TSH neonatal como marcador del estado de nutrición de yodo. Influencia de la yoduria y la función tiroidea maternas sobre la TSH neonatal / Neonatal TSH as a marker of iodine nutrition status. Effect of maternal ioduria and thyroid function on neonatal TSH

Introducción: La TSH neonatal (TSHn) es un marcador de nutrición de yodo en la población. La OMS relaciona una prevalencia<3% de TSHn>5mUI/L, obtenida a partir de las 72h del nacimiento, con un adecuado estado nutricional de yodo. El objetivo de este estudio es conocer la prevalencia de TSHn>5mUI/L en una población yodosuficiente y su relación con factores maternos, neonatales y obstétricos. Materiales y métodos: Se reclutaron 243 gestantes entre mayo-junio de 2017 en nuestra área sanitaria. Se realizó un cuestionario sobre consumo de yodo y determinación de yoduria, función y autoinmunidad tiroideas en el primer trimestre de gestación. Se analizó la TSHn entre 48-72h del nacimiento, así como otros factores obstétricos y neonatales. Resultados: La TSHn media fue 2,43±1,68mUI/L, con un 7,8% de neonatos con TSHn>5mUI/L. La TSHn más elevada pertenecía a los neonatos de madres con yodurias insuficientes (p=0,021) o con TSH>2,5mUI/L, tanto en autoinmunidad tiroidea negativa (p=0,049) como positiva (p=0,006). La yoduria materna<150μg/L fue un factor de riesgo de TSHn>5mUI/L (3,70 [1,06-14,60], p=0,046), mientras que el peso neonatal ≥2500g fue un factor protector (0,14 [0,02-1,00], p=0,038). Conclusiones: La prevalencia de TSHn>5mUI/L en nuestra área sanitaria fue elevada, según las recomendaciones de la OMS. Se asoció el déficit de yodo materno con mayor riesgo de TSHn>5mUI/L. Dado que en la actualidad la determinación de la TSHn se realiza antes de las 72h del nacimiento, precisamos de nuevos puntos de corte para continuar empleando la TSHn como marcador de nutrición de yodo. (AU)

Introduction: Neonatal thyroid stimulating hormone (nTSH) is a marker of iodine nutrition status in the population. The WHO considers a prevalence of less than 3% of nTSH levels greater than 5mIU/L in samples obtained within 72h from birth indicative of iodine sufficiency. The aim of this study was to determine the prevalence of nTSH levels greater than 5mIU/L in an iodine-sufficient population and its association with maternal, neonatal and obstetric factors. Materials and methods: A total of 243 pregnant women were recruited between May and June 2017 in our health area. A questionnaire of iodine intake was administered, in addition to determination of ioduria, thyroid function and autoimmunity in the first trimester of gestation. We analysed nTSH levels in samples collected between 48 and 72h post birth and other obstetric and neonatal factors. Results: The mean nTSH level (standard deviation) was 2.43 (1.68mIU/L), with 7.8% of neonates having levels greater than 5mIU/L. The highest nTSH levels corresponded to neonates of mothers with insufficient ioduria (p=.021) or TSH levels greater than 2.5mIU/L, in both the case of negative (p=0.049) and positive (p=0.006) thyroid autoimmunity results. Maternal ioduria greater than 150μg/L was a risk factor for nTSH levels greater than 5mIU/L (3.70 [1.06–14.60]; p=0.046), while a neonatal weight of 2500g or greater was a protective factor (0.14 [0.02–1.00]; p=0.038). Conclusions: The prevalence of nTSH levels greater than 5mIU/L in our health area was high based on the WHO recommendations. Maternal iodine deficiency was associated with a higher risk of nTSH levels less than 5mIU/L. Given that nTSH is currently measured before 72h post birth, we need new cut-off points to keep on using nTSH as a marker of iodine nutritional status. (AU)

Neonatal TSH as a marker of iodine nutrition status. Effect of maternal ioduria and thyroid function on neonatal TSH.

INTRODUCTION: Neonatal thyroid stimulating hormone (nTSH) is a marker of iodine nutrition status in the population. The WHO considers a prevalence of less than 3% of nTSH levels greater than 5 mIU/L in samples obtained within 72h from birth indicative of iodine sufficiency. The aim of this study was to determine the prevalence of nTSH levels greater than 5 mIU/L in an iodine-sufficient population and its association with maternal, neonatal and obstetric factors. MATERIALS AND METHODS: A total of 243 pregnant women were recruited between May and June 2017 in our health area. A questionnaire of iodine intake was administered, in addition to determination of ioduria, thyroid function and autoimmunity in the first trimester of gestation. We analysed nTSH levels in samples collected between 48 and 72h post birth and other obstetric and neonatal factors. RESULTS: The mean nTSH level (standard deviation) was 2.43 (1.68 mIU/L), with 7.8% of neonates having levels greater than 5 mIU/L. The highest nTSH levels corresponded to neonates of mothers with insufficient ioduria (P = 0.021) or TSH levels greater than 2.5 mIU/L, in both the case of negative (P = 0.049) and positive (P = 0.006) thyroid autoimmunity results. Maternal ioduria less than 150 µg/L was a risk factor for nTSH levels greater than 5 mIU/L (3.70 [1.06-14.60]; P = 0.046), while a neonatal weight of 2500 g or greater was a protective factor (0.14 [0.02-1.00]; P = 0.038). CONCLUSIONS: The prevalence of nTSH levels greater than 5 mIU/L in our health area was high based on the WHO recommendations. Maternal iodine deficiency was associated with a higher risk of nTSH levels greater than 5 mIU/L. Given that nTSH is currently measured before 72h post birth, we need new cut-off points to keep on using nTSH as a marker of iodine nutritional status.

