[1] Univ Washington, Dept Pediat, M-S CURE 3,POB 5371, Seattle, WA 98145 USA
[2] Univ Washington, Harborview Injury Prevent & Res Ctr, Firearm Injury & Policy Res Program, Seattle, WA 98145 USA
[3] Seattle Childrens Res Inst, Ctr Child Hlth Behav & Dev, Seattle, WA USA
[4] Univ Washington, Dept Epidemiol, Seattle, WA 98145 USA