[1] Univ Gothenburg, Inst Med, Sahlgrenska Acad, Dept Internal Med,Krefting Res Ctr, SE-40530 Gothenburg, Sweden
[2] Sunderby Cent Hosp Norrbotten, Dept Med, Obstruct Lung Dis No Sweden OLIN Studies, Lulea, Sweden
[3] Umea Univ, Dept Publ Hlth & Clin Med Environm Med & Occupat, Umea, Sweden
[4] Karolinska Univ Hosp, Dept Resp Med & Allergol, Huddinge, Sweden
[5] Karolinska Inst, Natl Inst Environm Med, Ctr Allergy Res, Stockholm, Sweden