Thumb sucking or nail biting in childhood and adolescence is associated with an increased risk of Crohn's disease: results from a large case-control study.

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. PMID: 32730708 [PubMed - as supplied by publisher]
Source: Scandinavian Journal of Gastroenterology - Category: Gastroenterology Tags: Scand J Gastroenterol Source Type: research