1 University Institute in Primary Care Research Jordi Gol i Gurina, Barcelona, Spain; Via Roma Health Centre, Catalonian Health Institute, Barcelona, Spain; Department of Public Health, General Practice, University of Southern Denmark, Denmark. Electronic address: cllor@idiapjgol.org.
2 University Institute in Primary Care Research Jordi Gol i Gurina, Barcelona, Spain; University Rovira i Virgili, Jaume I Health Centre, Tarragona, Spain.
3 Section and Research Unit of General Practice, Department of Public Health, University of Copenhagen, Denmark.