Table 4.

Results of difference-in-differences analysis on policies restricting the sale of handguns to age 21 or older and suicides in adolescents

Variables	Suicide fatalities per 100 000 adolescents (95% CI)
	Total suicides	Firearm suicides	Non-firearm suicides
Age 21 handgun sales	−1.91* (−3.13 to −0.70)	−1.83† (−2.66 to −1.00)	−0.08 (−0.70 to 0.54)
Per cent of firearm related suicides among ages ≥21 years	−8.99 (−16.10 to −1.88)	−3.88 (−8.65 to 0.89)	−5.11 (−11.66 to 1.44)
Population density	0.02 (−0.02 to 0.06)	0.01 (−0.02 to 0.04)	0.01 (−0.02 to 0.04)
Per cent of population of each race/ethnicity:
Native American	1.02 (−0.84 to 2.88)	−1.65 (−3.22 to −0.09)	2.68 (1.18 to 4.17)
White	0.65 (−0.22 to 1.52)	0.14 (−0.45 to 0.74)	0.50 (0.09 to 0.92)
Other	Reference
Handgun permit policy	−0.69 (−1.24 to −0.14)	−0.48 (−1.04 to 0.08)	−0.21 (−0.92 to 0.51)
Universal background checks	−0.23 (−1.23 to 0.77)	0.03 (−0.42 to 0.49)	−0.26 (−1.26 to 0.74)

Main effect estimates are in the top row. State and year fixed effects are also included adjusting for each state and year.

^*Permutation adjusted P<0.05.

^†Permutation adjusted P<0.01 for main effect estimates.