1. Department of Epidemiology and Public Health, University College London, London, U.K.;
2. Department of Behavioral Sciences, University of Helsinki, Helsinki, Finland;
3. MRC Social and Public Health Sciences Unit, University of Glasgow, Glasgow, U.K.;
4. Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, U.K.;
5. First Department of Medicine, Faculty of Medicine, Semmelweis University, Budapest, Hungary;
6. Finnish Institute of Occupational Health, Helsinki, Finland;
7. University of Turku, Turku University Hospital, Turku, Finland.