[1] I3 Innovus, S-11164 Stockholm, Sweden
[2] Karolinska Inst, Inst Environm Med, S-10401 Stockholm, Sweden
[3] Brunel Univ, Uxbridge UB8 3PH, Middx, England
[4] Danderyd Hosp, Karolinska Inst, Dept Clin Sci, Stockholm, Sweden
[5] Univ London Imperial Coll Sci Technol & Med, London, England
[6] Sahlgrens Univ Hosp, Gothenburg, Sweden
[7] Nord Sch Publ Hlth, Gothenburg, Sweden
[8] Stockholm Sch Econ, Ctr Hlth Econ, S-11383 Stockholm, Sweden