DESKcohort is a project led by Universitat de Vic – Universitat Central de Catalunya with the support of General Subdirectorate of drug addiction of the Public Health Agency of Catalonia and the Education Department. The project involves the collaboration of the Catalan Public Health Agency, the Center for Biomedical Research in Epidemiology and Public Health Network (CIBERESP), the Universitat Oberta de Catalunya and the Center of Epidemiological studies on sexually transmitted infections and AIDS in Catalonia.