1 Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Department of Gastroenterology and Hepatology, University Digestive Health Care Center Basel - Clarunis, Basel, Switzerland. Electronic address: fahim.ebrahimi@ki.se.
2 Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; Department of Pediatrics, Örebro University Hospital, Örebro, Sweden; Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA.