1. ENT and Head and Neck Surgery Department, Audiology and Balance Unit, Rumaillah Hospital and Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar
2. Department of Medical Statistics & Epidemiology, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar
3. Department of Public Health & Medical Education, Weill Cornell Medical College, New York, NY, USA
4. Evidence for Population Health Unit, School of Epidemiology and Health Sciences, The University of Manchester, Manchester, UK