Iodine Intake Based on a Survey from a Cohort of Women at Their Third Trimester of Pregnancy from the Bosque County Chile.

Adequate iodine nutrition is fundamental for all humans and is critical during pregnancy and lactation due to iodine forms part of the structure of thyroid hormones (THs) and it is required for THs function. Iodine is a scarce micronutrient that must be obtained from the diet. Sufficient iodine can be found in the nature from seafood and given it is not frequently consumed by Chileans, public health policies state that table salt in Chile must be iodized. Health plans must be monitored to determine if the intake of iodine is being appropriated and the population has not fallen in deficiency or excess. The aim of this work was to evaluate iodine intake in 26 women at the third trimester of pregnancy. Pregnant women are resident from El Bosque a low-income County located in Santiago de Chile. These Chilean pregnant women were recruited by nutritionist at the Centros de Salud familiar (CESFAM). A 24 h dietary recall (24 h-DR) was applied to them to evaluate iodine intake. Samples of urine and blood were taken by health professionals to analyze parameters of thyroid function and to measure urine iodine concentration (UIC). The survey analysis showed that the iodine consumption in these pregnant women derived mainly from salt, bread and milk and not from seafood. The survey analysis indicated that iodine intake was above the requirements for pregnant women. However, the average UIC indicated that iodine intake was adequate, suggesting the need to find a better parameter to determine iodine intake in pregnant women.

Improving Iodine Intake in Rural Haiti through Social Enterprise: A Cross-Sectional Study in the Central Plateau.

Iodine intake in Haiti has increased in recent years thanks to the "Bon Sel" social enterprise approach to salt fortification and distribution by the market segment. However, it was uncertain whether this salt reached remote communities. This cross-sectional study aimed to assess the iodine status of school-age children (SAC) and women of reproductive age (WRA) in a remote region of the Central Plateau. A total of 400 children (9-13 years) and 322 women (18-44 years) were recruited through schools and churches, respectively. Urinary iodine (UIC) and urinary creatinine (UCC) concentrations were measured in spot samples, and thyroglobulin (Tg) on dried blood spots. Their iodine intake was estimated, and dietary information collected. The median (IQR) UIC in SAC was 130 µg/L (79-204, n = 399), and in WRA, 115 µg/L (73-173, n = 322). The median (IQR) Tg in SAC was 19.7 µg/L (14.0-27.6, n = 370), and in WRA, 12.2 µg/L (7.9-19.0, n = 183); 10% of SAC had Tg > 40 µg/L. Estimated iodine intake was 77 µg/day and 202 µg/day in SAC and WRA, respectively. Iodized table salt was rarely consumed, though bouillon was used daily; this is hypothesized to be a major contributor to dietary iodine intake. Iodine intake in this remote region seems to have improved considerably since the 2018 national survey, though SAC remain at risk. These results point to the potential effectiveness of using social business principles to deliver humanitarian solutions.

High Iodine Urinary Concentration Is Associated with High TSH Levels but Not with Nutrition Status in Schoolchildren of Northeastern Mexico.

According to the Iodine Global Network, Mexico is considered a country with adequate national iodine intake (297 mg/L), but some regions have not been studied. We aimed to evaluate urinary iodine concentration (UIC) and its association with thyroid stimulating hormone (TSH) levels and the nutritional status in 307 children (aged 5 to 11 years) from three elementary schools of Monterrey, northern Mexico. UIC in spot urine samples and capillary TSH levels were measured to assess thyroid function, in addition to weight, height, body mass index (BMI), and waist circumference (WC). We found a median UIC of 442 mg/L and a significant association between UIC and TSH levels by logistic regression when data were adjusted for (1) age and sex; (2) age, sex, and WC; and (3) age, sex, and weight status. UIC values were higher in 7-year-old children compared to 11-year-old children. High prevalences of overweight/obesity (41%) and WC >90 pctl (22%) were observed. This study identified higher UIC levels in children than those previously reported in the country. The UIC showed a positive and significant correlation between TSH levels in the three models evaluated. More studies are needed to assess the causes and possible outcomes of high UIC levels.

Median Urinary Iodine Concentration in Colombian Children and Women is High and Related to Sociodemographic and Geographic Characteristics: Results from a Nationally Representative Survey.

