1 MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Box 285 Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands. Electronic address: [email protected].
2 Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands.
3 Department of Internal Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands.