Neighbors Do Matter: Between-State Firearm Laws and State Firearm-Related Deaths in the U.S., 2000-2017

Nearly 20 Years Since the Federal Ban: Can State-Level Assault Weapon Prohibitions Fill the Void? Comparative Analysis of Case Fatality and Assault Weapon Recovery in States With and Without an Assault Weapon Ban

INTRODUCTION

Few states established assault weapon bans (AWBs) after the federal AWB expired. The effectiveness of state AWBs as well as neighboring state legislation, in reducing the local prevalence of assault weapons (AWs) or in reducing overall shooting lethality is unknown.

METHODS

We queried the Gun Violence Archive (2014-2021) to identify US firearm injuries and fatalities. Shooting case fatality rates were compared among states with and without AWBs, as reported in the State Firearm Laws Database. Data on recovered firearms was obtained from the ATF Firearms Trace Database and used to estimate weapon prevalence. Recovered firearms were classified as AWs based on caliber (7.62 mm, 5.56 mm, 0.223 cal). We performed spatially weighted linear regression models, with fixed effects for state and year to assess the association between geographically clustered state legislation and firearm outcomes.

RESULTS

From 2014 to 2021, the US shooting victim case fatality rate was 8.06% and did not differ among states with and without AWBs. The proportion of AWs to total firearms was 5.0% in states without an AWB and 6.0% in states with an AWB (mean difference [95% CI] = -0.8% [-1.6% to -0.2%], P = 0.03). Most recovered firearms in AWB states originated from non-AWB states. On adjusted models, there was no association between state-level AWB and firearm case fatality; however, adjacency to states with an AWB was associated with lower case fatality (P < 0.001). Clustered AWB states with shared borders had lower AW prevalence and fatality rates than the rest of the US.

CONCLUSIONS

Isolated state AWBs are not inversely associated with shooting case fatality rates nor the prevalence of AWs, but AWBs among multiple neighboring states may be associated with both outcomes.

Reporting and Description of Research Methodology in Studies Estimating Effects of Firearm Policies

BACKGROUND

Evidence about which firearm policies work, to what extent, and for whom is hotly debated, perhaps partly because variation in research methodology has produced mixed and inconclusive effect estimates. We conducted a scoping review of firearm policy research in the health sciences in the United States, focusing on methodological considerations for causal inference.

METHODS

We identified original, empirical articles indexed in PubMed from 1 January 2000 to 1 September 2021 that examined any of 18 prespecified firearm policies. We extracted key study components, including policy type(s) examined, policy operationalization, outcomes, study setting and population, study approach and design, causal language, and whether and how authors acknowledged potential sources of bias.

RESULTS

We screened 7733 articles and included 124. A plurality of studies used a legislative score as their primary exposure (n = 39; 32%) and did not examine change in policies over time (n = 47; 38%). Most examined firearm homicide (n = 51; 41%) or firearm suicide (n = 40; 32%) as outcomes. One-third adjusted for other firearm policies (n = 41; 33%). Three studies (2%) explicitly mentioned that their goal was to estimate causal effects, but over half used language implying causality (n = 72; 58%). Most acknowledged causal identification assumptions of temporality (n = 91; 73%) and exchangeability (n = 111; 90%); other assumptions were less often acknowledged. One-third of studies included bias analyses (n = 42; 34%).

CONCLUSIONS

We identified a range of methodologic approaches in firearm policy research in the health sciences. Acknowledging the imitations of data availability and quality, we identify opportunities to improve causal inferences about and reporting on the effects of firearm policies on population health.

Bullet holes: A novel model to identify the most impactful gaps in the firearm homicide prevention laws of each state

BACKGROUND

Firearm homicides (FH) are a major cause of mortality in the United States. Firearm law implementation is variable across states, and legislative gaps may represent opportunities for FH prevention. For each state, we sought to identify which firearm law category would have been most effective if implemented and how effective it would have been.

METHODS

We conducted a retrospective cohort study examining the effects of firearm laws on FH rates in the 48 contiguous US states 2010 to 2019. Data were obtained from the CDC WONDER and FBI UCR databases, State Firearm Law Database, and US Census. Firearm laws were grouped into 14 categories. We assessed the association between the presence of each law category and FH rate as an incidence rate ratio (IRR) using a Poisson regression accounting for state population characteristics and laws of surrounding states. We estimated the IRR for each state that did not have a given law category present and determined which of these missing law categories would have been associated with the greatest reduction in FH rate.

RESULTS

FH rates varied widely across states and increased from a mean of 3.2 (SD = 1.7) to 4.2 (SD = 2.9) FH per 100,000. All law categories were significantly associated with decreased FH rate ( p < 0.05), with IRR ranging from 0.25 to 0.85. The most effective missing law category differed between states but was most commonly child access prevention (34.09% of states), assault weapons and large-capacity magazines (15.91%), preemption (15.91%), and concealed carry permitting (13.64%). In total across 2010 to 2019, we estimated that 129,599 fewer FH would have occurred with enactment of the most effective missing law category in each state.

