Identification of environmental risk factors associated with the development of Inflammatory Bowel Disease

ABSTRACT:

Background/aims: Multiple genetic and environmental factors are involved in the etiology of inflammatory bowel disease (IBD), consisting of Crohn’s disease (CD) and ulcerative colitis (UC) but data on these exposome factors are difficult to identify . Several exposome factors as smoking have been shown to be involved, as for other environmental factors, i.e. stress, results have been conflicting.

Methods: We performed a case-control study including 674 IBD patients of the 1000IBD cohort frequency-matched based on sex and age to 1,348 controls from population based Lifelines Cohort Study. Exposome data was obtained using the validated Groningen IBD Environmental Questionnaire (GIEQ), capturing exposome factors through different stages of life using 844 items, of which 454 applicable to study the role of 93 exposome factors in disease etiology. Logistic regression modeling with Bonferroni correction for multiple testing was applied to estimate the multivariable-adjusted effect of each exposome factor.

Results: For IBD, we identified four novel factors; stressful life-events (CD OR2.61/UC OR 2.92), high perceived stress (2.29/2.67), alcohol use (0.40/0.43), and bronchial hyperreactivity (3.04/2.36). Four novel factors were associated with only CD; prenatal smoke exposure (1.89), having a bedpartner (0.53), allergies (2.66) and cowmilk-hypersensitivity (5.87), two solely with UC; carpet flooring (0.57) and neuroticism (1.32). Nine factors were replicated.

Conclusions: In this study we identified ten novel and replicated nine previous reported exposome factors associated with IBD. Identifying these factors is important for both understanding disease etiology and future prevention strategies to decrease the development of IBD in genetically susceptible persons.