Effect of oral iodized oil on thyroid size and thyroid hormone metabolism in children with concurrent selenium and iodine de®ciency

Objectives: To determine the ef®cacy of oral iodized oil in goitrous children who are both selenium (Se) and iodine de®cient; to investigate if Se status modi®es the response of iodine de®cient, goitrous children to oral supplementation with iodized oil. Design: A longitudinal intervention trial. Setting: Two rural villages in the western CoÃte d'Ivoire. Subjects: 51 goitrous non-anemic schoolchildren with both iodine and Se de®ciency. Intervention: Each child received an oral dose of 0.4 ml iodized poppyseed oil containing 200 mg of iodine. They were followed for 1 y with measurements of urinary iodine (UI), thyrotropin (TSH), thyroxine (T4), and thyroid volume by ultrasound. Results: At baseline all children were goitrous and Se de®cient; median UI was 29 mg=l and mean serum Se (s.d.) was 14.8 (10.7) mg=l. After receiving iodized oil, thyroid volume decreased signi®cantly vs baseline at 10, 15, 30 and 50 weeks (P< 0.001). At 50 weeks mean percentage change in thyroid volume from baseline was746.6% and only ®ve children remained goitrous. Median TSH values at 5, 10, 15, 30 and 50 weeks were reduced signi®cantly (P< 0.001) compared to baseline. Among individual children the severity of Se de®ciency predicted the degree of response to iodized oil. Baseline serum Se and percentage change in thyroid volume from baseline at 50 weeks were strongly correlated (r2ˆ 0.554). Baseline Se and percentage decrease in TSH from baseline at 30 weeks were also well-correlated (r2ˆ 0.467). Conclusion: Although more severe Se de®ciency partially blunts the thyroid response to iodine supplementation, oral iodized oil is an effective method for iodine repletion in goitrous children who are Se de®cient. Sponsorship: The Swiss Federal Institute of Technology, ZuÈrich, the Foundation for Micronutrients in Medicine, Rapperswil, Switzerland, and the Thrasher Research Fund, Salt Lake City, USA. Descriptors: iodine; selenium; de®ciency; goiter; interaction; iodized oil European Journal of Clinical Nutrition (2000) 54, 209±213