1. Department of Epidemiology, School of Public Health, Brown University, 121 S. Main Street, Providence, Rhode Island 02903, United States
2. Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329, United States
3. Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, 423 Guardian Drive, Philadelphia, Pennsylvania 19104, United States
4. Health Sciences Center, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
5. Department of Epidemiology, Geisel School of Medicine, Dartmouth College, 1 Medical Center Drive, Lebanon, New Hampshire 03756, United States
6. College of Medicine, University of Cincinnati, 3230 Eden Avenue, Cincinnati, Ohio 45267, United States
7. General and Community Pediatrics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, United States