1. Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
2. Department of Life Sciences, University of Applied Sciences Utrecht, Utrecht, The Netherlands
3. MS Center Amsterdam, VU University Medical Centre, Amsterdam, The Netherlands
4. General Practice Research Database, London, UK
5. MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
6. Department of Clinical Pharmacy and Toxicology, Maastricht University Medical Centre, Maastricht, The Netherlands