Association of pediatric firearm injury with neighborhood social deprivation in Philadelphia.

Background: Firearm-related injury is the leading cause of death among children and adolescents. There is a need to clarify the association of neighborhood environment with gun violence affecting children. We evaluated the relative contribution of specific social determinants to observed rates of firearm-related injury in children of different ages. Methods: This was a population-based study of firearm injury in children (age <18 years) that occurred in Philadelphia census tracts (2015-2021). The exposure was neighborhood Social Deprivation Index (SDI) quintile. The outcome was the rate of pediatric firearm injury due to interpersonal violence stratified by age, sex, race, and year. Hierarchical negative binomial regression measured the risk-adjusted association between SDI quintile and pediatric firearm injury rate. The relative contribution of specific components of the SDI to neighborhood risk of pediatric firearm injury was estimated. Effect modification and the role of specific social determinants were evaluated in younger (<15 years old) versus older children. Results: 927 children were injured due to gun violence during the study period. Firearm-injured children were predominantly male (87%), of black race (89%), with a median age of 16 (IQR 15-17). Nearly one-half of all pediatric shootings (47%) occurred in the quintile of highest SDI (Q5). Younger children represented a larger proportion of children shot in neighborhoods within the highest (Q5), compared with the lowest (Q1), SDI quintile (25% vs 5%; p<0.007). After risk adjustment, pediatric firearm-related injury was strongly associated with increasing SDI (Q5 vs Q1; aRR 14; 95% CI 6 to 32). Specific measures of social deprivation (poverty, incomplete schooling, single-parent homes, and rented housing) were associated with significantly greater increases in firearm injury risk for younger, compared with older, children. Component measures of the SDI explained 58% of observed differences between neighborhoods. Conclusions: Neighborhood measures of social deprivation are strongly associated with firearm-related injury in children. Younger children appear to be disproportionately affected by specific adverse social determinants compared with older children. Root cause evaluation is required to clarify the interaction with other factors such as the availability of firearms and interpersonal conflict that place children at risk in neighborhoods where gun violence is common. Level of evidence: Level III - Observational Study.