1. Institute for Biometrics and Epidemiology, German Diabetes Centre (DDZ), Leibniz Centre for Diabetes Research, Heinrich Heine University, Auf’m Hennekamp 65, 40225 Duesseldorf, Germany
2. German Centre for Diabetes Research (DZD), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
3. Institute of Epidemiology and Medical Biometry, University of Ulm, Albert-Einstein-Allee 41, 89069 Ulm, Germany