1. From Hospital Clínic, University of Barcelona, Barcelona, Spain; London School of Hygiene and Tropical Medicine, London, United Kingdom; National Centre for Cardiovascular Research, Hospital Clínico San Carlos, Hospital Universitario 12 de Octubre, and Universidad Complutense, Madrid, Spain; Hospital General de Alicante, Alicante, Spain; Hospital Universitario Central de Asturias, Oviedo, Spain; and Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Spain.