BACKGROUND: Salt iodization has been mandatory in Colombia for over half a century. The iodine status of the population has not been recently evaluated using nationally representative data. OBJECTIVE: We estimated the median urinary iodine concentration (mUIC) of Colombian women and children overall and by individual and environmental characteristics. METHODS: Using data from spot urine samples collected in the 2015 Colombian National Nutrition Survey, we estimated mUIC in 24,248 boys and girls aged 1 to <13 y and 9122 women of reproductive age (WRA). Within each group, we compared mUIC by levels of sociodemographic, anthropometric, and geographic factors by using adjusted median differences with 95% CIs from quantile regression models. RESULTS: mUICs were 395 ± 3 µg/L among children and 381 ± 3 µg/L among WRA. Schoolchildren 5 to <13 y old had higher mUIC (407 ± 3 µg/L) than did preschoolers or toddlers. Girls had 21 µg/L (95% CI: -29, -14) lower mUIC than boys after adjustment. In addition, among children, mUIC was positively associated with household wealth and inversely associated with indigenous compared with mestizo ethnicity, living in the southern or Pacific compared with the central regions of Colombia, and altitude. Among WRA, mUIC was positively associated with obesity and inversely with age, indigenous compared with mestizo ethnicity, education, household wealth, living in southern compared with central Colombia, altitude, and alcohol intake frequency. CONCLUSION: Colombian children and WRA had mUIC well above conventional cutpoints of iodine excess. Whether excessive iodine affects other subpopulations and its functional consequences warrant urgent investigation.

Consequences of Iodine Deficiency and Excess in Pregnancy and Neonatal Outcomes: A Prospective Cohort Study in Rio de Janeiro, Brazil.

Background: Insufficient or excessive iodine intake during gestation may compromise adaptive mechanisms in maternal thyroid function and lead to adverse pregnancy outcomes. In this context, we aimed to study the effects of maternal iodine status in the first and third trimesters of gestation on obstetric and neonatal outcomes in an iodine-sufficient population in Rio de Janeiro, Brazil. Methods: A total of 214 pregnant women in the first trimester of gestation were enrolled and prospectively followed until delivery between 2014 and 2017. All participants were ≥18 and ≤35 years, had a spontaneous single pregnancy, and had no history of thyroid or other chronic diseases, nor were they taking iodine-containing supplements at enrollment. In the first trimester, we obtained clinical information and determined thyroid function and the urinary iodine concentration (UIC) of the participants. Thyroid function and UIC were reassessed in the third trimester. Iodine status was determined by the median of UIC obtained from six urine spot samples by the inductively coupled plasma mass spectrometry method. Pregnancy and neonatal outcomes and delivery information were obtained from medical records. Results: The median UIC in the whole population was 219.7 µg/L. The prevalence of UIC <150 µg/L was 17.2%, and 38.7% had UIC ≥250 µg/L. Gestational diabetes (GDM) was higher in the group with UIC 250-499 µg/L (n = 77) compared with the group with UIC 150-249 µg/L (n = 94) (20.3% vs. 9.7%, p < 0.05). Ultimately, UIC ≥250 µg/L was an independent risk factors for GDM (relative risk [RR] = 2.9 [confidence interval, CI = 1.1-7.46], p = 0.027) and hypertensive disorders of pregnancy (HDP) (RR = 4.6 [CI = 1.1-18.0], p = 0.029). Among 196 live-born newborns, lower birth length was observed in infants whose mothers had UIC <150µg/L (n = 37) in the first trimester compared with those with UIC 150-249 µg/L (n = 86) (median interquartile range: 48.0 [2.2] vs. 49.0 [4.0] cm, p = 0.01). Maternal UIC <150 µg/L was negatively associated with birth length of newborns (Exp (B) = 0.33 [CI = 0.1-0.9], p = 0.03). Conclusions: In a population whose median iodine intake is sufficient, extensive individual variation occurs. Such abnormalities are associated with increased GDM and HDP when UIC is ≥250 µg/L, and lower infant birth length when UIC is <150 µg/L.

Iodine Status of Brazilian School-Age Children: A National Cross-Sectional Survey.

Salt iodization is the main public health policy to prevent and control iodine deficiency disorders. The National Salt Iodization Impact Assessment Survey (PNAISAL) was conducted to measure iodine concentration among Brazilian schoolchildren. A survey including 6-14-year-old schoolchildren from public and private schools from all 26 Brazilian states and the Federal District was carried out in the biennia 2008-2009 and 2013-2014. Municipalities, schools, and students were randomly selected. Students were interviewed at school using a standard questionnaire, which included the collection of demographic, educational, weight, height, and 10 mL non-fasting urine collection information. The analyses were weighted according to the population of students per federative unit. The median urinary iodine concentration (MUIC) for the entire sample by region, federative unit per school, and student characteristics, was described from the cutoff points defined by the World Health Organization (severe disability: <20 µg/L, moderate: 20-49 µg/L, mild: 50-99 µg/L, adequate: 100-199 µg/L, more than adequate: 200-299 µg/L, and excessive: >300 µg/L). In total, 18,864 students (95.9% of the total) from 818 schools in 477 municipalities from all federative units were included in this study. Almost 70% were brown skin color, nine-years-old or older, studied in urban schools, and were enrolled in elementary school. The prevalence of overweight/obesity, as measured by body mass index (BMI) for age, was about twice as high compared to nutritional deficits (17.3% versus 9.6%). The MUIC arrived at 276.7 µg/L (25th percentile = 175.5 µg/L and 75th percentile = 399.71 µg/L). In Brazil as a whole, the prevalence of mild, moderate, and severe deficit was 6.9%, 2.6%, and 0.6%, respectively. About one-fifth of the students (20.7%) had adequate iodine concentration, while 24.9% and 44.2% had more than adequate or excessive concentration, respectively. The prevalence of iodine deficits was significantly higher among younger female students from municipal public schools living in rural areas with the lowest BMI. The median urine iodine concentration showed that Brazilian students have an adequate nutritional intake, with a significant proportion of them evidencing overconsumption of this micronutrient.

