Scouring a federal database of recorded deaths in the United States, researchers found "evidence of a spike in accidental firearm deaths to children exactly at the time of the increase in gun sales after Sandy Hook."
The bump in accidental deaths didn't look like a random blip: Researchers could find no jump of similar magnitude in any of the other time periods they searched. Further confirmation came from their statistical projections of the relationship between the number of guns in the U.S. and fatal gun accidents, which were a near-perfect match for the actual number of deaths.
Another piece of data further strengthened the argument that increased gun exposure boosted fatal gun accidents: When the researchers mapped the increases in accidental gun deaths recorded, they found them concentrated in states where the post-Sandy Hook spike in gun sales was very high.
"This is the pattern we would expect to see if those who purchase guns (and perhaps those who remove guns from storage) are more likely to succumb to accidents until those guns are stored in a safer environment," wrote the authors, Phillip B. Levine and Robin McKnight.
Levine and McKnight added that the findings support the passage and enforcement of safe gun-storage laws and underscore the value of having physicians counsel their patients about ways to reduce firearms injuries.
Stephen Teret, who directs Johns Hopkins University's Center for Law and the Public's Health, called the new study "a methodological tour de force."
But Teret, a pioneer in firearms injury research, said the researchers' suggestion that better gun-storage practices would drive down such injuries "represents a departure from their data."
"There still aren't good data that efforts to educate people to store guns more safely end up reducing gun deaths," Teret said. "And there are better ways to reduce gun deaths than to tell people to be more careful. Those include changing the design of these guns so kids can't operate them."
The study's results extend research that has found consistently higher rates of firearms deaths -- including suicide, homicide and accidents -- among those living in households with a gun or who have ready access to a gun. Higher rates of gun ownership across different states and countries also have been strongly linked to a higher incidence of firearms-related injury and death.
The new findings fit neatly with research published in October showing that, in the weeks following gun shows in Las Vegas, gun deaths and injuries in nearby California towns rose by 70 percent.