Background: Veterans have higher suicide rates than matched non-veterans, with firearm suicides being especially prevalent among veterans. We examined whether state firearm laws and state firearm ownership rates are important risk factors for suicide among veterans.

Methods: US veteran's and demographically matched non-veteran's suicide rates, 2002-2019, are modelled at the state level as a function of veteran status, lethal means, state firearm law restrictiveness, household firearm ownership rates and other covariates.

Results: Marginal effects on expected suicide rates per 100 000 population were contrasted by setting household firearm ownership to its 75th versus 25th percentile values of 52.3% and 35.3%. Ownership was positively associated with suicide rates for both veterans (4.35; 95% credible interval (CrI): 1.90, 7.14) and matched non-veterans (3.31; 95% CrI: 1.11, 5.77). This association was due to ownership's strong positive association with firearms suicide, despite a weak negative association with non-firearm suicide. An IQR difference in firearm laws corresponding to three additional restrictive laws was negatively associated with suicide rates for both veterans (-2.49; 95% CrI: -4.64 to -0.21) and matched non-veterans (-3.19; 95% CrI: -5.22 to -1.16). Again, these differences were primarily due to associations with firearm suicide rates. Few differences between veterans and matched non-veterans were found in the associations of state firearm characteristics with suicide rates.

Discussion: Veterans' and matched non-veterans' suicide risk, and specifically their firearm suicide risk, was strongly associated with state firearm characteristics.

Conclusions: These results suggest that changes to state firearm policies might be an effective primary prevention strategy for reducing suicide rates among veterans and non-veterans.