Association of socioeconomic status with iodine supply and thyroid disorders in northeast Germany

Urinary haloacetic acid concentrations and thyroid function among women: Results from the TREE study

BACKGROUND

Disinfection byproducts (DBPs) have been shown to impair thyroid function in experimental models. However, epidemiological evidence is scarce.

METHODS

This study included 1190 women undergoing assisted reproductive technology (ART) treatment from the Tongji Reproductive and Environmental (TREE) cohort from December 2018 to August 2021. Serum thyrotropin (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured as indicators of thyroid function. FT4/FT3 and TSH/FT4 ratios were calculated as markers of thyroid hormone homeostasis. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two most abundant HAAs, in urine were detected to assess individual DBP exposures.

RESULTS

After adjusting for relevant covariates, positive associations were observed between urinary TCAA concentrations and serum TSH and TSH/FT4 levels (e.g., percent change = 5.82 %, 95 % CI: 0.70 %, 11.21 % for TSH), whereas inverse associations were found for serum FT3 and FT4 (e.g., percent change = -1.29 %, 95 % CI: -2.49 %, -0.07 % for FT3). There also was a negative association between urinary DCAA concentration and serum FT4/FT3 (percent change = -2.49 %, 95 % CI: -4.71 %, -0.23 %). These associations were further confirmed in the restricted cubic spline and generalized additive models with linear or U-shaped dose-response relationships.

CONCLUSION

Urinary HAAs were associated with altered thyroid hormone homeostasis among women undergoing ART treatment.

Prevalence and risk factors of hypertension with thyroid dysfunction among indian adults: Synthesis from national family health survey (2015-16)

Background

Thyroid dysfunction (TD) is considered a common cause of secondary hypertension (HT). Therefore, correcting TD may help in quicker and sustained achievement of desired blood pressure goals. However, there is a paucity of literature from India which estimates the relationship of HT with TD.

Objectives

The objective of the study was to estimate the prevalence of TD with HT and to identify associated factors among Indian population.

Materials and Methods

The survey data of the National Family Health Survey 4 (NFHS-4), conducted in India during 2015-2016, were analyzed using R statistical software for estimating the relationship between a history of HT and TD among women (N = 687246) aged 15-49 years and men (N = 108492) aged 15-54 years. Descriptive statistical tests and logistic regression were applied.

Results

Among the persons suffering from the TD, the prevalence of HT was 32.8%, which was significantly higher than the prevalence of HT (21.9%) in euthyroid individuals. Further, the prevalence of TD was higher among hypertensive adults (2.5%) compared to nonhypertensive (1.5%).

Conclusions

The study reported a higher prevalence of TD among the hypertensive persons and higher prevalence of HT among cases of TD. Therefore, screening for thyroid disorders should be routinely considered for better management of HT.

Spatial-Temporal Analysis of Factors Influencing the Median Urine Iodine Concentration of 8-10-year-old Children in Xinjiang, China 25 Years after Implementation of the Salt Iodization Policy

The iodine status of children has improved and stabilized since China implemented salt iodization measures 25 years ago, but routine monitoring of iodine cannot reflect regional factors that influence the iodine level in children. Therefore, we conducted a regional spatial-temporal analysis of children's median urinary iodine concentration (MUIC) and searched for possible factors that might affect children's iodine levels by mining monitoring data. We analyzed data from Xinjiang collected as part of the "Iodine Deficiency Disease National Monitoring Program" from 2017 to 2020. The study population consisted of 76,268 children who participated in the study. We used global autocorrelation analysis to determine whether the MUIC of children was spatially clustered, local autocorrelation analysis to identify specific clustering areas, local cold and hot spot analysis to verify the reliability of the local autocorrelation results, and a spatial lag model to identify factors affecting the children's MUIC. The MUIC values were 217.70, 227.00, 230.67, and 230.67 µg/L in 2017, 2018, 2019, and 2020, respectively. Global autocorrelation analysis showed that the MUIC of all children in the study was significantly related to region (Z scores all > 1.96, P values all < 0.05) from 2017 to 2020. Partial auto-correlation analysis showed that counties with clusters of high values were mostly concentrated in the southwestern region of Xinjiang, whereas counties with clusters of low values were located in the northern part of Xinjiang. Partial cold spot and hot spot analysis showed the same trend, and there are more overlapping districts and counties in 4 years. Three-dimensional trend analysis indicated that children from the western part of Xinjiang had high levels of urinary iodine. According to spatial lag model, urine iodine concentration level is positively correlated with thyroid volume, average salary, and urbanization rate classification. The MUIC of 8-10-year-old children in Xinjiang was spatially clustered and related to geographic region. Our results show that spatial analysis of survey data combined with geographic technology and public health data can accurately identify areas with abnormal iodine concentrations in children. Additionally, understanding the factors that influence iodine levels in the human population is conducive to improving monitoring methods.

