Invited Commentary: Concealed Carrying of Firearms, Public Policy, and Opportunities for Mitigating Harm.

In the last 30 years, 25 US states have relaxed laws regulating the concealed carrying of firearms (concealed-carry weapons (CCW) laws). These changes may have substantial impacts on violent crime. In a recent study, Doucette et al. (Am J Epidemiol. 2023;192(3):342-355) used a synthetic control approach to assess the effects of shifting from more restrictive "may/no-issue" CCW laws to less restrictive "shall-issue" CCW laws on homicides, aggravated assaults, and robberies involving a gun or committed by other means. The study adds to the evidence that more permissive CCW laws have probably increased rates of firearm assault in states adopting these laws. Importantly, this study is the first to identify that specific provisions of shall-issue CCW laws-including denying permits to persons with violent misdemeanor convictions, a history of dangerous behavior, or "questionable character" and live-fire training requirements-may help mitigate harms associated with shall-issue CCW laws. These findings are timely and salient given the recent Supreme Court ruling striking down a defining element of may-issue laws. This thorough study offers actionable results and provides a methodological model for state firearm policy evaluations. Its limitations reflect the needs of the field more broadly: greater focus on racial/ethnic equity and within-state variation, plus strengthening the data infrastructure on firearm violence and crime.

Effects of Comprehensive Background-Check Policies on Firearm Fatalities in 4 States.

Despite promising results from individual-level studies, state-level studies of the effectiveness of comprehensive background-check (CBC) policies in reducing firearm fatalities have yielded null results in multiple states. These prior studies focused on CBC laws adopted in the 1990s, when record keeping was far less complete. We estimated the effect of the implementation of CBC policies on state-level firearm homicide and suicide rates in states implementing CBC policies from 2013 to 2015 (Colorado, Delaware, Oregon, and Washington). We compared age-adjusted firearm homicide and suicide rates, measured annually from 15 years prior to policy implementation until 2019, in each treated state to rates in control groups constructed using the synthetic control group method. Differences in firearm homicide rates for Colorado, Oregon, and Washington post treatment were all small (0.09 to 0.18 per 100,000 residents per year) and not well distinguished from natural variation. Oregon had on average 0.80 per 100,000 fewer firearm suicides per year than did synthetic Oregon post treatment. However, these results were inconsistent across modeling approaches and not well distinguished from natural variation. Our models produced poor fit for Delaware. Coupled with previous null results from Indiana, California, Maryland, Pennsylvania, and Tennessee, the present results suggest that extending background check requirements to private transfers alone and implementing these policies as is currently done is not sufficient to achieve significant state-level reductions in firearm fatalities.

SuperMICE: An Ensemble Machine Learning Approach to Multiple Imputation by Chained Equations.

Researchers often face the problem of how to address missing data. Multiple imputation is a popular approach, with multiple imputation by chained equations (MICE) being among the most common and flexible methods for execution. MICE iteratively fits a predictive model for each variable with missing values, conditional on other variables in the data. In theory, any imputation model can be used to predict the missing values. However, if the predictive models are incorrectly specified, they may produce biased estimates of the imputed data, yielding inconsistent parameter estimates and invalid inference. Given the set of modeling choices that must be made in conducting multiple imputation, in this paper we propose a data-adaptive approach to model selection. Specifically, we adapt MICE to incorporate an ensemble algorithm, Super Learner, to predict the conditional mean for each missing value, and we also incorporate a local kernel-based estimate of variance. We present a set of simulations indicating that this approach produces final parameter estimates with lower bias and better coverage than other commonly used imputation methods. These results suggest that using a flexible machine learning imputation approach can be useful in settings where data are missing at random, especially when the relationships among the variables are complex.

Effects of building demolitions on firearm violence in Detroit, Michigan.

