1. Department of Renal Medicine, University College London , London, UK
2. Wuqu’ Kawoq Maya Health Alliance , Chimaltenango, Guatemala
3. Department of Mathematics, Statistics, and Computer Science, Macalester College , St Paul, MN, USA
4. Research Centre on Health, Work and Environment, National Autonomous University of Nicaragua, León (UNAN-Leon) , León, Nicaragua
5. Department of Medical Statistics, London School of Hygiene and Tropical Medicine , London, UK
6. Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine , London, UK