indices

BACKGROUND: Firearm violence is a leading cause of death in the USA. It is an epidemic that disproportionately impacts people of colour, especially in marginalised and under-resourced communities and is the leading cause of death for black males aged 15-34 years. This cross-sectional study examines the relationship between social determinants of health (SDoH) indices and firearm victimisation rates in Chicago, exploring associations between structural disadvantage and community violence. METHODS: Firearm victimisation data, including 20 761 homicides and non-fatal shootings from 2018 to 2024, were obtained from the Chicago Mayor's Office of Violence Prevention and aggregated by census tract (n=800). Census tract-level SDoH data, including Social Vulnerability Index (SVI) and Childhood Opportunity Index (COI), were sourced from the Chicago Health Atlas. Index of Concentration at the Extremes (ICE) was calculated using American Community Survey data (2018-2022). Indices were divided into quantiles. Negative binomial regressions were conducted adjusting for population density. RESULTS: Firearm victimisation rates were significantly higher in more disadvantaged census tracts across all indices (p<0.05). For SVI, firearm victimisation rates in the most vulnerable quartile were 17.57 times higher than in the least vulnerable quartile. Similar trends were observed for COI and ICE, with the most disadvantaged quintiles showing 18.29 and 25.76 times higher, respectively, in the most privileged quintiles. DISCUSSION AND CONCLUSIONS: Structural disadvantage, captured by SDoH indices, is strongly associated with increased firearm victimisation rates. Reducing firearm victimisation in urban centres like Chicago requires policies and interventions that address population-level determinants captured by these indices.