From the Department of Public Health Sciences, Division of Social Medicine (T.H., P.A.); Department of Clinical Neuroscience, Division of Psychology, Karolinska Institute, Stockholm, Sweden (B.M.); School of Health & Environment, University of Massachusetts Lowell, Lowell, Massachusetts (D.K.); and Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden (I.L.).
Address correspondence and reprint requests to Tomas Hemmingsson, PhD, Department of Public Health Sciences, Division of Social Medicine, Karolinska Institute, Norrbacka, 171 76 Stockholm, Sweden. E-mail: [email protected]
Supported by a Research Grant from the Swedish Council for Working Life and Social Research (Project No. 2005-0960) (to T.H.).
Ethical approval: The Ethics Committee at the Karolinska Institute, Stockholm, approved the study.
Received for publication April 19, 2007; revision received March 14, 2008.