Gun rights advocates have argued that strict gun laws have failed to curb high murder rates in some cities, including Chicago and Washington, D.C. Fleegler said his study didn't examine city-level laws, while gun control advocates have said local laws aren't as effective when neighboring states have lax laws.
Previous research on the effectiveness of gun laws has had mixed results, and it's a "very challenging" area to study, said Dr. Daniel Webster, director of the Johns Hopkins Center For Gun Policy. He was not involved in the current study.
The strongest kind of research would require comparisons between states that have dissimilar gun laws but otherwise are nearly identical, "but there isn't a super nice twin for New Jersey," for example, a state with strict gun laws, Webster noted.
Fleegler said his study's conclusions took into account factors also linked with gun violence, including poverty, education levels and race, which vary among the states.
The average annual gun death rate ranged from almost 3 per 100,000 in Hawaii to 18 per 100,000 in Louisiana. Hawaii had 16 gun laws, and along with New Jersey, New York and Massachusetts was among states with the most laws and fewest deaths. States with the fewest laws and most deaths included Alaska, Kentucky, Louisiana and Oklahoma.
But there were outliers: South Dakota, for example, had just two guns laws but few deaths.
Editorial author Dr. Garen Wintemute, director the Violence Prevention Research Program at the University of California, Davis, said the study doesn't answer which laws, if any, work.
Wintemute said it's likely that gun control measures are more readily enacted in states with few gun owners — a factor that might have more influence on gun deaths than the number of laws.