Institution: | 1.Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;2.Department of Pulmonology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;3.National Institute for Public Health and the Environment, Bilthoven, The Netherlands;4.Department of Medical Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands |