Mohsen Naghavi, MD, PhD

Just days removed from another public shooting that took 3 lives in Jacksonville, FL, a new study reports that the United States was among the 6 countries that contributed to the majority of all global firearm-related deaths in 2016.

An investigation from The Global Burden of Disease 2016 Injury Collaborators, which estimated per capita gun ownership to better evaluated global relationships between firearm access and related injury deaths, reported that an estimated 251,000 (95% CI; 195,000-276,000) people died from firearm injuries in 2016. The United States, along with Mexico, Brazil, Columbia, Venezuela, and Guetamala, accounted for 50.5% (95% UI; 42.2-54.8) of all deaths.

In their comparative analysis of estimates garnered from 1990, investigators estimated that annual global firearm injury deaths have increased 20%, from the 209,000 annual estimate set 26 years ago.

Led by Mohsen Naghavi, MD, PhD, of the Global Health Department at the Institute for Health Metrics and Evaluation, University of Washington, investigators sought to create a comprehensive assessment of firearm-related mortality patterns—set by cause, age, sex, and location—based on updated data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016).

Applying these discovered patterns to current discussion surrounding national firearm access is a clearly distinguished bridge.

“Comparative studies of the magnitude of firearm violence are rare but present an important opportunity to examine national, regional, and local patterns that may inform public health strategies,” investigators wrote. “Although national and regional assessments of firearm deaths are available, to our knowledge, no other assessment that evaluates firearm deaths among the 195 countries and territories included in this study has occurred.”

As part of their analysis, investigators assessed for the various causes of firearm injury death (homicide by firearm, suicide by firearm, and unintentional firearm death) on a global scale. They also estimated for per-country age-standardized mortality rates, percent change since 1990 in mortality rate, a five-star rating system for respective certification of firearm-related deaths, and in firearm ownership index scores.

In 2016, homicides were estimated to account for 64.1% (n = 161,000) of all firearm deaths, followed by suicide (67,500) and unintentional deaths (22,900). Since 1990, estimated annual firearm homicides had increased 37.6%, and suicide increased 5.9%. Unintentional deaths, however, decreased 18.2%.

Age-standardized mortality rate 100,000 individuals had actually decreased 0.9% since 1990, from 4.2 (95% UI; 3.5-4.7) to 3.4 (95% UI; 2.6-3.7 [P = .001]).

In the US, the age-standardized mortality rate per 100,000 similarly decreased 0.9% from 1990 to 2016 (13.6 vs 10.6 [P < .001]). However, estimated total annual firearm deaths increased 3.9% (35,800 vs 37,200). In 2016, US firearm suicides represented 35.3% of all global firearm suicides—despite the US just comprising 4.3% of the global population.

Though they were accredited with a five-star (out of 5) rating in firearm death certification, the US also scored the maximum in firearm access index. Using estimates from the 2007 Small Arms Survey and a proxy measure of the proportion of suicides for which a firearm was the lethal means, investigators created a 0-100 combined metric scale to configure country’s per capita access to firearms (with 100 being the maximum).

The US was not just the sole country to report a 100 access index score; it was the only country in the world to report a score above 50.

Investigators noted that, in Central American countries with high rates of firearm access and mortality, drug cartels, as well as the manufacture and sale of firearms and illegal trade from the US account for the increased rates. In fact, just a “comparatively small” stock of legal firearms is accounted for in these countries.

“Difficulties with accounting for illegal firearm ownership and the effect of trafficking in firearms on rates of violence in countries with otherwise strong firearm control legislation, may explain some of the variability found in the relationship between firearm availability and associated mortality, particularly for firearm homicide,” investigators wrote.

In a previous assessment of US-based firearm legislation, investigators note an association between restrictive laws on required background checks or permits and reductions in firearm homicide rates. In Central and South America, rates have been decreased by similar legislation, as well as firearm control acts, improved policing, and firearm buy-back programs.

“The hypothesis that differences in levels of violence between countries reflect the availability of firearms and the extent of firearm control at a national level is consistent with these findings, although more disaggregated data are needed to transfer the analysis to other settings,” investigators wrote.

In an essay accompanying the study, Frederick P. Rivara, MD, MPH, of the Departments of Pediatrics and Epidemiology, University of Washington, and colleagues call the prevalence of civilian access to firearms an “obvious candidate” for the explanation to global disparities in firearm injury deaths.

Adversely, these noted disparities may also help countries better learn how to reduce their rates.

“What can countries in the Americas learn from Japan and Singapore that might help reduce gun deaths?” Rivara asked. “To what extent have particular national laws contributed to prevention, and how transferrable are those laws to other countries with different cultures, political structures, and histories?”

That said, the US will need sustained action from governments involved in both research and policy to improve what Rivara called the “vast public health problem” laid out by the investigators’ findings.

The study, "Global Mortality From Firearms, 1990-2016," was published in JAMA on Tuesday.