Clinical value of molecular markers as diagnostic and prognostic tools to guide treatment of thyroid cancer

OBJECTIVE

Advances in our understanding of the molecular biology of thyroid tumours is being rapidly translated into their clinical management. This review summarizes the current use of molecular testing in thyroid tumours, focusing on their usefulness as diagnostic and prognostic tools to guide treatment with consideration of present limitations.

DESIGN

Considerations about molecular testing applications for the diagnosis and treatment of thyroid tumours are divided into four sections/roles: (1) evaluating cytologically indeterminate thyroid nodules; (2) guiding extent of surgery in indeterminate thyroid nodules; (3) completing histological characterization of thyroid tumours and (4) identifying actionable mutations in advanced progressive thyroid cancers.

RESULTS

Genomic testing can improve the presurgical malignancy risk assessment in indeterminate thyroid nodules. However, a prior in-depth analysis of institutional quality and outcomes of sonographical, cytological and histological characterization of thyroid tumours is necessary. Presently, it remains uncertain whether knowing the molecular profile of a cytologically indeterminate thyroid nodule might be advantageous to modify the extent of initial surgery. Molecular characterization of thyroid tumours can be a valuable adjunct to morphological diagnosis in some challenging cases, such as in low-risk follicular cell-derived neoplasms, or rare tumours. Finally, as selective kinase inhibitors are available, molecular testing in locally advanced/metastatic progressive thyroid cancers should also be integrated into the institutional clinical management pathway to improve outcomes and limit toxicity.

CONCLUSIONS

Molecular testing needs to be implemented into the local evidence-based clinical management thyroid nodule/cancer pathways to improve its diagnostic and prognostic value and to optimize cost-effectiveness.

Universal salt iodization potentially contributes to health equity: socio-economic status of children does not affect iodine status

OBJECTIVES

Many studies have shown that socio-economic status (SES) contributes to health inequalities, with nutrition as one of the major risk factors. Iodine intake entirely depends on external sources, and deficiencies are known to be more prevalent in lower social groups, especially in countries with limited access to iodized salt. This study aimed to determine the influence of SES on iodine status and iodine availability from household salt in North Macedonia.

METHODS

Using cluster sampling, 1,200 children were recruited, and 1,191 children participated (response rate: 99.2%). Iodine status was assessed through urinary iodine concentration (UIC), and iodine availability through iodine content in household salt requested from participants. SES was assessed using standardized Family Affluence Score (FAS).

RESULTS

No statistically significant correlation was found between FAS and iodine in salt. Median regression revealed no significant associations of middle vs. low FAS (β=0.00; 95%-confidence interval (CI)=[-0.61, 0.62]; p=0.999) or high vs. low affluence (β=0.48; 95% CI=[-1.37, 0.41]; p=0.291) with iodine content in household salt. UIC levels were significantly lower in middle FAS children compared to low FAS children (β=-16.4; 95% CI=[-32.3, -0.5]; p=0.043). No statistically significant differences in UIC were found between children with high and low affluence (β=-12.5; 95% CI=[-35.5, 10.5]; p=0.287), possibly due to lowered statistical power for this comparison.

CONCLUSIONS

Universal salt iodization (USI) proves to be a cost-effective measure for appropriate iodine intake in healthy children and adults, irrespective of their social status. It can thus be concluded that USI contributes to reducing health inequalities related to iodine status among population of different social strata.

Lower educational status interferes with maternal iodine intake during both pregnancy and lactation

OBJECTIVE

To investigate factors affecting conscious iodine intake among pregnant and lactating women in a rural area in Hungary.

