1. Danish Headache Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
2. Faculty of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
3. Department of Neurology, Herlev University Hospital, Herlev, Denmark
4. Headache Clinic, Department of Neurology, Odense University Hospital, Odense, Denmark
5. Department of Clinical Research, University of Southern Denmark, Odense, Denmark
6. OPEN, Odense Patient data Explorative Network, Odense University Hospital, Odense, Denmark