1. Centre for Pharmacoepidemiology, Department of Medicine Solna, Karolinska Institutet and Department of Internal MedicineDanderyd Hospital Stockholm Sweden
2. Centre for Pharmacoepidemiology, Department of Medicine Solna and Department of Laboratory MedicineKarolinska Institutet Stockholm Sweden
3. Clinical Epidemiology Division, Department of Medicine SolnaKarolinska institutet Stockholm Sweden
4. Information Services DepartmentTHL National Institute for Health and Welfare, Helsinki, Finland and Division of Family Medicine, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet Stockholm Sweden
5. Information Services DepartmentTHL National Institute for Health and Welfare Helsinki Finland
6. Department of Clinical EpidemiologyAarhus University Denmark
7. Dermatology, Department of Public Health and Clinical MedicineUmeå University Umeå Sweden