Association Between Markers of Structural Racism and Mass Shooting Events in Major US Cities

The root cause of mass shooting events (MSEs) and the populations most affected by them are poorly understood.To examine the association between structural racism and mass shootings in major metropolitan cities in the United States.This cross-sectional study of MSEs in the 51 largest metropolitan statistical areas (MSAs) in the United States analyzes population-based data from 2015 to 2019 and the Gun Violence Archive. The data analysis was performed from February 2021 to January 2022.Shooting event where 4 or more people not including the shooter were injured or killed.MSE incidence and markers of structural racism from demographic data, Gini income coefficient, Black-White segregation index, and violent crime rate.There were 865 MSEs across all 51 MSAs from 2015 to 2019 with a total of 3968 injuries and 828 fatalities. Higher segregation index (ρ = 0.46, P = .003) was associated with MSE incidence (adjusted per 100 000 population) using Spearman ρ analysis. Percentage of the MSA population comprising Black individuals (ρ = 0.76, P < .001), children in a single-parent household (ρ = 0.44, P < .001), and violent crime rate (ρ = 0.34, P = .03) were other variables associated with MSEs. On linear regression, structural racism, as measured by percentage of the MSA population comprising Black individuals, was associated with MSEs (β = 0.10; 95% CI, 0.05 to 0.14; P < .001). Segregation index (β = 0.02, 95% CI, -0.03 to 0.06; P = .53), children in a single-parent household (β = -0.04, 95% CI, -0.11 to 0.04; P = .28), and Gini income coefficient (β = -1.02; 95% CI, -11.97 to 9.93; P = .93) were not associated with MSEs on linear regression.This study found that major US cities with higher populations of Black individuals are more likely to be affected by MSEs, suggesting that structural racism may have a role in their incidence. Public health initiatives aiming to prevent MSEs should target factors associated with structural racism to address gun violence.