Former industrial cities facing economic challenges and depopulation often experience high levels of firearm and other forms of violence. Within these cities, violent crime often clusters in neighborhoods affected by high levels of vacant and abandoned housing. This study estimates the effects of building demolition in Detroit, Michigan on the subsequent risk of violent crime using property-level data and longitudinal targeted maximum likelihood estimation. The primary outcome is violent Crime Index crimes (homicide, rape, robbery and aggravated assault). We estimate effects for this category of crimes as a whole and for the subset involving firearms. Drug and other lower-level crimes are included as secondary outcomes. We compare the risk of experiencing each crime type following building demolition in Census blocks and block groups to an estimate of the risk had there been no demolition in the 1-3 quarters prior in 2017. There were >2600 total demolitions in about 1700 blocks in 2017 in Detroit. Nearly all demolished buildings were sourced from tax foreclosures. Estimates suggest the risk for all crime types tested would have been statistically indistinguishable from the observed crime risk had demolitions in the prior 1-3 quarters of 2017 not occurred. Our results run counter to most previous research on this topic, which tends to show a protective effect of demolition on violent crime. Understanding why our results differ may provide important insights into the types of demolition programs with the greatest potential to reduce violent crime.

Firearm purchases without background checks in California.

Background checks are designed to prevent firearm acquisition by people prohibited from purchasing or possessing firearms. There is limited information about background checks, particularly on a state by state basis. We conducted a state-representative, probability-based, Internet survey of California adults in 2018 (n=2558; completion rate 49%) to describe where, when, and how firearms are acquired and to estimate the proportion of current firearm owners who purchased their most recent firearm without a background check. An estimated 17.2% (95% CI: 9.6-28.8) of firearm owners who purchased their most recent firearm within California in 1991 or later, following implementation of the state's comprehensive background check law, reported doing so without a background check. This percentage was 44.6% (95% CI: 27.1-63.5) among owners who purchased their most recent firearm before 1991 and 27.1% (95% CI: 13.1-47.7) among those who purchased their most recent firearm outside California. Firearm purchases without background checks occurred more often for firearms purchased from private sellers (72.3%; 95% CI: 35.5-92.5) than retailers (8.5%; 95% CI: 3.4-19.7). Overall, firearm purchases without background checks are considerably less common in California than in states without regulations on private sales. However, gaps in implementation and proper enforcement remain. Future research could investigate reasons for such lapses, as well as complementary state policy approaches that require background checks prior to point of purchase.

Alcohol and drug offenses and suicide risk among men who purchased a handgun in California: A cohort study.

Firearm access is a risk factor for firearm suicide; substance use may confer additional risk. In this retrospective cohort study, we estimated the associations between prior alcohol and drug charges at the time of handgun purchase and subsequent suicide among men in California. The sample comprised all men who legally purchased a handgun in California in 2001 and who were age ≥ 21 at the time of acquisition (N = 101,377), identified in the California Department of Justice (CA DOJ) Dealer's Record of Sale database. Exposures included alcohol and drug criminal charges and convictions accrued January 1, 1990 until the first ('index') handgun acquisition in 2001, recorded in the CA DOJ Criminal History Information System. Outcomes included suicide and firearm suicide occurring after the index purchase and before January 1, 2016. A total of 1907 purchasers had alcohol charges, 1248 had drug charges, and 304 had both; 594 purchasers died by suicide (516 by firearm suicide). Compared with those with neither alcohol nor drug charges, those with alcohol charges had 2.20 times the hazard of suicide (95% confidence interval [CI], 1.39-3.46) and 2.22 times the hazard of firearm suicide (95% CI, 1.36-3.62). Risk was most elevated among those with more recent charges and those with 2 or more charges, and in the time period closest to the purchase. The associations for drug charges and the combination of alcohol and drug charges were not distinguishable from the null. Firearm owners with alcohol offenses may benefit from intervention to reduce firearm access and alcohol use.

Purchaser Licensing, Point-of-Sale Background Check Laws, and Firearm Homicide and Suicide in 4 US States, 1985-2017.

