Universal Salt Iodization Program Research Articles

Evaluation of the Universal Salt Iodization (USI) surveillance system in Tanzania, 2022.

The evaluation of surveillance systems has been recommended by the World Health Organization (WHO) to identify the performance and areas for improvement. Universal salt iodization (USI) as one of the surveillance systems in Tanzania needs periodic evaluation for its optimal function. This study aimed at evaluating the universal salt iodization (USI) surveillance system in Tanzania from January to December 2021 to find out if the system meets its intended objectives by evaluating its attributes as this was the first evaluation of the USI surveillance system since its establishment in 2010. The USI surveillance system is key for monitoring the performance towards the attainment of universal salt iodization (90%). This evaluation was guided by the Center for Disease Control Guidelines for Evaluating Public Health Surveillance Systems, (MMWR) to evaluate USI 2021 data. The study was conducted in Kigoma region in March 2022. Both Purposive and Convenient sampling was used to select the region, district, and ward for the study. The study involved reviewing documents used in the USI system and interviewing the key informants in the USI program. Data analysis was done by Microsoft Excel and presented in tables and graphs. A total of 1715 salt samples were collected in the year 2021 with 279 (16%) of non-iodized salt identified. The majority of the system attributes 66.7% had a good performance with a score of three, 22.2% had a moderate performance with a score of two and one attribute with poor performance with a score of one. Data quality, completeness and sensitivity were 100%, acceptability 91.6%, simplicity 83% were able to collect data on a single sample in < 2 minutes, the system stability in terms of performance was >75% and the usefulness of the system had poor performance. Although the system attributes were found to be working overall well, for proper surveillance of the USI system, the core attributes need to be strengthened. Key variables that measure the system performance must be included from the primary data source and well-integrated with the Local Government (district and regions) to Ministry of Health information systems.

Iodized household salt utilization and associated factors among households in East Africa: a multilevel modelling analysis using recent national health surveys

IntroductionIodine deficiency disorders (IDDs) are a significant global public health issue that affects the physical and mental development of every age group, with children and nursing mothers being the most vulnerable. Approximately 50 million of approximately 2 billion people with iodine deficiency (ID) globally exhibit clinical symptoms. Identifying iodine levels using various techniques is important when considering treatment choices. Screening programs and early ID diagnostics are crucial for the follow-up of pregnant women, especially in iodine-deficient nations. There have been calls for universal salt iodization programs, but only approximately 71% of people have access to them. The problem is more common in developing nations; however, there is a shortage of literature on the individual-, family-, and community-level factors influencing iodized salt use in East Africa. This study aimed to investigate individual- and community-level factors of household iodized salt usage in East Africa.MethodsUsing Stata 17, this study used the most recent demographic and health survey datasets from twelve East African countries. The survey included a weighted sample of 154,980 households. To assess factors related to iodized salt use in the region, bivariable and multivariable multilevel logistic regressions were used. P values less than or equal to 0.2, and < 0.05 were used in the binary regression, and to deem variables statistically significant in the final model respectively.ResultsAbout 87.73% (95% CI = 87.56,87.89) households have utilized iodized household salt. Secondary and above education (AOR = 1.23, 95% CI = 1.17–1.30), household heads with ages of 25–35 years, 36–45 years (AOR = 1.20, 95% CI = 1.12,1.28), 36–45 years (AOR = 1.16, 95% CI = 1.09,1.24), and more than 45 years (AOR = 1.18, 95% CI = 1.11,1.25), lower and middle wealth (AOR = 0.89, 95% CI = 0.76,0.89) and (AOR = 0.97, 95% CI = 0.81,0.93), media exposure (AOR = 1.10, 95% CI = 1.07–1.14), female household leaders (AOR = 1.08, 95% CI = 1.04–1.12), access to improved drinking water and better toilet facility (AOR = 2.26, 95% CI = 2.18–2.35) and (AOR = 1.50, 95% CI = 1.44,1.56), larger than five family members (AOR = 0.96, 95% CI = 0.93–0.99), high community level wealth (AOR = 1.54, 95% CI = 1.27–1.87), and low community education(AOR = 0.40, 95% CI = 0.33,0.49) were statistically associated with utilization of iodized household salt in East Africa respectively.ConclusionIn East Africa, household salt iodization is moderately good. To expand the use of iodized salt in the region, access to improved drinking water and toilet facilities, participating family leaders, using the opportunity of family planning services, media sources, and the improvement of the community’s socioeconomic level are all needed.

