1. Free Universtity of Amsterdam; Institute for Research in Extramural Medicine; van de Boechorststraat 7 Amsterdam Netherlands 1081 BT
2. University Medical Centre Utrecht; Department of Internal Medicine; P.O.Box 85500 3508 GA Utrecht Netherlands
3. Institute of Metabolic Science; MRC Epidemiology Unit; Box 285 Addenbrooke's Hospital, Hills Road Cambridge UK CB2 0QQ
4. Group Health Cooperative; MacColl Institute for Healthcare Innovation; 1730 Minor Ave, Suite 1600 Seattle Washington USA 98101
5. Capaciteitsgroep Medische Sociologie; Deleyeplein 1 PO Box 616 Maastricht Netherlands 6200 MD
6. Leiden University Medical Centre; Department of Public Health and Primary Care; PO Box 9600, Postzone V 06-P Leiden Netherlands 2300 RC