METHODS

Pregnant women were studied and followed during lactation. Urinary and breast milk iodine concentration (UIC and MIC) were measured by inductively coupled plasma mass spectrometry. Potential interfering factors, including age, educational status and smoking were assessed.

RESULTS

During pregnancy and lactation, mild iodine deficiency was observed; median UIC were 66 and 49 µg/L, respectively. Educational status was found to be a strong determinant of both iodine nutrition and smoking status during pregnancy (P < 0.01 and P < 0.001) and lactation (P < 0.001 and P < 0.01). While smoking and non-smoking lactating mothers had similar concentrations of urinary iodine (median UIC: 47 and 51 µg/L, P = 0.95), the breast milk of smoking mothers contained less iodine (median MIC: 150 and 203 µg/L, P = 0.03).

CONCLUSIONS

Both low iodine intake and smoking contribute to the higher risk of iodine deficiency in women with lower educational status. In smokers, MIC is often low in spite of normal UIC, presumably due to the iodine transport blocking effect of the cigarette smoke towards breast milk; normal UIC may be misinterpreted as sufficient iodine supply towards the child. Antenatal health promotion strategies should focus on young women with lower educational status, even in regions where sufficient iodine intake has been achieved in non-pregnant adults.

Factors influencing the iodine status of children aged 12 to 59 months from Jaffna District, Sri Lanka in the post-iodization era; a descriptive, cross-sectional study

BACKGROUND

Iodine status, including Iodine Deficiency (ID) of the children aged 12-59 months of Jaffna District, Sri Lanka, have never been studied. This study thus aimed to assess ID among children aged 12-59 months by monitoring the Urinary Iodine Concentrations (UIC), the prevalence of goitre, and the factors causing ID.

METHOD

A cross-sectional study was conducted among 846 children aged 12-59 months in Jaffna District, Sri Lanka. Sociodemographic characteristics and other factors were collected using an interviewer-administered questionnaire. Dietary pattern of children was obtained using semi-quantitative food frequency questionnaire. We performed urinary iodine estimation and physical examinations to detect the goitre, according to the World Health Organization criteria. A multivariate logistic linear regression model was used to identify the factors that causing ID.

RESULT

The median UIC was 146.4 μg/L (interquartile range = 112.6-185.3 μg/L). Based on the UIC (<100 μg/L), 17.8% had ID, of which 15.7% and 2.1% had mild and moderate ID. The mean consumption of iodine from food was 128.7 (±20.2) μg/day. Gender variation had no influence on ID (p>0.05). Median UIC was significantly associated with living area, wealth status, type of drinking water, and method of iodized salt usage. A higher percentage of ID was significantly associated with younger age [AOR 2.32 (95% CI: 1.31-4.10)], urban area [AOR 1.94 (95% CI 1.27-2.96)], inland regions [AOR 3.20 (95% CI 1.85-5.55)], improper method of iodized salt usage [AOR 3.63 (95% CI: 1.38-9.56)], and low consumption of iodine-containing foods. The neck palpation revealed that only three children had goitre (0.4%).

CONCLUSION

This study revealed that high ID among the children in Jaffna children was due to improper usage of iodized salt, even though the iodized salt is freely available in the region, living area, and age, while the prevalence of goitre was not significantly identified as a public health problem.

Influence of educational level on test and treatment for incident hypothyroidism

OBJECTIVE

The incidence of hypothyroidism is not expected to differ by socioeconomic factors. However, the decision to test and initiate treatment may differ. We aimed to examine whether educational level influences the probability of thyroid stimulation hormone (TSH)-measurement and initiation of levothyroxine treatment.

DESIGN

Citizens in the greater Copenhagen Area during 2001-2015 were included. Individual-level data on educational level, diagnoses, GP-contact, TSH-measurement and medication were derived from administrative and healthcare registers. The relative risks (RR) between educational levels of annual TSH-measurement and treatment initiation following a TSH-measurement were analysed in Poisson regression models with generalized estimation equations.

