Early life lead exposure from private well water increases juvenile delinquency risk among US teens.

Early life exposure to environmental lead (Pb) has been linked to decreased IQ, behavior problems, lower lifetime earnings, and increased criminal activity. Beginning in the 1970s, limits on Pb in paint, gasoline, food cans, and regulated water utilities sharply curtailed US environmental Pb exposure. Nonetheless, hundreds of thousands of US children remain at risk. This study reports on how unregulated private well water is an underrecognized Pb exposure source that is associated with an increased risk of teenage juvenile delinquency. We build a longitudinal dataset linking blood Pb measurements for 13,580 children under age 6 to their drinking water source, individual- and neighborhood-level demographics, and reported juvenile delinquency records. We estimate how early life Pb exposure from private well water influences reported delinquency. On average, children in homes with unregulated private wells had 11% higher blood Pb than those with community water service. This higher blood Pb was significantly associated with reported delinquency. Compared to children with community water service, those relying on private wells had a 21% (95% CI: 5 to 40%) higher risk of being reported for any delinquency and a 38% (95% CI: 10 to 73%) increased risk of being reported for serious delinquency after age 14. These results suggest that there could be substantial but as-yet-unrecognized social benefits from intervention programs to prevent children's exposure to Pb from private wells, on which 13% of the US population relies.

Children drinking private well water have higher blood lead than those with city water.

Although the Flint, Michigan, water crisis renewed concerns about lead (Pb) in city drinking water, little attention has been paid to Pb in private wells, which provide drinking water for 13% of the US population. This study evaluates the risk of Pb exposure in children in households relying on private wells. It is based on a curated dataset of blood Pb records from 59,483 North Carolina children matched with household water source information. We analyze the dataset for statistical associations between children's blood Pb and household drinking water source. The analysis shows that children in homes relying on private wells have 25% increased odds (95% CI 6.2 to 48%, P < 0.01) of elevated blood Pb, compared with children in houses served by a community water system that is regulated under the Safe Drinking Water Act. This increased Pb exposure is likely a result of corrosion of household plumbing and well components, because homes relying on private wells rarely treat their water to prevent corrosion. In contrast, corrosion control is required in regulated community water systems. These findings highlight the need for targeted outreach to prevent Pb exposure for the 42.5 million Americans depending on private wells for their drinking water.

The emerging infrastructure of US firearms injury data.

For every fatal shooting in the United States, detailed information from reports of coroners or medical examiners, police departments, and other sources is recorded in the National Violent Death Reporting System. There is no such system in place for nonfatal shootings, which far outnumber fatalities. Hospital data systems are in place that could, with some improvements, provide access to reliable local, state and national estimates of firearm injuries. Such estimates are possible because most firearms injuries are treated in hospitals, and hospitals routinely assign "external cause of injury" codes to all injury encounters. Federal health agencies supervise a number of data systems that centralize hospital data. Challenges currently being addressed are public access, timeliness, and accuracy of coding of intent. (Hospitals misclassify many firearm assaults as accidents.) Law enforcement agencies provide detailed data on shootings in criminal circumstances, including shootings that are not treated in a hospital. The FBI's Uniform Crime Reports (UCR) system aggregates data from agencies. The FBI instituted a radical reform of this system beginning in 2021, resulting in a sharp agency participation drop that prevents valid national estimates. The reform requires agencies to report incident-level data instead of summary counts, which is all that was required for the previous 90 years. There are ongoing efforts to increase participation in the new system and restore its former status as the leading source of national crime estimates. In the meantime, data on nonfatal gunshot cases are available from a number of police departments. We discuss additional reforms needed to generate timely, accurate, publicly accessible data from hospitals and police.

Gunshot-victim cooperation with police investigations: Results from the Chicago Inmate Survey.

Just one in ten nonfatal shootings in Chicago lead to an arrest. Unlike in fatal cases, gunshot victims who survive can often provide information of use in the police investigation. Nonetheless, nonfatal shooting cases in Chicago and elsewhere have much lower arrest rates than fatal cases, in part because most victims do not cooperate. We use data from the Chicago Inmate Survey (CIS) to analyze the potential value that gunshot-victim cooperation could have for increasing arrest rates. Half of CIS respondents reported they had been shot before. Very few cooperated with police investigations of these shootings, although at least half of them could have provided useful information. In fact, victims were more likely to speak with the police when they did not have any information on their shooter. Respondents explained their choice not to cooperate by reference to "street codes" against snitching, mistrust of the police, and the desire to retaliate against the shooter personally. If more shooting victims could be persuaded to cooperate, the police could solve more cases and hence be more effective in curtailing gun violence.

