1. Research Unit Child Public Health, Department of Child and Adolescent Psychiatry, Psychotherapy, and Psychosomatics, Center for Psychosocial Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
2. European Commission, Health and Consumer DG, C4-Health Determinants, 2920 Luxembourg, Luxembourg
3. Gallup Organization, Regional Headquarter for CEE Hungary, 1033 Budapest, Hungary
4. Agència de Qualitat i Avaluació Sanitàries (AQuAS), 08005 Barcelona, Spain
5. Health Services Research Group, IMIM (Hospital del Mar Medical Research Institute), 08003 Barcelona, Spain
6. The Biomedical Research Centre in Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain