1. O’Neill School of Public and Environmental Affairs, Indiana University-Bloomington, Bloomington, U.S.A
2. Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, U.S.A
3. Department of Environmental and Occupational Health, Indiana University School of Public Health-Bloomington, Bloomington, U.S.A
4. Department of Epidemiology and Biostatistics, Indiana University School of Public Health-Bloomington, Bloomington, U.S.A
5. Harvard Center for Population and Development Studies, Cambridge, U.S.A
6. MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, Stephen Tollman, University of the Witwatersrand, Johannesburg, South Africa
7. INDEPTH Network, Health and Population Research Center, Accra, Ghana
8. Umeå Centre for Global Health Research, Division of Epidemiology and Global Health, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden