Lung function testing by spirometry
Spirometry prior to bronchodilation will be performed in line with ATS/ERS recommendations [Specific attention will be paid to the requirement to obtain very precise and reliable lung function data. In addition to strictly following ATS/ERS recommendations, we will reach the goal of high-quality lung function testing by experienced and well-trained study nurses, the additional visual control by a pulmonologist and the repetition of tests for each subject. There is long-standing, well-documented expertise on lung function assessment in the investigators involved in this study.