1. University Clinic of Respiratory and Allergic Diseases Golnik , Golnik 36, 4204 Golnik , Slovenia
2. University of Ljubljana, Medical Faculty , Vrazov trg 2, 1000 Ljubljana , Slovenia
3. University of Ljubljana, Medical Faculty, Institute of Pathophysiology , Zaloška cesta 4, 1000 Ljubljana , Slovenia
4. University of Ljubljana, Medical Faculty, Institute for Biostatistics and Medical Informatics , Vrazov trg 2, 1000 Ljubljana , Slovenia