Objectives. To estimate and compare the effects of state background check policies on firearm-related mortality in 4 US states.Methods. Annual data from 1985 to 2017 were used to examine Maryland and Pennsylvania, which implemented point-of-sale comprehensive background check (CBC) laws for handgun purchasers; Connecticut, which adopted a handgun purchaser licensing law; and Missouri, which repealed a similar law. Using synthetic control methods, we estimated the effects of these laws on homicide and suicide rates stratified by firearm involvement.Results. There was no consistent relationship between CBC laws and mortality rates. There were estimated decreases in firearm homicide (27.8%) and firearm suicide (23.2%-40.5%) rates associated with Connecticut's law. There were estimated increases in firearm homicide (47.3%), nonfirearm homicide (18.1%), and firearm suicide (23.5%) rates associated with Missouri's repeal.Conclusions. Purchaser licensing laws coupled with CBC requirements were consistently associated with lower firearm homicide and suicide rates, but CBC laws alone were not.Public Health Implications. Our results contribute to a body of research showing that CBC laws are not associated with reductions in firearm-related deaths unless they are coupled with handgun purchaser licensing laws.

Violence and Emergency Department Use among Community-Recruited Women Who Experience Homelessness and Housing Instability.

Women who experience housing instability are at high risk for violence and have disproportionately high rates of emergency department (ED) use. However, little has been done to characterize the violence they experience, or to understand how it may be related to ED use. We recruited homeless and unstably housed women from San Francisco shelters, free meal programs, and single room occupancy (SRO) hotels. We used generalized estimating equations to examine associations between violence and any ED use (i.e., an ED visit for any stated reason) every 6 months for 3 years. Among 300 participants, 44% were African-American, and the mean age was 48 years. The prevalence of violence experienced in the prior 6 months included psychological violence (87%), physical violence without a weapon (48%), physical violence with a weapon (18%), and sexual violence (18%). While most participants (85%) who experienced physical violence with a weapon or sexual violence in the prior 6 months had not visited an ED, these were the only two violence types significantly associated with ED use when all violence types were included in the same model (ORphysical/weapon = 1.83, 95% CI 1.02-3.28; ORsexual = 2.15, 95% CI 1.30-3.53). Only violence perpetrated by someone who was not a primary intimate partner was significantly associated with ED use when violence was categorized by perpetrator. The need to reduce violence in this population is urgent. In the context of health care delivery, policies to facilitate trauma-informed ED care and strategies that increase access to non-ED care, such as street-based medicine, could have substantial impact on the health of women who experience homelessness and housing instability.

Psychiatric Disorders and Gun Carrying among Adolescents in the United States.

OBJECTIVES: To estimate associations between psychiatric disorders and gun carrying among adolescents and to estimate the total number of adolescents in the US who have psychiatric disorders and report carrying guns. STUDY DESIGN: We used cross-sectional data from the National Comorbidity Survey - Adolescent Supplement, a nationally representative sample of adolescents age 13-18 years (N = 10 123; response rate = 75.6%). Psychiatric disorders were assessed using the Composite International Diagnostic Interview. Gun carrying in the 30 days prior to the interview was assessed by self-report. We used multivariable Poisson regression to test for associations. RESULTS: The analytic sample included 10 112 adolescents, 2.4% of whom reported carrying a gun in the prior 30 days. The prevalence of gun carrying was greater among adolescents with conduct disorder (adjusted prevalence ratio [APR] = 1.88, 95% CI 1.38, 2.57), drug use disorders (APR = 1.91, 95% CI 1.05, 3.45), and specific phobias (APR = 1.54, 95% CI 1.07, 2.22) compared with adolescents without these disorders. We estimated that 1.1% (95% CI 0.77, 1.48) of adolescents with a disorder associated with self- or other-directed violence also carry guns. Nationally, that is approximately 272 000 adolescents with both risk factors. CONCLUSIONS: Specific psychiatric disorders are associated with an increased risk of gun carrying among adolescents, but the vast majority of adolescents with psychiatric disorders did not report gun carrying. Targeted efforts to assess access to and use of firearms in mental healthcare and other clinical settings are important, as are efforts to identify population approaches to prevention.

Repeal of Comprehensive Background Check Policies and Firearm Homicide and Suicide.