Iodine nutritional status in urban and rural Mexican schoolchildren. / Estado nutricional de yodo en niños escolares mexicanos de zonas urbanas y rurales.

INTRODUCTION: Deficient or excess iodine intake has effects on human health. Assessment of the prevalence and risk factors in children can therefore support effective prevention or treatment. METHOD: A cross-sectional probabilistic study in 631 children aged 5 to 12 years in whom iodine levels were measured in urine and salt samples. Results are reported by type of location and indigenous condition. Association of these variables to urinary iodine levels was assessed using a binary logistic regression. RESULTS: Median urinary iodine level was 278.4µg/L (177.3-360.9, IQR), 13.2% of children assessed had iodine levels <100µg/L, and 41.8% had values ≥300µg/L. Indigenous schoolchildren had the greatest risk of urinary iodine levels <100µg/L (ß = 2.29, CI 1.1-4.6, p <.05), while children from urban and non-indigenous localities had a high risk of iodine levels >300µg/L (ß = 2.2, CI 1.3 -3.9, p <.01, and ß = 3.8, CI 2.2-6.5, p <.01 respectively). Median iodine level in salt was 35.9ppm (29.1-42.4 IQR), and there were no differences in iodine levels in salt by type of location or ethnicity. CONCLUSIONS: In Mexican schoolchildren living in rural and indigenous areas, iodine levels <100µg/L have not been eradicated. There was high prevalence of urinary iodine levels ≥300µg/L in schoolchildren living in urban areas which was associated to high sodium intake from processed food.

Evaluation of the effects of chronic occupational exposure to metallic mercury on the thyroid parenchyma and hormonal function.

INTRODUCTION: Experiments in animals exposed to mercury (Hg) in different chemical states have shown thyroid parenchymal and hormone alterations. However, these experiments did not allow the establishment of dose-response curves or provide an understanding of whether these Hg effects on the thyroid parenchyma occur in humans. OBJECTIVE: To evaluate the association between chronic occupational exposure to metallic Hg and alterations in thyroid hormones and gland parenchyma 14 years after the last exposure. METHODS: A cross-sectional study including 55 males exposed in the past to metallic Hg and 55 non-exposed males, paired by age, was conducted in the Hospital das Clínicas (Brazil) from 2016 to 2017. Serum concentrations of total and free triiodothyronine (TT3 and FT3), free thyroxine (FT4), thyrotropin (TSH), reverse T3 (RT3), selenium and antithyroid antibody titers were obtained. The Hg and iodine concentrations were measured in urine. The thyroid parenchyma was evaluated by B-mode ultrasonography with Doppler. The nodules with aspects suspicious for malignancy were submitted to aspiration puncture with a thin needle, and the cytology assessment was classified by the Bethesda system. The t test or Mann-Whitney test, Chi-square test and Spearman correlation were used to compare the exposed and non-exposed groups and examine the relationships between the variables. Univariate and multivariate logistic regression models were used to trace determinants of the risk of thyroid hormone alteration. Statistical significance was defined by p < 0.05. RESULTS: The urinary Hg average was significantly higher in the exposed group than in the non-exposed group (p < 0.01). The mean TSH serum concentration in the exposed group was higher, with a statistically significant difference between the groups (p = 0.03). Serum concentrations of TSH exceeded the normality limit (4.20 µIU/ml) in 13 exposed individuals (27.3%) and 4 non-exposed individuals (7.3%), with a statistically significant association between the hormonal increase and exposure to Hg (p = 0.02). In the logistic regression model, exposure to Hg (yes or no) showed an odds ratio = 4.86 associated with an increase of TSH above the normal limit (p = 0.04). The serum concentrations of RT3 showed a statistically borderline difference between the groups (p = 0.06). There was no statistically significant difference between the mean TT3, FT3 and FT4 serum concentrations in the Hg-exposed group compared to the non-exposed group. The proportions of the echogenicity alterations were higher in the exposed group compared to the non-exposed group (27.3% versus 9.1%; p = 0.03). Papillary carcinomas were documented in three exposed individuals and one non-exposed individual. A follicular carcinoma was recorded in one non-exposed individual. CONCLUSIONS: Due to the higher serum TSH concentration and the prevalence of parenchymal alterations in the Hg-exposed group, even after cessation of exposure, it is recommended that the thyroid status of exposed workers be followed for a long period.

Variation of iodine status during pregnancy and its associations with thyroid function in women from Rio de Janeiro, Brazil.

