Mild-to-moderate iodine deficiency in a sample of pregnant women and salt iodine concentration from Zhejiang province, China.

Since 2011, Zhejiang province has eliminated iodine deficiency disorders (IDD) in its populations. Following this achievement, a new revised iodine concentration in iodised salt was implemented in Zhejiang in 2012. However, the re-emergence of iodine deficiency has been reported in pregnant women. Therefore, the aim of this study was to assess household salt iodine concentration and iodine status of pregnant women in Zhejiang province, China. We conducted a cross-sectional study between April 2018 and August 2018 in Quzhou, Zhejiang province. Pregnant women aged ≥ 18 years who did not have a history of thyroid disease were recruited into the study. They were asked to complete socio-demographic questionnaires including a food frequency questionnaire (FFQ). In addition, a spot urine sample and a household table salt sample were also provided by each participant. A total of 625 pregnant women agreed to participate. The overall median urinary iodine concentration (UIC) was 130 µg/L, indicating mild-to-moderate iodine deficiency in pregnant women. The coverage of iodised salt was 85.2%, and of these, the rate of adequately iodised salt was 98.1%. In conclusion, our results confirmed the re-emergence of iodine deficiency in pregnant women as reported by other studies conducted in Zhejiang province. Therefore, urgent public health actions are needed to improve iodine status of pregnant women in order to prevent the adverse consequences of IDD on the neurodevelopment of foetus.

Assessment of iodine supplementation program on thyroid function in Sudan.

The aim of this Study is to investigate whether the Iodine Supplementation Programme is successful or not. This Programme was implemented in Nyala to treat the Iodine deficiency. In this Study Nyala was selected to act as (a study area), due to the history of Iodine deficiency of this region, while Khartoum was selected to act as (a control area). 2000 samples were collected from Khartoum versus 450 samples from Nyala. Thyroxine (T4) and triiodothyronine (T3) levels in two regions were measured and performed by using radioimmunoassay (RIA), also the immunoradiometric assay (IRMA) used for measurement of thyroid stimulating hormone (TSH). The obtained results analyzed by using Statistical Package for Social Sciences (SPSS). (Coherent retrospective) used to determine differences between the study groups. The results of this study showed, there was no significant difference between the mean serum concentrations of T3 and TSH for Khartoum and Nyala. T4of Khartoum (117.93 ±â€¯42.797) nmol/L and the mean serum T4 of Nyala (114.54 ±â€¯45.526) nmol/L, the (P-value = 0.133).T3for Khartoum (1.8040 ±â€¯0.99047) nmol/L and T3of Nyala (1.7307 ±â€¯0.96508) nmol/L, the (P-value = 0.153). TSH for Khartoum (1.4480 ±â€¯0.95807)mIU/Land the mean serum TSH of Nyala (1.4553 ±â€¯1.0244) mIU/L, the (P-value = 0.885). The study showed a clear observation of improvement of hypothyroidism cases in Nyala while the ratio decreased from 64.09% to 0.6%. All the results were carried out according to normal range of Sudanese. The conclusion from this study the iodine supplementation programme is successful. The study recommends rising the health awareness among people by explain the severity of iodine deficiency, and continue in iodine supplementation programme, also establishment of monitoring system including monitoring the presence of iodized diets (sugar, salt, oils, and bread) in the markets. Finally, further studies are needed in other parts of Sudan to assess the size of iodine deficiency problem.

Simultaneous assessment of iodine, iron, vitamin A, malarial antigenemia, and inflammation status biomarkers via a multiplex immunoassay method on a population of pregnant women from Niger.

