[1
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Department of Medicine (Drs Søyseth, Johnsen, and Kongerud), Faculty Division Akershus
University Hospital, University of Oslo, Lørenskog, Norway; Faculty of Medicine (Dr
Søyseth), University of Oslo, Oslo, Norway; National Institute of Occupational Health
(Dr Johnsen), Oslo, Norway; National Institute for Occupational Safety and Health
(Dr Henneberger), Centers for Disease Control and Prevention, Morgantown, W Va; and
Departement of Respiratory Medicine (Dr Kongerud), Faculty Division Rikshospitalet
Radiumhospitalet, University of Oslo, Oslo, Norway.