1. African Population and Health Research Center (APHRC), Nairobi, Kenya;
2. Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya;
3. Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK;
4. International Youth Alliance for Family Planning (IYAFP), Washington, DC, USA;
5. Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA;
6. Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark;
7. Faculty of Health Sciences, OPEN, University of Southern Denmark/Odense University Hospital, Odense, Denmark;
8. Bandim Health Project, Bissau, Guinea-Bissau;
9. Center for Public Health Research, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya