Bidirectional Association of Type 2 Diabetes Mellitus and Inflammatory Bowel Diseases: A Large-scale Prospective...

Type 2 diabetes (T2DM) and inflammatory bowel disease (IBD) are 2 distinct diseases that share a similar pathophysiology; however, the association between the 2 diseases remains elusive. We aimed to investigate the bidirectional association between T2DM and IBD in a large prospective population cohort.

Participants were recruited from the prospective cohort of UK Biobank. We included 4921 patients with IBD and 438,948 non-IBD to assess the incident risk of T2DM, and 11,649 patients with T2DM and 438,948 non-T2DM to assess the incident risk of IBD. Multivariable Cox proportional hazards regression model was used to calculate adjusted hazard ratio (HR).

A total of 27,373 incident T2DM and 2696 incident IBD cases were identified during a median of 12.6- and 12.9-years' follow-up, respectively. After adjustment for potential confounders, participants with IBD, UC, or CD showed an excess risk of incident T2DM (HR=1.44, 95% CI: 1.31-1.59 for IBD, HR=1.41, 95% CI: 1.26-1.58 for UC, and HR=1.62, 95% CI: 1.39-1.89 for CD, respectively), compared with non-IBD. By contrast, compared with non-T2DM, participants with T2DM also showed higher risk of incident IBD (HR=1.40, 95% CI: 1.15-1.69), UC (HR=1.41, 95% CI: 1.13-1.76), or CD (HR=1.48, 95% CI: 1.08-2.04). Furthermore, the increased risk of incident T2DM was more evident when accompanied with the severity of IBD, and vice versa. Sensitivity analyses and subgroup analyses according to age, sex, and body mass index demonstrated similar results.

IBD and T2DM are bidirectionally associated with higher comorbidity risks. Further investigations are needed to elucidate the shared pathogenesis underlying these 2 diseases.