Introduction

Gun ownership is associated with firearm mortality, although this association differs across victim–offender relationships. This study examines the relationship between gun ownership and domestic versus nondomestic homicide rates by victim sex.

Methods

Several sources of state-level panel data from 1990 through 2016 were merged from each of the 50 states to model domestic (i.e., family and intimate partners) and nondomestic firearm homicide as a function of state-level household firearm ownership. Firearm ownership was examined using a validated proxy measure and homicide rates came from the Supplemental Homicide Reports of the Federal Bureau of Investigation's Uniform Crime Reports. Negative binomial regression with fixed effects was used to model the outcomes and employed generalized estimating equations to account for clustering within states. Statistical analyses were completed in 2018.

Results

State-level firearm ownership was uniquely associated with domestic (incidence rate ratio=1.013, 95% CI=1.008, 1.018) but not nondomestic (incidence rate ratio=1.002, 95% CI=0.996, 1.008) firearm homicide rates, and this pattern held for both male and female victims. States in the top quartile of firearm ownership had a 64.6% ( p<0.001) higher incidence rate of domestic firearm homicide than states in the lowest quartile; however, states in the top quartile did not differ significantly from states in the lowest quartile of firearm ownership in observed incidence rates of nondomestic firearm homicide.

Conclusions

State-level firearm ownership rates are related to rates of domestic but not nondomestic firearm homicide.