Gun owners who carry guns outside their homes and stash them in their cars — or simply own lots of them — are more likely to have their guns stolen, according to a study published Monday in the journal Injury Epidemiology.

The study, by leading public health researchers at Harvard and Northeastern universities, is the first to delve into how different characteristics among gun owners can increase the risk of weapons theft. It comes as several cities have seen sharp jumps in gun theft reports, and as many states have watered down prohibitions on bringing guns in public spaces or using them against another person.

Many stolen guns are never recovered, but when they do resurface, it’s often in connection with a crime or in the hands of someone legally barred from possessing one. In February, a man in Leesburg, Florida, was arrested on charges he shot his wife and daughter with a stolen gun during a family argument. Last month in Sarasota, Florida, five teenagers were charged after a revolver stolen from an apartment days earlier was found on their middle school bus.

People who owned guns for protection or had carried a gun in the previous month were more than three times as likely to have experienced a theft in the last five years, the report concludes. People who owned six or more guns, stored their guns loaded or unlocked — or kept guns in their vehicles — were more than twice as likely to have had their weapons stolen.

“There may be something about people wanting easy access to guns that makes them more susceptible to the theft of their guns,” said Deborah Azrael, a researcher at the Harvard School of Public Health and one of the study’s authors.

Despite the public safety risks, most states have failed to impose storage requirements that would make it harder for a thief to take a gun. An analysis by The Trace of police records from more than 100 large cities and counties in the United States found at least 326,500 guns had been reported lost or stolen between 2006 and 2015.

The study draws from a landmark 2015 survey of more than 1,600 gun owners by many of the same authors. That study found that number of the guns had grown increasingly concentrated and that self-defense had replaced hunting as the primary motivation for gun ownership.

The new study also found that non-white gun owners were at nearly three times the risk of having a firearm stolen, though the authors noted that non-whites as a population are more often victims of burglaries and robberies in general.

Two-thirds of gun thefts occurred in the South, where firearm restrictions are generally more permissive, even though less than half — 43 percent — of all gun owners in the United States live there, the study found. The Northeast registered the lowest rates of gun theft.

The findings validate the warnings of law enforcement officials in several major cities where reports of gun thefts are increasing.

“Most of our criminals, they go out each and every night hunting for guns, and the easiest way to get them is out of people’s cars,” said Sgt. Warren Pickard of the Atlanta Police Department. “We’re finding that a majority of stolen guns that are getting in the hands of criminals and being used to commit crimes were stolen out of vehicles.”

The study’s authors previously found that about 2.5 percent of gun owners had had a gun stolen in the previous five years, resulting in an estimate of between 300,000 and 600,000 guns stolen in the United States annually. The study published Monday refines that estimate to 380,000, a number that while on the lower end of the previous range still highlights theft as a major source of guns for the illegal market, the authors wrote.

The study does not evaluate the connection between theft and state gun carrying laws, but routinely taking a firearm outside the home seems to increase the odds that a weapon will be left in an unsecure place, like a vehicle, and stolen.

In March, Arkansas became the latest state to open up college campuses to concealed-carry permit holders. Kansas, Mississippi, and Missouri are among the most recent states to do away with permitting requirements for carrying concealed weapons altogether.

Second Amendment rights supporters argue that gun owners are forced to leave their weapons in vulnerable locations, like their cars, because of rules limiting where they can carry them. That is what happened in 2015 to John Gioffre, a real estate investor who left his .40-caliber Glock G27 pistol in the center console of his pickup truck because the Best Western Plus motel where he was staying in Austin, Texas, banned firearms. When he returned to his truck the next morning, the passenger-side window was shattered, and his gun was missing.

“That is insane,” said Gioffre, 27, after The Trace told him about the estimated number of annual gun thefts. “You can’t bring guns into certain situations for various reasons, but if you leave them, they are getting into the hands of people we don’t want them in anyways. So it’s kind of like a double-edged sword.”

The authors of the study said gun owners who own many firearms may be at an increased chance of theft because they make more attractive targets for burglars.

They suggested that gun thefts could be curtailed with changes in laws that require guns to be locked, as well as change in social norms surrounding gun storage.

According to the Law Center to Prevent Gun Violence, Massachusetts is the only state that generally requires gun owners to keep all their firearms locked. Critics of such laws say they prevent gun owners from accessing their weapons in an emergency.

Some law enforcement officials and gun violence-prevention advocates contend that laws encouraging people to carry guns outside their homes increases the risk that thieves will find and take them. People who keep a gun in their waistband when they are, say, out running errands could forget to bring it inside after parking their car at home.

Gioffre said he has a concealed-carry permit and often keeps his gun on hand because it makes him feel safer. But the theft of his Glock in 2015 prompted him to take greater precautions, including spending $200 on a safe that attaches to his truck’s center console.

“I was pretty willy-nilly with it,” he said about his gun. “If anyone broke into my car, they would have stolen my gun. Now, I’m a lot more conscious about it.”