1. London School of Hygiene & Tropical Medicine; Department of Non-communicable Disease Epidemiology; Keppel Street London UK WC1E 7HT
2. University College London; Farr Institute of Health Informatics Research; 222 Euston Road London UK NW1 2DA
3. Johns Hopkins Bay View Medical Centre; 4940 Eastern Avenue Baltimore USA MD Z122Y
4. University of Exeter Medical School; Institute of Health Research; South Cloisters, St Luke's Campus, Heavitree Road Exeter UK EX2 4SG