The Thyroid in Ulcerative Colitis and Crohn's Disease

Abstract

In order to investigate the prevalence of iodine depletion in chronic inflammatory bowel disease two separate studies have been performed. One was devoted to the 24‐hour urinary iodine excretion and 50 patients with ulcerative colitis or Crohn's disease were examined and compared with 102 controls. In the other study the thyroid 131I uptake was compared in 38 patients and 36 controls. Ten of the 50 patients with chronic inflammatory bowel disease had a 24‐hour urinary iodine excretion less than 40 μ.g, compared with 5 of the 102 controls (p < 0.01). Sixteen of the 38 patients had a 24‐hour thyroid 131I uptake of 50% or more of the administered test dose, compared with 4 of the 36 controls (p < 0.01). These results are compatible with an increased occurrence of iodine deficiency in patients with chronic inflammatory bowel disease. Treatment with corticosteroids or Salazopyrin® or a milk‐free diet did not influence these findings. No evidence was found of an impaired absorption of inorganic iodide from the gut.

Dietary I− Absorption

“…Moreover, 16 out of 38 patients showed a 24-h thyroid radioiodide uptake higher than 50% of the administered dose, compared with 4 out of 36 controls. Although these results suggested an increased occurrence of I À deficiency in patients with chronic inflammatory bowel diseases, no evidence was found of impaired absorption of inorganic iodide from the gut as the amount of orally administered radioiodide they absorbed was not significantly different from the corresponding amount for control patients ( Jarnerot, 1975). However, an accurate classification of patients with Crohn's disease according to the location of the inflammation (ileum, colon, or both) will shed light on the role of the small intestine in dietary I À absorption.…”