1. Department of Occupational Medicine; University of Perugia; Perugia Italy
2. Division of Asthma and Allergy; Department of Chest Diseases; University Hospital Strasbourg; University of Strasbourg; Strasbourg France
3. Department of Occupational Medicine; Terni Hospital; University of Perugia; Perugia Italy
4. Allergy and Immunology Unit; Fondazione ‘Salvatore Maugeri’; Institute of Care and Research; Scientific Institute of Pavia; Pavia Italy
5. Unit of Occupational Medicine; University Hospital of Verona; Verona Italy
6. Department of Allergy; Hospital La Paz Institute for Health Research (IdiPAZ) and CIBER of Respiratory Diseases CIBERES; Madrid Spain
7. Institute of Prevention and Occupational Medicine of the German Social Accident Insurance; Institute of the Ruhr University Bochum; Bochum Germany
8. Department of Allergy; CIBER de Enfermedades Respiratorias, Ciberes and Fundación Jiménez Díaz; Madrid Spain
9. Toronto Western Hospital; Toronto ON Canada
10. Nofer; Institute of Occupational Medicine; Lodz Poland
11. Centre for Research in Environmental Epidemiology (CREAL); Barcelona Spain
12. Hospital del Mar Medical Research Institute (IMIM); Barcelona Spain
13. CIBER Epidemiología y Salud Pública (CIBERESP); Barcelona Spain