1. Institute for Epidemiology, University Medical Hospital Schleswig Holstein, Campus Kiel, Niemannsweg 11, 24105 Kiel, Germany
2. Lung Clinic Grosshansdorf, Airway Disease Center North (ARCN), German Center for Lung Research (DZL), 22949 Großhansdorf, Germany
3. Department of Respiratory Medicine, Hannover Medical School, 30625 Hannover, Germany
4. Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), 30625 Hannover, Germany