1. Department of Pulmonology, University Hospital of Zurich, 8091 Zurich, Switzerland
2. Department of Health Sciences and Medicine, University of Lucerne, 6002 Lucerne, Switzerland
3. Istituto Auxologico Italiano IRCCS, Department of Cardiology, San Luca Hospital, 20149 Milan, Italy
4. School of Medicine and Surgery, University of Milano-Bicocca, 20122 Milan, Italy
5. Medical Faculty, University of Zurich, 8006 Zurich, Switzerland