Deficiencies of vitamin A, iron, and iodine are major public health concerns in many low- and middle-income countries, but information on their status in populations is often lacking due to high costs and logistical challenges associated with assessing micronutrient status. Accurate, user-friendly, and low-cost analytical tools are needed to allow large-scale population surveys on micronutrient status. We present the expansion of a 7-plex protein microarray tool for the simultaneous measurement of up to seven biomarkers with relevance to the assessment of the key micronutrients iron, iodine, and vitamin A, and inflammation and malaria biomarkers: α-1-acid glycoprotein, C-reactive protein, ferritin, retinol binding protein 4, soluble transferrin receptor, thyroglobulin, and histidine-rich protein II. Assay performance was assessed using international reference standards and then verified by comparing the multiplexed and conventional immunoassay results on a training panel of plasma samples collected from US adults. These data were used to assign nominal concentrations to the calibrators of the assay to further improve performance which was then assessed by interrogating plasma samples from a cohort of pregnant women from Niger. The correlation between assays for each biomarker measured from this cohort was typically good, with the exception of thyroglobulin, and the sensitivity ranged from 74% to 93%, and specificity from 81% to 98%. The 7-Plex micronutrient assay has the potential for use as an affordable tool for population surveillance of vitamin A, iron, and iodine deficiencies as well as falciparum malarial parasitemia infectivity and inflammation. The assay is easy-to-use, requires minimal sample volume, and is scalable, rapid, and accurate-needing only a low-cost reader and basic equipment present in most reference laboratory settings and so may be employed by low and middle income countries for micronutrient surveillance to inform on status in key populations. Micronutrient deficiencies including iron, iodine, and vitamin A affect a significant portion of the world's population. Efforts to assess the prevalence of these deficiencies in vulnerable populations are challenging, partly due to measurement tools that are inadequate for assessing multiple micronutrients in large-scale population surveys. We have developed a 7-plex immunoassay for the simultaneous measurement of seven biomarkers relevant to assessing iodine, iron, and vitamin A status, inflammation and Plasmodium falciparum parasitemia by measuring levels of thyroglobulin, ferritin, soluble transferrin receptor, retinol binding protein 4, α-1-acid glycoprotein, C-reactive protein, and histidine-rich protein II. This 7-plex immunoassay technique has potential as a rapid and effective tool for use in large-scale surveys and assessments of nutrition intervention programs in low- and middle-income countries.

Knowledge about Iodine in Pregnant and Lactating Women in the Oslo Area, Norway.

BACKGROUND: Lack of knowledge about iodine may be a risk factor for iodine deficiency in pregnant and lactating women. The aim of this study was to assess knowledge about iodine and predictors of iodine knowledge scores among pregnant and lactating women. The study also examined whether iodine knowledge scores were associated with iodine status. METHODS: A cross-sectional study was performed on 804 pregnant women and 175 lactating women from 18 to 44 years of age in 2016 in the Oslo area, Norway. Knowledge about iodine was collected through a self-administered, paper-based questionnaire. Iodine concentrations in urine and breast milk were measured using an inductively coupled plasma mass spectrometer (ICPMS). RESULTS: 74% of the pregnant women and 55% of the lactating women achieved none to low iodine knowledge scores. Higher educated pregnant women and those who had received information about iodine had significantly higher knowledge scores. In lactating women, increased age was associated with higher knowledge scores. Knowledge scores were not associated with participants' iodine status. CONCLUSION: This study revealed a lack of knowledge about the importance of iodine in pregnant and lactating women, as well as about the most important dietary sources. Public education initiatives are required to increase the awareness about iodine in these population groups.

Adequate Iodine Status in New Zealand School Children Post-Fortification of Bread with Iodised Salt.

Iodine deficiency re-emerged in New Zealand in the 1990s, prompting the mandatory fortification of bread with iodised salt from 2009. This study aimed to determine the iodine status of New Zealand children when the fortification of bread was well established. A cross-sectional survey of children aged 8-10 years was conducted in the cities of Auckland and Christchurch, New Zealand, from March to May 2015. Children provided a spot urine sample for the determination of urinary iodine concentration (UIC), a fingerpick blood sample for Thyroglobulin (Tg) concentration, and completed a questionnaire ascertaining socio-demographic information that also included an iodine-specific food frequency questionnaire (FFQ). The FFQ was used to estimate iodine intake from all main food sources including bread and iodised salt. The median UIC for all children (n = 415) was 116 µg/L (females 106 µg/L, males 131 µg/L) indicative of adequate iodine status according to the World Health Organisation (WHO, i.e., median UIC of 100-199 µg/L). The median Tg concentration was 8.7 µg/L, which was <10 µg/L confirming adequate iodine status. There was a significant difference in UIC by sex (p = 0.001) and ethnicity (p = 0.006). The mean iodine intake from the food-only model was 65 µg/day. Bread contributed 51% of total iodine intake in the food-only model, providing a mean iodine intake of 35 µg/day. The mean iodine intake from the food-plus-iodised salt model was 101 µg/day. In conclusion, the results of this study confirm that the iodine status in New Zealand school children is now adequate.

A novel framework for analysing stakeholder interest in healthy foods: A case study on iodine biofortification.

Despite the availability of novel strategies to prevent micronutrient malnutrition, such as biofortification, limited understanding of stakeholders often hampers their success. We build upon the existing literature on protection motivations (PMT) and technology acceptance (TAM) to develop an integrated PMTAM model for analyzing stakeholders' reactions, on both the supply and demand sides. Regarding the latter, the case of the iodine biofortified food chain is used to evaluate African households' interest. All model constructs, and threat appraisal in particular, are decisive in determining the uptake of biofortification, while also social demographics and own nutrition status play an important role.

Neurotoxicant exposure during pregnancy is a confounder for assessment of iodine supplementation on neurodevelopment outcome.

CONTEXT: The developing brain is vulnerable to iodine deficiency (ID) and environmental neuro-toxicants. OBJECTIVES: To assess neurocognitive development of children whose mothers have received (or not) iodine supplementation during pregnancy, in an area of borderline ID, while assessing in utero exposure to environmental neuro-toxicants. DESIGN/PATIENTS: Among 86 children born from normal euthyroid women who participated in our prospective interventional study on iodine supplementation (150 µg/day) started early in pregnancy, 44 (19 with iodine supplementation, 25 controls) were assessed at two years using the Bayley test. Information on parents' education and habits (smoking), and on child development was recorded. Thyroid tests at each trimester of pregnancy and on cord blood (CB) were available, as well as milk concentrations of selected environmental compounds known for their neurotoxicity, including heavy metals and PCBs. RESULTS: There was no difference in Bayley tests for children born to mothers with and without iodine supplementation, but sample size was small. Language and Social-Emotional Scales were negatively correlated with TBG at all times tested, while PCB 118 correlated negatively with all Language scales. Among maternal and CB thyroid tests, only CB thyroglobulin, the best marker of iodine status, correlated (negatively) with neurodevelopment scales (Motor and Expressive Language). CONCLUSIONS: This pilot study suggests that PCB118 has a negative impact on neurocognitive development, possibly mitigating the benefit of iodine supplementation in an area of borderline ID. We propose that exposure to environmental neurotoxicants should be taken into account when designing studies on the benefit of iodine supplementation in pregnancy. The potential interactions between TBG, environmental neurotoxicants and brain development warrant further studies.

SUFFICIENT IODINE INTAKE IN SCHOOLCHILDREN FROM THE ZAGREB AREA: ASSESSMENT WITH DRIED BLOD SPOT THYROGLOBULIN AS A NEW FUNCTIONAL BIOMARKER FOR IODINE DEFICIENCY.

Current methods for assessment of iodine intake in a population comprise measurements of urinary iodine concentration (UIC), thyroid volume by ultrasound (US-Tvol), and newborn TSH. Serum or dried blood spot thyroglobulin (DBS-Tg) is a new promising functional iodine status biomarker in children. In 1996, a new act on universal salt iodination was introduced in Croatia with 25 mg of potassium iodideper kg of salt. In 2002, Croatia finally reached iodine sufficiency. However, in 2009, median UIC in 101 schoolchildren from Zagreb, the capital of Croatia, was 288 µg/L, posing to be excessive. The aim of the study was to assess iodine intake in schoolchildren from the Zagreb area and to evaluate the value of DBS-Tg in schoolchildren as a new functional biomarker of iodine deficiency (and iodine excess). The study was part of a large international study in 6- to 12-year-old children supported by UNICEF, the Swiss Federal Institute of Technology (ETH Zurich) and the International Council for the Control of Iodine Deficiency Disorders (ICCIDD). According to international study results, the median cut-off Tg < 13 µg/L and/or < 3% Tg values > 40 µg/L indicate iodine sufficiency. The study included 159 schoolchildren (median age 9.1 ± 1.4 years) from Zagreb and a nearby small town of Jastrebarsko with measurements of UIC, US-Tvol, DBS-Tg, T4, TSH and iodine content in salt from households of schoolchildren (KI/kg of salt). Overall median UIC was 205 µg/L (range 1-505 µg/L). Thyroid volumes in schoolchildren measured by US were within the normal range according to reference values. Median DBS-Tg in schoolchildren was 12.1 µg/L with 3% of Tg values > 40 µg/L. High Tg values were in the UIC range < 50 µg/L and > 300 µg/L (U-shaped curve of Tg plotted against UIC). All children were euthyroid with geometric mean TSH 0.7 ± 0.3 mU/L and arithmetic mean T4 62 ± 12.5 nmol/L. The mean KI content per kg of salt was 24.9 ± 3.1 mg/kg (range 19-36 mg/kg). Study results indicated iodine sufficiency in schoolchildren from the Zagreb area. Thyroglobulin proved to be a sensitive indicator of both iodine deficiency and iodine excess in children. Iodine content in salt from households of schoolchildren was in good compliance with the Croatian act (20-30 mg KI/kg of salt).

