A comparison of the history of antibiotic therapy in individuals with and without inflammatory bowel disease (IBD) showed that the risk of developing this chronic pathology increases significantly with the increased use of systemic antibiotics, especially broad-spectrum ones.

It should be noted that IBDs, which include Crohn's disease and ulcerative colitis, are relapsing diseases characterized by chronic inflammation of various parts of the gastrointestinal tract, accompanied by diarrhea and abdominal pain. While a link between antibiotic use in early childhood and the development of IBD in childhood has been proven, the picture for adults is more controversial, as relevant studies must take into account numerous genetic, environmental, and other factors. To fill this gap, a large population-based case-control study was conducted in Sweden using data from the Swedish Patient Register and the Prescription Registry*.

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The study included 23,982 patients with IBD, first diagnosed between 2007 and 2016 (15,951 cases of ulcerative colitis, 7,898 cases of Crohn's disease, 133 cases of unclassified IBD). Each patient with IBD was compared with several individuals from the general population who were matched for age, gender, and region of residence (a total of 117,827 people). An additional control group consisted of sisters and brothers of patients with IBD (a total of 28,732 people). For each participant, information on antibiotic therapy was available: for the patient with IBD, for 1 year before the first diagnosis, and for individuals in the control groups, for the same period. When calculating the risk of developing IBD, we adjusted for several known risk factors.

The odds ratio for developing IBD in individuals who received antibiotics compared with those who did not was 1.88 for IBD, 1.74 for ulcerative colitis, and 2.27 for Crohn's disease. This means that antibiotic use more than doubles the risk of developing Crohn's disease. The odds ratio increased with the number of courses of antibiotic therapy. It was 1.11 for patients who received one course, 1.38 for two courses, and 1.55 for three or more courses of antibiotic therapy, compared with individuals who did not take antibiotics. The risk further increased with the use of broad-spectrum antibiotics. The odds ratio was similar, although slightly lower, when the siblings of patients served as a control group.

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Thus, increased cumulative exposure to systemic antibiotics, particularly broad-spectrum antibiotics, may be associated with an increased risk of developing IBD, and this association persists when comparing genetically related individuals. This demonstrates the important role of the gut microbiota in the development of IBD and further underscores the need for more responsible and rational use of antibiotics.

* Nguyen LH, Örtqvist AK, Cao Y et al. Antibiotic use and the development of inflammatory bowel disease: a national case-control study in Sweden. The Lancet Gastroenterology & Hepatology, Published: August 17, 2020. https://doi.org/10.1016/S2468-1253(20)30267-3