[1] Uppsala Univ, Dept Med Sci Resp Allergy & Sleep Res, SE-75185 Uppsala, Sweden
[2] Landspitali Univ Hosp, Dept Sleep, Reykjavik, Iceland
[3] Univ Iceland, Fac Med, Reykjavik, Iceland
[4] Tartu Univ Hosp, Lung Clin, Tartu, Estonia
[5] Univ Tartu, Inst Family Med & Publ Hlth, Tartu, Estonia
[6] Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, Umea, Sweden
[7] Uppsala Univ, Dept Med Sci Occupat & Environm Med, Uppsala, Sweden