Hormone synthesis and storage in the thyroid of human preterm and term newborns: Effect of thyroxine treatment

Beckers, Christian; Devlieger, Hugo; Zegher, Francis de; Nayer, Philippe De

doi:10.1016/s0300-9084(99)80111-4

Cited by 74 publications

(47 citation statements)

References 30 publications

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“…A model illustrating the estimated iodine balance in a breastfeeding mother with recommended iodine intake and her child, based on data from several studies 1,4,5. Calculated values are rounded to the nearest 5 μg.…”

mentioning

confidence: 99%

Breast milk—a gateway to iodine-dependent brain development

Laurberg

Andersen

2014

Nat Rev Endocrinol

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confidence: 99%

Breast milk—a gateway to iodine-dependent brain development

Laurberg

Andersen

2014

Nat Rev Endocrinol

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“…The theoretical turnover of the intrathyroidal T4 pool in preterm infants born after six months of gestation has been determined (early after birth) to be 1-10 times per day (van den Hove et al, 1999).…”

Section: Fetal and Neonatal Thyroidmentioning

confidence: 99%

Scientific Opinion on Dietary Reference Values for iodine

Products¹

2014

EFS2

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Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values (DRVs) for iodine, which are provided as Adequate Intake (AI). Iodine is essential for the synthesis of thyroid hormones. Through these hormones, iodine has an important role in energy-yielding metabolism and many other physiological processes. Iodine deficiency is associated with an increased frequency of goitre and hypothyroidism in a population. The AI for iodine is based on a large epidemiological study in European school-aged children showing that goitre prevalence is lowest for a urinary iodine concentration above around 100 µg/L. From this study, a urinary iodine concentration of ≥ 100 µg/L has been accepted as the threshold indicating sufficient iodine intake of school-aged children. In the absence of similar suitable data for other age groups it is proposed that this threshold also be applied for adults, infants and young children. Taking into account urinary volume and an absorption efficiency for iodine of 92 %, an AI of 150 µg/day is proposed for adults. For infants aged 7-11 months and for children, AIs range between 70 µg/day and 130 µg/day. For pregnant women, an AI of 200 µg/day is proposed, taking into account additional needs due to increased maternal thyroid hormone production and the iodine uptake by the fetus, placenta and amniotic fluid. The proposed AI for lactating women of 200 µg/day takes into account the existence of large iodine stores in conditions of adequate iodine status before pregnancy and considers that a full compensation for the iodine secreted in breast milk is not justified for the derivation of an AI for iodine for lactating women. Iodine is an essential nutrient for mammals, required as a mandatory structural and functional element of thyroid hormones. Through these hormones, iodine has an important role in energy-yielding metabolism and on the expression of genes that impact many physiological functions, including embryogenesis and growth, and the development of neurological and cognitive functions. © EuropeanThe clinical effects of iodine deficiency, referred to as iodine deficiency disorders, are the result of insufficient intakes leading to insufficient thyroid function. Iodine deficiency disorders are seen at all stages of development and are particularly of concern in pregnancy and infancy. Chronic iodine deficiency may lead to compensatory thyroid hypertrophy with an enlargement of the thyroid gland denoted as goitre.Intestinal absorption efficiency of ingested iodine is considered to be high (> 90 %). The thyroid is the major storage site for iodine in the body. Goitrogenous substances in foods, drinking water or cigarette smoke may inhibit the thyroidal uptake of iodide or its incorporation into the tyrosine precursors of thyroid hormones. The synthesis of normal quantities of thyroid hormones requires an adequate dietary intake of iodine. The kidney is the main route of excretion of iodine. In a steady state, th...

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“…First, the serum half-life of T 4 is approximately 7–10 days in adults (Chopra and Sabatino 2000), but is approximately 3 days in neonates (Lewander et al 1989; van den Hove et al 1999). Thus, the rate of replacement of T 4 (i.e., T 4 secretion from the thyroid gland) must be considerably higher in early life to maintain steady-state levels.…”

Section: Literature Review: Why Focus On Perchlorate Effects In Infants?mentioning

confidence: 99%

Evaluation of the U.S. EPA/OSWER Preliminary Remediation Goal for Perchlorate in Groundwater: Focus on Exposure to Nursing Infants

Ginsberg

Hattis

Rice³

2007

Environ Health Perspect

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BackgroundPerchlorate is a common contaminant of drinking water and food. It competes with iodide for uptake into the thyroid, thus interfering with thyroid hormone production. The U.S. Environmental Protection Agency’s Office of Solid Waste and Emergency Response (OSWER) set a groundwater preliminary remediation goal (PRG) of 24.5 μg/L to prevent exposure of pregnant women that would affect the fetus. This does not account for the greater exposure that is possible in nursing infants or for the relative source contribution (RSC), a factor normally used to lower the PRG due to nonwater exposures.ObjectivesOur goal was to assess whether the OSWER PRG protects infants against exposures from breast-feeding, and to evaluate the perchlorate RSC.MethodsWe used Monte Carlo analysis to simulate nursing infant exposures associated with the OSWER PRG when combined with background perchlorate.ResultsThe PRG can lead to a 7-fold increase in breast milk concentration, causing 90% of nursing infants to exceed the reference dose (RfD) (average exceedance, 2.8-fold). Drinking-water perchlorate must be < 6.9 μg/L to keep the median, and < 1.3 μg/L to keep the 90th-percentile nursing infant exposure below the RfD. This is 3.6- to 19-fold below the PRG. Analysis of biomonitoring data suggests an RSC of 0.7 for pregnant women and of 0.2 for nursing infants. Recent data from the Centers for Disease Control and Prevention (CDC) suggest that the RfD itself needs to be reevaluated because of hormonal effects in the general population.ConclusionsThe OSWER PRG for perchlorate can be improved by considering infant exposures, by incorporating an RSC, and by being responsive to any changes in the RfD resulting from the new CDC data.

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Hormone synthesis and storage in the thyroid of human preterm and term newborns: Effect of thyroxine treatment

Cited by 74 publications

References 30 publications

Breast milk—a gateway to iodine-dependent brain development

Breast milk—a gateway to iodine-dependent brain development

Scientific Opinion on Dietary Reference Values for iodine

Evaluation of the U.S. EPA/OSWER Preliminary Remediation Goal for Perchlorate in Groundwater: Focus on Exposure to Nursing Infants

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