OBJECTIVE: To assess iodine status and its effects on maternal thyroid function throughout pregnancy. DESIGN: In the present prospective cohort study, three urinary samples were requested for urinary iodine concentration (UIC) determinations in both the first and third gestational trimesters. Serum thyrotropin (TSH) and free thyroxine (FT4) were analysed in both trimesters and thyroid antibodies were assessed once. SETTING: Rio de Janeiro, Brazil.ParticipantsFirst-trimester pregnant women (n 243), of whom 100 were re-evaluated during the third trimester. RESULTS: Iodine sufficiency was found in the studied population (median UIC=216·7 µg/l). The first- and third-trimester median UIC was 221·0 and 208·0 µg/l, respectively. TSH levels (mean (sd)) were higher in the third trimester (1·08 (0·67) v. 1·67 (0·86) mIU/l; P<0·001), while FT4 levels decreased significantly (1·18 (0·16) v. 0·88 (0·12) ng/dl; P<0·001), regardless the presence of iodine deficiency (UIC<150 µg/l) or circulating thyroid antibodies. UIC correlated (ß; 95% CI) independently and negatively with age (-0·43; -0·71, -0·17) and positively with multiparity (0·15; 0·02, 0·28) and BMI (0·25; 0·00, 0·50). Furthermore, median UIC per pregnant woman tended to correlate positively with TSH (0·07; -0·01, 0·14). Women with median UIC≥250 µg/l and at least one sample ≥500 µg/l throughout pregnancy had a higher risk of subclinical hypothyroidism (OR=6·6; 95% CI 1·2, 37·4). CONCLUSIONS: In this cohort with adequate iodine status during pregnancy, excessive UIC was associated with an increased risk of subclinical hypothyroidism.

Avaliação do status nutricional de iodo em gestantes atendidas no pré-natal do Hospital das Clínicas da Universidade Federal de Minas Gerais / Assessment of the nutritional status of iodine in pregnant women attended at the prenatal care at the Hospital das Clínicas of the Federal University of Minas Gerais

As disfunções tireoidianas durante a gestação cursam com maior morbidade materno-fetal. Uma das causas de disfunção tireoidiana é a deficiência ou excesso de iodo. Durante a gestação há um aumento da produção de hormônios tireoidianos, um incremento significativo do clearance renal de iodo e aumento do turnover de tiroxina (T4) pela deiodinase tipo 3 placentária na 2ª metade da gestação, ocasionando assim, uma necessidade aumentada de iodo. O objetivo deste estudo foi avaliar o estado nutricional de iodo em gestantes atendidas no pré-natal do Hospital das Clínicas da UFMG. Analisamos a concentração urinária de iodo em 30 gestantes com gestação única e idade gestacional menor que 20 semanas. Foram coletadas amostras únicas ocasionais de urina para dosagem da concentração urinária de iodo através do método de plasma indutivamente acoplado com detector de massas. A mediana da concentração urinária de iodo das gestantes estudadas foi de 216,73 mcg/L, que está adequada para o grupo segundo a Organização Mundial de Saúde (OMS). Esse estudo demonstra que apesar do aumento da demanda de iodo pelas gestantes e da recomendação da ANVISA (Agência Nacional de Vigilância Sanitária) da redução dos níveis de iodação do sal, a população de gestantes atendidas no ambulatório de pré-natal de risco habitual do Instituto Jenny de Andrade Faria de Atenção à Saúde do Idoso e da Mulher da Universidade Federal de Minas Gerais é considerada suficiente em iodo. Apesar de uma maior amostragem ser necessária para a confirmação destes achados, acreditamos que é cedo para recomendar a suplementação universal de iodo para as gestantes brasileiras e mais estudos precisam ser realizados para uma conclusão. A suplementação de iodo para gestantes em áreas suficientes em iodo está associada aos riscos da exposição excessiva de iodo ao feto.

During pregnancy, there is an increased of thyroid hormone, a significant increased iodine renal clearance and increased thyroxine (T4) turnover by placental type 3 deiodinase in the second half of pregnancy, thus leading to increased iodine demand. The aim of this study was to evaluate the nutritional status of iodine in pregnant women attending in prenatal care at the hospital of the Universidade Federal de Minas Gerais. We analyzed urinary iodine concentration in 30 pregnant women with single pregnancy and gestational age less than 20 weeks. Casual single urine samples were collected for urinary iodine concentration measurement by inductively coupled plasma detector method. Median urinary iodine concentration of the pregnant women studied was 216.73 mcg/L, which is adequate for the group according to World Health Organization (WHO). This study demonstrates that despite the increased demand for iodine among pregnant women and ANVISA's recommendation to reduce salt iodine levels, the population of pregnant women attended at the Instituto Jenny Faria de Atenção à Saúde do Idoso e da Mulher of the Universidade Federal de Minas Gerais is considered sufficient in iodine. Although a larger sample is needed to consolidate these findings, we believe it is early to recommend universal iodine supplementation for Brazilian pregnant women and more studies are necessary to a conclusion. Iodine supplementation for pregnant women in accessible iodine areas is associated with risk of excessive iodine exposure to the fetus.

