States with the strongest gun laws have fewer gun-related suicides and murders, a new study suggests.

In the study, researchers analyzed U.S. Centers for Disease Control and Prevention statistics on deaths between 2007 and 2010. They also looked at five categories of gun laws in all 50 states to create a gun law “strength score” for each state. The highest possible score was 28.

Over the four-year study period, there were more than 121,000 gun deaths in the United States. Average gun-related death rates ranged from a high of 17.9 per 100,000 people in Louisiana to a low of 2.9 per 100,000 in Hawaii. State gun law strength scores ranged from zero in Utah to 24 in Massachusetts.

States with the highest gun law strength scores (nine or higher) had a lower overall gun-related death rate—6.4 fewer deaths per 100,000—than those with the lowest scores (two or lower).

The study also found that states with the strongest gun laws had a lower rate of gun-related suicides (6.3 fewer deaths per 100,000) and a lower rate of gun-related deaths (0.4 fewer deaths per 100,000) than states with the weakest gun laws.

The study was published online March 6 in the journal JAMA Internal Medicine.

“In conclusion, we found an association between the legislative strength of a state’s firearm laws—as measured by a higher number of laws—and a lower rate of firearm fatalities,” Dr. Eric Fleegler, of Boston Children’s Hospital, and colleagues said in a JAMA news release. “The association was significant for firearm fatalities overall and for firearm suicide and firearm homicide deaths, individually. As our study could not determine a cause-and-effect relationship, further studies are necessary to define the nature of this association.”

In an accompanying editorial, Dr. Garen Wintemute, of the University of California, Davis, said this would be an important study “if it were robust and if its meaning were clear.” He said the study provides “no firm guidance.”

“Do the laws work or not? If so, which ones?” he said. “Should policymakers enact the entire package? Some part? Which part?”

Wintemute called for improvements in the way research into gun violence is conducted, including better data and better data systems.

“To prevent firearm violence, our research efforts must be substantial and sustained,” he wrote.

More than 30,000 people die each year in the United States from gun-related injuries.

SOURCE: HealthDay News; JAMA Internal Medicine, news release, March 6, 2013