1. a International Agency for Research on Cancer, 150, cours Albert-Thomas, 69372 Lyon cedex 08, France
2. b Environmental and Occupational Health Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Yalelaan 2, De Uithof, 3508TD Utrecht, The Netherlands
3. c Corresponding author: Environmental and Occupational Health Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Yalelaan 2, De Uithof, 3508TD Utrecht, The Netherlands; E-mail: H.Kromhout@iras.uu.nl.