1. Department of Medical Epidemiology and Biostatistics; Karolinska Institutet; Stockholm Sweden
2. Department of Medicine; Visby Hospital; Visby Sweden
3. Department of Medicine, Gastroenterology and Hepatology Unit; Karolinska Institutet; Stockholm Sweden
4. Department of Mathematics; Stockholm University; Stockholm Sweden
5. Clinical Epidemiology and Biostatistics, School of Medical Sciences; Örebro University; Örebro Sweden
6. Clinical Epidemiology Unit, Department of Medicine, Solna; Karolinska Institutet; Stockholm Sweden
7. Department of Epidemiology and Public Health; University College London; UK
8. Department of Infectious Diseases, School of Medical Sciences; Örebro University; Örebro Sweden