- Correspondence to Dr Elizabeth V Arkema, Clinical Epidemiology Unit, T2, Karolinska Institutet, Stockholm 17176, Sweden;
- Received November 22, 2013
- Revised January 31, 2014
- Accepted February 16, 2014
- First published March 7, 2014.
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.