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A call for research to address gun violence

Newtown. Orlando. Las Vegas. Parkland. The names of cities and towns impacted by mass shootings, now synonymous with tragedy, have come to symbolize our nation’s gun violence dilemma.

Among high-income countries, gun violence is a uniquely American crisis. In 2016, more than 39,000 people were killed by firearms in the United States.1 At 3.85 per 100,000 people, the rate of death by firearms in the U.S. is more than eight times Canada’s and 55 times the United Kingdom’s.2 Nearly one-third of all mass shootings that have occurred globally in the past five decades happened in the United States.3 Potential solutions to this problem are complex and highly politicized in a country that is one of just three worldwide to protect the right to bear arms in its constitution.4

Several studies presented at the 2018 Clinical Congress of the American College of Surgeons suggest that gun laws may only be part of solution to reducing gun deaths. Researchers say unbiased research and a better understanding of the social factors impacting gun violence are urgently needed to identify the most effective steps.

A Recipe for Mass Murder: The Social Factors of Gun Violence

Americans own far more firearms than people in other high-income countries. Of the 857 million civilian firearms worldwide, it’s estimated half are owned by Americans. That equates to 120 for every 100 people.5 In total, Americans own about 393 million firearms, far more than the 71 million owned in India, 50 million in China, or 17 million in Brazil.

The deaths of 20 children and six adults at Sandy Hook Elementary, in Newtown, CT, six years ago sparked a renewed push for stricter gun laws in the United States. Two years after the tragedy, a report by the Connecticut State Attorney’s office painted a more complex picture of the incident. It cited access to weapons, as well as the gunman’s severe and deteriorating mental health and atypical preoccupation with violence, as important factors that “proved a recipe for mass murder.”6

Studies since then have pointed to many social factors that likely contribute to gun violence. One study at the 2018 Clinical Congress by surgeons from the University of Toledo, OH and Bowling Green State University, Bowling Green, OH identified 155 communities that had experienced a mass shooting involving four or more people between 2005–2018. Then the researchers reviewed 180 measures of social determinants of health in counties where the shooting occurred.

“We definitely found some of the factors surprising, particularly related to the legal aspects,” said Stephen Markowiak, MD, of the University of Toledo. “The states that were more urban, and anecdotally more liberal, had both stronger gun laws, but also more instances of mass shooting events.”

After controlling for the urban-rural distribution, researchers found most gun control laws were not associated with fewer gun deaths. In fact, communities with strict gun laws had a 1.5 times greater risk of a mass shooting than those without strict laws. Two exceptions were states that require reporting of significant mental illness to their background check systems, and those that restrict open carry of firearms. These states had fewer mass shootings.

Those at lower risk of a mass shooting, according to researchers, also had more than twice as many mental health professionals per capita. Cities most likely to have a mass shooting were less social, had populations with less leisure time and physical activity, were more likely to experience overcrowding and had higher income inequality.

While urbanization and economic issues are challenging to address, healthy socialization habits, public recreation areas, and a focus on inequality are important opportunities for communities to act on, researchers said.

“Those are the safe answers to gun violence because they have little to no downside and they solve other health problems too,” Dr. Markowiak said.

The Mixed Impact of Gun Laws

A second study at Clinical Congress presented by surgeons from Stanford University, Stanford, CA, looked at the impact of child-access prevention (CAP) laws – which require gun owners to safely store firearms and impose liabilities when a minor gains access to a gun – on the pediatric firearm deaths. Using mortality data, 2014 Brady scores (used to quantify the stringency of state gun regulations), and child-access prevention laws as of 2014, the study identified 2,715 pediatric firearm deaths. Nearly two-thirds were homicides and one-third were suicides.

“States with lenient laws are having their children die at alarmingly greater rates. Those with lenient CAP legislation had a pediatric firearm mortality rate nearly double that of states with strict legislation,” Dr. Chao said. “The stringency of a neighboring state’s firearm legislation is also associated with pediatric firearm mortality rates.” These correlations remained significant even after controlling for a state’s poverty, unemployment, and educational attainment rates.

“We also found that laws specific to preventing children from accessing firearms, such as laws that mandate locking mechanisms or storage requirements, are associated with decreased firearm suicide rates among children. States without CAP laws had pediatric firearm suicide rates more than four times as high as those with CAP laws,” she said.

While CAP laws may help prevent gun deaths in children, another study presented at the 2018 Clinical Congress found lenient concealed carry legislation likely does not increase the rate of gun deaths. A team from Virginia Tech Carilion School of Medicine, Roanoke, VA and the Mayo Clinic, Rochester, MN, reviewed 30 years of violent crime and homicide data and state-level concealed carry legislation. The study found no significant association between shifts from prohibited to unrestricted carry and homicide and violent crime rates.

“We found no relationship between the type of concealed carry process or the general permissiveness of the process and increased rates of homicide or other violent crime,” said Mark Hamill, MD, FACS, Virginia Tech Carilion School of Medicine. “There has been a trend in all states over the past 30 years toward less restrictive concealed carry. Every state and the District of Columbia now has some legislation in place to allow for some form of civilian concealed carry. Changes to concealed carry legislation likely won’t reduce firearm violence.”

The study presented here builds on a previous study the same team presented at the 2018 American Association for the Surgery of Trauma (AAST) meeting in September. That study looked at associations between concealed carry legislation and the rate of firearm suicides, and did find an association.

“We found a statistically significant increase in firearm suicides when you have less restrictive concealed carry legislation. There was a trend in overall suicides also,” Dr. Hamill said. “It’s still a relatively rare event compared to the number of people who own firearms.”

Finding a Solution with Unbiased Research

An important part of the solution, Dr. Hamill says, is not restricting legal gun ownership but keeping guns out of the hands of those looking to commit a crime. Dr. Hamill approaches his views on gun violence from a unique perspective. He began his career as a patrol officer in Brooklyn, NY in the 1990s, in one of the city’s most violent precincts. The year before he left the police department to begin medical school his precinct experienced 79 homicides and 350 shootings.  

“As a police officer, I saw that it’s not the people who legally own firearms who are the problem. It’s the people who use firearms for nefarious purposes that are the problem. So how do we keep the guns out of those hands?” he said. “We need to pursue people who fail background checks. We need to pursue straw purchases, where someone intentionally purchases a gun for someone who is disqualified. These laws aren’t consistently enforced.”

Unbiased research also is urgently needed to identify solutions that will bridge the gap between gun ownership and gun safety, Dr. Hamill says.

“Any policy decisions need to be based on high-quality, unbiased research,” Dr. Hamill said. “It should be the same kind of evidence we would require to make clinical care decisions. We shouldn’t accept biased research. We shouldn’t accept lower-quality evidence to make policy decisions than we would to take care of our own patients.”

Dr. Markowiak also pointed to the need for more research. “What we really proved with our study is that these events can be studied in a scientific sense, and done from an apolitical framework,” he said. “Great harm has been done to our nation by legally restricting the CDC and the Bureau of Alcohol, Tobacco, and Firearms from doing research on gun-related violence.”


  1. “Six countries in the Americas account for half of all firearm deaths.” Institute for Health Metrics and Evaluation. http://www.healthdata.org/news-release/six-countries-americas-account-half-all-firearm-deaths Aug. 28, 2018. Accessed Oct. 9, 2018.
  2. “Six countries in the Americas account for half of all firearm deaths.” Institute for Health Metrics and Evaluation. http://www.healthdata.org/news-release/six-countries-americas-account-half-all-firearm-deaths Aug. 28, 2018. Accessed Oct. 9, 2018.
  3. Lankford, University of Alabama, 2016. https://www.cnn.com/2017/10/03/americas/us-gun-statistics/index.html
  4. McCormick, Ty. “How many countries have gun rights enshrined in their constitutions?” Foreign Policy. https://foreignpolicy.com/2013/04/05/how-many-countries-have-gun-rights-enshrined-in-their-constitutions/ Apr. 5, 2013. Accessed Oct. 9, 2018.
  5. Karp, Aaron. “Estimating Global Civilian-Held Firearm Numbers.” Small Arms Survey. http://www.smallarmssurvey.org/fileadmin/docs/T-Briefing-Papers/SAS-BP-Civilian-Firearms-Numbers.pdf June 2, 2018. Accessed Oct. 9, 2018.
  6. “Shooting at Sandy Hook Elementary School.” Report to the Office of the Child Advocate. State of Connecticut. http://www.ct.gov/oca/lib/oca/sandyhook11212014.pdf Nov. 21, 2014. Accessed Oct. 9, 2018.