Footnotes

• Contributors LW: study concept and design, data collection, analysis and interpretation of data, drafting of the manuscript and statistical analysis. RYT and MC: data collection, analysis and interpretation of data, and revision of the manuscript. AO, LR and CV: data collection and revision of the manuscript. JS, MF and SV: study concept and design, and revision of the manuscript. TV and JR: study concept and design, analysis and interpretation of data, revision of the manuscript and study supervision.

• Funding LW and TV are supported by the Flanders Research Foundation (FWO Vlaanderen) through a doctoral fellowship (1190619N) and senior clinical research mandate (1830517N). RYT is supported by an FWO postdoctoral fellowship (1234321N). Jan Tack is supported by a Methusalem grant of KU Leuven (EZX-C9725-METH/14/05). The Raes lab is supported by KU Leuven, the Rega Institute and VIB. This research was funded by a grant of the Belgian IBD Research group (BIRD).

• Competing interests None declared.

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

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