Women in America are shot to death by their current or former romantic partners with alarming regularity — once every 16 hours, as my colleague Jennifer Mascia has written.

New research published today in the American Journal of Epidemiology offers some clues into state laws that may help reduce those killings. The study found that states that place broader restrictions on who can purchase or own guns experience fewer intimate partner homicides.

Under federal law, people convicted of domestic violence misdemeanors are prevented from owning or purchasing a gun. But some states add an additional layer of protection: barring those convicted of a violent misdemeanor — no matter the relationship to the victim — from getting guns. At least 10 states require potential gun buyers to obtain a permit, and 29 states have laws to restrict gun access for people who have been served with domestic violence restraining orders. All of these measures are associated with fewer intimate partner homicides, researchers said.

“This study adds to that body of literature that suggests that gun restrictions can save lives, if we are restricting people who have shown that they are willing to use violence — and sometimes severe violence,” said April Zeoli, a professor of criminal justice at Michigan State University, and the paper’s lead author.  

To reach their findings, Zeoli and a team of public health researchers examined the effects of various state gun laws on intimate-partner homicide. They looked at data from 45 states during a 34-year period from 1980 through 2013.

They found that states with laws prohibiting those convicted of violent misdemeanors from buying guns had 23 percent fewer domestic violence deaths. In other words: states that made it harder for any violent person to buy a gun — even if that person did not have a criminal history of domestic abuse — saw reductions in intimate partner homicides.

Laws to prevent people who are subject to domestic violence restraining orders from purchasing or possessing guns were associated with a 9 percent reduction in intimate partner homicides.

Zeoli said the reduction was driven primarily by laws where restraining orders extended to dating partners, not just spouses. She noted that 50 percent of domestic violence homicides are carried out by dating partners.

“It doesn’t make sense to not include someone who is perpetrating the same kind of violence that a spouse might just because they’re not married,” she said.

She added that states with gun restrictions that extend to emergency restraining orders — not just those restraining orders served after a hearing before a judge — experienced fewer intimate partner homicides.

The researchers also found that permit-to-purchase laws — in which people are required to pass a background check and obtain a permit from a law enforcement agency in order to buy a gun — were associated with an 11 percent reduction in intimate partner homicides. At least 10 states, including Massachusetts and New York, have such laws on the books.

“Legislators have numerous gun bills in front of them every single year,” Zeoli said, “and they often don’t have the research evidence they need to figure out what the consequences of any gun bill will be.”

She said she hopes her data will be considered by policymakers as they think about ways to save lives.