Background Firearm fatalities are a major public health concern, claiming the lives of 40,000 Americans each year. While firearm fatalities have pervasive effects, it is unclear how social determinants of health (SDOH) such as residential racial segregation, income inequality, and community resilience impact firearm fatalities. This study investigates the relationships between these SDOH and the likelihood of firearm fatalities. Methods County-level SDOH data from the Agency for Health Care Research and Quality for 2019 were analyzed, covering 72 Wisconsin counties. The dependent variable was the number of firearm fatalities in each county, used as a continuous variable. The independent variable was residential racial segregation (Dissimilarity Index), defined as the degree to which non-White and White residents were distributed across counties, ranging from 0 (complete integration) to 100 (complete segregation), and higher values indicate greater residential segregation (categorized as low, moderate, and high). Covariates were income inequality ranging from zero (perfect equality) to one (perfect inequality) categorized as low, moderate, and high, community resilience risk factors (low, moderate, and high risks), and rural-urban classifications. Descriptive/summary statistics, unadjusted and adjusted negative binomial regression adjusting for population weight, were performed using STATA/MPv.17.0; P-values ≤ 0.05 were considered statistically significant. ArcMap was used for Geographic Information System analysis. Results In 2019, there were 802 firearm fatalities. The adjusted model demonstrates that the risk of firearm fatalities was higher in areas with high residential racial segregation compared to low-segregated areas (IRR.:1.26, 95% CI:1.04–1.52) and higher in areas with high-income inequality compared to areas with low-income inequality (IRR.:1.18, 95% CI:1.00–1.40). Compared to areas with low-risk community resilience, the risk of firearm fatalities was higher in areas with moderate (IRR.:0.61, 95% CI:0.48–0.78), and in areas with high risk (IRR.:0.53, 95% CI:0.41–0.68). GIS analysis demonstrated that areas with high racial segregation also have high rates of firearm fatalities. Conclusion Areas with high residential racial segregation have a high rate of firearm fatalities. With high income inequality and low community resilience, the likelihood of firearm fatalities increases.

Background: Firearm fatalities are a major public health concern, claiming the lives of 40,000 Americans each year. While firearm fatalities affect all, it is unclear how social determinants such as residential segregation affect firearm fatalities. To address this knowledge gap, this study investigates the relationship between residential segregation and the likelihood of firearm fatalities. Methods: Ecological county-level data for 72 Wisconsin counties from the American Community Survey (ACS) were merged with Vital Statistics System mortality records (2015-2019). The study outcome was firearm fatalities, defined as the number of deaths due to firearms per 100,000 population from 2015 to 2019 (used as a continuous variable). The independent variable was residential segregation, using the 2015-2019 ACS-Dissimilarity Index (DI), which measures the degree to which non-white and white residents are distributed across counties and ranges from 0 (complete integration) to 100 (complete segregation), with higher values indicating greater residential segregation. Confounders included income inequality (2015-2019) and community resilience (2019). Poisson regression analyses were conducted using STATA/MP-v.17.0. P-values of ≤0.05 were considered statistically significant. Results: From 2015 to 2019, there were 843 firearm fatalities. Mean (SD) residential segregation was 32.4 (13.1). Bivariate analysis indicates that an increase in residential segregation was significantly associated with increased firearm fatalities (Coef.:0.1,95%CI:0.05-0.06). Adjusted model results indicate that for every increase in residential segregation (by DI), the likelihood of firearm fatalities increased by 0.01% (Coef.:0.01,95%CI:0.007-0.02). Conclusion: Residential segregation, among other social determinants, increases the likelihood of firearm fatalities. This research helps healthcare systems-based practitioners understand how the larger social context influences gun violence disparities.