[1] Univ Penn, Sch Med, Div Gen Internal Med, Philadelphia, PA 19104 USA
[2] Inst Safe Families, Philadelphia, PA USA
[3] Univ Penn, Sch Med, Dept Family Med & Community Hlth, Philadelphia, PA 19104 USA
[4] Univ Penn, Sch Med, Firearm & Injury Ctr Penn, Philadelphia, PA 19104 USA
[5] Univ Penn, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[6] Philadelphia VA Med Ctr, Ctr Hlth Equity Res & Promot, Philadelphia, PA USA
[7] Univ Penn, Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA