1. Centre for Global Child Health, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
2. Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, 155 College Street, Toronto, ON M5T 3M7, Canada
3. Institut de Recherche et Formation en Population, Développement et Santé de la Reproduction, Université Cheik Anta Diop, P.O. Box 45 550 Dakar Fann, Dakar, Senegal
4. Division of Adolescent Medicine, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
5. Department of Pediatrics, University of Toronto, 555 University Ave, Toronto, ON M5G 1X8, Canada