RESULTS

A TSH-measurement was performed in 19% of 9,390,052 person years. The probability of TSH-measurement was higher with short (RR 1.16 [95% CI 1.15-1.16]) and medium (RR 1.11 [95% CI 1.06-1.12]) compared with long education. Treatment was initiated after 0.8% of 2,049,888 TSH-measurements. For TSH < 5 mIU/L, RR for treatment initiation ranged between 0.47 (95%CI 0.39-0.57) and 0.78 (95%CI 0.67-0.91) for short and medium compared with long education. For TSH 5-10 mIU/L, there was no statistically significant difference. For TSH > 10 mIU/L, RR was 1.07 (95% CI 1.02-1.12) for short and 1.08 (95% CI 1.03-1.13) for medium compared with long education.

CONCLUSION

The probability of TSH-measurement was higher with shorter education, and the probability of treatment initiation with TSH > 10 mIU/L was marginally higher with short-medium education compared with long education. However, the probability of treatment initiation with TSH < 5 mIU/L, that is treatment incongruous with guidelines, was substantially higher in persons with long education.

Obesity and Monitoring Iodine Nutritional Status in Schoolchildren: is Body Mass Index a Factor to Consider?

Background: The frequency of overweight (OW) and obese (OB) children has increased worldwide, particularly in economically developed countries. No studies have been conducted to verify whether the increasing frequency of OW and obesity in schoolchildren may affect the evaluation of iodine nutritional status in populations. The aim of this study was to verify whether urinary iodine concentration (UIC), thyroid volume (TV), and thyroid hypoechoic pattern may be affected by body mass index (BMI) in schoolchildren. Methods: The children included in this study (aged 11-13 years) were a part of the schoolchildren recruited in the second nationwide survey (period 2015-2019) conducted in Italy to monitor by law (Atto di Intesa Stato-Regioni February 26, 2009) the nationwide iodine prophylaxis program. Specifically, 1281 schoolchildren residing in iodine-sufficient areas (IS group) and 384 children residing in a still mildly iodine-deficient area (ID group) were recruited between January and March 2015 in the first-degree secondary state schools. In all the children, spot UIC was measured, thyroid ultrasound was performed to evaluate TV, and hypoechogenicity was assessed to indirectly evaluate iodine-associated thyroid autoimmunity. Results: The frequency of OW, OB, and adequate weight (AW) children was similar in the IS and ID groups at any age. After adjusting for sex and age, the regression analysis showed lower UIC values in OB children than in AW children of the IS group (beta coefficient = -34.09 [95% confidence interval -65.3 to -2.8]), whereas no significant differences were observed in the ID group. In both the IS and ID groups, the distribution of TV in AW children was significantly shifted toward lower values in comparison to the distribution of OB children (p < 0.001 in the IS group; p = 0.012 in the ID group). Furthermore, the frequency of thyroid hypoechogenicity was higher in the ID group than in the IS group (10.9% vs. 6.6%, p = 0.005); however, in both groups, it was significantly lower in AW children than in OB children (p < 0.01). Conclusions: This study for the first time demonstrates that BMI may be a confounding factor in monitoring iodine nutritional status in schoolchildren. Since in Italy as in other Western countries the number of OW and OB children is high, BMI is a factor to consider in monitoring salt iodization programs worldwide.

Changing Dietary Habits in Veneto Region over Two Decades: Still a Long Road to Go to Reach an Iodine-Sufficient Status

Background: Fifteen years after a nationwide voluntary iodine prophylaxis program was introduced, the aims of the present study were: (a) to obtain an up-to-date assessment of dietary iodine intake in the Veneto region, Italy; and (b) to assess dietary and socioeconomic factors that might influence iodine status. Methods: Urinary iodine concentration (UIC) was obtained in 747 school students (median age 13 years; range: 11–16 years). Results: The median UIC was 111 μg/L, with 56% of samples ≥ 100 μg/L, but 26% were < 50 μg/L, more frequently females. Iodized salt was used by 82% of the students. The median UIC was higher among users of iodized salt than among non-users, 117.0 ug/L versus 90 ug/L (p = 0.01). The median UIC was higher in regular consumers of cow’s milk than in occasional consumers, 132.0 μg/L versus 96.0 μg/L (p < 0.01). A regular intake of milk and/or the use of iodized salt sufficed to reach an adequate median UIC, although satisfying only with the combined use. A trend towards higher UIC values emerged in regular consumers of cheese and yogurt. Conclusion: Iodine status has improved (median UIC 111.0 μg/L), but it is still not adequate as 26% had a UIC < 50 μg/L in the resident population of the Veneto region. A more widespread use of iodized salt but also milk and milk product consumption may have been one of the key factors in achieving this partial improvement.

