1. Centre d’Estudis Demogràfics, Bellaterra, Spain
2. Department of Geography, Universitat Autonoma de Barcelona, Bellaterra, Spain
3. Centre for Epidemiological Studies on STI and AIDS of Catalonia (CEEISCAT), Department of Health, Generalitat de Catalunya, Badalona, Spain
4. CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
5. Department of Sociology and Social Anthropology, Universitat de València, Valencia, Spain