1. Department of Clinical Medicine, University of Turku, Turku, Finland
2. Department of Biostatistics, University of Turku, Turku, Finland
3. Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
4. Clinic of Occupational Medicine, Tampere University Hospital, Tampere, Finland
5. Department of Occupational Medicine, University of Turku, Turku, Finland