Search

Selenium deficiency is associated with impaired bone metabolism and osteopenia in rats. However, it is not known how combined selenium and iodine deficiency affects bone metabolism. Therefore, we investigated the effect of selenium and iodine deficiency on bone metabolism in 2nd-generation selenium- and iodine-deficient rats. Selenium-deficient (Se-), iodine-deficient (I-), selenium- and iodine-deficient (Se-/I-), and control rats (Se+/I+), were pair-fed their respective diets until they were 74 d old. Each pair-fed rat was fed a selenium-adequate diet in the same amount as that consumed the day before by its selenium-deficient counterpart, taking food spillage into account. The skeletal phenotype was analyzed by dual energy X-ray absorptiometry, histomorphometry, and bone metabolism markers. Erythrocyte glutathione peroxidase activity (Gpx) and plasma thyroid hormones were measured to assess selenium and iodine status, respectively. In both Se-/I+ and Se-/I- rats, Gpx was reduced by 99% compared with pair-fed Se +/I+ and Se+/I- rats (P < 0.001). Iodine deficiency reduced plasma thyroxine by 64% in the 2 iodine-deficient groups (P < 0.001). Body weight, tail length, plasma insulin-like growth factor, pituitary growth hormone concentration, and femur and tibia bone mineral density were significantly greater in the Se-/I- rats than in the Se-/I+ rats. This study shows that iodine deficiency mitigated growth retardation and osteopenia in 2nd-generation selenium-deficient rats and suggests that adequate selenium status should be ensured before measures are taken to correct iodine deficiency. KEYWORDS: * seleniumdeficiency * iodinedeficiency * bonemineraldensity * osteopenia * bonemetabolism

Objective: To determine the adequacy of iodine nutrition of Tasmanian primary school-aged children and to examine possible associations with socio-economic status (SES), location and dietary factors. Methods: Urinary iodine levels and measures of SES, geographical information and dietary habits were surveyed in a population-based sample of 170 children (4 to 12 years) at baseline (1998/99) and at follow-up (2000/01). Results: Median urinary iodine concentration in 1989-99 and 2000-01 were 75 [micro]g/L (range 15 [micro]g/L to 240 [micro]g/L) and 76 [micro]g/L (range 18 [micro]g/L to 480 [micro]g/L) respectively. No significant associations with SES or geographical location were found. More frequent or recent intake of foods that are likely to be dietary sources of iodine tended to be associated with greater prevalence of adequate urinary iodine, particularly consumption of yoghurt and 'fruche' (p=0.04). Conclusions: After several decades of iodine sufficiency, Tasmanian primary school-aged children are again mildly iodine-deficient by WHO criteria. Despite reduction in iodophor use by the dairy industry in the past decade, consumption of dairy products continues to be associated with higher levels of iodine nutrition. Implications: The lack of association of iodine levels with SES and geographical location within Tasmania found in our study, and the results of studies of iodine levels in Melbourne and Sydney, suggest that inadequate iodine nutrition is a widespread problem in south-eastern Australia. Our study suggests that milk-containing products continue to be an important source of iodine for children.

Despite remarkable progress in the control of the iodine deficiency disorders (IDD), they remain a significant global public health problem. Assessing the severity of IDD and monitoring the progress of salt iodization programs are cornerstones of a control strategy. Because thyroid size decreases only gradually in response to iodized salt, the goiter rate in children may be a poor IDD monitoring indicator for several years after the introduction of salt iodization. During this period, the goiter rate reflects chronic iodine deficiency, and will be inconsistent with measurements of urinary iodine. Thyroglobulin is a promising new biochemical indicator for monitoring thyroid function after the introduction of iodized salt. Recent development of a dried blood spot thyroglobulin assay makes sample collection practical even in remote areas. Interpretation of thyroid volume data from ultrasound surveys requires valid references from iodine-sufficient populations, but defining normal values for thyroid size in children has been difficult. New international reference criteria for thyroid volume were published recently and can be used for goiter screening in the context of IDD monitoring. Ensuring sustainability is one of the great remaining challenges in the global fight to eliminate IDD. A recent cohort study demonstrated the vulnerability of children in IDD-affected areas to even short-term lapses in iodized salt programs. KEY WORDS: * iodine * monitoring * goiter * thyroglobulin * thyroid

Jerome Dobson recently proposed a controversial explanation for the morphological characteristics found among 'classic' Pleistocene Neandertals from central Europe (1998). Chronic iodine deficiency in these hominids, he suggests, either due [...]

Introduction Iodine deficiency produces a spectrum of disorders--endemic goiter, hypothyroidism, cretinism and congenital anomalies-that are termed the iodine deficiency disorders (IDD; WHO/UNICEF/ICCIDD, 1994). Mild iodine deficiency also impairs intellectual development [...], Objectives: To determine the efficacy of oral iodized oil in goitrous children who are both selenium (Se) and iodine deficient; to investigate if Se status 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 Cote d'Ivoire. Subjects: 51 goitrous non-anemic schoolchildren with both iodine and Se deficiency. 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 ([T.sub.4]), and thyroid volume by ultrasound. Results: At baseline all children were goitrous and Se deficient; median UI was 29 µg/l and mean serum Se (s.d.) was 14.8 (10.7) µg/l. After receiving 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 thyroid volume from baseline was-46.6% and only five children remained goitrous. Median TSH values at 5, 10, 15, 30 and 50 weeks were reduced significantly (P Conclusion: Although more severe Se deficiency partially blunts the thyroid response to iodine supplementation, oral iodized oil is an effective method for iodine repletion in goitrous children who are Se deficient. Sponsorship: The Swiss Federal Institute of Technology, Zurich, the Foundation for Micronutrients in Medicine, Rapperswil, Switzerland, and the Thrasher Research Fund, Salt Lake City, USA. Descriptors: iodine; selenium; deficiency; goiter; interaction; iodized oil

The authors present research regarding selenium and iodine metabolism interactions investigated in children with iodine deficiencies manifested in goiter. Results indicate differences in free thyroxine concentrations are linked to selenium deficiency, but only in females.

