1. Leiden University Medical Center; Department of Epidemiology; Leiden Netherlands 2300 RC
2. Leiden University Medical Center; Dept. of Clinical Epidemiology; PO Box 9600 Albinusdreef 2 Leiden Netherlands NL 2300 RC
3. Leiden University Medical Center; Department of Medical Statistics; PO Box 9600 Leiden Netherlands 2300 RC
4. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care/University Department of Neurology and Neurosurgery; PO Box 85500 Utrecht Netherlands 3508 GA
5. Leiden University Medical Center; Department of Clinical Epidemiology; PO Box 9600 Leiden Netherlands 2300 RC