IBD & extraintestinal cancers

IBD & extraintestinal cancers

August 10, 2021

Issue 10

Clinical Question

Does IBD increase the risk of Type 2 diabetes?

Editor’s Bottom Line

Patients with IBD may be at increased risk of Type 2 diabetes mellitus. Clinicians managing IBD patients should encourage weight control, healthy eating and physical exercise. 


Jess T, Jensen BW, Andersson M, et al. Inflammatory Bowel Diseases Increase Risk of Type 2 Diabetes in a Nationwide Cohort Study. Clin Gastroenterol Hepatol. 2020;18(4):881–88.e1; https://doi.org/10.1016/j.cgh.2019.07.052


Ileal L-cells secrete glucagon-like peptide 1 (GLP-1) that regulates insulin secretion. Accordingly, Danish researchers set out to determine whether IBD affects the risk of Type 2 diabetes (T2D). They analyzed two national databases, including 6,028,844 individuals 30 years of age or older living in Denmark between 1977 and 2014. The study population included 44,915 individuals with ulcerative colitis and 20,265 with Crohn’s disease. Forty-two percent of IBD patients were male and a similar proportion were younger than 40 years of age at the time of IBD diagnosis.

Standardized incidence ratio (SIR) analysis found that the incidence rate of T2D among IBD patients was 4.67 per 1,000 patient years, compared to 3.02 cases per 1,000 patient-years among the general population (SIR: 1.54; 95% Confidence Interval [CI], 1.49–1.60). Although the risk of T2D was higher among IBD patients for the entire duration of follow-up, the risk of developing T2D was highest during the first year after IBD diagnosis (SIR: 4.48; 95% CI, 4.16–4.83). The risk of T2D did not differ by sex or number of comorbidities. Patients diagnosed with IBD after 40 years of age were more likely than those diagnosed at a younger age to develop diabetes (SIR: 1.57 vs. 1.45 for >40 vs. younger; P=0.05). In an analysis limited to those who had at least two hospital visits annually, those with IBD still had higher rates of T2D than those in the general population who had at least two hospital visits annually. Additionally, although corticosteroid use increased the risk of T2D both in the IBD population and the general population, an analysis limited to those unexposed to corticosteroids showed rates of T2D were still higher among IBD patients.

Patients diagnosed with IBD between 2003 and 2014 were significantly more likely to have T2D (SIR: 1.79; 95% CI, 1.67–1.91) than those diagnosed with IBD between 1977 and 1988 (SIR: 1.47; 95% CI, 1.39–1.56) or between 1989 and 2002 (SIR: 1.48; 95% CI, 1.41–1.56) (P<.001). This finding prompted the authors to call for further research into the effects of newer IBD treatments on diabetes risk.


Study Design: Retrospective cohort
Funding: The study was supported by a grant from the Novo Nordisk Foundation
Allocation: Not applicable
Setting: National database
Level of Evidence: 2b (Oxford Levels of Evidence)