Institution: | a Research Unit of General Practice, Institute of Public Health, University of Southern Denmark, J. B. Winsløws Vej 9A, 1, DK-5000 Odense C, Denmark b Department of Respiratory Medicine, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark c Center for Pharmacoepidemiology, Karolinska Institute, Karolinska University Hospital, SE-171 76 Stockholm, Sweden |