Survey focusing on nearly 600,000 Californians shows that 12 out of every 100,000 are likely to get shot dead when living in a household with a handgun.
People who live with handgun owners are shot to death at a higher rate than those who don't have such weapons at home, a new study has said, despite most American gun owners saying they own firearms to protect themselves and their loved ones.
"We found zero evidence of any kind of protective effects" from living in a home with a handgun, said David Studdert, a Stanford University researcher who was the lead author of the Annals of Internal Medicine study released on Monday.
The study has several shortcomings. For example, the researchers said they could not determine which victims were killed by the handgun owners or with in-home weapons. They couldn't account for illegal guns and looked only at handguns, not rifles or other firearms.
The dataset also was limited to registered voters in California who were 21 and older. It's not clear that the findings are generalisable to the whole state, let alone to the rest of the country, the authors acknowledged.
But some outside experts said the work was well done, important and the largest research of its kind.
"I would call this a landmark study," said Cassandra Crifasi, a gun violence policy researcher at Johns Hopkins University.
"This contributes to our understanding of the potential causal relationship between guns in the home and homicides," she said.
California is unusual in that it offers gun ownership data and other information not obtainable in almost any other state. That allowed the researchers to follow millions of people over many years to try to better establish what happens when a person begins living in a home with a handgun, they said.
The study focused on nearly 600,000 Californians who did not own handguns but began living in homes with handguns between October 2004 and December 2016 — either because they started living with someone who owned one or because someone in their household bought one.
84% of victims are women
Separately, the researchers found that those who lived with handgun owners had a much higher rate of being fatally shot by a spouse or intimate partner. The vast majority of such victims — 84-percent — were women, they said.
The study was confined to California, but the risk is likely even greater in states with less stringent gun laws and where gun ownership is more common, Crifasi said.
Previous research estimated that nearly 3 percent of US adults became new gun owners between January 2019 and April 2021, which translates to about 7.5 million Americans. Of those, about 5.4 million previously lived in a home with no guns.
For decades, studies have shown that guns in the home raise the risk of violent death. Much of that work, including an earlier study by Studdert and his colleagues, focused on suicide.
The new study goes further in addressing the perception that handguns are still worthwhile because of the safety they provide against being murdered, some experts said.
"The reason people have guns in their home is for protection from strangers," said David Hemenway, director of Harvard University's Injury Control Research Center. "But what this is showing that having a gun in the home is bad for people in the home."