aDepartment of Medicine, Massachusetts General Hospital, Boston, Massachusetts

bDivision of Gastroenterology, Department of Medicine

cDepartment of Population Health, NYU Grossman School of Medicine, New York, New York

dDivision of Gastroenterology, Massachusetts General Hospital

eThe Mongan Institute

fHarvard Medical School, Boston, Massachusetts, USA

Correspondence to Bharati Kochar, MD, MS, MGH Crohn's and Colitis Center, 165 Cambridge Street, 9th Floor, Boston, MA 02114, USA. Tel: +1 617 724 3405; e-mail: [email protected]