1. Department of Medicine, Pulmonary Division, Sleep Disorders Center, King Abdulaziz Medical City, King Saudi University for Health Sciences, Riyadh, Saudi Arabia
2. College of Medicine, King Saud University for Health Sciences, Riyadh, Saudi Arabia
3. Department of Epidemiology and Biostatistics, King Abdullah International Medical Research Center, College of Public Health and Health Informatics, King Saud University for Health Sciences, Riyadh, Saudi Arabia