Iodine status of school-aged children in the changing context of universal salt iodization program during 1997–2018 in Chongqing, China

ObjectiveTo illustrate the changes of iodized salt usage, goiter rate of school-aged children and median urinary iodine concentration (MUIC) of school-aged children in Chongqing for the last 21 years. This study aims to estimate the variational provincial status of iodine nutrition and provide scientific evidence for fine-tuning and adaptation of the current program. MethodsDifferent number of families and school children aged 8–10 years from Chongqing during 1997–2018 participated in the study. UIC and iodine content in table salt were measured. Thyroid volumes of students were examined and goiter prevalence was calculated across years. ResultsThe median iodine content of table salt was negatively associated with years(r = −0.727, P < 0.01). The MUIC were decreased annually (ranged between 200 and 300 μg/L) and was negatively associated with year(r = −0.831, P < 0.01). Goiter of school-aged children in Chongqing was decreased from the highest rate of 23.58% in 1999 to 1.62% in 2018(Cochran-Armitage Trend Test: χ2=-30.695, P < 0.01). Thyroid volume were negatively associated with years(r = −0.962, P < 0.01) and had a positive relationship with MUIC 1997–2018 (r = 0.862, P < 0.01). ConclusionsThe consumption of adequately iodized salt can eliminate Iodine deficiency disorders (IDD) in children, but possible excessive iodine intake from salt could result in high urinary iodine excretion and even goiter. A systematic, well-designed and continual program monitoring is essential to ensure the adequacy of iodine fortification levels and to regularly change the iodine concentration in household table salt.

Systematic review and meta-analysis of iodine nutrition in modern vegan and vegetarian diets.

Vegan and vegetarian diets are widely supported and adopted, but individuals following such diets remain at greater risk of iodine deficiency. This systematic review and meta-analysis was conducted to assess the iodine intake and status in adults following a vegan or vegetarian diet in the modern day. A systematic review and quality assessment were conducted from October 2020 to December 2022 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidance. Studies were identified in Ovid MEDLINE, Web of Science, PubMed, and Scopus. Eleven articles were eligible for review containing 4421 adults (aged ≥ 18 years). Vegan groups had the lowest median urinary iodine concentration (mUIC) (12·2/l). None of the dietary groups had mUIC within the optimal range for iodine status (100-200 µg/l) (WHO). Vegan diets had the poorest iodine intake (17·3 µg/d) and were strongly associated with lower iodine intake (P = < 0·001) compared with omnivorous diets. Lower intake in vegan diets was influenced by sex (P = 0·007), the presence of voluntary or absence of Universal Salt Iodisation (USI) programmes (P = 0·01 & P = < 0·001), and living in a country with adequate iodine nutrition (P = < 0·001). Vegetarians and particularly vegans living in countries with no current USI programme continue to have increased risk of low iodine status, iodine deficiency and inadequate iodine intake. Further research into the usefulness of mandatory fortification of vegan appropriate foods is required.

Iodine deficiency and thyroid dysfunction: Current scenario in Nepal

Iodine deficiency is a major cause of thyroid disorders worldwide. Nepal lies in the endemic area of iodine deficiency which was previously referred to as Himalayan goiter belt, with high prevalence of iodine deficiency disorders including goiter, cretinism and hypothyroidism. With effective implementation of universal salt iodization program, Nepal has a successful public health story to share having drastically reduced the iodine deficiency disorders. Moreover, challenge has appeared with rising number of excess iodine states. Thyroid dysfunction is growing higher and the increasing proportion of hyperthyroidism is particularly concerning. Time has come for us to suitably review the standards of salt iodization and control the increasing number of cases with thyroid dysfunction by the coordinated efforts of all stakeholders, along with sustaining the optimal level of iodine.

Mandatory Versus Voluntary Implementation of Salt Iodization Program for the Last Two Decades in Ethiopia: A Comparative Review of Existing Literatures.

Ethiopian government was implementing mandatory salt iodization program for the last decade to eliminate iodine deficiency disorders, but several recent studies reported mixed findings. This review aimed to assess the difference in implementation of iodized salt program 10 years before and after mandatory salt iodization being implemented in Ethiopia since 2011. In Ethiopia, legislation that enforces salt producers to iodize all salts used for human consumption started in February 2011. All studies about iodine deficiency and iodized salt conducted in Ethiopia in the last 2 decades were searched. Searches were performed in PubMed database. Google Scholar, Iodine Global Network, and Ethiopian Public Health Institute websites were also searched. A total of 235 titles and abstracts were identified. After scanning the abstracts and full papers, 43 articles were remained for final data synthesis. In this review, all studies conducted before 2011 reported a urinary iodine concentration (UIC) value of < 100 μg/L and 66.7% of them reported a goiter prevalence of > 30%. On the other hand, among studies conducted after 2011, 88.9% reported UIC value < 100 μg/L and 73.7% reported goiter prevalence of > 30%. Household availability of adequately iodized salt increased from nearly 20% in pre 2011 to more than 50% in post 2011 period. Despite the efforts made by the Ethiopian government on mandatory salt iodization for the last decade, iodine deficiency is sustained in the country. Moreover, the goal of universal salt iodization program is offtrack and needs urgent revision. Registered on PROSPERO register with reg. no CRD42021251124.

Excessive iodine in iodized household salt in Nepal.

Iodine is an essential trace element required for the regulation of physiological processes involving the thyroid gland. However, inadequate and excessive intake of iodine are responsible for health problems, such as iodine deficiency disorders, hypothyroidism, hyperthyroidism, thyroiditis, thyroid papillary cancer, and thyrotoxicosis. The Universal Salt Iodization (USI) program has become successful in providing supplemental iodine at the population level globally. Packaging quality, fortification level, and transportation and storage conditions of iodized salt determine the availability of iodine. Previous studies have reported severe health issues caused by excessive iodine intake after the implementation of the USI program. To understand the levels of iodine, we collected 2117 household salt samples from seven districts of Nepal and tested them for iodine content; among them, 98.1% were iodized. Overall median concentration of iodine was 53.9ppm (range: 43.5-61.4ppm). The majority (67.2%) of samples had iodine in the range of 45-75ppm. Approximately 0.9% of samples had inadequate, 13.3% contained adequate, and 83.9% had excessive iodine than the World Health Organization-recommended value. Iodine content varied among the sampling districts and seasons, to some extent. Our study confirmed that iodized salt is widely used in Nepal and is excessively iodized. Excessive intake of iodine through iodized salt requires further attention by policy makers. The iodine level may need adjustment to address the health impact.

The Characteristics of Iodine Nutrition Status in China After 20 Years of Universal Salt Iodization: An Epidemiology Study Covering 31 Provinces.

Background: Despite the implementation of the universal salt iodization (USI) program for correction of iodine deficiency in China for ∼20 years, the actual iodine nutrition status of Chinese residents and the prevalence of iodine deficiency and iodine excess are issues that need to be addressed. This nationally representative cross-sectional study was conducted across all 31 provinces of mainland China to gather extensive data on iodine nutrition status and the influential factors. Methods: This study included 78,470 participants, aged 18 years or older, who were interviewed and asked to answer a questionnaire. Urine iodine concentration (UIC) was measured by the inductively coupled plasma mass spectrometry method, and goiter was examined by thyroid ultrasonography. In addition, sixty 9-11 years old school children in each province were randomly selected to evaluate the UIC and thyroid ultrasonography. The iodine nutrition status was determined according to the World Health Organization guidelines. Results: The iodized salt coverage was 95.37%. The median urine iodine (MUI) was 177.89 μg/L (interquartile range [IQR], 117.89-263.90 μg/L) and goiter prevalence was 1.17% (confidence interval [95% CI 0.95-1.43]) in the adult population. The MUI was 199.75 μg/L (IQR, 128.41-303.37 μg/L) in school-age children, and goiter prevalence was 3.50% [95% CI, 2.93-4.13]. The percentage of individuals with UIC <50 μg/L was 3.43%, <20%. Analysis indicated that sex, age, geographic factors, body mass index, and smoking habits influence the iodine nutrition level. Conclusion: The mandatory USI program has successfully eliminated iodine deficiency disorders, and the findings indicate that the iodine nutrition level in the general population is within the safe range.

Excess iodine exposure

To prevent iodine deficiency disorders, the universal salt iodization programme has been introduced all over the globe, including environmentally iodine sufficient regions irrespective of their iodine status. As a result, iodine-induced thyroid dysfunctions namely hyperthyroidism, hypothyroidism, autoimmune thyroid diseases, endemic goiter and even thyroid cancer including infertility, still births, abortions and embryo toxicity have emerged as a major public health problem. In other words, the consequence of iodine deficiency and excess is almost ‘U’-shaped. Hypothyroidism caused by iodine deficiency affects reproductive functions of organisms; however, such undesirable effects of iodine overload on male gonadal physiology together with hormonal profiles are yet to be adequately explored. The discovery of iodide transporter in the testis justifies an independent role of iodine in male reproductive function, which is not entirely known. Recent studies on human subjects and animal models are now revealing further perceptions into the effect of excess iodine on male infertility with euthyroid status. Excess iodine exposure has been linked with deterioration of structural and functional changes of testis leading to compromised spermatogenesis by affecting various cellular and molecular signaling pathways culminating into disrupted the blood-testis barrier and cytoskeleton. This review provides an update and summarizes various novel insights of excess iodine exposure on reproduction by establishing the independent role of iodine on male reproductive endocrinology, which might help in formulating future strategies to prevent iodine-induced male infertility, an emerging global concern, especially in the post-salt iodization era.

Smartphone-based optical transduction for the rapid microscale assessment of iodate in table salt

The measurement of iodine in table salt is vital for the successful implementation of the universal salt iodization (USI) program to fight iodine deficiency disorders (IDDs). This paper presents a smartphone-based optical transduction system for iodine measurement in table salt. The method was based on the response in the blue color space generated by the complex formed between the starch/iodide reagent and iodate in the salt sample. The parameters for the color reaction and for the image capture affected the response and were optimized. A matrix effect caused by NaCl was observed and was eliminated through matrix matching by incorporating NaCl in the standard solutions. The optimized method yielded a highly linear response to iodate concentrations ranging from 10 to 160 mg kg−1 (r = 0.9993) with a limit of detection of 2.8 mg kg−1. The method exhibited good accuracy and precision, based on AOAC standards. It produced results that were in agreement with those obtained using the reference method at the 95% confidence level. The smartphone performs optical transduction, as well as signal processing, to yield a display of the iodate concentration in the salt sample. The use of smartphones presents a simple, inexpensive, portable, and widely available device for on-site analysis of iodate in table salt.