A contemporary analysis of goiters undergoing surgery in the United States

INTRODUCTION

We identified disparities and at-risk populations among patients with goiters undergoing thyroidectomy.

MATERIALS AND METHODS

The National Inpatient Sample (NIS) database was queried for patients with goiter who underwent thyroidectomy between 2009 and 2013. Multivariable logistic regression was used to determine factors associated with goiters undergoing thyroidectomy.

RESULTS

The study consisted of 103,678 patients with thyroidectomy and a goiter diagnosis, which included: simple goiter (n = 7,692, 7.42%), nodular goiter (n = 73,524, 70.92%), thyrotoxicosis (n = 14,043, 13.54%), thyroiditis (n = 1,248, 1.20%), and thyroid cancer (n = 7,169, 6.92%). Factors associated with operation for simple goiter included age >65 years (AOR 1.43 [1.15-1.79]), black race (AOR 1.35 [1.14-1.58]), and being uninsured (AOR 2.13 [1.52-2.98]). Patients with cancerous goiters undergoing thyroidectomy were less likely to be Black (AOR 0.38 [0.31-0.48]) or uninsured (AOR 0.25 [0.07-0.89]).

DISCUSSION

Understanding disparities within populations undergoing thyroidectomy for goiter may allow for targeted efforts to more effectively treat goiters nationwide.

Urinary iodine levels of primary school children in Ilorin, Nigeria

Background: Iodine deficiency is one of the commonest micronutrient deficiencies. Globally, it is the commonest cause of preventable mental retardation and also associated with impaired physical growth. The current iodine nutrition of school children in Ilorin, North-Central Nigeria is not known. Objective: The study aimed to determine the urinary iodine levels(UIL) of school children in Ilorin and explored the relationship with socio-demographic variables. Methods: This cross-sectional study was carried out among primary schools children in Ilorin, Nigeria. We recruited school children aged 6-12 years through a multi-staged sampling method. Relevant data including socio-demographic variables were obtained with a pretested study proforma. The recruited school children had urinary iodine determined using the Sandell-Kolthoff method. Data analysis was with Statistical Package for Social Sciences version 20.0. Results: The median with interquartile range (IQR) of urinary iodine level was 117.2 (99.6-148.6) g/L. Of the 480 recruited children, 336 (70.0%) had normal urinary iodine levels while 144 (25%) had mild iodine deficiency and two (0.4%) had excess urinary iodine levels. Pupils with iodine deficiency was higher among public schools than those in private schools (33.3% vs 23.6%, 2 = 150.149, p < 0.022). The median UIL of the age-group 6-9 years was higher than the 10-12year age group (p = 0.026). However, the median UIL values were comparable across gender, socioeconomic strata and mother's educational level. Conclusions: This study showed that a quarter of the children still had mild iodine deficiency despite salt iodisation policy adopted by the country. Also, the iodine levels were not influenced by socio-demographics.

Low Iodine Intake from Dairy Foods Despite High Milk Iodine Content in Israel

BACKGROUND

Milk is a major source of iodine in human nutrition. Because both iodine content and the consumption of milk and dairy vary widely over time and populations, their contribution to iodine intake must be evaluated regularly. A recent national iodine survey found Israel's population to be mildly iodine deficient, possibly due to unmonitored changes in the food content of dietary iodine. Accounting for dairy iodine content can help guide efforts to prevent iodine deficiency.

OBJECTIVES

This study aimed to determine the iodine concentration of dairy products typically consumed in the Israeli diet, and to estimate iodine intake from dairy products among Israeli adults.

METHODS

Iodine was analyzed in 33 selected dairy products that account for 89% of the total population's dairy intake according to the "MABAT" Israeli National Health and Nutrition survey. Based on these data, the distribution of iodine intake from milk, dairy, and dairy-based foods in the adult population was calculated.

RESULTS

Israeli milk is rich in iodine, with a mean concentration of 22 μg/100 g. However, due to low dairy consumption, the mean iodine intake from milk and dairy was only 34 μg/day (median 23 μg/day; range: 0-337 μg/day) or 22% of the recommended daily allowance. Self-reported intake among poor, male, and Arab subgroups was even lower.

