Hala Ghattas1, Zeina Jamaluddine2, Chaza Akik3. 1. Center for Research on Population and Health, Faculty of Health Sciences, American University of Beirut, Beirut 1107 2020, Lebanon. Electronic address: hg15@aub.edu.lb. 2. London School of Hygiene and Tropical Medicine, London, UK. 3. Center for Research on Population and Health, Faculty of Health Sciences, American University of Beirut, Beirut 1107 2020, Lebanon.