1. School of Medicine, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Western Australia, Australia
2. Rural Clinical School Western Australia, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Western Australia, Australia
3. Finnish Institute of Occupational Health, Helsinki, Finland
4. Occupational Safety and Health, North Metropolitan Health Service, Perth, Western Australia, Australia
5. University of Helsinki, Department of General Practice and Helsinki University Hospital, Unit of Primary Health Care, Helsinki, Finland