Concentração de iodo urinário em urina de 24 horas de gestantes e sua associação com bócio tireoidiano materno, aborto e peso neonatal: estudo piloto / Urinary iodine concentration in 24-hour urine of pregnant women and its association with goiter in the mother, abortion and neonatal weight: pilot study

Introdução: A comida tem um papel proeminente na obtenção do iodo e uma das melhores estratégias é a iodização do sal. No Brasil, a Anvisa reduziu as doses de iodo no sal de cozinha desde 2014. Portanto, é importante avaliar a concentração urinária de iodo (CIU) em nossa população. Com base no exposto, propõe-se avaliar a CIU das gestantes, associando-a à frequência de bócio materno, aborto e peso neonatal. Métodos: Trata-se de um estudo observacional com um corte transversal composto por 37 pacientes atendidos no Serviço de Obstetrícia da Faculdade de Medicina de Barbacena e uma clínica particular em Juiz de Fora. A CIU foi verificada em 24 horas de urina. Resultados: A média de CIU foi de 213,6 µg/l de urina, com dose mínima de 29 µg/l e máxima de 437 µg/l. A glândula tireoide foi avaliada durante o exame clínico prénatal (palpação da glândula) e em 24 pacientes (38,1%) foi considerada normal. A palpação da glândula tireoide foi associada à CIU. Houve maior iodúria em gestantes com glândula não palpável (p = 0,004; T = 14,13). Não houve associação entre a CIU e história de aborto ou peso fetal ao nascimento (p > 0,05). Conclusões: Apesar de ser uma amostra pequena da população, identificamos pacientes expostas ao déficit. No entanto, a CIU não parece estar associada ao peso do recém-nascido ou a abortos, mas à dosagem de TSH e ao tamanho da glândula tireoide. Assim, a palpação da glândula tireoide poderia ser usada como uma medida indireta do CIU. (AU)

Introduction: Food has a prominent role in providing iodine and one of the best strategies is salt iodization. The Brazilian Health Regulatory Agency has reduced iodine content in table salt since 2014. Therefore, there is a need for evaluating urinary iodine concentration in our population, especially after the modified recommendations. Based on the above, we sought to assess urinary iodine concentration in pregnant women, associating it with frequency of maternal goiter, abortion and neonatal weight. Methods: This observational, cross-sectional study included 37 patients seen at the Obstetrics Service of Barbacena Medical School and a private clinic in Juiz de Fora, both in the state of Minas Gerais, Brazil. Iodine concentration was determined in 24- hour urine through chromatography. Results: The mean 24-hour urine iodine was 213.6 µg/l, with minimum and maximum measures of 29 µg/l and 437 µg/l, respectively. The thyroid gland was assessed by prenatal clinical examination (palpation of the gland). In 24 patients (38.1%) it was considered normal. Palpation of the thyroid gland was associated with 24-hour urine iodine concentration, although a higher iodine concentration was identified in pregnant women with non-palpable gland (p = 0.004; T = 14.13). There was no association between 24-hour urine iodine concentration and history of abortion or birth weight (p > 0.05). Conclusions: This study, although based on a small sample of the population, was important to identify that even in areas where iodine is considered sufficient there may be patients exposed to iodine deficit. However, urinary iodine concentration does not appear to be associated with birth weight or abortion frequency but is associated with thyroid-stimulating hormone (TSH) level and thyroid gland size, suggesting that clinical evaluation of the thyroid gland is an important element for predicting urinary iodine concentration. Thus, palpation of the thyroid gland could be used as an indirect measure of urinary iodine concentration. (AU)

Comparison of Iodine Concentrations in Kitchen Salt and Urine with the Thyroid Volume of Schoolchildren from Ribeirão Preto, São Paulo, Brazil: Warning of Worsening After 10 Years of Study.

Background: In 2007 and 2015, two studies were conducted in Ribeirão Preto, São Paulo, Brazil, on schoolchildren of both sexes attending schools of three different socioeconomic levels (school 1: low; school 2: middle; school 3: high). Methods: Iodine concentrations were measured in samples of kitchen salt from the home provided by the schoolchildren and in urine samples, and these levels were compared to the thyroid volume by clinical assessment. Results: In 2007, a marked discrepancy in iodine concentrations was found in salt samples in 300 schoolchildren of both sexes (age range 8-10 years). Urinary iodine excretion >100 µg/L was detected in all cases, and 55.2% had concentrations of >300 µg/L (considered to be the upper limit by the World Health Organization). There was no increase in thyroid volume among the schoolchildren. In 2015, after a change in the norms for salt iodination from 20-60 to 15-45 mg/kg, the study was repeated in 295 schoolchildren (age range 8-10 years) from the same three schools studied previously. An improved standardization of iodine concentration was observed in the salt samples provided by the children, as well as a significant reduction in ioduria, with 10.9% of the samples showing an iodine concentration of <100 µg/L and with a reduction to 30.5% of samples with >300 µg/L. An increase in thyroid volume was also observed in a greater proportion of children from school 1, with a 7.92%, 5.19%, and 0.85% prevalence of goiter at schools 1, 2, and 3, respectively. Conclusions: Despite the limitations of the present study, which include sample size and thyroid evaluation by palpation, it is inferred that the iodination of the Ribeirão Preto schoolchildren studied is adequate. However, the individual iodine intake of some students was <100 µg/L, and some students also had an increased thyroid volume, raising the possibility of a deterioration of iodine intake in 2015 compared to 2007.