CONCLUSIONS

Because Israeli milk and dairy products are iodine rich, their contribution to the population's iodine intake would increase if they were consumed in greater amounts, particularly by high-risk groups. Dairy's potential contribution to iodine nutrition should be considered in recommendations for dairy consumption and iodine prophylaxis.

Efficacy of educational intervention to improve awareness of the importance of iodine, use of iodized salt, and dietary iodine intake in northeastern Italian schoolchildren

OBJECTIVE

An educational program was conducted among school-aged children to improve their knowledge about iodine prophylaxis, their iodine status, and their dietary habits.

METHODS

At the baseline (T0) and after 6 mo (T1), participants (970 at T0 and 949 at T1) answered questionnaires testing their knowledge about iodine prophylaxis and their eating habits. Urine samples were collected from a randomly selected subgroup of participants (313 at T0 and 312 at T1).

RESULTS

From T0 to T1 there was a significant improvement in respondents' knowledge about iodine prophylaxis (from 44% to 70%), iodized salt consumption (from 78% to 84%), and median urine iodine concentrations (from 70 µg/L to 91 µg/L). Milk and iodized salt intakes were associated with a better iodine status per se, and more so when used simultaneously. Girls drank milk less often than boys did (daily in 52% and 59% of cases, respectively). Children of foreign origin ate sodium-rich food more often than Italians did.

CONCLUSION

Educational intervention improved the children's knowledge about iodine prophylaxis and use of iodized salt. Consuming salt in addition to milk improves iodine status. Children of foreign origin have different eating habits.

Factors affecting sustainable iodine deficiency elimination in Pakistan: A global perspective

Iodine deficiency remains a considerable challenge worldwide, even after decades of efforts to address the problem. The aim of this review is to present the current situation in historically iodine-deficient Pakistan regarding iodine nutritional status and place it in a global perspective. We collected relevant articles from online bibliographic databases and websites of concerned organizations that addressed prevalence of goiter/iodine deficiency and barriers to sustainable control. We divided the studies into pre- and post-1994, a landmark year when Pakistan formally adopted the universal salt iodization (USI) programme. Overall, 56 studies reported goiter/iodine deficiency prevalence in Pakistan. Before 1994, six studies (30%) reported a goiter prevalence ≥70%, while nine studies (45%) reported a goiter prevalence between 30% and 70%. Only five studies (25%) found a goiter prevalence less than 30%, of which only two studies reported prevalence <10%. From 1994 onwards, 15 studies (41.7%) reported a goiter/iodine deficiency (ID) prevalence ≥50%, of which seven studies reported prevalence ≥70%, while three studies (8.3%) found a goiter prevalence of 30%-49%, nine studies (25%) found a goiter prevalence of 10%-29%, and five studies (13.9%) reported prevalence of <10%. Four studies (11.1%) reported lower goiter prevalence but higher prevalence of iodine deficiency. The efforts in the past two decades resulted in up to a 50% decline in iodine deficiency disorders (IDD). Variable remaining factors and the recent results, however, indicate that this decline may be non-uniform and even over-estimated. Coordinated and regionally adopted efforts for eradication of IDD from all stakeholders should be pursued. Policy makers should take steps to protect future generations and alert concerned organizations about the importance of careful assessments and estimates of iodine nutritional status.

Large-scale fortification of condiments and seasonings as a public health strategy: equity considerations for implementation

Fortification of staple foods with vitamins and minerals is an effective approach to increase micronutrient intake and improve nutritional status. The specific use of condiments and seasonings as vehicles in large-scale fortification programs is a relatively new public health strategy. This paper underscores equity considerations for the implementation of large-scale fortification of condiments and seasonings as a public health strategy by examining nonexhaustive examples of programmatic experiences and pilot projects in various settings. An overview of conceptual elements in implementation research and equity is presented, followed by an examination of equity considerations for five implementation strategies: (1) enhancing the capabilities of the public sector, (2) improving the performance of implementing agencies, (3) strengthening the capabilities and performance of frontline workers, (3) empowering communities and individuals, and (4) supporting multiple stakeholders engaged in improving health. Finally, specific considerations related to intersectoral action are considered. Large-scale fortification of condiments and seasonings cannot be a standalone strategy and needs to be implemented with concurrent and coordinated public health strategies, which should be informed by a health equity lens.

