Participating centres
| City/country | University | Hospital/affiliations | Investigators |
| Athens, Greece | University of Athens | Sotiria Chest Hospital Evgenidio Hospital AstraZeneca | M. Gaga, N. Papageorgiou C. Gratziou G. Yourgioti |
| Barcelona, Spain | Institut Municipal d'Investigació Mèdica | Hospital del Mar Novartis Global Epidemiology | J.M. Antó, E. Barreiro, C. Sanjuas J. Castellsague |
| Ferrara, Italy | Universita degli Studi di Ferrara | Clinica di Malattie dell’Apparato Respiratorio | L.M. Fabbri#, A. Papi, M. Romagnoli |
| Ghent, Belgium | University of Ghent | Ghent University Hospital | J.C. Kips, R.A. Pauwels |
| Groningen, The Netherlands | University of Groningen | University Hospital, Groningen | H.A.M. Kerstjens, D.S. Postma, W. Timens |
| Hamburg, Germany | University of Hamburg | Krankenhaus Groβhansdorf | N. Drews, F. Kanniess, H. Magnussen, K. Richter |
| Heraklion, Greece | University of Heraklion | Heraklion University Hospital | N.M. Siafakas, N. Tzanakis |
| Leiden, The Netherlands | Leiden University | Leiden University Medical Centre Leyenburg Hospital | E.H.D. Bel, K.F. Rabe A.C. Roldaan |
| Montpellier, France | University of Montpellier | Hopital Arnaud de Villeneuve | J. Bousquet, P. Chanez, I. Vachier |
| Palermo, Italy | Universita degli Studi di Palermo | Ospedale V Cervello | G. Bonsignore, F. Cibella, G. Cuttitta, G. Guerrera, A.M. Vignola |
| Southampton, UK | University of Southampton | Southampton General Hospital | B. Abraham, R. Djukanovic, S.T. Holgate, P.H. Howarth, S.L. Johnston¶, L. Watson |
| Stockholm, Sweden | Karolinska Institutet | Karolinska Hospital | B. Dahlén+, S-E. Dahlén, M. Kumlin, A. Roquet |
| Utrecht, The Netherlands | University of Utrecht | (analytical centre) | G. Folkerts, F.P. Nijkamp |
Current affiliations: #: University of Modena, Italy
¶: Imperial College, London, UK
+: Huddinge University Hospital, Stockholm, Sweden