1. Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark
2. Department of Pediatrics, Aarhus University Hospital, Aarhus N, Denmark
3. Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark3Department of Health Research and Policy (Epidemiology), Stanford University, Stanford, California4Department of Neurology and Neurological Sciences, Stanford University, S