1. Institute of Public Health, University of Southern Denmark, Winsløwparken 17, DK-5000 Odense, Denmark, Department of Environmental Health, Harvard School of Public Health, 401 Park Drive 3E, Boston, Massachusetts 02215, Institute of Public Health, University of Copenhagen, Øster Farimagsgade 5, P.O. Box 2099 1014 Copenhagen K, Copenhagen, Denmark, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 1600 Clifton Rd Atlanta, Georgia 30333,...