Footnotes

• Presented at This article is being published jointly in Gastroenterology, Gut and Journal of Clinical Gastroenterology. The article is identical except for minor stylistic and spelling differences in keeping with each journal’s style. Citations from any of the 3 journals can be used when citing this article.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Not commissioned; internally peer reviewed.

• Author note All authors contributed to the concept, content and final text, and review of the work, with the first five authors playing a lead role.