Review Article

The Relationship Between Obesity, Bariatric Surgery, and Inflammatory Bowel Disease

Fiorella Cañete; Míriam Mañosa; Ariadna Clos; Eduard Cabré; Eugeni Domènech


Aliment Pharmacol Ther. 2018;48(8):807-816. 

In This Article


Obesity has become a worldwide epidemic in the 21st century. Traditionally, IBD was associated with low body weight, and obese patients were considered infrequent. However, recent studies demonstrate that the prevalence of both overweight and obesity in IBD patients is now similar to that of the general population. Although bariatric surgery is a safe and effective treatment for severe obesity and results in long-term weight loss, improvement and remission of obesity and related comorbidities (particularly arterial hypertension and diabetes), and improvement in quality of life and prolonged survival,[54] its impact on IBD has not been suitably assessed. The convoluted relationship between obesity, bariatric surgery and IBD reveals itself in two different ways. First, there are morbidly obese patients undergoing bariatric surgery who develop de novo IBD, particularly CD; and second, there are patients with established IBD and morbid obesity who undergo bariatric surgery. In the first scenario, it remains unknown whether bariatric surgery itself may be a trigger for some obese individuals to develop IBD by means of anatomical changes, induction of dysbiosis and/or mucosal barrier dysfunction, or a massive release of pro-inflammatory cytokines during rapid weight loss from fat tissue.[55] In obese patients undergoing bariatric surgery, CD should be considered in the differential diagnosis of the delayed onset of worsening diarrhoea or new/worsening abdominal pain. Finally, the scarce data available suggest that gastric sleeve appears to be a safe procedure for obese patients with known CD as worsening of the disease was not observed in any of 19 of 24 patients undergoing bariatric surgery. Therefore, taking into account this data and to preserve the small bowel from anatomic alterations, gastric sleeve could be the procedure of choice in these patients. Of note, morbidly obese IBD patients experience dramatic weight loss and an improvement in their comorbities after bariatric surgery. Moreover, no increased risk of IBD worsening following surgery has been observed, although larger series and prospective studies are warranted.