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.

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.

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.

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.

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.

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.

Intimate Partner Violence and Subsequent Violent Offending Among Handgun Purchasers.

Perpetrators of intimate partner violence (IPV) often reoffend, and firearm access increases risk of severe injury or fatality. Prior research identifies an association between a history of violent misdemeanor convictions among handgun purchasers and increased risk of subsequent arrest for a violent crime; the risk associated specifically with an IPV criminal history remains largely unexplored. The current study examined a cohort of 76,311 California adults who legally purchased a handgun in 2001 and followed them through 2013. Compared with purchasers who had no criminal history at the time of purchase, those with a history of only IPV (n = 178) charges were at increased risk of subsequent arrest for a violent Crime Index crime (murder, rape, robbery, aggravated assault; adjusted hazard ratio [AHR], 2.6; 95% confidence interval [CI]: 1.4-5.1), any violent crime (AHR, 3.2; 95% CI: 2.0-5.1), and an IPV crime (AHR, 5.2; 95% CI: 3.0-9.0). Purchasers with both IPV and non-IPV charges demonstrated the greatest risk of re-arrest relative to those with no criminal history. Despite the strength of the relationship between IPV and subsequent arrest, a small proportion of handgun purchasers with an IPV criminal history were re-arrested for firearm violence crimes, limiting application for risk assessment purposes. Results affirm prior research identifying IPV as a risk factor for future offending.

Handgun purchasing characteristics and firearm suicide risk: a nested case-control study.

BACKGROUND: Firearms are the most lethal method of suicide and account for approximately half of all suicide deaths nationwide. We describe associations between firearm purchasing characteristics and firearm suicide. METHODS: Data on all legal handgun transactions in California from 1996 to 2015 were obtained from the California Department of Justice Dealer's Record of Sale database. Handgun purchasers were linked to mortality data to identify those who died between 1996 and 2015. To account for variation in timing and duration of observation time, analyses were stratified by birth cohort. The primary analysis focused on those aged 21-25 in 1996. A secondary analysis tested associations among those aged 50-54 in 1996. Using incidence density sampling, purchasers who died by firearm suicide (cases) were each gender-matched to 5 purchasers (controls) who remained at risk at the case's time of death. We examined the characteristics of purchasers and transactions, focusing on the transaction closest in time to the case's death. Data were analyzed with conditional logistic regression. RESULTS: There were 390 firearm suicides among the younger cohort and 512 firearm suicides among the older cohort. Across both cohorts, older age at first purchase and the purchase of a revolver were associated with greater risk of firearm suicide. For example, among the younger cohort, those who purchased a revolver versus semiautomatic pistol had 1.78 times the risk of firearm suicide (95% CI 1.32, 2.40) in multivariable models. Other associations varied across cohorts, suggesting cohort or age effects in purchasing patterns. CONCLUSIONS: Findings add to the evidence on firearm suicide risk and may help inform prevention strategies and future research.

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.

Gun violence against unhoused and unstably housed women: A cross-sectional study that highlights links to childhood violence.

BACKGROUND: Unstably housed women experience high levels of violence. While previous studies have investigated psychological, physical, and sexual violence, weapon and gun violence are rarely delineated. We examined factors associated with experiencing violence as an adult among unhoused and unstably housed women, with a focus on gun violence. METHODS: We recruited women with a history of housing instability from San Francisco homeless shelters, street encampments, free meal programs, low-income hotels, and health clinics. Participants completed interviews including questions regarding both childhood and adult violence. We used multivariable logistic regression to examine associations of specific types of childhood violence (i.e., physical, sexual, gun, other weapon-involved violence), age, race, ethnicity, educational attainment, and sexual orientation, with risk of experiencing specific types of violence as an adult (i.e., gun, other weapon-involved, physical violence). Because the violence outcomes were not rare, odds ratios were transformed to approximate risk ratios. RESULTS: Nearly half of women (n = 110, 45%) had been attacked with a gun as an adult. Violent victimization in adulthood was common, with 33% having experienced all three forms of violence. The probability of being attacked with a gun as an adult was almost 70% higher among women who had been hit or kicked hard enough to cause injury as a child (RR = 1.68; 95% CI = 1.24, 2.11), and this association was present for all three violence outcomes. No other risk factors explored, including other types of violence experienced as a child, met the statistical threshold to be considered significant. CONCLUSIONS: The high prevalence of gun violence reported here is consistent with prior studies of violence conducted in similar populations. Considered in combination with prior research, findings suggest multi-generational violence prevention interventions for low-income women and girls are needed. They also emphasize the need to more actively include people who experience unstable housing in statewide and national violence surveys to better understand the extent of the problem and address on a broader scale the high rates of violence experienced by unstably housed populations, which have been consistently documented in local research.

