1. Respiratory Medicine Unit, Policlinico “G. Rodolico-San Marco” University Hospital, 95123 Catania, Italy
2. Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy
3. Department of Health Sciences, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy
4. Department of Respiratory Medicine, University “Federico II” of Naples, 80138 Naples, Italy
5. Department of Translational Biomedicine and Neuroscience, Institute of Respiratory Disease, University “Aldo Moro”, 70121 Bari, Italy
6. Department of Clinical and Experimental Medicine, University of Messina, 98166 Messina, Italy
7. Department of Medical and Surgical Sciences, University of Foggia, 71100 Foggia, Italy
8. Division of Respiratory Diseases, Department of Health Promotion Sciences, Maternal and Infant Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90128 Palermo, Italy
9. Department of Medicine, Surgery and Dentistry, University of Salerno, 84081 Salerno, Italy