1. Division of Primary Care and Population Health, Department of Medicine, Stanford University School of Medicine, 1265 Welch Road, Stanford, CA 94305, USA
2. Heidelberg Institute of Global Health (HIGH), Heidelberg University, Im Neuenheimer Feld 130.3, 69120 Heidelberg, Germany
3. Department of Statistics, University of Oxford, 24-29 St Giles', Oxford OX1 3LB, UK
4. Department of Family Medicine and Primary Care, School of Clinical Medicine, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
5. Management and Development for Health, Plot #802, Mwai Kibaki Road, Mikocheni, Dar es Salaam, Tanzania
6. National AIDS Control Program, Lithuli Street, Dar es Salaam, P.O. Box 11857, Tanzania
7. Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
8. Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
9. Department of Nutrition, Harvard T.H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA
10. Africa Health Research Institute (AHRI), Africa Centre Building, Via R618 to Hlabisa, Somkhele, P.O. Box 198, Mtubatuba 3935, South Africa