BACKGROUND: In 2016, firearms killed 38,658 people in the United States. Federal law requires licensed gun dealers, but not private parties, to conduct background checks on prospective firearm purchasers with the goal of preventing prohibited persons from obtaining firearms. Our objective was to estimate the effect of the repeal of comprehensive background check laws-requiring a background check for all handgun sales, not just sales by licensed dealers-on firearm homicide and suicide rates in Indiana and Tennessee. METHODS: We compared age-adjusted firearm homicide and suicide rates, measured annually from 1981 to 2008 and 1994 to 2008 in Indiana and Tennessee, respectively, to rates in control groups constructed using the synthetic control method. RESULTS: The average rates of firearm homicide and suicide in Indiana and Tennessee following repeal were within the range of what could be expected, given natural variation (differences = 0.7 firearm homicides and 0.5 firearm suicides per 100,000 residents in Indiana and 0.4 firearm homicides and 0.3 firearm suicides per 100,000 residents in Tennessee). Sensitivity analyses resulted in similar findings. CONCLUSION: We found no evidence of an association between the repeal of comprehensive background check policies and firearm homicide and suicide rates in Indiana and Tennessee. In order to understand whether comprehensive background check policies reduce firearm deaths in the United States generally, more evidence on the impact of such policies from other states is needed. See video abstract at, http://links.lww.com/EDE/B353.

Comprehensive background check policy and firearm background checks in three US states.

BACKGROUND: Comprehensive background check (CBC) policies are hypothesised to reduce firearm-related violence because they extend background checks to private party firearm sales, but no study has determined whether these policies actually increase background checks, an expected intermediary outcome. We evaluate the association between CBC policies and the rates of firearm background checks in three states that recently implemented these policies: Delaware (July 2013), Colorado (July 2013) and Washington (December 2014). METHODS: We used the synthetic control group method to estimate the difference from estimated counterfactual postintervention trends in the monthly rate of background checks per 1 00 000 people for handguns, long guns and both types combined, using data for January 1999 through December 2016. Inference was based on results from permutation tests. We conducted multiple sensitivity analyses to assess the robustness of our results. RESULTS: Background check rates increased in Delaware, by 22%-34% depending on the type of firearm, following enactment of its CBC law. No overall changes were observed in Washington and Colorado. Our results were robust to changes in the comparison group and statistical methods. CONCLUSIONS: The enactment of CBC policies was associated with an overall increase in firearm background checks only in Delaware. Data external to the study suggest that Washington experienced a modest, but consistent, increase in background checks for private party sales, and Colorado experienced a similar increase in checks for sales not at gun shows. Non-compliance may explain the lack of an overall increase in background checks in Washington and Colorado.

The experience of adolescent motherhood: An exploratory mixed methods study.

AIM: To identify and better understand opportunities for and challenges in attaining the maternal role among women who began childbearing in adolescence in rural Mexico. BACKGROUND: Adolescent mothers often face challenges rising from their socioeconomic status and developmental stage that can strain the process of developing confidence and competence in the maternal role. In Mexico, 19% of births are to women under age 20. Little is known about these mothers' experiences with parenting. DESIGN: Mixed methods. METHODS: Quantitative data collected in 2008 from a cluster-random sample of mothers (n = 1,381) in rural, impoverished areas of three southern states provided objective measures of mothers' socioeconomic position, well-being, and parenting practices. Semi-structured interviews conducted in 2013 with mothers (n = 30) provided insight into perceptions of motherhood and opportunities for and challenges in attaining the maternal role. FINDINGS: Ever-adolescent mothers scored lower than never-adolescent mothers on the total HOME and the parental responsivity and learning materials subscales. They also occupied the most economically disadvantaged positions, showing the lowest levels of education and wealth and the most depressive symptoms compared with never-adolescent mothers. The qualitative analysis supported these challenges and highlighted areas of opportunity: (1) early-adolescent parents faced economic challenges; (2) adolescent childbearing was normative with some exceptions; (3) participants' mothers and mothers-in-law provided social support; and (4) mothers focused on learning to parent and helping their children "get ahead" in life. CONCLUSION: Findings have important implications for identifying how to support young women as they become mothers and continue in this role.

Individual, firearm, and purchasing characteristics associated with risk of firearm-related violent crime arrest: a nested case-control study.