Research presented concerns the health risks associated with insufficient or excessive iodine intake in America. Topics addressed include thyroid responses to iodine intake, the process of iodine metabolism, and certain subsets of the population at risk for iodine deficiencies.

Iodine deficiency in pregnancy leads to poor cognitive function in the offspring; however, the effect of concurrent iodine deficiency on school-aged children is not clear. Several studies have shown that school children in iodine-deficient villages have poorer cognitive function than children in iodine-sufficient villages. However, villages differ in many factors that may also detrimentally affect children's development. In addition, the children's nutritional and health status has not usually been taken into account. In this study, we compared the cognitive function and school achievement levels of 170 children who had recently had low thyroxine ([T.sub.4]) levels [[T.sub.4] [less than or equal to] 45 nmol/L (hypothyroid)] with children who had not had low [T.sub.4] levels [[T.sub.4] [greater than or equal to]70 nmol/L (euthyroid)]. The children were matched for school and grade level and came from the same iodine-deficient regions in rural Bangladesh. They were given a battery of cognitive, motor and school achievement tests. We also measured their nutritional status, examined their stools for geohelminths and assessed their home environments. A factor analysis of cognitive and motor function tests yielded two factors, a general cognitive factor and a fine motor factor. The children's height and arm circumference, experience of hunger, parental characteristics and stimulation in the home made independent contributions to their test scores. Controlling for these variables, the hypothyroid children performed worse than the euthyroid children on reading and spelling and the general cognitive factor. These findings indicate that a large number of disadvantages including hypothyroidism are related to the poor development of these children. KEY WORDS: iodine deficiency; academic achievement; cognitive function; school children

The relationship between fluoride in the drinking water and endemic goiter in the Northern Cape Province of South Africa was examined using a dental survey of schoolchildren. No relationship was found between fluoride in water and the mild goiter prevalence in the four towns with either a low or near optimal fluoride content in the water. Other results indicated that either a fluoride level in the water or another associated goitrogen other that iodine deficiency may have been responsible for these goiters.

To empower local authorities to plan and evaluate adequate interventions, appropriate iodine deficiency disorders (IDD) indicators need to be identified. The aim of this study was to describe the magnitude and severity of IDD with different outcome indicators and associate them with functional indicators. Schoolchildren (n = 544) aged 8-10 y were assessed in 11 villages within five subdistricts of Malang District, East Java, Indonesia. Outcome indicators of IDD were goiter size as measured by palpation and ultrasonography (USG), urinary iodine excretion (UIE) and serum thyroid stimulating hormone (TSH) concentration in blood as well as functional indicators such as intellectual performance (IQ: Catell's Culture Fair Intelligence Test) and anthropometric indices. The total goiter rate (TGR) measured by palpation and USG were 35.7 and 54.4%, respectively. based on UIE and TSH, the prevalence of iodine deficiency was 63.7 and 3.4%, respectively. In individuals, goiter, thyroid volume and UIE were associated significantly (r = -0.35; P < 0.001 and r = -0.30; P = 0.02 respectively). Among villages, TGR measured by palpation was significantly correlated with thyroid volume (r = 0.61; P = 0.045) and UIE (r = 0.68; P = 0.021), whereas TSH was not significantly associated with any of the observed indicators in individuals or groups. Multiple regression analysis showed that USG ([Beta] = -0.67; P < 0.001) and UIE ([Beta] = 4.39; P = 0.008) related significantly with cognitive performance (IQ). The associations between IDD indicators and cognitive performance and height-for-age Z scores suggest that socioeconomically advantaged children had better iodine status. We suggest that UIE is the best indicator for local authorities to assess iodine deficiency. KEY WORDS: goiter; intellectual performance; iodine; thyroid stimulating hormone; humans

Although reports suggest that infant mortality is increased during iodine deficiency, the effect of iodine supplementation on infant mortality is unknown. A double-masked, randomized, placebo-controlled, clinical trial of oral iodized oil was conducted in Subang, West Java, Indonesia to evaluate the effect of iodine supplementation on infant mortality. Infants were allocated to receive placebo or oral iodized oil (100 mg) at about 6 wk of age and were followed to 6 mo of age. Six hundred seventeen infants were enrolled in the study. Infant survival was apparently improved, as indicated by a 72% reduction in the risk of death during the first 2 mo of follow-up (P < 0.05) and a delay in the mean time to death among infants who died in the iodized oil group compared with infants who died in the placebo group (48 days vs. 17.5 d, P = 0.06). Other infant characteristics associated with reduced risk of death included weight-for-age at base line, consumption of solid foods, female gender and recent history of maternal iodine supplementation. Oral iodized oil supplementation had a stronger effect on the mortality of males compared with females. This study suggests that oral iodized oil supplementation of infants may reduce infant mortality in populations at risk for iodine deficiency. KEY WORDS: * infants * mortality * iodine deficiency * goiter * cretinism

A study of the role of iodine deficiency in causing goitre among pregnant rural women in Bangladesh reveals the existence of goitre even in the absence of iodine deficiency. Vitamin A and selenium deficiency and high goitrogen intake may be other causative factors. Iodine supplementation alone is insufficient to prevent goitre.

Thyroid hormones in relation to iodine status were studied in a group of Sudanese pregnant women with goitre (n = 66). These women were compared with a healthy, non-pregnant control [...]