1. Dalla Lana School of Public Health, Division of Epidemiology, University of Toronto, 155 College Street, 5th floor, Toronto, Ontario M5T 3M7, Canada.
2. School of Medicine, Moi University College of Health Sciences, Eldoret, Kenya.
3. School of Public Health, Brown University, Providence, United States of America.
4. Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya.
5. Moi Teaching and Referral Hospital, Eldoret, Kenya.