BACKGROUND: Firearm purchasing records offer a potentially important administrative data source to identify individuals at elevated risk of perpetrating firearm violence. In this study, we describe individual, firearm, and transaction characteristics of purchasers in California who were arrested for a firearm-related violent crime (FRV) as compared to the general population of registered purchasers in the state. METHODS: Relying on a dataset of all individuals with transaction records in California (1996-2021), linked to criminal records (1980-2021), we enrolled a cohort of individuals for whom we could capture the legal firearm purchase history. We identified those arrested for FRV post purchase, and using incidence density sampling, gender-matched cases to ten purchasers (controls) who remained "at risk" at the time the case was arrested. We focused on the purchase closest in time prior to the arrest ("index" purchase). We implemented conditional logistic regression and included models with controls for individual- and community-level demographics, as well as interactions between firearm and purchasing characteristics and criminal history. RESULTS: The cohort included 1,212,144 individuals, of whom 6153 were arrested for FRV (0.5%). Cases were matched to 61,530 controls to form the study sample. The largest risk factor was a prior criminal history: purchasers had 5.84 times the risk of FRV if they had a prior arrest within three years of the index purchase (CI 5.44-6.27). Several transaction and firearm characteristics were also associated with FRV. For example, risk increased if the firearm was redeemed at a pawn shop (aIRR: 1.37, CI 1.05-1.77) and decreased if the transaction was a registered private party transfer (vs. retail purchase) (aIRR: 0.83, CI 0.76-0.90) or the firearm was a bolt action firearm (vs. semi-automatic) (aIRR: 0.64, CI 0.51-0.79). In the interaction models, most of the purchase and firearm features only remained significant among those with no criminal history. CONCLUSIONS: Given limited data on firearm transactions, there has been little research on whether the type of firearm an individual purchases or the nature of the purchase might serve as indicators of risk for FRV. We found several transaction and firearm features were associated with risk of FRV. Notably, these features provided little evidence of additional risk for those with a prior criminal record.

Drugs, guns, and violent crime in California.

BACKGROUND: There is evidence linking use of controlled substances with perpetration of interpersonal violence. While the United States constitution protects the right to own a firearm, federal law prohibits firearm purchase and possession by persons believed to be at high risk for violence, including those who use controlled substances unlawfully. METHODS: We report here the results of a 13-year prospective observational study on the risk of violent crime associated with a history of criminal drug charges in a cohort of 79,678 legal purchasers of handguns in California in 2001. The main outcomes were post-purchase charges for any violent crime, violent Crime Index crimes (murder, rape, robbery, aggravated assault), and firearm-related violent crimes. The main exposure of interest was a history of pre-purchase charge(s) for drug-related offenses; we examined as a secondary exposure a history of marijuana-related charges. We estimated adjusted hazard ratios (aHR) with 95 % confidence intervals (CI) using Cox proportional hazards multiple events models. RESULTS: We found that legal handgun purchasers in California with a history of drug-related charges, even those with marijuana charges only, had triple the risk of a post-purchase violent crime charge compared to purchasers with no criminal charges (drug charges only: aHR=2.9, 95 % CI 2.2-3.8; marijuana charges only: aHR=3.3, 95 % CI 1.8-6.0). In addition, a criminal history of drug charges only vs. no criminal history was associated with increased risk of one or more violent crime charges after the first post-purchase arrest event (aHR=1.6, 95 % CI 1.2-2.3). CONCLUSION: It is incumbent on researchers and policy makers to understand the nature and causes of this risk in order to take effective steps towards mitigation.

Association of medical conditions and firearm suicide among legal handgun purchasers in California: a case-control study.

