1. Copenhagen City Heart Study, Frederiksberg-Bispebjerg Hospital, Copenhagen University Hospital, Copenhagen, Denmark
2. Department of Clinical Biochemistry and
3. Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, United Kingdom
4. North West Lung Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom; and
5. Medical Department, Respiratory Section, Herlev-Gentofte Hospital, Copenhagen University Hospital, Herlev, Denmark
6. Institute of Public Health, Section of Epidemiology, University of Copenhagen, Copenhagen, Denmark