1. Department of Epidemiology and Public Health, University College London, London, U.K.;
2. INSERM U 888 and University Montpellier 1, Montpellier, France;
3. Department of Medicine, Semmelweis University Faculty of Medicine, Budapest, Hungary;
4. Department of Psychology, University of Helsinki, Helsinki, Finland;
5. Finnish Institute of Occupational Health, Helsinki, Finland;
6. INSERM U687 and Centre de Gérontologie, Hôpital Ste Périne, Assistance Publique-Hôpitaux de Paris, Paris, France.