1. 1 Department of Public Health, Erasmus Medical Center, Rotterdam, The Netherlands
2. 2 Health Studies and Research Unit, Department of Health and Consumer Affairs, Basque Government, Vitoria-Gasteiz, Spain
3. 3 Department of Sociology 2, University of the Basque Country (UPV/EHU), Leioa, Spain
4. 4 Agència de Salut Pública de Barcelona, Barcelona, Spain
5. 5 Department of Preventive Medicine and Public Health, Universidad Complutense de Madrid, Madrid, Spain