[1] Oregon Hlth & Sci Univ, Pediat Psychol & Gastroenterol, Portland, OR 97201 USA
[2] Childrens Mercy Kansas City, Gastroenterol Hepatol & Nutr, Kansas City, MO USA
[3] Univ Missouri Kansas City, Dept Pediat, Kansas City, MO USA
[4] Kansas City Univ, Coll Osteopath Med, Kansas City, MO USA
[5] Med Coll Wisconsin, Sect Gastroenterol Hepatol & Nutr, Milwaukee, WI 53226 USA
[6] Sheffield Childrens Hosp NHS Fdn Trust, Sheffield, S Yorkshire, England