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DOP001 European Crohn's and Colitis Organisation topical review on environmental factors in IBD

Maaser C.*1, Langholz E.2, Gordon H.3, Burisch J.4, Ellul P.5, Hernández V.6, Karakan T.7, Katsanos K.H.8, Krustins E.9, Levine A.10, Mantzaris G.J.11, O'Morain C.12, Yuksel E.S.13, Strid H.14, Annese V.15

1Klinikum Lueneburg, Lueneburg, Germany 2Department C, Gastroenterology Section, Herlev and Gentofte University Hospital, Hellerup, Denmark 3Department of Gastroenterology, Royal London Hospital, Barts Health NHS Trust, London, United Kingdom 4Department of Gastroenterology, North Zealand University Hospital, Fredrikssund, Denmark 5Department of Gastroenterology, Division of Gastroenterology, Mater Dei Hospital, Msida, Malta 6Department of Gastroenterology, Hospital Άlvaro Cunqueiro, Vigo, Spain 7Department of Gastroenterology, Ankara, Turkey 8Department of Gastroenterology and Hepatology, University and Medical School of Ioannina, Ioannina, Greece 9Department of Gastroenterology, Hepatology and Nutrition Therapy, Pauls Stradins Clinical University Hospital, Riga, Latvia 10Paediatric Gastroenterology & Nutrition Unit, Wolfson Medical Center, Tel Aviv, Israel 11Department of Gastroenterology, Evangelismos Hospital, Athens, Greece 12Department of Gastroenterology, Dublin, Ireland 13Department of Gastroenterology, Izmir Katip Celebi University, Izmir, Turkey 14Department of Internal Medicine, Södra Älvsborgs Hospital, Borås, Sweden 15Department of Emergency, Division of Gastroenterology, University Hospital Careggi, Florence, Italy


This ECCO topical review of the European Crohn's and Colitis Organisation (ECCO) focuses on the role of environmental factors in respect to the development of IBD as well as the influence on the course of established IBD. The objective was to reach expert consensus to provide evidence-based guidance for clinical practice.


The ECCO Environmental Factors Working Group was selected from applications following response to an ECCO call. A literature search was undertaken by members of the group. The search was conducted via PubMed. Drafting of text and statements was divided between members of the Working Groups. Statements were voted upon anonymously during a face-to-face meeting in Amsterdam at ECCO 2016. Statements with >80% agreement from all members were included within the paper in accordance with ECCO standards.


The literature research and discussion of the workgroup members led to the development of a total of 22 ECCO current practise positions.

Established risk factors for CD, beside smoking are oral contraception before the development of IBD, exposure to antibiotics, previous tonsillectomy and probably appendectomy. Risk factors for UC are oral contraceptive and moving to areas with high prevalence. A positive association with IBD is found with caesarian sections, high animal fat and animal proteins, food additives and low fibre, symbiosis, urban air pollution and vitamin D deficiency. Data regarding hygiene hypothesis, exercise, sedentary, and seasonality are conflicting or lacking. Protective factors for CD are having been breastfed as well as smoking cessation, while appendectomy appears to be protective against UC onset.


Questions regarding the influence of environmental factors are among the most frequent ask questions from patients. This topical review will help the treating IBD team to get an updated balanced overview of the enormous number of published studies on the role of environmental factors with often conflicting results.