1. Brighton and Sussex University Hospitals NHS Trust; Brighton UK
2. University of York; Department of Health Sciences; Seebohm Rowntree Building Heslington York UK YO10 5DD
3. Idaho State University; Department of Community and Public Health; Meridian Idaho USA
4. London School of Hygiene and Tropical Medicine; Sigma Research, Department of Social & Environmental Health Research; London UK
5. York University; Department of Health Sciences/Hull York Medical School; York UK YO10 5DD