Effects of Iodized Salt and Iodine Supplements on Prenatal and Postnatal Growth: A Systematic Review.

Hypothyroidism due to iodine deficiency can impair physical development, most visibly in the marked stunting of myxedematous cretinism caused by severe in utero iodine deficiency. Whether iodine repletion improves growth in noncretinous children is uncertain. Therefore, the aim of our systematic review was to assess the effects of iodine fortification or supplementation on prenatal and postnatal growth outcomes in noncretinous children.

Systematic review of the effects of iodised salt and iodine supplements on prenatal and postnatal growth: study protocol.

Introduction: Iodine is an essential micronutrient and component of the thyroid hormones. Sufficient ingestion of iodine is necessary for normal growth and development. If iodine requirements are not met, growth can be impaired.

A lowered salt intake does not compromise iodine status in Cape Town, South Africa, where salt iodization is mandatory.

Objective: Universal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification.

Methods for determination of iodine in urine and salt.

Good quality data on iodine concentrations in urine and salt samples are indispensable for the efficient management of national salt iodisation programmes and for evaluating iodine interventions. Most of the analytical methods for urinary iodine concentration are based on the manual spectrophotometric measurement of Sandell-Kolthoff reduction reaction catalysed by iodine using different oxidising reagents in the initial digestion step. Other analytical methods include semi-quantitative methods, a microplate method, automated methods; and the technologically advanced methods include the inductively coupled plasma mass-spectrometer method.

Iodine treatment in children with subclinical hypothyroidism due to chronic iodine deficiency decreases thyrotropin and C-peptide concentrations and improves the lipid profile.

Background: Chronic iodine deficiency (ID) increases thyrotropin (TSH) concentrations and produces a thyroid hormone pattern consistent with subclinical hypothyroidism (ScH). ScH may be associated with cardiovascular disease risk factors. Thus, the study aim was to determine if iodine treatment of children with elevated TSH concentrations due to ID would affect their lipid profile, insulin (C-peptide) levels, and/or subclinical inflammation.

Iodine-deficiency disorders.

2 billion individuals worldwide have insufficient iodine intake, with those in south Asia and sub-Saharan Africa particularly affected. Iodine deficiency has many adverse effects on growth and development. These effects are due to inadequate production of thyroid hormone and are termed iodine-deficiency disorders.

Assessment of the sustainability of the iodine-deficiency disorders control program in Lesotho.

Background: Evaluation of the sustainability of iodine-deficiency disorders control programs guarantees successful and sustained virtual elimination of iodine deficiency. The Lesotho universal salt iodization legislation was enacted in 2000 as an iodine-deficiency disorders control program and has never been evaluated.

Objectives: To assess the sustainability of the salt iodization program in Lesotho, 2 years after promulgation of the universal salt iodization legislation.

Vitamin A supplementation in iodine-deficient African children decreases thyrotropin stimulation of the thyroid and reduces the goiter rate.

Background: Vitamin A (VA) deficiency (VAD) and iodine deficiency (ID) often coexist in children in Africa. VAD may affect thyroid function and the response to iodine prophylaxis.

Objective: The aim was to investigate the effects of supplementation with iodine or VA alone, and in combination, in children with concurrent VAD and ID.

Assessment of iodine status using dried blood spot thyroglobulin: development of reference material and establishment of an international reference range in iodine-sufficient children.

Context: Thyroglobulin (Tg) may be a valuable indicator of improving thyroid function in children after salt iodization. A recently developed Tg assay for use on dried whole blood spots (DBS) makes sampling practical, even in remote areas.

Objective: The study aim was to develop a reference standard for DBS-Tg, establish an international reference range for DBS-Tg in iodine-sufficient children, and test the standardized DBS-Tg assay in an intervention trial.

Iodine content of salt 2 years after the introduction of the universal salt iodisation legislation in Lesotho.

The aim of the present study was to assess the impact of the universal salt iodisation legislation on I levels of salt at household, retail and entry level in Lesotho. We used a multistage proportion to population size method to select thirty-one clusters from all the districts and ecological zones of Lesotho. In each cluster, thirty households were randomly selected and salt samples were collected.

Monitoring the effect of introducing mandatory iodisation at an elevated iodine concentration on the iodine content of retailer salt after 1, 3 and 5 years in South Africa.

In this study we monitored the short-term, medium-term and long-term effects of introducing mandatory iodisation at an elevated iodine concentration on the iodine content of retailer salt. In 1995 retailer salt samples were purchased in 48 sentinel towns, situated in three of the nine provinces of South Africa, shortly before the introduction of mandatory iodisation at an elevated iodine concentration of 40-60 ppm, and again 1, 3 and 5 years later. The iodine concentrations in these salt samples were determined by means of the iodometric titration method.

Sources of household salt in South Africa.

Marketing of non-iodized salt through unconventional distribution channels is one of the factors weakening the national salt iodization program in South Africa. The aim of this study was therefore to quantify the various sources of household salt, and to relate this information to socio-economic status. Questionnaire information was collected by personal interview during home visits from a multistage, cluster, probability sample of 2164 adults representative of the adult population.

Iodine status as determined by urinary iodine excretion in Lesotho two years after introducing legislation on universal salt iodization.

Objective: Mild to severe iodine deficiency has been documented in Lesotho since 1960. To eliminate the persisting iodine deficiency, legislation on universal salt iodization was introduced in 2000 as a long-term public health intervention strategy. We assessed the urinary iodine status of school children and women of child-bearing age in Lesotho 2 y after the introduction of legislation on universal salt iodization.

New reference values for thyroid volume by ultrasound in iodine-sufficient schoolchildren: a World Health Organization/Nutrition for Health and Development Iodine Deficiency Study Group Report.

Background: Goiter prevalence in school-age children is an indicator of the severity of iodine deficiency disorders (IDDs) in a population. In areas of mild-to-moderate IDDs, measurement of thyroid volume (Tvol) by ultrasound is preferable to palpation for grading goiter, but interpretation requires reference criteria from iodine-sufficient children.

Objective: The study aim was to establish international reference values for Tvol by ultrasound in 6-12-y-old children that could be used to define goiter in the context of IDD monitoring.

Assessment of the iodine concentration in table salt at the production stage in South Africa.

Objective: To determine the iodine content of iodized salt at the production stage, to assess the perceptions and knowledge of salt producers about the prevention and control of iodine deficiency, and to examine the internal quality control procedures used during iodization in South Africa.

Method: Salt samples were collected for iodine analysis by titration from the 12 producers iodizing salt in South Africa. Information on the producers' knowledge of iodine deficiency disorders and on internal quality control was obtained by means of questionnaires.

Prevalence of goitre and urinary iodine status of primary-school children in Lesotho.

Objective: To estimate the prevalence of goitre, urinary iodine status, coverage of supplementation of iodized oil capsules, and current use of iodized salt in children in Lesotho.

Methods: Cross-sectional study of children from 50 primary schools in Lesotho. Thyroid glands of children aged 8-12 years were measured by palpation and graded according to the WHO, UNICEF, and the International Council for the Control of Iodine Deficiency's (ICCIDD) joint criteria.