Background: 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.
Methods: 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.
Results: 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.
Conclusions: 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.