[1] Univ Helsinki, Fac Med, Res Program Unit, POB 9, Helsinki, Finland
[2] Finnish Inst Hlth & Welf, Helsinki, Finland
[3] Univ Helsinki, Dept Psychol & Logoped, Helsinki, Finland
[4] Finnish Inst Occupat Hlth, Helsinki, Finland
[5] UCL, Dept Epidemiol & Publ Hlth, London, England
[6] Univ Helsinki, Fac Med, Clinicum, Helsinki, Finland
[7] Univ Eastern Finland, Sch Educ Sci & Psychol, Joensuu, Finland
[8] Univ Eastern Finland, Inst Publ Hlth & Clin Nutr, Kuopio, Finland