BACKGROUND: Suicide is a pressing public health problem, and firearm owners are at especially elevated risk. Certain health conditions are markers of suicide risk, but more research is needed on clinical risk markers for suicide among firearm owners specifically. Our goal was to examine associations of emergency department and inpatient hospital visits for behavioral and physical health conditions with firearm suicide among handgun purchasers. METHODS: This was a case-control study of 5415 legal handgun purchasers in California who died between January 1, 2008, and December 31, 2013. Cases were firearm suicide decedents; controls were motor vehicle crash decedents. Exposures were emergency department and hospital visits for six categories of health diagnoses in the 3 years prior to death. To account for selection bias due to deceased controls, we used probabilistic quantitative bias analysis to generate bias-adjusted estimates. RESULTS: There were 3862 firearm suicide decedents and 1553 motor vehicle crash decedents. In multivariable models, suicidal ideation/attempt (OR 4.92; 95% CI 3.27-7.40), mental illness (OR 1.97; 95% CI 1.60-2.43), drug use disorder (OR 1.40; 95% CI 1.05-1.88), pain (OR 1.34; 95% CI 1.07-1.69), and alcohol use disorder (OR 1.29; 95% CI 1.01-1.65) were associated with higher odds of firearm suicide. When adjusting for all conditions simultaneously, only the associations for suicidal ideation/attempt and mental illness remained significant. Quantitative bias analysis indicated that observed associations were generally biased downward. For example, the bias-adjusted OR for suicidal ideation/attempt was 8.39 (95% simulation interval 5.46-13.04), almost twice that of the observed OR. CONCLUSIONS: Diagnoses for behavioral health conditions were markers for firearm suicide risk among handgun purchasers, even for conservative estimates that did not adjust for selection bias. Encounters with the healthcare system may provide opportunities to identify firearm owners at high risk of suicide.

Importance of categories of crime for predicting future violent crime among handgun purchasers in California.

BACKGROUND: Prohibiting the purchase and possession of firearms by those at risk of violence is an established approach to preventing firearm violence. Prior studies of legal purchasers have focused on convictions for specific crimes, such as violent misdemeanors and driving under the influence (DUI). We broaden that line of inquiry by investigating and comparing the associations between prior arrests for most categories of crime and subsequent arrest for violent offenses among legal handgun purchasers in California. METHODS: In this longitudinal cohort study of 79,678 legal handgun purchasers in California in 2001, we group arrest charges prior to their first purchases in 2001 according to categories defined by the Uniform Crime Report (UCR) Handbook. We use a gradient boosting machine to identify categories of offenses that are most important for predicting arrest for violent crime following firearm purchase. For each category identified, we then estimate the difference in risk of subsequent arrest for a violent offense using survival regression models. RESULTS: We identified eight crime categories with high predictive importance: simple assaults, aggravated assaults, vehicle violations, weapon, other crimes, theft, drug abuse, and DUI. Compared to purchasers with no prior arrests, those with a prior arrest for any one of the eight important categories and no other categories were found to be at increased risk of arrest for a Crime Index-listed violent crime (murder, rape, robbery, aggravated assault), with the greatest estimated risk corresponding to the simple assault UCR category (adjusted hazard ratio 4.0; 95% CI 2.8-5.9). Simple assault was also associated with the greatest risk for subsequent arrest for firearm violence (adjusted hazard ratio 4.6; 95% CI 2.4-9.0) and any violent offense (adjusted hazard ratio 3.7; 95% CI 2.7-5.0). CONCLUSION: The findings of this study suggest that prior arrests for a broad array of crimes, both violent and non-violent, are associated with risk of subsequent violent crimes, including Crime Index-listed violent crimes and firearm violence, among legal purchasers of firearms. Current policies aimed at restricting access to firearms for individuals at increased risk of violence should be re-examined considering these findings.

Crime and Building Rehabilitation or Demolition: A Dose-Response Analysis.

Thousands of buildings in Cleveland, Ohio were demolished or rehabilitated since the Great Recession in the 2000s. Recent evidence suggests removing vacant and decaying buildings reduces violent and firearm-involved crime. This study examines the dose-response relationship between demolitions, rehabilitations, and crime. We use Bayesian spatiotemporal models to estimate the association of interest for five types of crime outcomes: violent crimes, violent crimes involving a firearm, drug crimes, and crimes often associated with building vacancy. We estimate associations in quarterly time periods from 2012 through 2017 in 569 hexagons approximately the size of a neighborhood (2000 feet, approximately 610 m, in diameter), stratified by vacancy level. Across vacancy levels, the majority of our models do not identify statistically significant associations between demolition and rehabilitation dose and crime incidence. However, in some cases, we identify positive associations between demolition and crime. These associations generally appeared at higher levels of demolition (2 or 3 or more demolitions) in areas characterized by medium to high levels of vacancy. We also find that the presence of a property rehabilitation is associated with an increase in drug crimes in areas with medium levels of vacancy.

Simulating the bounds of plausibility: Estimating the impact of high-risk versus population-based approaches to prevent firearm injury.

BACKGROUND: Firearm violence remains a persistent public health threat. Comparing the impact of targeted high-risk versus population-based approaches to prevention may point to efficient and efficacious interventions. We used agent-based modeling to conduct a hypothetical experiment contrasting the impact of high-risk (disqualification) and population-based (price increase) approaches on firearm homicide in New York City (NYC). METHODS: We simulated 800,000 agents reflecting a 15% sample of the adult population of NYC. Three groups were considered and disqualified from all firearm ownership for five years, grouped based on prevalence: low prevalence (psychiatric hospitalization, alcohol-related misdemeanor and felony convictions, 0.23%); moderate prevalence (drug misdemeanor convictions, domestic violence restraining orders, 1.03%); and high prevalence (all other felony/misdemeanor convictions, 2.30%). Population-level firearm ownership was impacted by increasing the price of firearms, assuming 1% price elasticity. RESULTS: In this hypothetical scenario, to reduce firearm homicide by 5% in NYC, 25% of the moderate prevalence group, or 12% of the high prevalence group needed to be effectively disqualified; even when all of the low prevalence group was disqualified, homicide did not decrease by 5%. An 18% increase in price similarly reduced firearm homicide by 5.37% (95% CI 4.43-6.31%). Firearm homicide declined monotonically as the proportion of disqualified individuals increased and/or price increased. A combined intervention that both increased price and effectively disqualified "high-risk" groups achieved approximately double the reduction in homicide as any one intervention alone. Increasing illegal firearm ownership by 20%, a hypothetical response to price increases, did not meaningfully change results. CONCLUSION: A key takeaway of our study is that adopting high-risk versus population-based approaches should not be an "either-or" question. When individual risk is variable and diffuse in the population, "high-risk approaches" to firearm violence need to focus on relatively prevalent groups and be highly efficacious in disarming people at elevated risk to achieve meaningful reductions in firearm homicide, though countering issues of social justice and stigma should be carefully considered. Similar reductions can be achieved with population-based approaches, such as price increases, albeit with fewer such countering issues.

Prior Drug-Related Criminal Charges and Risk for Intimate Partner Violence Perpetration Among Authorized Purchasers of Handguns in California.

Intimate partner violence (IPV) is a considerable public health problem in the US, and evidence suggests that both drugs and firearms contribute to the risk of IPV and its severity. This study uses a retrospective, longitudinal cohort design to explore the association between past arrests, charges incurred in the legal process, and convictions for drug-related crimes, and risk of future arrest for IPV among legal handgun purchasers. The cohort included all legal purchasers of handguns in California in 2001 between the ages of 21 and 49 (n = 79,678), 156 of whom had pre-purchase drug charges and post-purchase IPV charges. We used Cox proportional hazards regression with age at time of handgun purchase, sex, and race/ethnicity, and an array of community characteristics as covariates. Over the study period (2001-2013), in comparison to handgun purchasers who had no charges or convictions prior to their index purchase, risk for future IPV arrest was increased for purchasers whose only prior charges were drug-related (aHR = 3.4 [95% CI: 2.4-4.9]) and purchasers who had both prior drug- and non-drug related charges (aHR = 4.9 [95% CI: 4.1-6.0]). The magnitude of the risk ratio was greater when multiple drug types were involved and when the person had been charged with both the use and sale of drugs. Our findings suggest that, among legal handgun purchasers, prior drug charges are associated with future risk of IPV arrests or convictions. Given the established link between firearm access and IPV severity and fatality, these findings may inform the development and enforcement of policies that reduce firearm access for those at elevated risk of perpetrating intimate partner violence.