Determination of total iodine in serum and urine samples by ion chromatography with pulsed amperometric detection - studies on analyte loss, optimization of sample preparation procedures, and validation of analytical method.

A fast, accurate and precise ion chromatography method with pulsed amperometric detection was applied to evaluate a variety of parameters affecting the determination of total iodine in serum and urine of 81 subjects, including 56 obese and 25 healthy Polish children. The sample pretreatment methods were carried out in a closed system and with the assistance of microwaves. Both alkaline and acidic digestion procedures were developed and optimized to find the simplest combination of reagents and the appropriate parameters for digestion that would allow for the fastest, least time consuming and most cost-effective way of analysis. A good correlation between the certified and the measured concentrations was achieved. The best recoveries (96.8% for urine and 98.8% for serum samples) were achieved using 1ml of 25% tetramethylammonium hydroxide solution within 6min for 0.1ml of serum/urine samples. Using 0.5ml of 65% nitric acid solution the best recovery (95.3%) was obtained when 7min of effective digestion time was used. Freeze-thaw stability and long-term stability were checked. After 24 weeks 14.7% loss of iodine in urine, and 10.9% in serum samples occurred. For urine samples, better correlation (R(2)=0.9891) of various sample preparation procedures (alkaline digestion and application of OnGuard RP cartidges) was obtained. Significantly lower iodide content was found in samples taken from obese children. Serum iodine content in obese children was markedly variable in comparison with the healthy group, whereas the difference was less evident when urine samples were analyzed. The mean content in serum was 59.12±8.86µg/L, and in urine 98.26±25.93 for obese children when samples were prepared by the use of optimized alkaline digestion reinforced by microwaves. In healthy children the mean content in serum was 82.58±6.01µg/L, and in urine 145.76±31.44µg/L.

Thailand nutrition in transition: situation and challenges of maternal and child nutrition.

Double burden of malnutrition (DBMN), the coexistence of under- and overnutrition in the same population, is an emerging public health concern in developing countries, including Thailand. This paper aims to review the maternal and child nutrition situation and trends as the country moved from a low-income to a middle-income country, using data from large scale national surveys. Protein-energy malnutrition and micronutrient deficiencies predominantly affected mothers and children prior to the 1980s. The situation greatly improved during the 1980s- 1990s, with the implementation of multi-sectoral policies and programs focusing on poverty alleviation and primary health care. Economic development, improved access to health services and effective community-based nutrition programs contributed to these positive trends. However, the prevalence of low birth weight remained at 8- 10%, while stunting and underweight declined to about 10% by the 1990s, with small change thereafter. The prevalence of anemia among pregnant women and children decreased by half and vitamin A deficiency is no longer a public health problem. Iodine deficiency, especially during pregnancy is still a major concern. As the country progressed in terms of economic and social development, overnutrition among women and children affected all socio-economic levels. Changes in lifestyles, food access and eating patterns are observed both in urban and rural areas. Although efforts have been made to address these challenges, harmonized policy and strategic programs that address DBMN in the complex social and economic environment are urgently needed. Early life undernutrition should be considered along with measures to address obesity and chronic diseases in children.

The prevalence of iodine deficiency disorder in two different populations in northern province of Iran: a comparison using different indicators recommended by WHO.

Comparison of the prevalence of iodine deficiency disorder (IDD) in neonates and school children using two different WHO indicators. From 2006 to 2010, 119701 newborns were screened by measurement of serum TSH level by heel prick. Neonates who had blood TSH ≥ 5 mIU/l were recalled for more evaluation. In the same period of time, urine iodine was measured in 1200 school-aged children. The severity of IDD was classified using WHO, UNICEF, ICCIDD criteria. Between 2006 and 2010 a total of 138832 neonates were screened in Guilan province and the total recall rate (neonates with TSH level ≥ 5 mIU/l) was 1.8 %. The incidence rate of Congenital Hypothyroidism (CH) was 1/625. The median urine iodine level in school-aged children was 200-299 µg/l. Considering the WHO, UNICEF, ICCIDD criteria, Guilan province would be classified as a none-IDD endemic area. However, health care systems should pay attention to the iodine excess and the risk of iodine induced hyperthyroidism in this population.

Therapeutic drug monitoring during pregnancy and lactation: thyroid function assessment in pregnancy-challenges and solutions.