Supervisión del déficit de yodo en Salta Capital / Surveillance of iodine deficiency in Salta Capital

El déficit de yodo (IDD) es un problema de Salud Pública que afecta a millones de personas en todo el mundo causando alteraciones en la neuromaduración que pueden ser evitados si se realiza una yodoprofilaxis adecuada. Objetivo: Realizar un monitoreo de IDD en la localidad de Salta Capital, por su ubicación geográfica y hábitos alimentarios con posible consumo regional de sal no iodada. Material y métodos: En 442 escolares (221 mujeres) de 5 a 14 años de edad, se evaluaron: peso, SDS talla y, SDS BMI. Se realizó la palpación tiroidea y el volumen glandular fue clasificado según los criterios de la OMS. En 97 niños se determinó la yoduria en muestras casuales de orina por el método de Sandell y Kolthof modificado. Se analizó la distribución de los niveles de TSH de la pesquisa neonatal (IFMA-DELFIA) realizada en la región de los 18 meses previos al estudio Se aplicaron los criterios de suficiencia iodada establecidos por la OMS/ ICCDD Resultados: La prevalencia de bocio fue de 6.3 %. Los niveles de yoduria fueron: mediana de 127.5 ug/l con 20 % < 50 ug/l. Sólo el 1.6 % de las muestras de TSH neonatal fueron > 5 uU/ml. Cuando se aplicaron los criterios de la OMS la prevalencia de bocio superaba levemente lo esperado para una zona suficiente y los niveles de ioduria correspondían con un aporte iodado adecuado pero marginal en su distribución. La distribución de TSH fue la esperada para una zona suficiente. Conclusión: Si bien el aumento de la prevalencia de bocio podría explicarse por factores ambientales la distribución marginal de la ioduria señala un aporte de yodo suficiente pero con necesidad de supervisión estrecha.

The iodide deficit disorder (IDD) is a worldwide Public Health problem that affects more than a million subjects causing neuromadurative disorders that could be avoided with adequate iodide supply. Objective: To monitor IDD in Salta Capital, due to its geographic location and possible utilization of non iodated salt. Population and methods:. SDSHeight , SDS BMI and weight were assessed in 442 scholars (221 girls) aged 5 to 14. Thyroid volume was evaluated and classified according to WHO criteria. In 97 children iodide urinary concentration was measured in casual urine samples by the modified Sandell and Kolthof method.TSH level's distribution of the neonatal screening performed in the region 18 months prior to this study (n 310) was evaluated. Criteria suggested by WHO to indicate iodide deficiency were applied. Results: Goitre prevalence was 6.3%, Iodide urine median levels were 127.5 ug/l with 20% < 50 ug/l. Only 1.6% of the 310 TSH samples were > 5 μU/ml. Applying WHO criteria goiter prevalence was higher that expected for a iodide sufficient area and urine iodide content was normal but marginal in its distribution. Neonatal TSH levels were the expected for a sufficient area. Conclusion: Although high goiter prevalence could be explained by environmental factors the distribut-ion of urinary iodide points out an adequate but marginal iodide supply underscoring the need of close monitoring.

Pesquisa neonatal de hipotiroidismo congénito: supervisión del déficit de yodo en la provincia de Misiones / Screening neonatal for congenital hypothyroidism: surveillance of iodine deficiency in Misiones

El déficit de yodo (IDD) es un problema de la Salud Pública que afecta a millones de personas en todo el mundo y es causante de alteraciones en la neuromaduración que pueden ser evitados si se realiza una yodoprofilaxis adecuada. Objetivo: Realizar un monitoreo de IDD en la localidad de Wanda, provincia de Misiones, por su ubicación geográfica y hábitos alimentarios con posible consumo regional de sal no iodada. Se estudiaron en 502 escolares de 5 a 14 años de vida , se evaluaron: peso, talla , BMI y palpación tiroidea. En 114 de ellos se determinó la yoduria en muestras casuales de orina. Se analizaron los niveles de TSH de la pesquisa neonatal de los 18 meses previos al estudio, realizados por métodos sensibles (IFMA-DELFIA). Se aplicaron los criterios de suficiencia establecidos por la OMS/ ICCDD. Resultados: La prevalencia de bocio en la región fue de 6.2 %. Los niveles de yoduria tuvieron una mediana de 239 ug/l. El valor de TSH neonatal mediano fue 1.25 uU/ml. Sólo el 1.4 % de las muestras estaban por encima de 5 uU/ml . Cuando se aplicaron los criterios de la OMS pudo observarse que la prevalencia de bocio superaba levemente lo esperado para una zona suficiente, pero no así los niveles de ioduria ni la distribución de TSH neonatal. Conclusión: El aporte iodado de la región evaluada es suficiente como lo demuestran la ioduria y los niveles de TSH neonatal. La presencia de bociógenos como la mandioca en la dieta puede explicar el leve aumento en la prevalencia de bocio. La utilización de la pesquisa neonatal de hipotiroidismo congénito en la supervisión de la deficiencia de yodo añade un beneficio al objetivo primario que es la prevención del retraso mental.