Recent recommendations from ATA guidelines to define the upper reference range for serum TSH in the first trimester match reference ranges for pregnant women in Rio de Janeiro.

OBJECTIVES: American Thyroid Association (ATA)'s new guidelines recommend use of population-based trimester-specific reference range (RR) for thyrotropin (TSH) in pregnancy. The aim of this study was to determine first trimester TSH RR for a population of pregnant women in Rio de Janeiro State. SUBJECTS AND METHODS: Two hundred and seventy pregnant women without thyroid illness, defined by National Academy of Clinical Biochemistry, and normal iodine status were included in this sectional study. This reference group (RG) had normal median urinary iodine concentration (UIC = 219 µg/L) and negative anti-thyroperoxidase antibodies (TPOAb). Twin pregnancy, trophoblastic disease and use of drugs or supplements that influence thyroid function were excluded. In a second step, we defined a more selective reference group (SRG, n = 170) by excluding patients with thyroiditis pattern on thyroid ultrasound and positive anti-thyroglobulin antibodies. This group also had normal median UIC. At a final step, a more selective reference group (MSRG, n = 130) was defined by excluding any pregnant women with UIC < 150 µg/L. RESULTS: In the RG, median, 2.5th and 97.5th percentiles of TSH were 1.3, 0.1, and 4.4 mIU/L, respectively. The mean age was 270 ± 5.0 and the mean body mass index was 25.6 ± 5.2 kg/m2. In the SRG and MSRG, 2.5th and 975th percentiles were 0.06 and 4.0 (SRG) and 0.1 and 3.6 mIU/L (MSRG), respectively. CONCLUSIONS: In the population studied,TSH upper limit in the first trimester of pregnancy was above 2.5 mIU/L. The value of 3.6 mIU/L, found when iodine deficiency and thyroiditis (defined by antibodies and ultrasound characteristics) were excluded, matches recent ATA guidelines.

Contemporary Dietary Intake: Too Much Sodium, Not Enough Potassium, yet Sufficient Iodine: The SALMEX Cohort Results.

Initiatives to reduce sodium intake are encouraged globally, yet there is concern about compromised iodine intake supplied through salt. The aim of the present study was to determine baseline sodium, potassium, and iodine intake in a sample of workers from our Institution in Mexico City (SALMEX Cohort). Methods. From a cohort of 1009 workers, appropriate 24-h urine and three-day dietary recall was collected in a sample of 727 adult subjects for assessment of urinary sodium, potassium, and iodine concentrations. Median urinary iodine excretion (UIE) was compared across categories of sodium intake of <2, 2⁻3.6, and ≥3.6 g/day. Results. Average sodium intake was 3.49 ± 1.38 g/day; higher in men than women (4.14 vs. 3.11 g/day, p ≤0.001). Only 10.6% of the population had sodium intake within the recommended range (<2 g/day); 45.4% had high (2⁻3.6 g/day) and 44% had excessive intake (>3.6 g/day). Average urinary Na/K ratio was 3.15 ± 1.22 (ideal < 1), higher in men (3.42 vs. 3.0, p ≤ 0.001). The multivariate analysis showed that sodium intake was associated with age (p = 0.03), male sex (p < 0.001), caloric intake (p = 0.002), UKE (p < 0.001) and BMI (p < 0.001). Median iodine intake was 286.7 µg/day (IQR 215⁻370 µg/day). Less than 2% of subjects had iodine intake lower than recommended for adults (95 µg/day); 1.3% of subjects in the recommended range of salt intake had low iodine intake. There is a direct relationship between iodine and sodium urinary excretion (r = 0.57, p < 0.0001). Conclusions. In the studied population, there was an excessive sodium intake and an imbalance between sodium and potassium intake. Only 10.6% of the population had sodium intake within the recommended values, but iodine intake in this group appears to be adequate.

Iodine status of pregnant women from a coastal Brazilian state after the reduction in recommended iodine concentration in table salt according to governmental requirements.

