1. Sociology, Mississippi State University, Starkville, MS, USA
2. Health Sciences, University of Missouri, Columbia, MO, USA
3. MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
4. World Health Organization, Geneva, Switzerland
5. University of Newcastle Research Centre on Generational Health and Ageing, New Lambton, Australia