1. Respiratory Epidemiology and Public Health, National Heart and Lung Institute, Imperial College, London, UK
2. Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico
3. Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
4. Kaiser-Permanente Center for Health Research, Portland, Oregon, USA
5. Post-Graduate Programme in Epidemiology, Federal University of Pelotas, Capão do Leão, Rio Grande do Sul, Brazil