- Correspondence to Dr María José Belza, National School of Public Health, Carlos III Health Institute, Avenida Monforte de Lemos 5, Madrid E-28029, Spain;
- Received December 5, 2016
- Revised February 27, 2017
- Accepted March 18, 2017
- First published April 17, 2017.
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.