Iodine Nutritional Status in Schoolchildren from Public Schools in Brazil: A Cross-Sectional Study Exposes Association with Socioeconomic Factors and Food Insecurity

INTRODUCTION

National programs of salt iodization were implemented in Brazil to combat iodine deficiency (ID) in children of school age. Currently, there are limited data in Brazil on those still vulnerable to this deficiency and the state of nutritional iodine status in the northeast region of Brazil, where children are vulnerable to malnutrition.

OBJECTIVE

The aim of this study was to analyze the iodine nutritional status, household food insecurity, socioeconomic and demographic characteristics among schoolchildren from the public school system living in state the state of Bahia, Brazil.

METHODS

A cross-sectional study was conducted on 1419 schoolchildren in Bahia between the ages of 6 and 14 years old. Anthropometric parameters, urinary iodine concentrations (UIC), and thyrotropin (TSH) measurements were evaluated from blood spots on filter paper.

RESULTS

The mean UIC was 206.4 ± 80.5 μg/L, with a median of 221.6 μg/L, indicating sufficient iodine intake in the region. Low urinary iodide concentration (<100 μg/L) was detected in 12.3% of the schoolchildren (n = 174), with 6.2% with mild (<100 μg/L), 3.0% with moderate (20-49 μg/L), and 3.1% with severe ID (<20 μg/L). Moreover, 9.4% (n = 134) had a urinary iodide concentration of >300 μg/L, indicating the coexistence of excessive iodine intake (EII). The mean TSH was 1.0 ± 0.6 mIU/L. The body mass index category "overweight/obesity" was a protective factor against EII (odds ratio [OR] = 0.64 [confidence interval (CI) 0.4-1.0]; p = 0.07). Urban areas (73%) had a mean UIC of 213.1 ± 80 μg/L compared with 176.8 ± 76.1 μg/L in rural areas. The risk for EII increased in children living in a house with more than six people (OR = 1.62 [CI 0.9-2.6]; p < 0.05) and water consumption from shallow wells (OR = 1.70 [CI 0.9-3.1]; p = 0.09). The risk of ID was increased by 70% in schoolchildren who had moderate or severe food insecurity (OR = 1.70 [CI 0.9-3.0]; p > 0.05).

CONCLUSION

A significant proportion of schoolchildren still have ID or EII in the northeast region of Brazil, emphasizing the importance of committed public policies to address this problem. Socioeconomic factors and the lack of education about nutritional importance of iodine were important influencing factors in the presence of ID in schoolchildren.

Iodine excretion has decreased in Denmark between 2004 and 2010--the importance of iodine content in milk

Fortification with the essential trace element iodine is widespread worldwide. In the present study, results on iodine excretion and intake of iodine-rich foods from a cross-sectional study carried out in 2004-5, 4 to 5 years after the implementation of mandatory iodine fortification, were compared with data in a study carried out in 2008-10. The 2008-10 study was a follow-up of a cross-sectional study carried out before iodine fortification was implemented. Participants in the cross-sectional studies were randomly selected. Both studies were carried out in the cities of Aalborg and Copenhagen in Denmark. The median urinary iodine concentration decreased in women from 97 μg/l (n 2862) to 78 μg/l (n 2041) (P< 0.001). The decrease persisted after adjustment for age, city and education, and if expressed as estimated 24 h iodine excretion. The prevalence of users of iodine containing dietary supplements increased from 29.4 to 37.3 % (P< 0.001). The total fluid intake increased in women (P< 0.001), but the intake of other iodine-rich foods did not change. The median urinary iodine concentration did not change in men (114 μg/l (n 708) and 107 μg/l (n 424), respectively), while the total fluid intake decreased (P= 0.001). Iodine content was measured in milk sampled in 2000-1 and in 2013. The iodine content was lower in 2013 (12 (sd 3) μg/100 g) compared with that in 2000-1 (16 (sd 6) μg/100 g) (P< 0.001). In conclusion, iodine excretion in women has decreased below the recommended level. The reason might probably, at least partly, be a decreased content of iodine in milk.

