Christer Hogstedt, Marcus Hugosson, and Per Gustavsson are with the Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. Catarina Jansson is with the Division of Insurance Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm. Håkan Tinnerberg is with the Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Skåne University Hospital, Lund University, Lund, Sweden.