Underground Gun Markets and the Flow of Illegal Guns into the Bronx and Brooklyn: A Mixed Methods Analysis.

New York City (NYC) has experienced large reductions in violent crime over the last two decades, but gun-related violence continues to pose a threat to public safety. Despite strong gun laws, high-risk individuals in NYC neighborhoods are unfortunately still able to access and misuse firearms. This research analyzes NYC's underground gun market by closely examining the flow of guns into the two boroughs where gun violence and crime gun recoveries are most prevalent: the Bronx and Brooklyn. A mixed methods approach is utilized that consists of an assessment of firearms trace data and in-depth interviews with individuals considered to be at high risk for involvement in gun violence. Findings suggest that guns recovered in the Bronx and Brooklyn were significantly more likely to originate in states with less restrictive gun laws and more likely to have changed ownership in unregulated transactions relative to guns recovered elsewhere in NYC. Interviews revealed three primary avenues for illegal guns reaching Bronx and Brooklyn neighborhoods: high-volume gun brokers, middlemen, and individuals who make episodic low-level acquisitions from straw purchasers in other states. No subjects identified theft as a meaningful source of crime guns.

The Last Link: from Gun Acquisition to Criminal Use.

Guns that are used in crime and recovered by the police typically have changed hands often since first retail sale and are quite old. While there is an extensive literature on "time to crime" for guns, defined as the elapsed time from first retail sale to known use in a crime, there is little information available on the duration of the "last link"-the elapsed time from the transaction that actually provided the offender with the gun in question. In this article, we use data from the new Chicago Inmate Survey (CIS) to estimate the duration of the last link. The median is just 2 months. Many of the gun-involved respondents to the CIS (42%) did not have any gun 6 months prior to their arrest for the current crime. The CIS respondents were almost all barred from purchasing a gun from a gun store because of their prior criminal record-as a result, their guns were obtained by illegal transactions with friends, relatives, and the underground market. We conclude that more effective enforcement of the laws governing gun transactions may have a quick and pervasive effect on gun use in crime.

Gun Theft and Crime.

Some law enforcement officials and other observers have asserted that theft is the primary source of guns to crime. In fact, the role of theft in supplying the guns used in robbery, assault, and murder is unknown, and current evidence provides little guidance about whether an effective program to reduce gun theft would reduce gun violence. The current article analyzes publicly available national data on gun theft together with a unique data set for Chicago. The results tend to support a conclusion that stolen guns play only a minor role in crime. First, publicly available data are used to calculate that thefts are only about 1% of all gun transactions nationwide. Second, an analysis of original data from Chicago demonstrates that less than 3% of crime guns recovered by the police have been reported stolen to the Chicago Police Department (CPD). If a gun is reported stolen, there is a 20% chance that it will be recovered, usually in conjunction with an arrest for illegal carrying. Less than half of those picked up with a stolen gun have a criminal record that includes violent offenses. Third, results from surveys of convicted criminals, both nationally and in Chicago, suggest that it is rare for respondents to have stolen the gun used in their most recent crime. The data on which these results are based have various shortcomings. A research agenda is proposed that would provide more certainty about the role of theft.

Suicide and Additional Homicides Associated with Intimate Partner Homicide: North Carolina 2004-2013.

Intimate partner homicide (IPH) is a critical public health and safety issue in the USA. In this study, we determine the prevalence and correlates of perpetrator suicide and additional homicides following intimate partner homicide (IPH) in a large, diverse state with high quality data. We extract IPHs from the North Carolina Violent Death Reporting System for 2004-2013 and identify suicides and other homicides that were part of the same incidents. We analyze the likelihood (in odds ration form) of perpetrator suicide and additional homicides using logistic regression analysis. Almost all IPH-suicide cases were by men with guns (86.6%). Almost one-half of IPHs committed by men with guns ended with suicide. Male-perpetrated IPH incidents averaged 1.58 deaths if a gun was used, and 1.14 deaths otherwise. It is well-known that gun access increases the chance that a violent domestic relationship will end in death. The current findings demonstrate that gun IPH is often coupled with additional killings. As suicidal batterers will not be deterred from IPH by threat of punishment, the results underline the importance of preemption by limiting batterers' access to guns.

