[1] Finnish Inst Occupat Hlth, Ctr Expertise Hlth & Work Abil, FI-00251 Helsinki, Finland
[2] Univ Copenhagen, Bispebjerg Hosp, Dept Occupat & Environm Med, Copenhagen, Denmark
[3] Natl Inst Occupat Hlth, Dept Occupat Med & Epidemiol, Oslo, Norway
[4] Univ Oslo, Inst Hlth & Soc, Oslo, Norway