Iodine Deficiency and Iodine Prophylaxis: An Overview and Update (original) (raw)
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Value and pitfalls in iodine fortification and supplementation in the 21st century
British Journal of Nutrition, 2011
Although the number of iodine-deficient countries has been reduced by almost 50 % over the last decade, it still remains a frequently misunderstood health problem. The most devastating effects of iodine deficiency occur during fetal development and childhood, periods in which sufficient iodine delivery remains critical. Besides the determination of thyroid size, the concentration of urinary iodine, serum thyroid-stimulating hormone and serum thyroglobulin are useful biomarkers to assess iodine status. Severe iodine deficiency is associated with neurological complications, cretinism, endemic goitre development, hypothyroidism, decreased fertility and increased infant mortality. The recommended iodine supplementation strategies are based on correction of iodine deficiency, close monitoring and evaluation of iodine administration, cooperation of the salt industry, training of local health care professionals and education of the population. Besides the multiple beneficial effects of supplementation, we present in this review a critical look at the possible side effects.
Iodine Deficiency in the World: Where Do we Stand at the Turn of the Century?
Thyroid, 2001
Iodine deficiency is the leading cause of preventable mental retardation. Universal salt iodization (USI), calling for all salt used in agriculture, food processing, catering and household to be iodized, is the agreed strategy for achieving iodine sufficiency. This article reviews published information on programs for the sustainable elimination of the iodine deficiency disorders and reports new data on monitoring and impact of salt iodization programs at the population level. Currently, 68% of households from areas of the world with previous iodine deficiency have access to iodized salt, compared to less than 10% a decade ago. This great achievement, a public health success unprecedented in the field of noncommunicable diseases, must be better recognized by the health sector, including thyroidologists. On the other hand, the managers and sponsors of programs of iodized salt must appreciate the continuing need for greatly improved monitoring and quality control. For example, partnership evaluation of iodine nutrition using the ThyroMobil model in 35,223 schoolchildren at 378 sites of 28 countries has shown that many previously iodine deficient parts of the world now have median urinary iodine concentrations well above 300 mg/L, which is excessive and carries the risk of adverse health consequences. The elimination of iodine deficiency is within reach but major additional efforts are required to cover the whole population at risk and to ensure quality control and sustainability.
The Republic of Srpska Iodine Deficiency Survey 2006
Hormones (Athens, Greece)
A survey related to iodine deficiency in the Republic of Srpska was first conducted in 1999 and resulted in the adoption of regulations concerning the quality of salt for human consumption. In order to reassess iodine status, we conducted the Republic of Srpska Iodine Deficiency Survey in 2006. The survey was conducted in a sample of 1,200 schoolchildren using parameters recommended by WHO, UNICEF and ICCIDD: palpation of thyroid gland, iodine urinary excretion, thyroid utrasonography and content of iodine in salt. The goiter prevalence in the total group indicated mild iodine deficiency in the Republic of Srpska, whereas urinary iodine excretion suggested iodine sufficiency. Only 35.7% of salt samples were adequately iodinated, 51.2% were hypo-iodinated and 13.1% were hyper-iodinated. Of the salt samples tested, 40.9% were iodinated using potassium iodide, despite the fact that this method of salt iodination is forbidden by regulations related to the quality of salt for human consu...
Public Health Nutrition, 2009
Objective: The aim of the present study was to determine the impact of universal salt iodization (USI) on the prevalence of iodine deficiency in the population of an area previously known to have severe iodine deficiency in India. Design: In a cross-sectional survey, a total of 2860 subjects residing in fifty-three villages of four sub-districts of Gonda District were examined for goitre and urinary iodine concentration. Free thyroxine and thyroid-stimulating hormone levels were also measured. Salt samples from households were collected for estimation of iodine content. Results: A reduction in goitre prevalence was observed from 69 % reported in 1982 to 27?7 % assessed in 2007. However, 34 % of villages still had very high endemicity of goitre (goitre prevalence .30 %). Twenty-three per cent of households consumed a negligible amount (,5 ppm) and 56 % of households consumed an insufficient amount (5-15 ppm) of iodine from salt. Conclusions: Although there was an overall improvement in iodine nutrition as revealed by decreased goitre prevalence and increased median urinary iodine levels, there were several pockets of severe deficiency that require a more targeted approach. Poor coverage, the use of unpackaged crystal salt with inadequate iodine and the washing of salt before use by 90 % of rural households are the major causes of persisting iodine-deficiency disorders. This demonstrates lapses in USI implementation, lack of monitoring and the need to identify hot spots. We advocate strengthening the USI programme with a mass education component, the supply of adequately iodized salt and the implementation of complementary strategies for vulnerable groups, particularly neonates and lactating mothers.
Iodine Nutrition Improves in Latin America
Thyroid, 2004
Iodine deficiency has been a public health problem in most Latin American countries. Massive programs of salt iodization have achieved great progress toward its elimination but no consistent monitoring has been applied. We used the ThyroMobil model to visit 163 sites in 13 countries and assess randomly selected schoolchildren of both genders 6-12 years of age. The median urinary iodine concentration (8208 samples) varied from 72 to 540 g/L. One national median was below the recommended range of 100-200 g/L; five were 100-200 g/L, and seven were higher than 200 g/L, including three greter than 300 g/L. Urinary iodine concentration correlated with the iodine content of salt in all countries. Median values of thyroid volume were within the normal range for age in all countries, but the goiter prevalence varied markedly from 3.1% to 25.0% because of scatter. The median iodine content of salt from local markets (2734 samples) varied from 5.9 parts per million (ppm) to 78 ppm and was greater than 15 ppm in 83.1% of all samples. Only seven countries had higher than 15 ppm iodine in 80% of the samples, and only three had greater than 15 ppm in at least 90%. Iodized salt was available at retail level in all countries but its median iodine content was within the recommended range (20-40 ppm) in only five. This study, the first to apply a standardized assessment strategy to recent iodine nutrition in Latin America, documents a remarkable success in the elimination of iodine deficiency by iodized salt in all but 1 of the 13 countries. Some iodine excess occurs, but side effects have not been reported so far, and two countries have already decreased their legal levels of salt iodization and improved the quality control of iodized salt, in part because of our results. The present work should be followed by regular monitoring of iodine nutrition and thyroid function, especially in the countries presently exposed to iodine excess.