Constant Lethality of Gunshot Injuries From Firearm Assault: United States, 2003-2012.

OBJECTIVES: To investigate the validity of the apparent downward trend in the national case-fatality rate for gunshot wounds from assault. METHODS: We reanalyzed the estimated annual number of nonfatal firearm injuries the National Electronic Injury Surveillance System reported from 2003 to 2012. We adjusted the estimates for discontinuities created by the substitution of 1 hospital for another in the sample and for a downward trend in the percentage of gunshot injuries classified as "unknown circumstance." Firearm homicide data are from the Centers for Disease Control and Prevention, Web-based Injury Statistics Query and Reporting System. RESULTS: The unadjusted National Electronic Injury Surveillance System estimate increased by 49%, yielding a decline in the case-fatality rate from 25% to 18%. Our adjustments eliminated these trends; the case-fatality rate was 22% in both 2003 and 2012. CONCLUSIONS: With reasonable adjustments, the trend in nonfatal injuries from interpersonal firearms assault tracks the flat trend in firearms homicides, suggesting that there was no increase in firearms violence during this period. The case-fatality rate did not change, and trauma care improvements did not influence the firearms homicide trend.

Regulating Assault Weapons and Large-Capacity Magazines for Ammunition.

This Viewpoint discusses the history and current status of assault weapons bans in the US, provides evidence of the potential effectiveness of a US ban and information regarding the Australian ban, and explores potential next steps.

Epidemiologic Evidence to Guide the Understanding and Prevention of Gun Violence.

Gunfire from assaults, suicides, and unintentional shootings exacts an enormous burden on public health globally. The epidemiologic reviews in this special issue enhance our understanding of various forms of gun violence, inform interventions, and help chart directions for future research. The available science, however, is limited to answer many important questions necessary for mounting successful efforts to reduce gun violence. Certain data are lacking, and there are numerous analytical challenges to deriving unbiased estimates of policy impacts. Significant investments in research over the long term are warranted to answer questions central to successful prevention of gun violence.

Sources of guns to dangerous people: what we learn by asking them.

Gun violence exacts a lethal toll on public health. This paper focuses on reducing access to firearms by dangerous offenders, contributing original empirical data on the gun transactions that arm offenders in Chicago. Conducted in the fall of 2013, analysis of an open-ended survey of 99 inmates of Cook County Jail focuses on a subset of violence-prone individuals with the goal of improving law enforcement actions. Among our principal findings: *Our respondents (adult offenders living in Chicago or nearby) obtain most of their guns from their social network of personal connections. Rarely is the proximate source either direct purchase from a gun store, or theft. *Only about 60% of guns in the possession of respondents were obtained by purchase or trade. Other common arrangements include sharing guns and holding guns for others. *About one in seven respondents report selling guns, but in only a few cases as a regular source of income. *Gangs continue to play some role in Chicago in organizing gun buys and in distributing guns to members as needed. *The Chicago Police Department has a considerable effect on the workings of the underground gun market through deterrence. Transactions with strangers and less-trusted associates are limited by concerns over arrest risk (if the buyer should happen to be an undercover officer or a snitch), and about being caught with a "dirty" gun (one that has been fired in a crime).

Sibling Spillovers: Having an Academically Successful Older Sibling May be More Important for Children in Disadvantaged Families.

This paper examines causal sibling spillover effects among students from different family backgrounds in elementary and middle school. Family backgrounds are captured by race, household structure, mothers' educational attainment, and school poverty. Exploiting discontinuities in school starting age created by North Carolina school-entry laws, we adopt a quasi-experimental approach and compare test scores of public school students whose older siblings were born shortly before and after the school-entry cutoff date. We find that individuals whose older siblings were born shortly after the school-entry cutoff date have significantly higher test scores in middle school, and that this positive spillover effect is particularly strong in disadvantaged families. We estimate that the spillover effect accounts for approximately one third of observed statistical associations in test scores between siblings, and the magnitude is much larger for disadvantaged families. Our results suggest that spillover effects from older to younger siblings may lead to greater divergence in academic outcomes and economic inequality between families.

Interpreting the empirical evidence on illegal gun market dynamics.

Thousands of Americans are killed by gunfire each year, and hundreds of thousands more are injured or threatened with guns in robberies and assaults. The burden of gun violence in urban areas is particularly high. Critics suggest that the results of firearm trace data and gun trafficking investigation studies cannot be used to understand the illegal supply of guns to criminals and, therefore, that regulatory and enforcement efforts designed to disrupt illegal firearms markets are futile in addressing criminal access to firearms. In this paper, we present new data to address three key arguments used by skeptics to undermine research on illegal gun market dynamics. We find that criminals rely upon a diverse set of illegal diversion pathways to acquire guns, gun traffickers usually divert small numbers of guns, newer guns are diverted through close-to-retail diversions from legal firearms commerce, and that a diverse set of gun trafficking indicators are needed to identify and shut down gun trafficking pathways.

Cigarette taxes and youth smoking: new evidence from national, state, and local Youth Risk Behavior Surveys.

Several studies have examined the effects of state cigarette tax increases on youth substance use over the 1990s, with most--but not all--finding that higher taxes reduce youth consumption of tobacco. We advance the literature by using data from the 1991 to 2005 waves of the national Youth Risk Behavior Surveys (YRBS), providing information on over 100,000 high school age youths. We also are the first to make use of hundreds of independently fielded state and local versions of the YRBS, reflecting data from over 750,000 youths. Importantly, these data are to our knowledge the only sources of relevant information on youth smoking that were explicitly designed to be representative of the sampled state or locality. We estimate two-way fixed effects models of the effect of state cigarette taxes on youth smoking, controlling for survey demographics and area and year fixed effects. Our most consistent finding is that--contrary to some recent research--the large state tobacco tax increases of the past 15 years were associated with significant reductions in smoking participation and frequent smoking by youths. Our price elasticity estimates for smoking participation by high school youths are generally smaller than previous cross-sectional approaches but are similar to recent quasi-experimental estimates.

The Association of Firearm Caliber With Likelihood of Death From Gunshot Injury in Criminal Assaults.

Importance: A foundational issue in firearms policy has been whether the type of weapon used in an assault affects the likelihood of death. Objective: To determine whether the likelihood of death from gunshot wounds inflicted in criminal assaults is associated with the power of the assailant's firearm as indicated by its caliber. Design, Setting, and Participants: Cross-sectional study with multivariate analysis of data on shooting cases extracted by the authors from police investigation files for assaults that took place in Boston, Massachusetts, between January 1, 2010, and December 31, 2014. These data were analyzed between October 1, 2017, and February 18, 2018. In all cases the victim sustained 1 or more gunshot wounds in circumstances that the Boston Police Department deemed criminal. The working sample included all 221 gun homicides and a stratified random sample of 300 nonfatal cases drawn from the 1012 that occurred during the 5-year period. Seven nonfatal cases were omitted because they had been misclassified. Exposures: The primary source of variation was the caliber of the firearm used to shoot the victim. Main Outcomes and Measures: Whether the victim died from the gunshot wound(s). Results: The final sample of 511 gunshot victims and survivors (n = 220 fatal; n = 291 nonfatal) was predominantly male (n = 470 [92.2%]), black (n = 413 [80.8%]) or Hispanic (n = 69 [13.5%]), and young (mean [SD] age, 26.8 [9.4] years). Police investigations determined firearm caliber in 184 nonfatal cases (63.2%) and 183 fatal cases (83.2%). These 367 cases were divided into 3 groups by caliber: small (.22, .25, and .32), medium (.38, .380, and 9 mm), or large (.357 magnum, .40, .44 magnum, .45, 10 mm, and 7.62 × 39 mm). Firearm caliber had no systematic association with the number of wounds, the location of wounds, circumstances of the assault, or victim characteristics, as demonstrated by χ2 tests of each cluster of variables and by a comprehensive multinomial logit analysis. A logit analysis of the likelihood of death found that compared with small-caliber cases, medium caliber had an odds ratio of 2.25 (95% CI, 1.37-3.70; P = .001) and large caliber had an odds ratio of 4.54 (95% CI, 2.37-8.70; P < .001). Based on a simulation using the logit equation, replacing the medium- and large-caliber guns with small-caliber guns would have reduced gun homicides by 39.5%. Conclusions and Relevance: Firearms caliber was associated with the likelihood of death from gunshot wounds in criminal assault. Shootings with larger-caliber handguns were more deadly but no more sustained or accurate than shootings with smaller-caliber handguns. This conclusion is of direct relevance to the design of gun policy.