[1] Stanford Univ, Sch Med, Div Gastroenterol & Hepatol, Stanford, CA 94305 USA
[2] Univ Copenhagen, Herlev Hosp, Med Sect, Dept Gastroenterol, Copenhagen, Denmark
[3] Stanford Univ, Dept Pediat, Sch Med, Stanford, CA 94305 USA
[4] Univ Southern Denmark, Dept Sports Sci & Biomech, Odense, Denmark
[5] Univ Copenhagen, Herlev & Gentofte Hosp, Div Physiotherapy & Occupat Therapy, Copenhagen, Denmark
[6] Mt Sinai Hosp, Dept Obstet & Gynaecol, Toronto, ON, Canada