Genetic and non-iodine-related factors in the aetiology of nodular goitre

Genetic and a large number of environmental non-iodine-related factors play a role in the cause of nodular goitre. Most evidence for the influence of genetic and environmental factors in the cause of goitre is from cross-sectional, population-based studies. Only a few studies have included prospective data on risk factors for nodular goitre, although few prospective data are available on the effect of iodine and tobacco smoking on goitre development. Goitre is not one single phenotype. Many epidemiological studies do not distinguish diffuse from nodular goitre, as the investigated parameter is often thyroid volume or frequency with increased thyroid volume. Moreover, information on the presence and effect of gene-environment, gene-gene, and environment-environment effect modifications is limited. Thus, firm conclusions about the relative contributions and causality of the investigated risk factors should be made with caution. Smoking seems to be an established risk factor for nodular goitre, possibly with effect modification from iodine intake, as the risk associated with smoking is smaller or absent in areas with sufficient iodine intake. The use of oral contraceptives might have protective effects against goitre, and childbirth is an increased risk factor for goitre in areas with non-optimal iodine intake. Insulin resistance is a recently investigated risk factor, and the risk of goitre may be reversible with metformin treatment. Iodine remains the major environmental risk factor for nodular goitre.

A cross-sectional survey of urinary iodine status in Latvia

BACKGROUND AND OBJECTIVE

A nationwide survey of schoolchildren was conducted to detect regional differences in urinary iodine excretion in Latvia and to compare the results with data from the newborn thyroid-stimulating hormone (TSH) screening database as well with the results of a similar study performed in Latvia 10 years ago.

MATERIALS AND METHODS

We conducted a cross-sectional school-based cluster survey of 915 children aged 9-12 years in 46 randomly selected schools in all regions of Latvia. Urine samples, questionnaires on the consumption of iodized salt and information on socioeconomic status were collected. TSH levels in newborns were also measured.

RESULTS

The median creatinine-standardized urinary iodine concentration (UIC) in our study was 107.3μg/g Cr. UIC measurements indicative of mild iodine deficiency were present in 31.6%, moderate deficiency in 11.9% and severe deficiency in 2.8% of the participants. The prevalence of iodine deficiency was the highest in the southeastern region of Latgale and the northeastern region of Vidzeme. The prevalence of TSH values >5mIU/L followed a similar pattern. The self-reported prevalence of regular iodized salt consumption was 10.2%. Children from urban schools had a significantly lower UIC than children from rural schools.

CONCLUSIONS

Our findings suggest that although the overall median UIC in Latvian schoolchildren falls within the lower normal range, almost 50% of the schoolchildren are iodine deficient, especially in urban schools and in the eastern part of Latvia. The absence of a mandatory salt iodization program puts a significant number of children and pregnant women at risk.

Mandatory iodine fortification of bread and salt increases iodine excretion in adults in Denmark - a 11-year follow-up study

BACKGROUND & AIMS

Iodine fortification is widespread. Systematic monitoring of iodine fortification programs should be carried out to secure an optimal fortification level. Our aim was to investigate the effectiveness of the Danish iodine fortification program by comparing iodine excretion at baseline and at 11-year follow-up, and to study determinants for any change in iodine intake including dietary habits, education, life style factors and health parameters.

METHODS

A follow-up study based on the Danish DanThyr cohort examined in 1997-1998 just before iodine fortification was introduced, and reexamined in 2008-2010. In total, 2465 (59.1%) adult participants were reexamined.

RESULTS

Median (IQR) iodine concentration in urine had increased by 19 (-25-68) μg/L to 83 (47-133) μg/L. Estimated 24-h iodine excretion had increased by 36 (-21-95) μg/24-h to 134 (93-206), and calculated total iodine intake (diet plus supplements) had increased by 16 (-18-48) μg/day. Iodine excretion had increased significantly in all age and gender groups, but was still below the recommended amount at follow-up. The increase in iodine excretion was positively associated with changes in milk intake, with changes in the use of iodine supplements, and with bread intake at follow-up. Salt intake, education, self-rated health, smoking, alcohol intake and physical activity were not associated with the increase in iodine excretion.

CONCLUSIONS

The strategy to combat iodine deficiency in Denmark seems to be working because the fortification led to increased urinary iodine excretion in (almost) all participants. However, the level of iodine fortification of salt is too low.