Mild to moderate iodine deficiency in pregnancy: A matter of debate

During the last few decades painstaking efforts have been made to eliminate iodine deficiency through the world. Nowadays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Severe iodine deficiency during pregnancy increases the risk of irreversible brain damage, intellectual disability, neurologic abnormalities, stunted growth, increased pregnancy loss, infant mortality, impairments in child development and cretinism. The potential effects of mild-to-moderate iodine deficiency are debated. Results from animal studies and observational human studies indicate that maternal mild-to-moderate iodine deficiency disturbs thyroid function in pregnancy and it also may affects fetal neurodevelopment. The effect of supplementation of iodine on thyroid function of pregnant women and their newborn, neurodevelopment of infants and cognitive performance of children have been investigated using iodine nutrition in pregnancy, based on median urinary iodine concentration. However they have found conflicting results regarding the benefits or harms of iodine supplementation in pregnancy. Although many epidemiological, interventional and clinical studies have supported the association between thyroid function in pregnant women and later psychomotor and mental development of their children, the effect of iodine supplementation in pregnant women on neurodevelopment of children is inconclusive. Even in areas with well-established universal salt iodization program, pregnancy could be at risk of having iodine deficiency and despite WHO/ICCIDD/UNICEF recommendation which believe that dietary iodine fortification during pregnancy depends primarily on the extent of pre-existing iodine deprivation, systematic dietary fortification needs to be implemented in this vulnerable group. However, iodine supplementation of mildly iodine deficient pregnant women may not have beneficial effects in their thyroid function or neurodevelopment of their children.

Assessment of iodine nutritional status in school children concerning autoimmune thyroiditis in Tamil Nadu, India

Objective: To eliminate iodine deficiency disorders (IDD) in children, the Indian government implemented a universal salt iodization program more than 3 decades ago. Recently, it was identified that excess iodine intake could lead to autoimmune thyroiditis in children. We aimed to measure the level of iodine excretion as well as thyroid profiles as an option to identify autoimmune thyroiditis in school-going children. Materials and Methods: A total of 111 children between the ages of 6 and 12 years were subjected to a blood test to measure free thyroxine, thyroid-stimulating hormone, anti-thyroglobulin, and anti-thyroperoxidase levels. The children were categorized into control and case groups based on the clinical outcome. Biochemical analysis, thyroid gland assessment, fine-needle aspiration cytology (FNAC), and ultrasound sonography were performed. Urinary iodine excretion (UIE) level was measured by the Sandell-Kolthoff reaction method. Results: Approximately 90% of the study population was identified with a higher level of iodine in urine. A positive correlation was observed between the UIE, anti-TPO, and anti-TGO titers among the cases. Out of 61 cases, 21 children showed overt hypothyroidism (34.43%) and the remaining were identified with subclinical thyroid symptoms (65.57%). FNAC confirmed autoimmune thyroiditis in 43 children within the case group. Conclusion: Excess iodine intake may trigger thyroid autoimmunity in children. Children who are having higher levels of anti-thyroid antibodies are at risk of developing thyroid dysfunction if they consume more than the required iodine for metabolism. High levels of iodine in the urine of control children indicate that the IDD program in our nation is running successfully.

Iodine status and thyroid parameters of pregnant women living in an iodine sufficient area

During the last few decades painstaking efforts have been made to eliminate iodine deficiency throughout the world. Todays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Objective: The aim of this study was to obtain longitudinal data on urinary iodine excretion and the changes of maternal thyroid parameters in two groups of healthy women with mild-to-moderate iodine deficiency and iodine sufficiency residing in an iodine replete area of Tehran capital city of IR Iran, for more than one decade. Research designs and methods: The present study is part of a cohort study, investigating the relative influences of iodine intake on thyroid size and function of mothers and their infants during and after pregnancy. A total of 500 pregnant women enrolled from two mother-child health care centers and was divided into group I, with median urinary iodine excretion (MUIE) &lt; 150 µg/L, and group II with MUIE ≥ 150 µg/L. Sonographic thyroid volume measurement, urinary iodine excretion and thyroid function tests were measured sequentially in all pregnant women during the three trimesters (T) of pregnancy. Results: The mean ± SD age of the participants was 25.1 ± 5.1 years. The MUIE in group I and II in the first, second and third trimester were 123 and 250 µg/L, 127 and 166 µg/L, 120 and 150 µg/L, respectively. The MUIE in the third trimester of pregnancy in group I did not differ significantly from the values in the first and second trimesters (p = 0.67), but it did decline significantly in group II (p &lt; 0.001). The median thyroid volume of subjects, in the first, second and third trimesters were 7.8, 8.2 and 8.1 ml in group I and 7.5, 8.0 and 8.4 ml in group II, respectively. No difference in thyroid volume was found between two groups in each of the three trimesters of pregnancy (p &gt; 0.05). The mean (± SD) TSH concentration of subjects in first, second and third trimester was 2.3(± 2.6), 2.1(± 1.8), 2.3(± 1.7) mIU/L in group I and 2.1(± 3.1), 2.1(± 1.8) and 2.0(± 1.3) mIU/L in group II, respectively. The trend of TSH rising in group I was 26.7% and in group II it was 13.3%. The mean TSH value in three trimesters did not differ significantly in either groups (p &gt; 0.05). The mean (± SD) total T4 concentrations of subjects in first, second and third trimesters were 13.2(± 3.4), 13.8(± 3.3), 13.0(± 2.9) µg/dl in group I and 13.1(± 3.2), 13.7(± 2.9), 13.4(± 3.2) µg/dl in group II, respectively. The mean total T4 value in three trimesters did not differ significantly in either groups (p &gt; 0.05). There was no correlation between the thyroid volume and three observed parameters (UIE, total T4 and TSH) during the pregnancy in either groups. Conclusion: Even in areas with well-established universal salt iodization program, pregnancy could be a risk of having iodine deficiency and systematic dietary fortification needs to be implemented in this vulnerable group.

