Gun laws in neighboring states affect state gun deaths, new evidence

Weaker gun laws in neighboring states appear to increase gun deaths in adjoining states, and strong gun laws may be negated by more permissive laws among neighboring states, according to the American Journal of Preventive Medicine

Ann Arbor, September 14, 2020

New research from the University of Alabama at Birmingham (UAB) shows that gun laws in neighboring states have an effect on gun death rates in adjoining states. In findings published in the American Journal of Preventive Medicine, published by Elsevier, weaker firearm laws in neighboring states correlated with more firearm deaths within a state. This is useful information for state policymakers who sometimes have to justify and defend the need for firearm laws in their state.

“Although stronger state gun policies were associated with decreased firearm deaths, the presence of permissive neighboring states undermined this protective effect,” said lead investigator Bisakha Sen, PhD, Blue Cross Blue Shield Endowed Chair in Health Economics, Department of Health Care Organization and Policy in the UAB School of Public Health, Birmingham, AL, USA. “Specifically, higher policy differences across states were associated with increased rates of total firearm deaths, suicides, and homicides, although results were statistically stronger for suicide than homicide.”

The study examined 578,022 firearm deaths during the 2000 to 2017 study period. The total number of firearm-related deaths by state was extracted from the Web-based Injury Statistics Query and Reporting System of the Centers for Disease Control and Prevention, including deaths from all intent, homicide, and suicide.

The investigators identified four categories of laws that had the potential to impact interstate movement of firearms and firearm-related mortality: background checks; dealer regulations; buyer regulations; and gun trafficking laws. They further assessed the total number of laws a state had within each category.

“A higher count of a state’s firearm laws was associated with fewer total firearm deaths, female firearm deaths, male firearm deaths, firearm homicide, and firearm suicide,” explained Ye Liu, MD, first author on the study and a doctoral student in the Department of Health Care Organization and Policy at UAB, who developed the empirical framework under Dr. Sen’s guidance. “Having adjacent states with fewer laws appeared to increase firearm deaths of the state.”

Dr. Sen’s team reports that failing to account for weaker firearm laws in neighboring states made it falsely appear that the own states’ laws were about 20 percent less effective in reducing firearm deaths than they actually were.

Heatmap of mean between-state law difference of 48 contiguous states of the US for 2000 and 2017, in quartiles. Deeper red indicates greater difference in the numbers of firearm laws between a state and its neighboring states that are more lenient in gun control (A: 2000; B: 2017). Laws including: (1) background checks, (2) dealer regulations, (3) buyer regulations; and (4) gun trafficking laws (Credit: “Neighbors Do Matter: Between-State Firearm Laws and State Firearm-Related Deaths in the US, 2000–2017,” by Ye Liu, MD, MPH, Michael Siegel, MD, MPH, and Bisakha Sen, PhD).

Dr. Sen’s team further reports that for each increase of 1 in the between-state law or policy differences, indicating more lax policies in a neighboring state, the incidence rate increased 2.5 percent for firearm homicide, 1.6 percent for total firearm-related deaths, 1.7 percent for female firearm deaths, 1.6 percent for male firearm deaths, and 0.6 percent for firearm suicide.

“This study adds to the growing literature emphasizing the role played by neighboring states’ firearm regulations in addition to own-state firearm regulations in firearm deaths,” Dr. Sen noted. “Failing to account for neighboring states with weaker laws can, in some instances, make a state’s own regulations appear less effective in reducing firearm deaths. The study suggests that without cooperative legislative actions in neighboring states, efforts in one state to strengthen firearm legislation and prevent firearm deaths may be undermined. Federal gun regulations may be particularly useful because they affect all states.”

This study also emphasizes the importance of state leaders “reaching across the state border” and trying to foster cooperative legislative actions with neighboring states, as well as the importance of federal gun-policy legislation.

“I think the main message of this study is that in order to solve a nationwide problem we need to think of a nationwide or at least a regional-level (i.e., multistate) approach, like we may also need for the COVID-19 pandemic,” added Dr. Liu. “An ‘each state on its own’ approach is ultimately inadequate to address one of the biggest public health challenges in this country.”


Notes for editors
The article is“Neighbors Do Matter: Between-State Firearm Laws and State Firearm-Related Deaths in the U.S., 2000–2017,” by Ye Liu, MD, MPH, Michael Siegel, MD, MPH, and Bisakha Sen, PhD ( It appears online in advance of the American Journal of Preventive Medicine, volume 59, issue 5 (November 2020) published by Elsevier.

This article is openly available at

Full text of this article is also available to credentialed journalists upon request; contact Jillian B. Morgan at +1 734 936 1590 or Journalists wishing to interview the authors should contact the UAB Office of Public Relations: Bob Shepard at +1 205 410 0915; or Adam Pope at +1 205 410 1353;

About the American Journal of Preventive Medicine
The American Journal of Preventive Medicine is the official journal of the American College of Preventive Medicine and the Association for Prevention Teaching and Research. It publishes articles in the areas of prevention research, teaching, practice and policy. Original research is published on interventions aimed at the prevention of chronic and acute disease and the promotion of individual and community health. The journal features papers that address the primary and secondary prevention of important clinical, behavioral and public health issues such as injury and violence, infectious disease, women's health, smoking, sedentary behaviors and physical activity, nutrition, diabetes, obesity, and alcohol and drug abuse. Papers also address educational initiatives aimed at improving the ability of health professionals to provide effective clinical prevention and public health services. The journal also publishes official policy statements from the two co-sponsoring organizations, health services research pertinent to prevention and public health, review articles, media reviews, and editorials.

About Elsevier
Elsevier is a global information analytics business that helps scientists and clinicians to find new answers, reshape human knowledge, and tackle the most urgent human crises. For 140 years, we have partnered with the research world to curate and verify scientific knowledge. Today, we’re committed to bringing that rigor to a new generation of platforms. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, SciVal, ClinicalKey and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, 39,000 e-book titles and many iconic reference works, including Gray's Anatomy. Elsevier is part of RELX, a global provider of information-based analytics and decision tools for professional and business customers.

Media contact
Jillian B. Morgan, MPH, Managing Editor
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