1. Department of Epidemiology and Population Health, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
2. Faculty of Health and Life Sciences, The University of Northumbria, Benton, Newcastle upon Tyne NE7 7XA, UK
3. Department of Public Health, College of Health Sciences, Qatar University, QU Health, Doha P.O. Box 2713, Qatar