[1] Univ Hosp Regensburg, Dept Internal Med 3, Regensburg, Germany
[2] Resp Ctr Ulm, Sleep & Ventilat Ctr Blaubeuren, Ulm, Germany
[3] ResMed Sci Ctr, Martinsried, Germany
[4] Heart & Diabet Ctr North Rhine Westphalia, Dept Cardiol, Bad Oeynhausen, Germany
[5] Univ Med Ctr Hamburg Eppendorf, Dept Med Biometry & Epidemiol, Hamburg, Germany
[6] Univ Hosp Cologne, Ctr Heart, Clin Internal Med 3, Cologne, Germany
[7] Univ Duisburg Essen, Univ Hosp Essen, Dept Pneumol, Ruhrlandklin,West German Lung Ctr, Essen, Germany