1. Department of Epidemiology University of Michigan School of Public Health Ann Arbor Michigan USA
2. Centre of Public Health Sciences University of Iceland Reykjavik Iceland
3. Faculty of Medicine University of Iceland Reykjavik Iceland
4. Icelandic Heart Association Kopavogur Iceland
5. Department of Medical Epidemiology and Biostatistics Karolinska Institutet Stockholm Sweden
6. Department of Epidemiology Harvard T.H. Chan School of Public Health Boston Massachusetts USA
7. Division Sleep and Circadian Disorders, Departments of Medicine and Neurology Brigham and Women's Hospital Boston Massachusetts USA
8. Division of Sleep Medicine Harvard Medical School Boston Massachusetts USA
9. Department of Urology Landspitali University Hospital Reykjavik Iceland
10. Laboratory of Epidemiology and Population Science National Institute on Aging Bethesda Maryland USA
11. Department of Population and Quantitative Health Sciences Case Western Reserve University Cleveland Ohio USA