Potential conflict of interest
Disclosure forms provided by the authors are available with the full text of this article at www.informahealthcare.com/lal.
This work has been funded with the help of the Spanish Ministry of Science and Innovation (SAF 2007–62473), the PIUNA Program of the University of Navarra, the Caja Navarra Foundation through the Program “You choose, you decide” (Project 10.830) and ISCIII-RTICC (RD06/0020/0078). PA receives a postdoctoral grant from the Government of Navarra.