The Influence of Breastfeeding, Cesarean Section, Pet Animals, and Urbanization on the Development of Inflammatory Bowel Disease: Data from the Swiss IBD Cohort Study

Abstract

<b><i>Introduction:</i></b> The pathophysiology of inflammatory bowel disease (IBD) is incompletely understood. Current concepts imply that environmental factors (EFs) trigger disease onset as well as flares in genetically susceptible individuals. <b><i>Objective:</i></b> The objective of this study is to analyze the association between IBD and various EFs, which may influence the pathogenesis of the disease. <b><i>Methods:</i></b> 2,294 patients from the Swiss IBD Cohort Study (SIBDCS) received a questionnaire regarding EF including mode of delivery, breastfeeding, animals in household, and place of residence. The control group comprised patients’ childhood friends, who grew up in a similar environment (“friends cohort”). <b><i>Results:</i></b> A total of 1,111 questionnaires were returned from SIBDCS patients (response rate: 48.4%). Breastfeeding for &#x3c;6 months was associated with a decreased risk for ulcerative colitis/indeterminate colitis (UC/IC) (OR: 0.473, <i>p</i> = 0.006). IBD patients reported less pet animals in the household than the control group (<i>p</i> = 0.004). The presence of cats or dogs (OR: 0.688, <i>p</i> = 0.015) and pet rodents (OR: 0.598, <i>p</i> = 0.001) in the household before the age of 20 was inversely associated with the risk for UC/IC. <b><i>Conclusion:</i></b> The present study underlines the importance of EFs in the pathogenesis of IBD. Overall, the development of UC/IC seems to be more affected from environmental influences than from Crohn’s disease. Our results imply a protective effect of possessing pet animals in household and short breastfeeding regarding the onset of UC/IC.