- Correspondence to Professor John Henderson, School of Social and Community Medicine, ALSPAC, University of Bristol, Oakfield House, Bristol BS8 2BN, UK;
- Received December 31, 2014
- Revised January 8, 2015
- Accepted January 14, 2015
- First published February 4, 2015.
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.