Criminal charge history, handgun purchasing, and demographic characteristics of legal handgun purchasers in California.

BACKGROUND: The prevalence and characteristics of handgun purchasers' criminal charge histories have never been described for a large population of firearm owners, but such information is critical to understanding risk factors for subsequent violence in this population. We sought to characterize legal handgun purchasers in California and compare this group to the state population, to quantify the proportion with a criminal charge history at purchase, and to identify modifiable factors associated with of having such a history. METHODS: This cross-sectional study of all 79,927 legal handgun purchasers aged 21-49 years in California in 2001 used log-linear generalized additive models to identify factors associated with having a criminal charge history at purchase. Subjects are from a longitudinal study of incident criminal activity among handgun purchasers. RESULTS: The majority (91.03%) of purchasers were male; whites were overrepresented and Hispanics were underrepresented relative to their population size. At the time of purchase, 16.68%  had a criminal charge history and 10.71% had a criminal conviction. Among men with such a history, 31.28% had been charged with a violent crime and 16.54% had been charged with a firearm-related crime. The strongest factor associated with having a criminal charge history was redeeming a pawned handgun (prevalence ratio: 1.82; 95% confidence interval: 1.71, 1.93). CONCLUSIONS: Despite California's stringent firearm purchase laws, more than 1-in-6 handgun purchasers had a criminal charge history at purchase. This proportion may be higher in states with less restrictive firearm purchasing eligibility criteria.

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.

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.

Distress level and daily functioning problems attributed to firearm victimization: sociodemographic-specific responses.

PURPOSE: The purpose of this study was to estimate the effect of firearm involvement during violent victimization on the level of distress experienced and daily functioning within sociodemographic subgroups. METHODS: We used cross-sectional data from the National Crime Victimization Survey (n = 5698) and Targeted Maximum Likelihood Estimation. Sociodemographic subgroups were defined by age, race, sex, and socioeconomic position. Outcomes included experiencing the victimization as severely distressing and problems in the workplace or at school, or with peers or family. RESULTS: Among people victimized with a firearm, nearly 40% experienced the victimization as severely distressing and 28% reported daily functioning problems as a result of the victimization, compared with 25% and 27% of those victimized without a firearm. In most of the subgroups examined, a greater proportion of people described the event as severely distressing when a firearm was involved in the victimization, ranging up to 19 percentage points higher among women and among black respondents (95% CI for women = 10%-28%; for blacks = 6%-31%). CONCLUSIONS: Our findings suggest an almost universal negative response to firearm involvement during a violent victimization as compared with violent victimizations involving other or no weapons. These findings highlight the need for efforts by medical and mental health practitioners to address the potential sequelae of experiencing severe distress during a firearm victimization.

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.

Association of Prior Convictions for Driving Under the Influence With Risk of Subsequent Arrest for Violent Crimes Among Handgun Purchasers.