OBJECTIVE: To evaluate iodine status among pregnant women from a coastal state after Brazilian governmental resolution reducing iodine concentrations in table salt. Secondarily, we correlated urinary iodine concentration (UIC) with thyroid volume and hormones. METHODS: Inductively coupled plasma mass spectrometry was used to assess UIC from 629 samples of 244 first trimester pregnant women. Thyroid ultrasound, serum thyroglobulin, thyrotropin, free thyroxine, and antithyroid antibodies were measured as iodine concentrations on samples of table salt from patient's home. RESULTS: Median UIC was adequate (221.0 µg/L); however, 48.7% of women had insufficient (<150 µg/L), and 4.5% excessive UIC (≥500 µg/L) in at least one sample. UIC was independently and negatively correlated with age (ß: -0.58; 95% confidence interval [CI], -0.89 to -0.27) and positively with multiparity (ß: 0.20; 95% CI, 0.04-0.34). In those without thyroiditis, UIC tended to be positively correlated with body mass index (P = 0.098) and thyrotropin (P = 0.072). Independent variables associated with iodine insufficiency were age >30 y (odds ratio [OR] = 2.0; 95% CI, 1.2-3.2) and obesity (OR = 0.2; 95% CI, 0.2-0.7). Excessive UIC was associated negatively with age (OR = 0.2; 95% CI, 0.04-0.8) and positively with multiparity (OR = 2.5; 95% CI, 1.0-6.0) and subclinical hypothyroidism (OR = 5.6; 95% CI, 1.0-30.2). CONCLUSION: This population has iodine sufficiency, and supplementation should not be generally considered, based on the risk association between excessive UIC and subclinical hypothyroidism.

Pathogenic Th17 and Th22 cells are increased in patients with autoimmune thyroid disorders.

PURPOSE: To study the levels of pathogenic and non-pathogenic Th17 and Th22 cells in autoimmune thyroid disorders patients. Although Th17 cells seem to play an important role in the pathogenesis of thyroid autoimmune disorders, the specific subsets of these lymphocytes have not been analyzed in this condition. METHODS: We assessed the levels of Th17 (pathogenic and non-pathogenic) and Th22 cells in peripheral blood and thyroid glands of autoimmune thyroid disorders patients (n = 26, 16 with Graves' disease and 10 with Hashimoto's thyroiditis) and 15 healthy controls by multi-parametric flow cytometry and immunofluorescence microscopy. RESULTS: We found increased levels of pathogenic Th17 lymphocytes and Th22 cells in peripheral blood from autoimmune thyroid disorders patients. In addition, these cells were detected in thyroid glands from HT patients. Furthermore, we found significant correlations between the levels of these cells and disease activity, disease duration, and the presence of ophthalmopathy. CONCLUSIONS: The increased levels of pathogenic Th17 lymphocytes and Th22 cells in autoimmune thyroid disorders suggest their involvement in the pathogenesis of this condition.

Iodine levels are associated with oxidative stress and antioxidant status in pregnant women with hypertensive disease

BACKGROUND: The antioxidant function of iodine and iodine deficiency as a risk factor of preeclampsia have been previously reported. AIM: To analyze the association between iodine deficiency, oxidative stress and antioxidant status with hypertensive disease of pregnancy (HPD). METHOD: Fifty-seven pregnant women were recruited in the last trimester of pregnancy; 20 were diagnosed with hypertensive disease (HPD) of pregnancy and 37 were normotensive pregnant women. Urinary iodine concentration (UIC), TSH, free T4 (fT4), total antioxidant status (FRP), superoxide dismutase (SOD), catalase (CAT), and oxidative stress (TBARS) were evaluated by colorimetric methods. RESULTS: UIC median for all pregnant women was 151.9 µg/l. The UIC for pregnant women with HPD was 50-149 µg/l, compared to 150-249 µg/l in normotensive women. No significant differences in levels of TSH and fT4 in normotensive pregnant compared with HPD women were found. Pregnant women with HPD had significant high levels of TBARS, and significant low levels of FRP, SOD, CAT and UIC compared to normotensive pregnant. In addition, pregnant women with optimal levels of UIC had a higher SOD activity (r = 0.354, p = 0.011), while iodine deficiency was associated with HPD (r = -0,281, p = 0.039). Similarly, pregnant women with HPD had a significant negative association with SOD activity (r = -0.702, p = 0.005), CAT (r = -0.409, p = 0.002), and FRP (r = -0.624, p = 0.003), and a positive association with TBARS (r = 0.744, p = 0.001). CONCLUSION: Iodine contributes to redox balance during pregnancy; its deficiency is associated with HPD. This study shows the importance of iodine during pregnancy.

Effect of exposure to p,p´-DDE during the first half of pregnancy in the maternal thyroid profile of female residents in a Mexican floriculture area.

