1. Division of Cardiovascular Medicine, Brigham and Women's Hospital; Boston Massachusetts
2. Center for Health Decision Science, T.H. Chan School of Public Health; Harvard University Boston; Massachusetts
3. Ageing and Health, School of Medicine; University of Dundee; Scotland United Kingdom
4. Medical Research Council
5. Rural Public Health and Health Transitions Research Unit, School of Public Health, Faculty of Health Sciences; University of the Witwatersrand; Johannesburg South Africa
6. Center for Population and Development Studies, T.H. Chan School of Public Health; Harvard University; Cambridge Massachusetts
7. INDEPTH Network; Accra Ghana