Importance: Alcohol use is a risk factor for firearm-related violence, and firearm owners are more likely than others to report risky drinking behaviors. Objective: To study the association between prior convictions for driving under the influence (DUI) and risk of subsequent arrest for violent crimes among handgun purchasers. Design: In this retrospective, longitudinal cohort study, 79 678 individuals were followed up from their first handgun purchase in 2001 through 2013. The study cohort included all legally authorized handgun purchasers in California aged 21 to 49 years at the time of purchase in 2001. Individuals were identified using the California Department of Justice (CA DOJ) Dealer's Record of Sale (DROS) database, which retains information on all legal handgun transfers in the state. Exposures: The primary exposure was DUI conviction prior to the first handgun purchase in 2001, as recorded in the CA DOJ Criminal History Information System. Main Outcomes and Measures: Prespecified outcomes included arrests for violent crimes listed in the Crime Index published by the Federal Bureau of Investigation (murder, rape, robbery, and aggravated assault), firearm-related violent crimes, and any violent crimes. Results: Of the study population (N=79 678), 91.0% were males and 68.9% were white individuals; the median age was 34 (range, 21-49) years. The analytic sample for multivariable models included 78 878 purchasers after exclusions. Compared with purchasers who had no prior criminal history, those with prior DUI convictions and no other criminal history were at increased risk of arrest for a Crime Index-listed violent crime (adjusted hazard ratio [AHR], 2.6; 95% CI, 1.7-4.1), a firearm-related violent crime (AHR, 2.8; 95% CI, 1.3-6.4), and any violent crime (AHR, 3.3; 95% CI, 2.4-4.5). Among purchasers with a history of arrests or convictions for crimes other than DUI, associations specifically with DUI conviction remained. Conclusions and Relevance: This study's findings suggest that prior DUI convictions may be associated with the risk of subsequent violence, including firearm-related violence, among legal purchasers of handguns. Although the magnitude was diminished, the risk associated with DUI conviction remained elevated even among those with a history of arrests or convictions for crimes of other types.

Alcohol-Related Crimes And Risk Of Arrest For Intimate Partner Violence Among California Handgun Purchasers.

Intimate partner violence is a major public health problem in the US. Both firearms and alcohol have been documented to contribute to the risk and severity of this violence. Yet there has been little research examining the nexus of the two risk factors. This study sought to determine whether alcohol-related problems, as indicated by a history of conviction for offenses such as driving under the influence (DUI), were associated with risk for future intimate partner violence among authorized purchasers of handguns in California. Using a longitudinal cohort design, we found that purchasers with prior DUI convictions (and no other criminal history) had close to three times the risk of subsequent arrest for an intimate partner violence offense than did those with no criminal history at the time of the index firearm purchase. The regulation of firearm ownership among people with alcohol use problems may represent an important opportunity to reduce intimate partner violence and the escalation of firearm-related harm.

The impact of spikes in handgun acquisitions on firearm-related harms.

BACKGROUND: Research has documented sharp and short-lived increases in firearm acquisitions immediately following high-profile mass shootings and specific elections, increasing exposure to firearms at the community level. We exploit cross-city variation in the estimated number of excess handgun acquisitions in California following the 2012 presidential election and the Sandy Hook school shooting 5 weeks later to assess whether the additional handguns were associated with increases in the rate of firearm-related harms at the city level. METHODS: We use a two-stage modeling approach. First, we estimate excess handguns as the difference between actual handgun acquisitions, as recorded in California's Dealer Record of Sales, and expected acquisitions, as predicted by a seasonal autoregressive integrated moving-average (SARIMA) time series model. We use Poisson regression models to estimate the effect of city-level excess handgun purchasing on city-level changes in rates of firearm mortality and injury. RESULTS: We estimate there were 36,142 excess handguns acquired in California in the 11 weeks following the election (95% prediction interval: 22,780 to 49,505); the Sandy Hook shooting occurred in week 6. We find city-level purchasing spikes were associated with higher rates of firearm injury in the 52 weeks post-election: a relative rate of 1.044 firearm injuries for each excess handgun per 1,000 people (95% CI: 1.000 to 1.089). This amounts to approximately 290 (95% CI: 0 to 616) additional firearm injuries (roughly a 4% increase) in California over the year. We do not detect statistically significant associations for shorter time windows or for firearm mortality. CONCLUSION: This study provides evidence for an association between excess handgun acquisitions following high-profile events and firearm injury at the community level. This suggests that even marginal increases in handgun prevalence may be impactful.