- Correspondence to Dr Iain M Carey, Population Health Research Institute, St George's University of London, London SW17 0RE, UK;
- Received March 24, 2016
- Revised May 20, 2016
- Accepted May 25, 2016
- First published June 16, 2016.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.