O b j e c t i v e : To estimate the adequacy of iodide intake in Wanda Misiones through the conventional parameters of ioduria and goiter prevalence in scholars as well as with the distribution of TSH neonatal levels as performed for the hypothyroidism screening program in newborns. Population and methods: Height , and BMI and weight were assessed in 502 scholars aged 5 to 14 and expressed as SDS. In 419 of them (215 female) thyro i d volume was evaluated and classified according to WHO (9). In 114 children iodide urinary concentration was measured in casual urine samples by Sandell y Kolthof method modified by Pino (17). Neonatal screening program for congenital hypothyroidism is carried out in the region measuring TSH in filter paper samples with IFMA DELFIA. Since 2000 7.102 newborn have been screened. TSH level's distribution of the 18 months prior to this study (n 267) were evaluated. Criteria suggested by WHO to indicate iodide deficiency were applied. Results: Height, weight and BMI were normal for the chronological age according to Argentinean population parameters. Goitre prevalence was 6.2 % (7.3 % in girls and 5.3 % in boys), higher that expected for a iodide sufficient area. Iodide urine median levels were 239 ug/l with a distribution that excluded iodide deficiency. Neonatal screening program detected 5 congenital hypothyroid children out of the 7102 newborn studied. All of them were early and adequately treated. Only 1.4 % of the 267 samples were > 5 µU/ml, excluding iodide deficiency. Conclusion: Iodide intake in Wanda, Misiones, is adequate as shown by the findings of iodide urine concentration and TSH neonatal levels. A higher prevalence of goitre than expected for this situation, could be explained by dietary intake of goitrogen food as mandioca. Congenital hypothyroidism screening program in this region was extremely effective. The possibility of using its results for iodide intake supervision is an additional benefit to the one of early prevention of mental retardation.

Desenvolvimento do UMELISA-TSH neonatal para dosagem de TSH em sangue coletado em papel filtro / Development of the ultramicroelisa for determination of neonatal TSH from blood spots on filter paper

O hipotireoidismo congênito, causado pela ausência anatômica ou funcional da glândula tireóide, apresenta freqüência mundial de aproximadamente 1:4000 recém-nascidos. A principal implicação da doença, o retardo mental, somente pode ser evitada se o tratamento se iniciar nas primeiras semanas de vida. Por isso, o diagnóstico precoce constitui a chave de êxito no tratamento da enfermidade. O Umelisa – TSH neonatal é um ensaio heterogêneo imunoenziomático tipo sanduíche, cuja fase sólida são micropoços de 10mL em tiras/placas pré-sensibilizadas com anticorpos policlonais anticadeia Beta do TSH. As amostras de sangue são eluídas com um conjugado anti_TSH policlonal/fosfatase alcalina e transferidas para placas de reação. A reação é revelada com substrato fluorigênico e a intensidade da fluorescência emitida é proporcional à concentração de TSH presente na amostra. A leitura é realizada automaticamente por um leitor fluorímetro-fotômetro computadorizado. A curva padrão validada contra ao padrão 80 558 da OMS varia dentro de uma faixa de 10-200 µUI/L, com limite de detecção de 2 µUI/L. Posteriormente, a curva foi ajustada para medir valores a partir de 0,1 µUI/L. A avaliação analítica mostrou uma precisão intra e inter-ensaio no ponto de corte (25 µUI/L) de 6,2 e 7,4 por cento, respectivamente. A correlação entre o Umelisa – TSH neonatal e o Delfia neonatal TSH foi boa (r = 0,99), além de não ser detectadas interferências significativas com outros hormônios hipofisários e proteínas séricas. A recuperação do teste foi de 101,1 +/- 3,7 por cento. Na prova de paralelismo, as concentrações calculadas de 3 amostras, após a correção com o fator de diluição, foi de +/- 6,4 por cento da concentração original da amostra pura. O Umelisa- TSH neonatal mostrou-se um método rápido e sensível, podendo ser utilizado como uma opção para programas de rastreamento em massa, já que permite operar com grandes quantidades de amostras garantindo eficiência e custo compatível com a tabela de exames complementares do Sistema Único de Saúde (SUS).