1. George Washington University School of Medicine and Health Sciences, Washington, DC, USA
2. Department of Economics, Yale University, New Haven, Connecticut, USA
3. Department of Epidemiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
4. Department of Otolaryngology, New York Eye and Ear Infirmary, New York, New York, USA
5. Division of Otolaryngology, Children’s National Medical Center, George Washington University School of Medicine and Health Sciences, Washington, DC, USA