BACKGROUND: Dichlorodiphenyldichloroethene (p,p´-DDE), the main metabolite of dichlorodiphenyltrichloroethane (DDT), has been associated with changes in human thyroid hormone levels. Maternal thyroid hormones are essential for adequate fetal neurodevelopment during the first half of pregnancy. OBJECTIVE: To evaluate the association between maternal p,p´-DDE concentration and the maternal thyroid profile during the first half of pregnancy. MATERIALS AND METHODS: We analyzed the information of 430 pregnant women from a Mexican floriculture area, with a gestational age ≤16 weeks. By questionnaire, we obtained sociodemographic, reproductive, and life-style, information. Serum concentrations of thyroid stimulating hormone (TSH), and total and free T3 and T4 were determined by means of Enzyme-Linked ImmunoSorbent Assay (ELISA). p,p´-DDE was analyzed by Gas Chromatography. The association between p,p´-DDE and thyroid profile was assessed through linear and logistic regression models. RESULTS: Thirty eight percent of women had p,p´-DDE levels below the Limit of Detection and 12.3% below the Limit of Quantification. Within the quantifiable range, median was 53.03ng/g. TSH >2.5 mIU/L was present in 9.3% of women; 47.7% had isolated hypothyroxinemia; 3.5% had subclinical hypothyroidism, and 5.8% had overt hypothyroidism. We observed a significant positive association between quantifiable p,p´-DDE and total T3 serum levels in comparison with those with concentrations below the Limit of Detection (ß=0.19; 95% CI=0.06, 0.34). There were no significant associations with other hormones of the thyroid profile or with clinical diagnosis. CONCLUSIONS: Our findings suggest that p,p´-DDE exposure, even at low concentrations, could disrupt thyroid homeostasis during pregnancy.

Impacto del empleo de umbrales específicos de referencia en el diagnóstico de las alteraciones funcionales tiroideas en la mujer gestante / Impact of using specific reference intervals on the diagnosis of thyroid dysfunction during pregnancy

Objetivo: Establecer los umbrales específicos de referencia de cada uno de los parámetros de función tiroidea en cada trimestre de la gestación y determinar el impacto del uso de umbrales no específicos en el diagnóstico de las alteraciones funcionales en el primer trimestre. Métodos: Entre enero y septiembre de 2014 se contactaron 759 mujeres embarazadas con edad mayor de 18 años y sin alteraciones funcionales tiroideas conocidas. Tras excluir a todas las pacientes que no completaron el seguimiento durante toda la gestación y las que presentaron inmunidad tiroidea positiva, 411 gestantes configuraron nuestra población de referencia. Se determinaron los niveles de TSH, T4L y T3L en cada trimestre, los anticuerpos antiperoxidasa tiroidea y antitiroglobulina en el primero y se recogió una muestra de orina en los trimestres primero y tercero para la determinación del yodo urinario. Resultados: Un total de 411 gestantes completaron el seguimiento en los 3 trimestres. Un 38,69% consumían sal yodada y un 72,20% suplementos yodados. Los valores de referencia de TSH expresados como mediana y percentiles 2,5 y 97,5 fueron: 1,53 μUI/ml (0,26-3,95), 1,90 μUI/ml (0,78-3,85) y 1,89 μUI/ml (0,71-3,61) en el primer, segundo y tercer trimestre, respectivamente. El nivel de yoduria fue de 171,31 μg/l (90,7-274,9) en el primer trimestre y de 190,37 μg/l (96,44-360,38) en el tercero. La aplicación en el primer trimestre de los umbrales propuestos por las sociedades internacionales ocasionaría una clasificación errónea del 19,8% de las gestantes en relación con su función tiroidea, mientras que los umbrales no específicos de nuestro laboratorio lo harían en el 8,52%. Conclusiones: La utilización de umbrales no específicos para el diagnóstico de las alteraciones funcionales tiroideas durante la gestación ocasiona un importante porcentaje de errores de clasificación, contribuyendo a una atención inadecuada.

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Population Survey of Iodine Deficiency and Environmental Disruptors of Thyroid Function in Young Children in Haiti.

Context: Iodine deficiency is the leading cause of preventable neurodevelopmental delay in children worldwide and a possible public health concern in Haiti. Objective: To determine the prevalence of iodine deficiency in Haitian young children and its influence by environmental factors. Design: Cross-sectional study, March through June 2015. Setting: Community churches in 3 geographical regions in Haiti. Participants: 299 healthy Haitian children aged 9 months to 6 years; one-third each enrolled in a coastal, mountainous, and urban region. Main Outcome Measures: Urinary iodide, serum thyrotropin (TSH), goiter assessment, and urinary perchlorate and thiocyanate. Results: Mean age was 3.3±1.6 years, with 51% female, median family income USD 30/week, and 16% malnutrition. Median urinary iodide levels were normal in coastal (145 µg/L, interquartile range [IQR] 97 to 241) and urban regions (187 µg/L, IQR 92 to 316), but revealed mild iodine deficiency in a mountainous region (89 µg/L, IQR 56 to 129), P < 0.0001. Grade 1 goiters were palpated in 2 children, but TSH values were normal. Urinary thiocyanate and perchlorate concentrations were not elevated. Predictors of higher urinary iodide included higher urinary thiocyanate and perchlorate, breastfeeding, and not living in a mountainous region. Conclusions: Areas of mild iodine deficiency persist in Haiti's mountainous regions. Exposure to two well-understood environmental thyroid function disruptors is limited.