Effect of Selenium Supplementation in Hypothyroid Subjects of an Iodine and Selenium Deficient Area : The Possible Danger of Indiscriminate Supplementation of Iodine-Deficient Subjects With Selenium.

Contempré, Bernard; Dumont, Jacques Emile; Ngo, Bebe; Thilly, Claude Hector; Diplock, A. T.; Vanderpas, Jean

doi:10.1210/jcem-73-1-213

Cited by 138 publications

(79 citation statements)

References 7 publications

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“…None of the children showed signs of iodine induced hyper-or hypothyroidism or other adverse effects. Studies in Zaire have shown that correcting Se de®ciency before improving iodine status of hypothyroid iodine-and Se-de®cient subjects can aggravate hypothyroidism (Contempre et al, 1991). Therefore, it is important to correct iodine de®ciency ®rst and, based on the results of this study, the use of iodized oil appears to be safe and effective in children who are both iodine and Se de®cient.…”

Section: Discussionmentioning

confidence: 72%

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

Zimmermann

Adou²,

Torresani³

et al. 2000

Eur J Clin Nutr

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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 Co Ãte 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 mgal and mean serum Se (s.d.) was 14.8 (10.7) mgal. 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 (r 2 0.554). Baseline Se and percentage decrease in TSH from baseline at 30 weeks were also well-correlated (r 2 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.

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Section: Discussionmentioning

confidence: 72%

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

Zimmermann

Adou²,

Torresani³

et al. 2000

Eur J Clin Nutr

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“…In combined iodine and selenium deficiency, selenium supplementation is not indicated without prior iodine supplementation (7,8). All these studies were conducted in severely selenium-and iodinedeficient populations.…”

Section: Introductionmentioning

confidence: 99%

Association of selenium with thyroid volume and echostructure in 35- to 60-year-old French adults

Derumeaux

Valeix

Castetbon³

et al. 2003

European Journal of Endocrinology

136

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Objective: To investigate the relationship between selenium status, thyroid volume and gland echostructure. Design: Cross-sectional. Methods: In 792 men (45-60 years) and 1108 women (35-60 years) from the SU.VI.MAX study, thyroid volume and gland echostructure were determined ultrasonographically. At baseline, thyrotropin, free thyroxine, selenium, zinc, a-tocopherol, b-carotene, retinol, urinary iodine and thiocyanate concentrations were measured. Alcohol consumption, smoking, and menopausal status were assessed by a questionnaire. A stepwise linear and a logistic regression model were used, adjusting for antioxidant vitamins, trace elements status and age. Results: In women, there was an inverse association between selenium status and thyroid volume ðP ¼ 0:003Þ: A protective effect of selenium against goiter (odds ratio ðORÞ ¼ 0:07; 95% confidence interval ðCIÞ ¼ 0:008 -0:6) and thyroid tissue damage ðOR ¼ 0:2; 95% CI ¼ 0:06 -0:7Þ was observed. There was no evidence of an association between menopausal status and other antioxidant elements, thyroid volume or thyroid hypoechogenicity. Smoking, but not alcohol consumption, was associated with an increased risk of thyroid enlargement in women ðOR ¼ 3:94; 95% CI ¼ 1:64 -9:48Þ: No association between thyroid volume, thyroid structure or selenium was found in men. Conclusion: Our findings suggest that selenium may protect against goiter. Selenium was related to thyroid echostructure, suggesting it may also protect against autoimmune thyroid disease.

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“…Selenium is also a component of the type I deiodinase enzyme which converts T 4 to T 3 (37). A decrease in the activity of this enzyme in selenium deficiency in combination with iodine deficiency may help in restoring T 4 levels to the brain, thus protecting it from further neurological damage (38). Glutathione peroxidase activity was found to be decreased in selenium-deficient areas in Zaire, and the enzyme activity in cretins was half the level in normal subjects (38).…”

mentioning

confidence: 99%

“…A decrease in the activity of this enzyme in selenium deficiency in combination with iodine deficiency may help in restoring T 4 levels to the brain, thus protecting it from further neurological damage (38). Glutathione peroxidase activity was found to be decreased in selenium-deficient areas in Zaire, and the enzyme activity in cretins was half the level in normal subjects (38). Combined iodine and selenium deficiency could thus explain the large predominance of the myxedematous cretin as typically seen in Zaire.…”

mentioning

confidence: 99%

Endemic cretinism in Thailand: a multidisciplinary survey

Rajatanavin

Chailurkit²,

Winichakoon³

et al. 1997

European Journal of Endocrinology

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Endemic cretinism has been classified into neurological and myxedematous types. Profound mental deficiency, deaf-mutism and cerebral diplegia are predominantly found in the former. The latter have been described as less mentally retarded but with severe growth retardation and myxedematous features. The pathogenesis of different clinical types of endemic cretinism is still unclear. Recently, a unifying hypothesis suggested that iodine deficiency, severe enough to cause maternal and fetal hypothyroxinemia, results in neurological defects in all cretins.We conducted the present study in northern Thailand to determine the validity of this hypothesis in another geographical area. The study consisted of a multidisciplinary survey on 112 endemic cretins aged 2-66 years in Nan. They were categorized clinically into three types of endemic cretins, neurological (n = 57), myxedematous (n = 19) and mixed form (n = 36). The subjects were generally short and the majority had severe mental retardation (mean intellectual quotient (I.Q.) 30.8 Ϯ 8.8), psychomotor defect and profound sensorineural hearing loss. The I.Q. score and proportion of cretins with sensorineural hearing loss and psychomotor defect were similar among the three types of cretins. The most frequent neurological abnormalities were spasticity, hyper-reflexia, the presence of primitive reflexes and gait disturbance. These abnormalities were distributed equally among the three types of endemic cretins. Delayed skeletal maturation and abnormal epiphysis were also present in all types of cretins. However, myxedematous cretins were shorter (P < 0.01), having more myxedematous features (P < 0.05 to P<0.001) and less sexual maturation (P < 0.05). Thyroid volume was lower in cretins with hypothyroidism (P < 0.01).In conclusion, our findings support the hypothesis that neurological features are present in all types of cretins, and are the consequence of maternal and fetal hypothyroxinemia due to severe iodine deficiency. The clinical manifestations of the cretins were subsequently modified by the length and severity of postnatal iodine deficiency and hypothyroidism.

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Effect of Selenium Supplementation in Hypothyroid Subjects of an Iodine and Selenium Deficient Area : The Possible Danger of Indiscriminate Supplementation of Iodine-Deficient Subjects With Selenium.

Cited by 138 publications

References 7 publications

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

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

Association of selenium with thyroid volume and echostructure in 35- to 60-year-old French adults

Endemic cretinism in Thailand: a multidisciplinary survey

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