Background: Senate Bill 1108 (SB-1108) allows adult citizens to carry concealed weapons without a permit and without completion of a training course. It is unclear whether the law creates a "deterrent factor" to criminals or whether it escalates gun-related violence. We hypothesized that the enactment of SB-1108 resulted in an increase in gun-related injuries and deaths (GRIDs) in southern Arizona.
Methods: We performed a retrospective cohort study spanning 24 months before (prelaw) and after (postlaw) SB-1108. We collected injury and death data and overall crime and accident trends. Injured patients were dichotomized based on whether their injuries were intentional (iGRIDs) or accidental (aGRIDs). The primary outcome was any GRID. To determine proportional differences in GRIDs between the two periods, we performed χ analyses. For each subgroup, we calculated relative risk (RR).
Results: The number of national and state background checks for firearms purchases increased in the postlaw period (national and state p < 0.001); that increase was proportionately reflected in a relative increase in state firearm purchase in the postlaw period (1.50% prelaw vs. 1.59% postlaw, p < 0.001). Overall, victims of events potentially involving guns had an 11% increased risk of being injured or killed by a firearm (p = 0.036) The proportion of iGRIDs to overall city violent crime remained the same during the two periods (9.74% prelaw vs. 10.36% postlaw; RR, 1.06; 95% confidence interval, 0.96-1.17). However, in the postlaw period, the proportion of gun-related homicides increased by 27% after SB-1108 (RR, 1.27; 95% confidence interval, 1.02-1.58).
Conclusion: Both nationally and statewide, firearm purchases increased after the passage of SB-1108. Although the proportion of iGRIDs to overall city violent crime remained the same, the proportion of gun-related homicides increased. Liberalization of gun access is associated with an increase in fatalities from guns.
Level of evidence: Epidemiologic study, level III.