The Characteristics of Iodine Nutrition Status in China after 20 Years of USI: An Epidemiology Study Covering 31 Provinces

Background: The mandatory universal salt iodization (USI) program has been implemented in China for about twenty years to correct iodine deficiency. At present, the actual iodine nutrition status of Chinese residents and whether they are adversely affected by iodine excess are issues of general concerns. Method: A nationally representative cross-sectional study was conducted. 78,470 participants, aged 18 or older, were enrolled from all 31 provincial regions of mainland China. The participants were interviewed and given a questionnaire. Urine iodine concentration (UIC) were measured by ICP-MS (inductively coupled plasma mass spectrometry) method. The goiter was examined by thyroid ultrasonography. The iodine category was based on the criteria of WHO. Results: The iodized salt coverage is 95·37% in the general population. The median urine iodine (MUI) was 177·89μg/L (interquartile range, 117·89-263·90μg/L) in the general population with goiter prevalence 1·17% (95%CI, 0·95-1·43%). The MUI was 199·7(interquartile range, 128·46-303·02) in school age children with prevalence of goiter 3·50% (95% CI, 2·93% to 4·13%). The percentage of moderate iodine deficiency (UIC<50μg/L) was 3·43%. The subjects with adequate iodine and more than adequate iodine in total accounting for 63·44% of the whole population. The data also manifested that gender, age, ethnic, geographic factors, BMI, smoking habits, education and income levels have a certain degree of influence on the iodine nutrition level. Conclusion: The mandatory USI program in China has successfully eliminated iodine deficiency disorders for 20 years. Our epidemiological investigation suggested that the iodine nutrition level of Chinese residents is generally within the safe range. Funding Statement: This work is supported by the Research Fund for Public Welfare from National Health and Family Planning Commission of China (Grant No. 201402005). Declaration of Interests: There is no conflict in interest. Ethics Approval Statement: The research protocols were approved by the Medical Ethics Committee of China Medical University.

Geographical influences on thyroid abnormalities in adult population from iodine-replete regions: a cross-sectional study

The studies on the increasing incidence of thyroid abnormalities are scarce. The aim of this current study was to ascertain the effects of geographical region on thyroid abnormalities under the context of universal salt iodization (USI). We randomly selected 1255 participants residing in inland and 1248 in coast, with the determination of urinary iodine concentration (UIC) and functional and morphological abnormalities of thyroid gland. The median UIC was significantly higher for the inland participants (188.5 μg/L) than the coastal participants (128.5 μg/L; p < 0.001), indicating iodine sufficiency in both populations according to the recommended assessment criteria by the World Health Organization. However, the spectrum of thyroid abnormalities varied between regions, with hypothyroidism prevalent in inland and thyroid nodules in coast. The associations between region and thyroid abnormalities via binary logistic regression models showed that the coastal participants were at a higher risk of total thyroid abnormalities than those from the inland (OR 1.216, 95% CI 1.020–1.449), after the adjustment of ten confounders (demographical characteristics, smoking status, metabolism syndrome, and hyperuricemia). These results indicated that further investigations of the adverse effects of hypothyroidism and thyroid nodules on health burden is urgently needed to sustain USI program.

