1. Department of Neurology and Neurophysiology; Faculty of Medicine and Health; Örebro University; Örebro Sweden
2. Department of Clinical Epidemiology and Biostatistics; Faculty of Medicine and Health; Örebro University; Örebro Sweden
3. Clinical Epidemiology Unit and Centre for Pharmacoepidemiology; Department of Medicine; Karolinska Institutet, Karolinska Hospital; Stockholm Sweden
4. Faculty of Medicine; Golestan University of Medical Sciences; Gorgan Iran
5. Faculty of Medicine and Health; Medicine; Örebro University; Örebro Sweden
6. Clinical Epidemiology Unit; Department of Medicine; Karolinska University Hospital; Karolinska Institutet; Stockholm Sweden
7. Research Department of Epidemiology and Public Health; University College; London UK