Permissiveness of firearm laws, pro-gun culture, and suicides by firearm in the U.S., 2000-2016

Objectives: Stricter firearm policies correlate with lower suicides by firearm in the US. However, much work examines policies in isolation and does not investigate firearm policies as they relate to US pro-gun culture. We examine the relation between permissiveness of state firearm laws, gun culture, and suicides by firearm. Study design: Panel longitudinal study.Methods: The count of suicides by firearm for 50 US states from 2000 to 2016 served as the outcome. Permissiveness of multiple state firearm laws, based on ratings from the Traveler's Guide to the Firearm Laws of the Fifty States, served as the exposure. These ratings, measured at the state-year, capture not only the overall policy environment but also the extent to which the state exhibits a pro-gun culture. We applied a fixed effects negative binomial count model, which controls for the population-at-risk, to examine suicides overall and by race/ ethnicity and gender.Results: A 10-unit increase in permissiveness of state firearm laws corresponds with 2% greater suicides by firearm overall (Incidence rate ratio [IRR] = 1.02; 95% CI: 1.01-1.03) and among non-Hispanic white males ([IRR] = 1.02, 95% CI: 1.01-1.02).Conclusions: Findings, if replicated, indicate that states enacting more restrictive firearm policies, and lessening a pro-gun culture, may lead to reductions in suicide by firearm.