Estimating the Health and Economic Benefits of Universal Salt Iodization Programs to Correct Iodine Deficiency Disorders.

Background: There has been tremendous progress over the past 25 years to control iodine deficiency disorders (IDDs) through universal salt iodization (USI). In 2019, using the median urinary iodine concentration (MUIC), only 19 countries in the world are classified as iodine deficient; in contrast in 1993, using the total goiter rate (TGR), 113 countries were classified as iodine deficient. However, few analyses have tried to quantify the global health and economic benefits of USI programs, and the shift from TGR to MUIC as the main indicator of IDDs complicates assessment of progress.Methods: We used a novel approach to estimate the impact of USI on IDDs, applying a regression model derived from observational data on the relationship between the TGR and the MUIC from 24 countries. The model was used to generate hypothetical national TGR values for 2019 based on current MUIC data. TGR in 1993 and modeled TGR in 2019 were then compared for 139 countries, and using consequence modeling, the potential health and economic benefits realized between 1993 and 2019 were estimated.Results: Based on this approach, the global prevalence of clinical IDDs (as assessed by the TGR) fell from 13.1% to 3.2%, and 720 million cases of clinical IDDs have been prevented by USI (a reduction of 75.9%). USI has significantly reduced the number of newborns affected by IDDs, with 20.5 million cases prevented annually. The resulting improvement in cognitive development and future earnings suggest a potential global economic benefit of nearly $33 billion. However, 4.8 million newborns will be affected by IDDs in 2019, who will experience life-long productivity losses totaling a net present value of $12.5 billion.Conclusions: The global improvements in iodine status over the past 25 years have resulted in major health and economic benefits, mainly in low- and middle-income countries. Efforts should now focus on sustaining this achievement and expanding USI to reach the continuing large number of infants who remain unprotected from IDDs.

Development of USI-Kit for Evaluation of Iodine Content in Iodized Salt

Iodine deficiency has been considered as a serious public health problem for the past decades. Universal salt iodization program is introduced and implemented to address such problem. To encourage this program in an effective and sustainable way, it is essential to regularly monitor whether salt is adequately iodized at various points along the supply chain. The traditional iodometric titration method has problems related to accessibility, cost, and time. Colorimetric test kits have been used extensively to measure coverage of iodized salt in household surveys due to its expediency and affordability. In Thailand, “I-KIT” is the most widely used. The visualization of intensive color, however, is inconvenient for untrained-user in determining the adequacy of iodine content. Thus, an improvement to make testing more precise and affordable is still required. In this respect, a new test kit namely USI-Kit was developed to assess iodine quality and semi-quantity in edible salt. The kit was tested to evaluate its performance, by comparing the result with the I-KIT and with the spectrophotometric method. Compared with I-Kit, the USI-Kit exerted the relative accuracy, sensitivity, specificity, false positive rate, false negative rate and Kappa coefficient value of 74.0, 76.3, 72.6, 27.4, 23.7 and 0.47, respectively. Compared to the spectrophotometric method, USI-Kit exerted the relative accuracy, sensitivity, specificity, false positive rate, false negative rate and Kappa coefficient value of 85.4, 80.1, 89.3, 10.7, 19.9 and 0.70, respectively. The finding suggested that a newly developed iodine test kit holds promise to be used in field inspection of iodine content in salt.

Universal Salt Iodisation: Lessons learned from Cambodia for ensuring programme sustainability.

