1. Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, USA
2. Department of Pediatrics, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, USA
3. Division of Pediatric Hematology/Oncology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, USA
4. Los Angeles County Fire Department, Los Angeles CA, USA
5. David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, USA