[1] Agencia Salut Publ Barcelona, Barcelona, Spain
[2] CIBERESP, Barcelona, Spain
[3] Inst Biomed Res IIB St Pau, Barcelona, Spain
[4] Univ E Anglia, Norwich Med Sch, Hlth Econ Grp, Norwich NR4 7TJ, Norfolk, England
[5] Univ York, Ctr Hlth Econ, York YO10 5DD, N Yorkshire, England
[6] Inst Publ Hlth, Ctr Diet & Act Res CEDAR, Cambridge, England