Rates of intimate-partner homicide are lower in states that require people served with domestic-violence restraining orders to surrender their guns, a study published today in the Annals of Internal Medicine concludes.

The study, from researchers at five different institutions, found that intimate-partner homicide rates are 9.7 percent lower on average in the 14 states with gun-surrender laws than in the other 36 states. Firearm-specific homicide rates are 14 percent lower in those states.

Victims of intimate-partner homicide — like Meredith Hight, who was shot to death by her estranged husband in last week’s mass shooting in Plano, Texas — are overwhelmingly female, and more than half are killed with firearms. More than 380 people have been killed by their intimate partners in domestic-violence-related shootings in 2017, according to the Gun Violence Archive.

A growing number of states have attempted to fill gaps in federal law by passing measures to curb domestic-violence offenders’ access to guns. Among these laws, only those that explicitly require subjects of domestic-violence restraining orders to surrender the guns in their possession — and give law enforcement officials the authority to confiscate guns — are associated with a statistically significant reduction in intimate-partner homicide rates, according to the study.

Michael Siegel, a professor at Boston University’s School of Public Health and senior author of the report, said in an email that the message to policymakers is clear. “Laws must explicitly require that those high risk individuals surrender firearms already in their possession,” he wrote.

Siegel cautioned that the study is limited by the relatively small number of states that have passed each type of law, and noted that apparent lack of impact of other laws could actually be chalked up to a lack of data.

The effectiveness of surrender laws depends heavily on law enforcement’s willingness to enforce them. In Dallas County, only 60 guns were collected from domestic abusers over the course of two years — less than 10 percent of the expected total.

Nine out of the 14 states with restraining-order surrender laws saw statistically significant lower intimate-partner homicide rates, compared to states without such laws. New Hampshire, which passed its law in 2000, had the biggest drop, coming in 33.9 percent below average, while Maryland’s 2009 law was associated with a 23.6 percent lower rate.

Only two states, Tennessee and Iowa, had elevated rates — 4.2 percent and 0.4 percent, respectively — though these results weren’t statistically significant.

The research provides perspective on the steadily growing number of state laws which aim to tighten domestic-violence offenders’ access to firearms. Virginia passed a relinquishment law last year, too late to be included in the study, which only includes data up to 2015. New Jersey signed one into law in January. Tennessee recently added a “procedure for a person convicted of domestic violence to terminate possession of all firearms” to its 2009 law. And a pending bill in Pennsylvania would tighten the state’s surrender procedure.

The study underscores the need for further research on laws that aim to curb the more than 1,800 intimate-partner homicides that are committed every year.

“That is the definition of a public health problem,” Siegel said.