1. Heart Research Center; Oregon Health and Science University; Portland OR 97201-3098 USA
2. MRC Epidemiology Resource Centre; University of Southampton, Southampton General Hospital; Southampton SO16 6YD UK
3. College of Medicine; King Saud University; Saudi Arabia
4. Department of Chronic Disease Prevention; National Institute for Health and Welfare; PL 30 00271 Helsinki Finland
5. Hospital for Children and Adolescents; Helsinki University Central Hospital; 00029 HUS Helsinki Finland
6. Department of General Practice and Primary Health Care; University of Helsinki; PL 20 00014 Helsingin yliopisto Finland
7. Vasa Central Hospital; Sandviksgatan 2-4 65130 Vasa Finland
8. Folkhälsan Research Centre; Helsingfors Universitet; PB 63 00014 Helsinki Finland
9. Unit of General Practice; Helsinki University Central Hospital; 00029 HUS Helsinki Finland