1. Institute for Medical Informatics, Biometry and Epidemiology, Medical Faculty, University Duisburg-Essen, Essen, Germany
2. Department of Neurology, Hannover Medical School, Hannover, Germany
3. BDH Clinic Elzach, Elzach, Germany
4. School of Public Health, Department of Epidemiology Boston University, Boston, MA, USA
5. Center for Clinical Trials Essen, University Hospital Essen, Essen, Germany
6. Human Pharma Germany, Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim, Germany