1. Department of Epidemiology and Biostatistics; College of Public Health and Health Informatics; King Saud bin Abdulaziz University for Health Sciences; Riyadh Saudi Arabia
2. Department of Medicine; Pulmonary Division-ICU; King Saud bin Abdulaziz University for Health Sciences; Riyadh Saudi Arabia
3. Asthma Research Chair and Prince Naif Center for Immunology Research; Department of Paediatrics; College of Medicine, King Saud University; Riyadh Saudi Arabia