[1] Ostfold Hosp Trust, Dept Pediat, Gralum, Norway
[2] Norwegian Inst Publ Hlth, Oslo, Norway
[3] Univ Oslo, Fac Med, Inst Clin Med, Oslo, Norway
[4] Charles Univ Prague, Fac Med 2, Dept Paediat, Prague, Czech Republic
[5] Univ Hosp Motol, Prague, Czech Republic
[6] Univ Gothenburg, Sahlgrenska Acad, Inst Clin Sci, Dept Pediat, Gothenburg, Sweden
[7] Queen Silvia Childrens Hosp, Gothenburg, Sweden
[8] Norwegian Inst Publ Hlth, Div Inst Resources, Dept IT & E Hlth, Oslo, Norway
[9] Oslo Univ Hosp, Dept Pediat Res, Oslo, Norway
[10] Oslo Univ Hosp, Rikshosp, Dept Gastroenterol, Oslo, Norway
[11] Univ Oslo, KG Jebsen Coeliac Dis Res Ctr, Oslo, Norway