For instance, New York, California and the District of Columbia bucked the national trend and saw decreases in their firearm death rates across most categories of people from 2015 to 2017. Those three areas, plus Arizona and Nevada, also saw an overall decrease in firearm deaths from 1999 to 2017.

Demographic differences

Across the country, nearly all demographic groups saw increases in firearm death rates, but the level of increase varied across groups.

For example, males had larger absolute increases than females. Hispanic whites were the only racial or ethnic group that saw reductions in mortality in recent years, while firearm mortality rates among both non-Hispanic whites and African-Americans increased significantly. There were broad increases across age groups.

Type of firearm death differences

Throughout the study period, suicides and homicides remained consistent in their share of all firearm-related deaths. Specifically, suicide accounted for about 60% of deaths, and homicides about 38%, in both 1999 to 2014 and 2015 to 2017. Rates of firearm deaths categorized as unintentional dropped in recent years, but made up less than 1% of all firearm deaths

Trends and implications for states

The researchers also point out state-specific trends in the demographics and causes of firearm deaths. For example, while many states saw their suicide and homicide rates change at about the same pace, some didn’t.

Delaware’s overall firearm mortality rate rise was mainly due to an increase in homicides in recent years, for instance, but this was not the case for most other states. Other states showed sub-population trends that departed from their overall state-level trends.

“In our home state of Michigan, homicide has remained at an unacceptably high, but steady, rate over the period from 1999 through 2017, and we’ve seen an increase in suicide rates in that same time,” says senior author Rebecca Cunningham, M.D., a professor of emergency medicine and interim vice president for research at U-M. “Also in Michigan, firearm mortality has remained concerningly high among all groups, but we now see increased rates among non-Hispanic whites, and older adults

Now that the data in the paper and its detailed state-by-state appendices are available, the authors point out that policymakers could identify which sub-populations are most affected by firearm deaths in their states. They could then seek to determine which approaches may be most appropriate based on evidence about the effects of different policy-based interventions on different subgroups.

“For instance, suicide remains the most common mechanism of firearm mortality in most states and prevention efforts could be concentrated into the highest-risk groups for suicide, such as older males and rural adults,” says Goldstick.

To address domestic violence-related homicides among women, states might want to heed research showing that restricting firearm access among domestic violence offenders and people convicted of violent crime can reduce domestic violence homicide.