DOP05 Morbid obesity, a new susceptibility factor for developing Inflammatory Bowel Disease. Results of a population-based study

Canete Pizarro, F.C.(1);Vela, E.(2);Calafat, M.(1);Clèries, M.(2);Mañosa, M.(1);Domènech, E.(1);

(1)Germans Trias i Pujol University Hospital and CIBEREHD, Gastroenterology, Badalona, Spain;(2)Servei Català de la Salut- Generalitat de Catalunya, Unitat d’Informació i Coneixement, Barcelona, Spain;


Some genetic polymorphisms (present in less than 30% of patients) and environmental factors, such as tobacco exposure, have been identified to increase the susceptibility for developing inflammatory bowel disease (IBD), but it is suspected that there may be other still unknown environmental or epidemiological factors. In this sense, some studies suggested an increased incidence of IBD in individuals undergoing bariatric surgery (BS) for morbid obesity (MO). We aimed to assess whether BS or MO are associated with an increased risk of developing IBD.


All individuals resident in Catalonia (7.7 million inhabitants in 2021) with a diagnosis of obesity or MO within the period 2005-2020 were identified from the Catalan Public Health System Database. Children under the age of 18 and those diagnosed with IBD prior to the diagnosis of obesity or MO were excluded. Individuals BS and those with a new diagnosis of IBD were identified, and the likelihood of developing IBD was analyzed by Kaplan-Meier survival analysis. A Cox regression multivariable analysis was performed to assess independent risk factors for the development of IBD, Crohn’s disease (CD) and ulcerative colitis (UC).


Three cohorts were identified: 94,473 individuals with MO; 1,009,256 with obesity; and 14,698 who underwent BS during the study period. A total of 4,277 new diagnoses of IBD were identified, of which 78 among individuals who underwent BS prior to IBD diagnosis (0.84 cases per 1000 person-years), 409 among individuals with OM but without BS (0.90 cases per 1000 person-years), and 3,790 in obese individuals (0.60 cases per 1000 person-years). The likelihood of developing IBD was significantly higher in patients with MO as compared with obese patients (HR 1.46; 95%CI 1.32-1.62). These differences were maintained when the likelihood of developing CD or UC were assessed separately. In the multivariable logistic regression analysis, MO (HR 1,68; CI95% 1.41-1.99), female gender (HR 1.17; 95%CI 1.05-1.31) and active smoking (HR 1.62; 95%CI 1.43-1.84) were associated with an increased risk of CD. In UC, MO (HR 1,36; 95%CI 1.19-1.55) and BS (HR 2.62; 95%CI 1.34-2.11) were independent risk factors, whereas female gender (HR 0.86; 95%CI 0.79-0.93) was an independent protective factor.


MO is an independent risk factor for the development of IBD, for both CD and UC, whereas BS seems to increase the risk only for UC.