1. Department of Pediatrics, University of California San Diego School of Medicine, San Diego, California
2. University of California San Diego School of Medicine, La Jolla, California
3. University of California San Diego Altman Clinical and Translational Research Institute, Biostatistics Unit, La Jolla, California
4. Department of Family Medicine and Public Health, University of California San Diego, La Jolla, California
5. Department of Mathematics, University of California San Diego, La Jolla, California
6. Division of Academic General Pediatrics, Department of Pediatrics, University of California San Diego, La Jolla, California