1. MRC Clinical Sciences Centre, Imperial College, London W12 0NN United Kingdom
2. Department of Epidemiology and Biostatistics, Imperial College, London W2 1PG, United Kingdom
3. University Heart Center, D-20246 Hamburg, Germany
4. INSERM UMRS 937, Pierre and Marie Curie University, 75013 Paris, France
5. National Heart and Lung Institute, Imperial College, London W2 1PG, United Kingdom
6. MRC–HPA Centre for Environment and Health, Imperial College, London-Harefield Hospital, Harefield, Middlesex UB9 6JH, United Kingdom