The diagnosis and monitoring of thyroid disease necessitates the knowledge of thyroid pathophysiology and of the technical limitations of current thyroid-related biochemical tests. Thyroid disease diagnosis and monitoring are further complicated during pregnancy and lactation, due to pregnancy-related changes in thyroid hormone metabolism. Dramatic changes that occur in thyroxine and triiodothyronine ranges during pregnancy pose challenges for hypothyroid gravidas. Very early in pregnancy, levothyroxine replacement needs to be increased. Moreover, increases in thyroid hormone replacement need to be conducted individually and on a timely basis. For reasons that are still not entirely clear, although dependent in part on changes in thyroxine binding, free thyroxine (FT4) levels decrease as pregnancy progresses necessitating the use of trimester-specific reference intervals for appropriate replacement. Thyroxine binding protein levels vary by hormonal status, inheritance, and disease states and are higher in pregnancy; hence, FT4 assays became popular because they measure the unbound hormone. However, current FT4 immunoassays are estimate tests that do not reliably measure FT4 and are known to be sensitive to alterations in binding proteins and therefore are method-specific. The need to reliably identify hypothyroxinemic pregnant patients, especially in the first trimester, is of prime importance for early fetal brain development before the fetal thyroid functions. This article addresses 1) the current limitations of laboratory-free thyroxine immunoassay methodologies and especially during pregnancy; 2) trimester-specific reference intervals for thyroid function tests; and 3) the study of levothyroxine pharmacokinetics in pregnant and nonpregnant women.

An assessment of progress toward universal salt iodization in Rajasthan, India, using iodine nutrition indicators in school-aged children and pregnant women from the same households.

BACKGROUND: In Rajasthan, an Indian State with significant salt production, the sale of non-iodized salt for human consumption was banned in 1992. This study explored the relationships between the use of iodized salt in Rajasthan and the iodine status of children and pregnant women living in the area. METHODS: In a State-wide survey, 30 clusters were selected proportionate-to-population-size and 40 school children, 6-12 years old, were enrolled by random house-to-house visits in each cluster. Twelve pregnant women from the same households were also sampled. Salt used for cooking and a casual urine sample from each child and pregnant woman were collected. The salt iodine content was measured by titration and the urinary iodine concentration (UIC) by a quality-assured colorimetric method. RESULTS: Salt iodine content was >or=15 mg/kg in 41.9% of the households, and 23.0% used non-iodized salt. Median UIC was 139 microg/L in children and 127 microg/L in pregnant women. In households using non-iodized salt, the median UIC's were 96 microg/L and 100 microg/L in children and women, respectively. Dis-aggregating the UIC distributions by salt iodine levels revealed a consistent, step-wise pattern of UIC in children with increasing salt iodine content. A similar but less steep pattern was observed in pregnant women. The iodine status of both children and pregnant women attained the optimal range only when the salt iodine content was close to 30 mg/kg. CONCLUSION: For optimum iodine status in the population of Rajasthan, the iodization of household salt should be mandated at a higher level than what is practiced at present.

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. DESIGN, PARTICIPANTS, AND INTERVENTIONS: Serum Tg reference material of the European Community Bureau of Reference (CRM-457) was adapted for DBS and its stability tested over 1 yr. DBS-Tg was determined in an international sample of 5- to 14-yr-old children (n = 700) who were euthyroid, anti-Tg antibody negative, and residing in areas of long-term iodine sufficiency. In a 10-month trial in iodine-deficient children, DBS-Tg and other indicators of iodine status were measured before and after introduction of iodized salt. RESULTS: Stability of the CRM-457 Tg reference standard on DBS over 1 yr of storage at -20 and -50 C was acceptable. In the international sample of children, the third and 97th percentiles of DBS-Tg were 4 and 40 microg/liter, respectively. In the intervention, before introduction of iodized salt, median DBS-Tg was 49 microg/liter, and more than two thirds of children had DBS-Tg values greater than 40 microg/liter. After 5 and 10 months of iodized salt use, median DBS-Tg decreased to 13 and 8 microg/liter, respectively, and only 7 and 3% of children, respectively, had values greater than 40 microg/liter. DBS-Tg correlated well at baseline and 5 months with urinary iodine and thyroid volume. CONCLUSIONS: The availability of reference material and an international reference range facilitates the use of DBS-Tg for monitoring of iodine nutrition in school-age children.

Nutritional status of indigenous children at boarding schools in northern Mexico.

