Crohn's Disease Is Associated with the Risk for Thyroid Cancer

It is known that inflammatory bowel disease (IBD) is associated with a high risk for some of extraintestinal cancers. The aim of this study was to identify whether IBD is associated with thyroid cancer using a large national database.

We performed a case-control study using the 2012 National Inpatient Sample (NIS) database. The study group included all patients with Crohn's disease (CD) (ICD-9 Code: 555) and ulcerative colitis (UC) (ICD-9 Code: 556), and the control group included all patients with diverticulitis (ICD-9 Code: 562.11, 562.13). Both univariable and multivariable analyses were performed to assess the risk factors associated with thyroid cancer.

We analyzed more than 28 million hospitalizations in 2012, with 289,935 being IBD-related admissions and 315,145 being diverticulitis-related admissions. Subjects who had IBD were found to be significantly more likely to have thyroid cancer than those with diverticulitis (odds ratio = 1.97 [1.5-2.6], P = 0.033). There was no difference between men and women in the prevalence of thyroid cancer in IBD (P = 0.6). There was no difference between CD and UC (P = 0.14) and between UC and diverticulitis (P = 0.93). In multivariate analysis, CD was found to be associated with thyroid cancer (odds ratio = 2.3 [1.06-5.1], P = 0.034). Age was shown to be a protective factor in the presence of thyroid cancer (P < 0.005), and a higher Charlson comorbidity index was associated with the presence of thyroid cancer (odds ratio, 1.5 [1.3-1.7]; P < 0.001).

Our study showed that CD, not UC, is associated with a higher risk for thyroid cancer. It is recommended that patients with CD may need a close monitoring of thyroid diseases.