Endotoxin levels in house dust samples and juvenile inflammatory bowel disease − a case−control study

Abstract

Background and aims: Animal contact may reduce the risk not only for allergic diseases but also for inflammatory bowel diseases (IBD). We aimed to clarify the association between endotoxin levels in the home environment and IBD.

Methods: A case-control study including 85 IBD cases (aged: 8-29 years) and 91 controls undergoing strabismus surgery (aged: 11-23 years) was conducted in Southern Germany. A questionnaire and a dust sampling sock were mailed to the parents (Response: 71% among cases, 58% among controls). Endotoxin levels were determined using Limulus Amoebocyte Lysate assay tests. Logistic regression models adjusting for age, sex, high parental school education, family history of IBD, environmental factors in the first year of life (urban place of living, farm animal or pet contact), and presence of cats or dogs in the room were performed.

Results: Geometric mean levels of endotoxin were lower among cases (50.67 Endotoxin Units (EU)/mg; geometric standard deviation (GSD); 2.32) than controls (60.25 EU/mg; GSD: 2.22). Endotoxin levels were inversely, but not statistically significantly, related to case status in the multivariate logistic regression analysis (OR for the interquartile range increase: 0.70; 95%CI: 0.46-1.04).

Conclusion: In our study sample, high endotoxin levels were inversely related to case status. Whether endotoxin is a marker of hygiene or causal needs further investigation.