[1] Western Gen Hosp, Gastrointestinal Unit, Edinburgh EH4 2XU, Midlothian, Scotland
[2] Univ Edinburgh, Edinburgh, Midlothian, Scotland
[3] Royal Hosp Sick Children, Dept Child Life & Hlth, Edinburgh EH9 1LF, Midlothian, Scotland
[4] Royal Hosp Sick Children, Dept Pediat Gastroenterol & Nutr, Edinburgh EH9 1LF, Midlothian, Scotland
[5] Yorkhill Hosp, Dept Pediat Gastroenterol, Glasgow, Lanark, Scotland
[6] Univ Glasgow, Dept Child Hlth, Glasgow G12 8QQ, Lanark, Scotland
[7] Royal Aberdeen Childrens Hosp, Dept Pediat Gastroenterol, Aberdeen, Scotland