More research is needed to elucidate natural history and underlying pathomechanisms of the most common airway diseases, Asthma and COPD. In the last decade risk factors affecting the natural history of lung function, defined by the decline of lung function over time, have been evaluated. Moreover, scientific methods have been extended and novel biomarkers, genetics, metabolomics, and epidemiology are dominant tools for investigating the natural history of lung function and potential risk factors. Evidence shows that lung function in childhood is a predictor for lung function in adulthood and risk factors starting in utero contribute to lung function decline during life. Therefore, recently it has been hypothesized that COPD begins in childhood. Thus, prospective investigation of lung function changes including novel scientific methodology has been advocated. The Austrian LEAD study has been initiated in the general population 2012 to investigate the natural history of obstructive airway diseases., (© Georg Thieme Verlag KG Stuttgart · New York.)