OBJECTIVE: To assess the nutritional status of Tarahumara children at indigenous boarding schools. DESIGN: Cross-sectional comprehensive nutritional survey. SETTING: The schools sampled were located in indigenous municipalities of the northern Mexican state of Chihuahua. SUBJECTS: The study was carried out in 2001 among 331 children aged 6-14 y from a sample of five schools. Anthropometric measurements, a thyroid exam and capillary haemoglobin levels were obtained from the children. Serum concentrations of ferritin, iron, total iron-binding capacity, vitamin B(12), folic acid and zinc were collected from a subsample of 100 children. RESULTS: The prevalence of wasting and overweight (children 6-9 y) was 1.1 and 4.6%, respectively, and of underweight, risk of overweight and overweight (10-14 y) was 3.2, 5.1 and 0.6%, respectively. Stunting (6-12 y) was present in 22.3% of the children. The total goitre rate was 5.4%. The prevalence of anaemia was 13% (boys 11.4, girls 14.5%). Overall, 24.2% of the children were iron deficient (depletion 11.1%, deficient erythropoiesis 3%, iron deficiency anaemia 10.1%). No child had folic acid values <3 ng/ml, but 20.2% had low (<200 microg/dl) and 27.3% marginal (200-300 microg/dl) vitamin B(12) levels, and 80.2% had low zinc concentrations (<60 microg/dl). CONCLUSIONS: Nutritional underweight and stunting were similar to those reported in rural localities at the national level, but overweight was less prevalent in children aged 10-14 y. Various micronutrient deficiencies was identified including zinc and vitamin B(12), but the prevalence of iron and folic acid deficiency was lower than expected. These results suggest that Tarahumara children attending boarding schools may be the better-off children from these extremely poor and marginalized areas. SPONSORSHIP: Swedish Agency for Research Cooperation with Developing Countries and the Mexican Social Security Institute.

Severe linear growth retardation in rural Zambian children: the influence of biological variables.

BACKGROUND: The prevalence of stunting in preschool children in Zambia is high; stunting has detrimental effects on concurrent psychomotor development and later working capacity. OBJECTIVE: Our objective was to investigate biological variables that may contribute to linear growth retardation in preschool children in Samfya District, Zambia. DESIGN: Children aged 6-9 mo (n = 108) and 14-20 mo (n = 102) attending mother-and-child health clinics were included. With a mixed-longitudinal design, they were followed up 9 and 21 mo later. Height and weight of children and their mothers were measured. Biochemical measures (eg, serum zinc, retinol, thyrotropin, iron, and acute phase protein concentrations), malaria parasitemia, and intestinal parasitosis were assessed. RESULTS: Height-for-age z scores (HAZ) were low, indicating a high prevalence of stunting (36-79%). Ninety percent of the children were anemic, 53-71% had elevated acute phase proteins, and 80% had malaria parasitemia. Regression analyses showed that maternal height predicted the children's height at 6-9 mo (regression coefficient = 0.05; 95% CI: 0.02, 0.08). The children's height at an early age (6-9 and 14-20 mo) showed a strong relation with their height at later ages (22-30 and 34-41 mo). Serum micronutrient status did not show a significant relation with later HAZ. CONCLUSION: Unlike other studies, we did not identify specific biological factors, such as health and micronutrient status, which contribute to the retardation of linear growth. The normal zinc and iodine statuses of the children suggest that at least these factors are not causal.

Thyroid parameters in iodine deficiency.

Thyroid Plasma Clearance and Free Thyroxine Index were compared in 20 Zambians with iodine deficiency with 12 Zambians and 10 expatriates without iodine deficiency. Mean clearance was similar in the non-deficient groups (19 and 22 ml/min.) but much higher (123 ml/min.) in the deficient group. Mean Free Thyroxine Index was similar in the non-deficient groups (11.2 and 10.3) but significantly lower (8.2) in the deficient group. A relationship between iodine deficiency and low income was seen. No racial difference was apparent.

Use of 99 Tc m for the routine assessment of thyroid function.

(99)Tc(m)-pertechnetate is concentrated in the thyroid in the same way as iodide but it does not become organically bound. The uptake of (99)Tc(m) is a measure of the thyroid trap, and this measurement is satisfactory as a routine test in the diagnosis of thyrotoxicosis. The reproducibility of the method is such that suppression tests can be carried out when necessary even when uptake is within the normal range of 0.4-3%. (99)Tc(m) gives a low radiation dose to the thyroid and has certain other advantages over radioactive isotopes of iodine for early thyroid uptake measurements. It is particularly suitable when serial tests of thyroid function are required during treatment with an antithyroid drug.