1The Swedish Foundation for Occupational Health and Safety for Construction Workers ("Bygghälsan"), Umeå, Sweden
2TIRECO AB, Skellefteå, Sweden
3The Swedish Board of Occupational Health and Safety, Solna, Sweden
4Department of Environmental Medicine, University of Umeå, Sweden
5The Swedish Foundation for Occupational Health and Safety for State Empoloyees ("Statshälsan"), Umeå, Sweden