1. London School of Hygiene & Tropical Medicine; Department of Population Health; Room 134b Keppel Street London UK WC1E 7HT
2. London School of Hygiene & Tropical Medicine; Cochrane Injuries Group; North Courtyard Keppel Street London UK WC1E 7HT
3. London School of Hygiene & Tropical Medicine; Clinical Trials Unit; Keppel Street London UK WC1E 7HT
4. Khon Kaen University; Department of Demography and Biostatistics; Faculty of Public Health Khon Kaen Thailand 40002
5. Prince of Songkla University; Division of Neurosurgery, Department of Surgery, Faculty of Medicine; Hadyai, Songkla Thailand
6. Khon Kaen Regional Hospital; Surgical Unit; Srichan Road Muang District Khon Kaen Thailand 40000