Firearm mortality in California, 2000-2015: the epidemiologic importance of within-state variation.

PURPOSE: Firearm mortality is a significant problem in the United States. Previous studies have largely focused on firearm mortality at the national or state level, leaving open the question of within-state variation. This study examined firearm mortality within California.

METHODS: We used Multiple Cause of Death data files to identify all firearm fatalities in California from 2000 to 2015. We described firearm mortality rates and counts over time, by age and county, stratifying by intent, gender, and race/ethnicity. County-level rates were smoothed with empirical Bayes estimates from random-effect Poisson models.

RESULTS: From 2000 to 2015, there were 24,922 firearm homicides and 23,682 firearm suicides in California. Rates of firearm homicide decreased 30% and suicide rates increased 1% since the mid-2000s, but these trends varied substantially by county. Due to a decline in firearm homicides in metropolitan areas, there was no significant difference in these rates between urban and rural counties by 2015. Non-Hispanic black men had the highest rate of firearm homicide, but Hispanic men had the greatest number of deaths.

CONCLUSIONS: We found considerable intrastate variation in firearm mortality in California. Our results will be of interest to researchers, policymakers, and public health practitioners. Similar epidemiologic profiles of firearm mortality are warranted for other states.