Gun deaths are twice as high among African Americans as they are among white citizens in the US, finds a study of national data, published in the online journal BMJ Open.

But the national figures, which have remained relatively steady over the past decade, mask wide variation in firearms deaths by ethnicity and state, the findings show.

The researchers looked at all recorded gun deaths across the USA between 2000 and 2010, to include murders, suicides, and unintentional shooting, using data from the Injury Statistics Query and Reporting System.

Hawaii recorded the lowest rate of gun deaths at 3.02 per 100 000 citizens, while the District of Columbia topped the league table at 21.71 per 100 000. Rates rose in Florida and Massachusetts, largely owing to more gun deaths among people of white and non-Hispanic ethnicities, and an increase in the gun related murder rate.

Firearm deaths fell in Arizona, California, Illinois, Maryland, Nevada, New York, North Carolina, and the District of Columbia, mostly among people of Hispanic and African-American ethnicities.

Nationally, unintentional firearm deaths fell significantly, but the number of gun related murders and suicides remained unchanged. In California, the fall in gun deaths was largely attributable to a reduction in suicides.

The national rate of gun deaths was twice as high among African-Americans as it was among people of white ethnicity. But these deaths fell in seven states and DC, compared with comparable falls in only four states among people of white ethnicity. Similarly, rates of gun deaths among Hispanics fell in four states, and rose among non-Hispanics in nine states.

The authors point out that the patterns of gun deaths they found didn’t seem to reflect firearm control efforts and legislation in individual states. Some of the states with the most stringent gun laws showed an expected fall in firearm deaths, while some with strong gun control laws reported an increase.

For example, The Brady Center to Prevent Gun Violence ranked Massachusetts the third most restrictive state for firearm legislation, while Florida was ranked 40th in 2011.

After Massachusetts passed its tough law restricting gun use in 1998, gun ownership rates plummeted, yet violent crimes and murders increased, possibly because of an influx of firearms from neighbouring states with weaker firearm laws, suggest the authors. And in Florida gun deaths rose, despite an overall fall in violent crime over the same period.

Clamping down on gun violence may require a broader approach, including curbing firearm availability and ramping up interstate border controls on the transport of firearms, the authors conclude.