[1] Australian Natl Univ, Sch Demog, Canberra, ACT 0200, Australia
[2] Univ Witwatersrand, Sch Publ Hlth, MRC Wits Rural Publ Hlth & Hlth Transit Res Unit, Faulty Hlth Sci, Johannesburg, South Africa
[3] Univ Colorado, CU Populat Ctr, Inst Behav Sci, Boulder, CO USA
[4] Univ Witwatersrand, Sch Publ Hlth, Faulty Hlth Sci, Johannesburg, South Africa
[5] Monash Univ, Sch Social Sci, Clayton, Vic, Australia
[6] Harvard Univ, Harvard Ctr Populat & Dev Studies, Cambridge, MA 02138 USA
[7] Umea Univ, Ctr Global Hlth Res, Umea, Sweden
[8] INDEPTH Network, Accra, Ghana
[9] Harvard TH Chan Sch Publ Hlth, Dept Social & Behav Sci, Boston, MA USA
[10] Harvard TH Chan Sch Publ Hlth, Dept Epidemiol, Boston, MA USA
[11] UCL, Inst Global Hlth, London, England
[12] Africa Hlth Res Inst, Kwa Zulu, South Africa
[13] Univ KwaZulu Natal, Coll Hlth Sci, Sch Nursing & Publ Hlth, Durban, South Africa