Niels Teich1,2, Wolfgang Mohl3, Christian Primas4, Gottfried Novacek4, Annika Gauss5, Jens Walldorf6, Gisela Felten7, Raja Atreya8, Wolfgang Kruis9, Dominik Bettenworth10, Artur Bartosz Roznowski11, Jost Langhorst12, Karen Schmidt13, Tony Bruns14, Andreas Stallmach2,15. 1. Internistische Gemeinschaftspraxis für Verdauungs-und Stoffwechselkrankheiten, Leipzig, Germany. 2. Medical Faculty, Friedrich Schiller University Jena, Jena, Germany. 3. Zentrum für Gastroenterologie Saar MVZ GmbH, Saarbrücken, Germany. 4. Department of Internal Medicine III, Division of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria. 5. Department of Gastroenterology and Hepatology, University Hospital Heidelberg, Heidelberg, Germany. 6. Department of Internal Medicine I, Martin-Luther-University of Halle-Wittenberg, Halle, Germany. 7. Gastroenterologische Gemeinschaftspraxis Herne, Herne, Germany. 8. Department of Medicine 1, University of Erlangen-Nürnberg, Erlangen. 9. Medical Faculty, University of Cologne, Köln, Germany. 10. Medizinische Klinik und Poliklinik B, Universitätsklinikum Münster, Münster, Germany. 11. Klinik am See, Rüdersdorf b. Berlin, Germany. 12. Department for Internal and Integrative Medicine, University of Duisburg-Essen, Duisburg, Germany. 13. Kompetenznetz Darmerkrankungen e.V, Kiel, Germany. 14. Medical Department III, University Hospital RWTH Aachen, Aachen, Germany. 15. Department of Internal Medicine IV, Jena University Hospital, Jena, Germany.
Abstract
BACKGROUND: The hygiene hypothesis suggests that a reduction in microbial exposure contributes to an impaired immune response later in life and increases the incidence of immune-mediated diseases such as inflammatory bowel diseases (IBD). Thumb sucking and nail biting are two early habits that modulate the oral microbiota composition and antigen load. OBJECTIVE: We hypothesized a lower risk of Crohn's disease (CD) and ulcerative colitis (UC) in adults with prior thumb sucking and nail biting. METHODS: 918 IBD cases and their 918 siblings without IBD were asked to fill out a survey containing 32 questions on environmental factors in childhood and early adulthood. Prevalence of thumb sucking and/or nail biting at the usually well-remembered time of (1) school enrollment and (2) coming-of-age ceremonies was the predefined combined risk factor of this study. RESULTS: 65% of the patients were female and 57% suffered from CD. About 49% of IBD patients but only 44% of their siblings reported thumb sucking/nail biting at the time of school enrollment or coming-of-age (p = .007). Sensitivity analysis revealed that this difference was observed in patients with CD (50% versus 41%; RR= 1.22; 95% CI 1.09-1.37, p = .001) but not in patients with UC (49% versus 48%; RR= 1.02; 95% CI 0.90-1.17; p = .83). CONCLUSION: Contrary to our expectation and challenging the hygiene hypothesis, we found that common oral habits are not protective against IBD. Instead, nail biting at the time of school enrollment and coming-of-age was a statistically significant risk factor for CD in our cohort. Key summary Evidence available before this study: The hygiene hypothesis suggests that a reduction in microbial exposure due to improved health activities has contributed to an immunological imbalance in the intestine and an increased incidence of allergic and autoimmune diseases. A population-based birth cohort study has demonstrated that thumb-sucking and nail biting in children lead to a reduction of the risk of atopic sensitization, asthma, and hay fever. Added value of this study: Contrary to the hypothesis, thumb sucking and nail biting were not associated with a reduced risk of IBD. Instead, thumb sucking and/or nail biting at the usually well-remembered points in time of school enrollment and of religious or secular coming-of-age ceremonies was associated with a higher risk of Crohn's disease but not of ulcerative colitis. Our data did not support the hygiene hypothesis, one pathogenic concept in the context of IBD.
BACKGROUND: The hygiene hypothesis suggests that a reduction in microbial exposure contributes to an impaired immune response later in life and increases the incidence of immune-mediated diseases such as inflammatory bowel diseases (IBD). Thumb sucking and nail biting are two early habits that modulate the oral microbiota composition and antigen load. OBJECTIVE: We hypothesized a lower risk of Crohn's disease (CD) and ulcerative colitis (UC) in adults with prior thumb sucking and nail biting. METHODS: 918 IBD cases and their 918 siblings without IBD were asked to fill out a survey containing 32 questions on environmental factors in childhood and early adulthood. Prevalence of thumb sucking and/or nail biting at the usually well-remembered time of (1) school enrollment and (2) coming-of-age ceremonies was the predefined combined risk factor of this study. RESULTS: 65% of the patients were female and 57% suffered from CD. About 49% of IBDpatients but only 44% of their siblings reported thumb sucking/nail biting at the time of school enrollment or coming-of-age (p = .007). Sensitivity analysis revealed that this difference was observed in patients with CD (50% versus 41%; RR= 1.22; 95% CI 1.09-1.37, p = .001) but not in patients with UC (49% versus 48%; RR= 1.02; 95% CI 0.90-1.17; p = .83). CONCLUSION: Contrary to our expectation and challenging the hygiene hypothesis, we found that common oral habits are not protective against IBD. Instead, nail biting at the time of school enrollment and coming-of-age was a statistically significant risk factor for CD in our cohort. Key summary Evidence available before this study: The hygiene hypothesis suggests that a reduction in microbial exposure due to improved health activities has contributed to an immunological imbalance in the intestine and an increased incidence of allergic and autoimmune diseases. A population-based birth cohort study has demonstrated that thumb-sucking and nail biting in children lead to a reduction of the risk of atopic sensitization, asthma, and hay fever. Added value of this study: Contrary to the hypothesis, thumb sucking and nail biting were not associated with a reduced risk of IBD. Instead, thumb sucking and/or nail biting at the usually well-remembered points in time of school enrollment and of religious or secular coming-of-age ceremonies was associated with a higher risk of Crohn's disease but not of ulcerative colitis. Our data did not support the hygiene hypothesis, one pathogenic concept in the context of IBD.
Entities:
Keywords:
Crohn’s disease; gut microbiota; hygiene hypothesis; nail biting; thumb sucking; ulcerative colitis