Athanasios G Kaditis1, Michael Miligkos1,2, Anna Bossi3, Carla Colombo4, Elpis Hatziagorou5, Nataliya Kashirskaya6, Isabelle de Monestrol7, Muriel Thomas8, Meir Mei-Zahav9, George Chrousos10, Anna Zolin3. 1. Paediatric Pulmonology Unit, First Department of Paediatrics, National and Kapodistrian University of Athens and Aghia Sophia Children's Hospital, Athens, Greece. 2. Laboratory of Biomathematics, University of Thessaly School of Medicine, Athens, Greece. 3. Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy. 4. Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy. 5. Paediatric Pulmonology Unit and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece. 6. Department of Genetic Epidemiology, Federal State Budgetary Institution 'Research Centre for Medical Genetics', Moscow, Russian Federation. 7. Stockholm Cystic Fibrosis Centre Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden. 8. Belgian Cystic Fibrosis Registry, Public Health and Surveillance, Scientific Institute of Public Health, Brussels, Belgium. 9. Respiratory Institute, Schneider Children's Medical Centre of Israel, Sackler School of Medicine, Tel Aviv University, Israel. 10. First Department of Paediatrics, National and Kapodistrian University of Athens, Athens, Greece.