Iodine deficiency is the leading cause of preventable intellectual disability in the world, but it has been successfully prevented in most countries through universal salt iodization (USI). In 2011, Cambodia appeared to be an example of this success story, but today, Cambodian women and children are once again iodine deficient. In 2011, Cambodia demonstrated high‐household coverage of adequately iodized salt and had achieved virtual elimination of iodine deficiency in school‐age children. However, this achievement was not sustained because the USI programme was dependent on external funding, and the national government and salt industries had not institutionalized their implementation responsibilities. Recent programmatic efforts, in particular the establishment of a regulatory monitoring and enforcement system, are turning the situation around. Although Cambodia has not yet fully regained the achievements of 2011 (only 55% of tested salt was adequately iodized in 2017 compared with 67% in 2011), the recent steps taken by the government and the salt industry point to greater sustainability of the USI programme and the long‐term prevention of iodine deficiency in children, women, and the general population.

Stable Iodine Nutrition During Two Decades of Continuous Universal Salt Iodisation in Sri Lanka.

Universal salt iodisation (USI) was introduced in Sri Lanka in 1995. Since then, four national iodine surveys have assessed the iodine nutrition status of the population. We retrospectively reviewed median urine iodine concentration (mUIC) and goitre prevalence in 16,910 schoolchildren (6–12 years) in all nine provinces of Sri Lanka, the mUIC of pregnant women, drinking-water iodine level, and the percentage of households consuming adequately (15 mg/kg) iodised salt (household salt iodine, HHIS). The mUIC of schoolchildren increased from 145.3 µg/L (interquartile range (IQR) = 84.6–240.4) in 2000 to 232.5 µg/L (IQR = 159.3–315.8) in 2016, but stayed within recommended levels. Some regional variability in mUIC was observed (178.8 and 297.3 µg/L in 2016). There was positive association between mUIC in schoolchildren and water iodine concentration. Goitre prevalence to palpation was a significantly reduced from 18.6% to 2.1% (p < 0.05). In pregnant women, median UIC increased in each trimester (102.3 (61.7–147.1); 217.5 (115.6–313.0); 273.1 (228.9–337.6) µg/L (p = 0.000)). We conclude that the introduction and maintenance of a continuous and consistent USI programme has been a success in Sri Lanka. In order to sustain the programme, it is important to retain monitoring of iodine status while tracking salt-consumption patterns to adjust the recommended iodine content of edible salt.

Assessment of the iodine nutritional status among Chinese school-aged children.

ObjectiveThe remarkable success of iodine deficiency disorders (IDD) elimination in China has been achieved through a mandatory universal salt iodization (USI) program. The study aims to estimate the relationship between urinary iodine concentration (UIC) and iodine content in edible salt to assess the current iodine nutritional status of school aged children.MethodsA total of 5565 students from 26 of 39 districts/counties in Chongqing participated in the study, UIC and iodine content in table salt were measured. Thyroid volumes of 3311 students were examined by ultrasound and goiter prevalence was calculated.ResultsThe overall median UIC of students was 222 μg/L (IQR: 150-313 μg/L). Median UIC was significantly different among groups with non-iodized salt (iodine content <5 mg/kg), inadequately iodized salt (between 5 and 21 mg/kg), adequately iodized (between 21 and 39 mg/kg) and excessively iodized (>39 mg/kg) salt (P < 0.01). The total goiter rate was 1.9% (60/3111) and 6.0% (186/3111) according to Chinese national and WHO reference values, respectively. Thyroid volume and goiter prevalence were not different within the three iodine nutritional status groups (insufficient, adequate and excessive, P > 0.05).ConclusionsThe efficient implementation of current USI program is able to reduce the goiter prevalence in Chongqing as a low incidence of goiter in school aged children is observed in this study. The widened UIC range of 100–299 μg/L indicating sufficient iodine intake is considered safe with a slim chance of causing goiter or thyroid dysfunction. Further researches were needed to evaluate the applicability of WHO reference in goiter diagnose in Chongqing or identifying more accurate criteria of normal thyroid volume of local students in the future.