J Pediatr Gastroenterol Nutr 2017 04;64(4):586-591
*Department of Pathology, Akershus University Hospital, Lørenskog †Department of Pediatric and Adolescent Medicine, Vestre Viken Hospital Trust, Drammen, Norway ‡Department of Pediatrics, Akureyri Hospital, Akureyri, Iceland §Department of Pediatrics, Oslo University Hospital, Ullevål, Oslo ||Department of Pediatric and Adolescent Medicine, Akershus University Hospital, Lørenskog ¶Institute of Clinical Medicine, University of Oslo, Oslo #Department of Pediatrics, Østfold Hospital Trust, Kalnes **Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.