[1] Univ Munich, Inst & Outpatient Clin Occupat Social & Environm, D-80336 Munich, Germany
[2] Univ Dusseldorf, Inst Occupat & Social Med, Dusseldorf, Germany
[3] Furstenfeldbruck Hosp, Furstenfeldbruck, Germany
[4] Imperial Coll London, Ctr Patient Safety & Serv Qual, Dept Surg & Canc, London, England