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

Objectives: To determine the efficacy of oral iodized oil in goitrous child ren who are both selenium (Se) and iodine deficient; to investigate if Se s tatus modifies the response of iodine deficient, goitrous children to oral supplementation with iodized oil. Design: A longitudinal intervention trial. Setting: Two rural villages in the western Gate d'Ivoire. Subjects: 51 goitrous non-anemic schoolchildren with both iodine and Se def iciency. Intervention: Each child received an oral dose of 0.4 mi iodized poppyseed oil containing 200 mg of iodine. They were followed for 1 y with measuremen ts of urinary iodine (UI), thyrotropin (TSH), thyroxine (T4), and thyroid v olume by ultrasound. Results: At baseline all children were goitrous and Se deficient; median UI was 29 mu g/l and mean serum Se (s.d.) was 14.5 (10.7) mu g/l. After recei ving iodized oil, thyroid volume decreased significantly vs baseline at 10, 15, 30 and 50 weeks (P < 0.001). At 50 weeks mean percentage change in thy roid volume from baseline was - 46.6% and only five children remained goitr ous. Median TSH values at 5, 10, 15, 30 and 50 weeks were reduced significa ntly (P < 0.001) compared to baseline. Among individual children the severi ty of Se deficiency predicted the degree of response to iodized oil. Baseli ne serum Se and percentage change in thyroid volume from baseline at 50 wee ks were strongly correlated (r(2) = 0.554). Baseline Se and percentage decr ease in TSH From baseline at 30 weeks were also well-correlated (r(2) = 0.4 67). Conclusion: Although more severe Se deficiency partially blunts the thyroid response to iodine supplementation, oral iodized oil is an effective metho d for iodine repletion in goitrous children who are Se deficient.