CONCLUSION

Modeling firearm law prevention of FH with regard to state legislative and population characteristics can identify the highest impact missing law categories in each state. These results can be used to inform efforts to reduce FH.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Firearm-Related Traumatic Brain Injuries in Adults: A Scoping Review

BACKGROUND AND OBJECTIVES

Firearm-related traumatic brain injury (TBI) has emerged as a significant public health issue in the United States, coinciding with a rapid increase in gun-related deaths. This scoping review aims to update our understanding of firearm-related TBI in adult populations.

METHODS

A comprehensive search of 6 online databases yielded 22 studies that met the inclusion criteria. The reviewed studies predominantly focused on young adult men who were victims of assault, although other vulnerable populations were also affected.

RESULTS

Key factors in evaluating patients with firearm-related TBI included low Glasgow Coma Scale scores, central nervous system involvement, hypotension, and coagulopathies at presentation. Poor outcomes in firearm-related TBIs were influenced by various factors, including the location and trajectory of the gunshot wound, hypercoagulability, hemodynamic instability, insurance status, and specific clinical findings at hospital admission.

CONCLUSION

Proposed interventions aimed to reduce the incidence and mortality of penetrating TBIs, including medical interventions such as coagulopathy reversal and changes to prehospital stabilization procedures. However, further research is needed to demonstrate the effectiveness of these interventions. The findings of this scoping review hope to inform future policy research, advocacy efforts, and the training of neurosurgeons and other treating clinicians in the management of firearm-related TBI.

Association of State-Level Firearm-Related Deaths With Firearm Laws in Neighboring States

IMPORTANCE

Firearms are easily transported over state borders; hence permissive firearm laws in one state may have an interstate association with firearm-related deaths in nearby states.

OBJECTIVES

To examine whether certain firearm laws have an interstate association with firearm-related deaths in nearby states.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional observational study used data on state firearm-related deaths in the 48 contiguous states of the US between January 1, 2000, and December 31, 2019. A spatial autoregressive model with fixed effects for state and year was used to evaluate within-state, interstate, and overall associations between firearm laws and firearm-related deaths. Analyses were performed during January 2022.

EXPOSURES

The following 9 types of laws were evaluated: universal background checks for all firearms purchase, background checks for handgun sales at gun shows, license requirement to purchase all firearms, state dealer license requirement for handgun sales, requirement of retaining records of handgun sales, ban on purchasing a handgun on behalf of another, prohibition of firearm possession by persons who committed violent misdemeanors, required relinquishment of firearms for persons becoming prohibited from possessing them, and discretion in granting a concealed carry permit.

MAIN OUTCOMES AND MEASURES

State-level total firearm-related death rates, suicide rates, and homicide rates.

RESULTS

In sum, the study period included 662 883 firearm-related deaths of all intents. License requirement for firearm purchase had a within-state association (effect size, -1.79 [95% CI, -2.73 to -0.84]), interstate association (effect size, -10.60 [95% CI, -17.63 to -3.56]), and overall association (effect size, -12.38 [95% CI, -19.93 to -4.83]) per 100 000 population decrease in total firearm-related deaths. This law also had within-state association (effect size, -1.26 [95% CI, -1.72 to -0.80]), interstate association (effect size, -9.01 [95% CI, -15.00 to -3.02]), and overall association (effect size, -10.27 [95% CI, -16.53 to -4.01]) per 100 000 population decrease in firearm-related homicide.

CONCLUSIONS AND RELEVANCE

The findings of this pooled cross-sectional analysis suggest that certain firearm laws in one state were associated with other states' firearm-related deaths. Synergic legislative action in adjacent states, federal firearm legislation, and measures that reduce migration of firearms across state borders should be part of the overarching strategy to prevent firearm-related deaths.

State firearm laws and nonfatal firearm injury-related inpatient hospitalizations: A nationwide panel study

BACKGROUND

Firearm injury remains a major cause of morbidity and mortality in the United States. Because of prior lack of comprehensive data sources, there is a paucity of literature on nonfatal firearm injury. Associations have previously been shown between state-level firearm laws and firearm fatalities, but few studies have examined the effects of these laws on nonfatal firearm hospitalization rates. Our objective was to examine the relationship between state firearm laws and firearm injury-related hospitalization rates across all 50 states over a 17-year period.

METHODS

In this panel study design, we used fixed effects multivariate regression models to analyze the relationship between 12 laws and firearm state-level injury-related hospitalization rates from 2000 to 2016 using the RAND Corporation Inpatient Hospitalizations for Firearm Injury Database. We used difference-in-differences to determine the impact of law passage in a given state compared with those states without the law, controlling for state-level covariates. The main outcome measure was the change in annual firearm injury-related inpatient hospitalization rates after passage or repeal of a state-level firearm law.

RESULTS

Examining each law individually, passage of violent misdemeanor, permitting, firearm removal from domestic violence offenders, and 10-round limit laws were associated with significant firearm injury-related hospitalization rate reductions. Examining multiple laws in the same model, passage of violent misdemeanor laws was associated with a 19.9% (confidence interval, 11.6%-27.4%) reduction, and removal of firearms from domestic violence offenders was associated with a 17.0% (confidence interval, 9.9%-23.6%) reduction in hospitalization rates.

CONCLUSION

State laws related to preventing violent offenders from possessing firearms are associated with firearm injury-related hospitalization rate reductions. Given significant physical, mental, and social burdens of nonfatal firearm injury, determining the efficacy of firearm-related policy is critical to violence and injury prevention efforts.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level IV.