1. Department of Public Health, Section for Environment Occupation and Health, University of Aarhus, Bartholins Allé, Aarhus C, Denmark
2. Institute of Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
3. Department of Occupational Medicine, Regional Hospital West Jutland - University Research Clinic, Herning, Denmark
4. National Research Centre for the Working Environment, Lersø Parkallé, Copenhagen, Denmark