Clinically relevant thyroid disorders and inflammatory bowel disease are inversely related: a retrospective case-control study

Abstract

Objectives: The risk of thyroid disorders (TDs) in inflammatory bowel disease (IBD) is still controversial. The aim of this retrospective, single-center, case-control study was to explore the association between clinically relevant functional TDs and IBD.

Methods: Consecutive individuals for a total of 313 IBD patients [90 Crohn's disease (CD); 223 ulcerative colitis (UC)], and 833 individuals undergoing colonoscopy for screening without IBD were collected. In the study, subject's information on thyroid status were retrieved. Thyroid disorders were classified, according to the functional status, as hypothyroidism or hyperthyroidism. Patients with TDs (cases) were compared with 941 without (controls) according to IBD exposure. Unadjusted and adjusted odds ratios (ORs) and their 95% confidence interval (CI) were calculated.

Results: Clinically relevant TDs were detected in 205 (17,9%) patients and the prevalence was significantly lower in IBD patients compared with subjects without (8.3% vs 12.9%; p = 0.029). After adjusting for potential confounders, a higher TDs risk was confirmed in female (OR 2.72; 95%CI 1.88‒3.92) and older subjects (OR 1.01; 95%CI 1.00‒1.03), and a lower risk in IBD (OR 0.51; 95%CI 0.34‒0.76), especially for hypothyroidism (OR 0.33; 95%CI 0.17‒0.66) in UC. Among four thyroid cancers, only one was detected in IBD patients.

Conclusions: Overall, in our study, the risk of TDs was lower in IBD patients. To assess routinely hormones and/or thyroid gland imaging in the absence of clinical signs or symptoms seems unnecessary in IBD patients, at least in our geographic area.

Keywords: Crohn's disease; Hypothyroidism; Thyroid cancer; Ulcerative colitis; hyperthyroidism.