Assessing the effect of cesarean section on Crohn’s Disease Pascale Gagnon1 1. Interdisciplinary School of Health Science, University of Ottawa INTRODUCTION METHODS RESULTS Objective to evaluate the effect of caesarean delivery on the subsequent development of Crohn's disease in developed countries. Background Crohn’s Disease (CD) is an Inflammatory Bowel Disease (IBD) characterize by a dysbiosis of the bowel. Incidence of CD is increasing in developed countries Cesarean section (CS) used to be a urgent procedure due to pregnancy complication. CS is also increasing in developed countries. Rationale Hygiene Hypothesis Early colonisation of the bowel Perinatal risk factors associated with inflammatory and autoimmune diseases: pregnancy and first years of life exposures associated with asthma and type 1 diabetes. How does CS could increase CD risk: vaginal delivery first expose the new born to vaginal tract bacteria while CS is likely to expose him to atypical bacteria. Why this review is important: CS and CD are increasing only in developed countries. study findings are conflicting. Exclusion Criteria Mothers with IBD No distinction between CD and others IBD Analysis 8 studies were included : 4 case-control and 4 cohort (figure 1) The assessment of methodological quality was based of the two systematic reviews published in 2014 9,10. Data extraction was done and potential bias were listed. The quality of the studies depend on the statistical analysis made to reduce those potential bias (table 1). Different outcomes measurements could lead to misclassification Not all reviews adjusted values for potential bias Socioeconomic status (ES) (selection bias, response bias) elective vs acute CS (difference in the procedure) Breastfeeding CONCLUSION & DISCUSSION The overall studies demonstrate no significant association between CS and CD. Two studies find a statistically significant association between CS and 1,4 Six studies demonstrated no significant associations2,3,5,6,7,8 Three studies find a significant increasing risk of CD for the boys delivered by CS 1,3,7 Two studies divided CS intervention in elective CS and acute CS. However, they find opposites results 4,8 Potential bias and limitation SES could induce potential bias Response bias Selection bias for case-control studies Misclassification bias due to self-report questionnaires Diagnosis criteria for CD are very similar to ulcerative colitis (UC) others Further research: Evaluate the risk of CD associate with elective CS vs acute CS Understanding the mechanism leading to the increased risk of CD among boys delivered by CS Investigate the impact of SES on CD RESULTS Odd ratio were calculated with 95% CI for evaluating the risk of CD associated with CS. Raw data were not always available. Studies characteristics and statistical analysis are showed in table 2 Two systematic review/meta-analysis (not included in the systematic review) had opposites findings. However, there were limitations and methodological mistakes in both9,10 All studies adjusted values for the most plausible confounders (age, gender, smoking, family history of IBD, preterm of birth) Three studies were done with pediatric populations: high heterogeneity and different statistical analysis METHODS Study Design Structured review / Literature review Search Strategy PUBMED Key words: Crohn’s disease, Inflammatory bowel disease, cesarean section, caesarean, mode of delivery, perinatal Peer reviewed Inclusion Criteria RCTs, case-control and cohort studies Complete medical data of perinatal context Confirmed diagnosis of CD (ICD codes: K50.0-K50.9; histologic and/or radiologic tests) Developed countries populations (for a better quality assessment and control of confounding) REFERENCES Andersen V, Erichsen R, Froslev T, Sorensen H & Ehrenstein V. (2013). Differential risk of ulcerative colitis and Crohn’s disease among boys and girls after cesarean delivery. 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Preterm birth but not mode of delivery is associated with an increased risk of developing inflammatory bowel disease later in life. Inflamm Bowel Dis, 13, 1385–1390 Bernstein C-N., Banerjee, A., Targownik, L-E., Singh, H., Ghia, J-E., Burchill, C., Chateau, D. & Roos, L-L. (2016). Cesarean Section Delivery Is Not a Risk Factor for Development of Inflammatory Bowel Disease: A Population-based Analysis. Clinical Gastroenterology and Hepatology, 14(1), 50 Kristensen,K. & Henriksen, L. Cesarean section and disease associated with immune function. The Journal of Allergy and Clinical Immunology, 137(2), 587-590. Li,Y., Yun, T. et all. (2014). Cesarean delivery and risk of inflammatory bowel disease: a systematic review and meta-analysis. Scandinavian Journal of Gastroenterology, 49(7), 834-844. Bruce A. et all. (2014). Mode of Delivery and Risk of Inflammatory Bowel Disease in the Offspring: Systematic Review and Meta-analysis of Observational Studies. Inflammatory bowel diseases, 20(2), 1217-1226. Higgins. (2008). Cochrane Handbook for Systematic Reviews of Interventions. England: Iley-Blackwell. ACKNOWLEDGEMENTS I would like to thanks Dr. Jacques Gagnon for the methodological advise and the moral support provided during this project.