1. Gondar University Referral and Specialized Hospital, Gondar, Ethiopia
2. Department of Medical Physiology, School of Medicine, College of Medicine and Health Science, University of Gondar, Gondar, Ethiopia
3. Department of Epidemiology and Biostatistics, Institute of Public Health, College of Medicine and Health Science, University of Gondar, Gondar, Ethiopia
4. College of Medicine and Public Health, Flinders University, SA 5001, Australia