[1] Stanford Univ, Div Gastroenterol & Hepatol, Sch Med, 300 Pasteur Dr,Alway M211 MC 5187, Stanford, CA 94305 USA
[2] Stanford Univ, Dept Obstet & Gynecol, Sch Med, Stanford, CA 94305 USA
[3] Stanford Univ, Dept Urol, Sch Med, Stanford, CA 94305 USA
[4] Univ Copenhagen, Herlev Hosp, Dept Gastroenterol, Med Sect, Copenhagen, Denmark
[5] Univ Southern Denmark, Dept Sports Sci & Biomech, Odense, Denmark
[6] Univ Copenhagen, Herlev & Gentofte Hosp, Dept Physiotherapy & Occupat Therapy, Copenhagen, Denmark
[7] Mt Sinai Hosp, Dept Obstet & Gynaecol, Toronto, ON, Canada