1. From the Gesellschaft für Strahlenforschung (GSF)-National Research Center for Environment and Health, Munich; Medical Clinic III, Klinikum Grosshadern Medical Center, Ludwig-Maximilians-University, Munich; Institute of Human Genetics, Technical University, Munich; Medical Clinic I, University of Cologne, Cologne; Medical Clinic, University of Bonn, Bonn; and Institute of Medical Statistics and Epidemiology, Technical University, Munich, Germany.