Interpretation of thyroid function in children

Bursell, James; Warner, Justin

doi:10.1016/j.paed.2007.06.010

“…Furthermore, although we did not observe an inverse association with free T 4 , which would also be expected in the case of hypothyroidism, our suggestive finding of increased free T 3 may be physiologically consistent. In the hypothyroid state, the thyroid may attempt to compensate and convert more thyroid hormone to the most biologically active form, T 3 (Bursell and Warner, 2007; Jameson and De Groot, 2010). Furthermore, although we found that PBDEs were associated with TSH, and potentially total T 4 and free T 3 , it is possible that these associations were not independent due to the thyroid’s negative feedback loop which results in functional relationships between hormones.…”

Section: Discussionmentioning

confidence: 99%

Serum polybrominated diphenyl ether concentrations and thyroid function in young children

Jacobson

¹

,

Barr

²

,

Marcus

³

et al. 2016

Environmental Research

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Thyroid hormones are essential for proper neurodevelopment in early life. There is evidence that exposure to polybrominated diphenyl ethers (PBDEs) affects thyroid function, but previous studies have been inconsistent, and no studies among children have been conducted in the United States where PBDE levels are particularly high. Serum levels of seven PBDE congeners and thyroid hormones and other thyroid parameters were measured in 80 children aged 1-5 years from the southeastern United States between 2011-2012. Parents of the children completed questionnaires with details on demographics and behaviors. Multivariate linear regression models were used to estimate the associations between serum PBDE levels, expressed as quartiles and as log-transformed continuous variables, and markers of thyroid function. BDE-47, 99, 100 and 153 were detected in >60% of samples, and were summed (ΣPBDE). PBDE congeners and ΣPBDE were positively associated with thyroid-stimulating hormone (TSH). A log-unit increase in ΣPBDE was associated with a 22.1% increase in TSH (95% CI: 2.0%, 47.7%). Compared with children in the lowest quartile of ΣPBDE exposure, children in higher quartiles had greater TSH concentrations as modelled on the log-scale (second quartile: β=0.32, 95% confidence interval (CI): -0.09, 0.74; third quartile: β=0.44, 95% CI: 0.04, 0.85; and fourth quartile: β=0.49, 95% CI: 0.09, 0.89). There was also a tendency toward lower total T4 and higher free T3 with increasing PBDE exposure. Results suggest that exposure to PBDEs during childhood subclinically disrupts thyroid hormone function, with impacts in the direction of hypothyroidism.

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“…Furthermore, although we did not observe an inverse association with free T 4 , which would also be expected in the case of hypothyroidism, our suggestive finding of increased free T 3 may be physiologically consistent. In the hypothyroid state, the thyroid may attempt to compensate and convert more thyroid hormone to the most biologically active form, T 3 (Bursell and Warner, 2007;Jameson and De Groot, 2010). Furthermore, although we found that PBDEs were associated with TSH, and potentially total T 4 and free T 3 , it is possible that these associations were not independent due to the thyroid's negative feedback loop which results in functional relationships between hormones.…”

Section: Discussionmentioning

confidence: 99%

Serum Polybrominated Diphenyl Ether Concentrations And Thyroid Function In Young Children

Jacobson¹,

Marcus²,

Barr³

et al. 2015

ISEE Conference Abstracts

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Thyroid hormones are essential for proper neurodevelopment in early life. There is evidence that exposure to polybrominated diphenyl ethers (PBDEs) affects thyroid function, but previous studies have been inconsistent, and no studies among children have been conducted in the United States where PBDE levels are particularly high. Serum levels of seven PBDE congeners and thyroid hormones and other thyroid parameters were measured in 80 children aged 1-5 years from the southeastern United States between 2011-2012. Parents of the children completed questionnaires with details on demographics and behaviors. Multivariate linear regression models were used to estimate the associations between serum PBDE levels, expressed as quartiles and as logtransformed continuous variables, and markers of thyroid function. BDE-47, 99, 100 and 153 were detected in >60% of samples, and were summed (ΣPBDE). PBDE congeners and ΣPBDE were positively associated with thyroid-stimulating hormone (TSH). A log-unit increase in ΣPBDE was associated with a 22.1% increase in TSH (95% CI: 2.0%, 47.7%). Compared with children in the

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“…However, TSH is regarded as a sensitive marker of thyroid disruption in humans since incremental changes in free T4 hormone concentrations will lead to logarithmic changes in TSH (Bursell et al, 2007). TSH has also been extensively evaluated as a marker of thyroid disruption in newborns due to its frequent use in screening programs.…”

Section: Discussionmentioning

confidence: 99%

Associations between brominated flame retardants in human milk and thyroid-stimulating hormone (TSH) in neonates

Eggesbø

¹

,

Thomsen

²

,

Jørgensen

³

et al. 2011

Environmental Research

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Background Brominated flame retardants (BFRs) have been in widespread use in a vast array of consumer products since the 1970s. The metabolites of some BFRs show a structural similarity to thyroid hormones and experimental animal studies have confirmed that they may interfere with thyroid hormone homeostasis. A major concern has been whether intrauterine exposure to BFRs may disturb thyroid homeostasis since the fetal brain is particularly susceptible to alterations in thyroid hormones. However, few reports on newborns have been published to date. Objectives To evaluate the association between BFRs and neonatal thyroid-stimulating hormone (TSH). Methods We studied six polybrominated diphenyl ethers (PBDEs) measured in milk samples from 239 women who were part of the “Norwegian Human Milk Study” (HUMIS), 2003–2006. Hexabromocyclododecane (HBCD) and BDE-209 were measured in a subset of the women (193 and 46 milk samples, respectively). The milk was sampled at a median of 33 days after delivery. TSH was measured in babies three days after delivery as part of the routine national screening program for early detection of congenital hypothyroidism. Additional information was obtained through the Medical Birth Registry and questionnaires to the mothers. Results The PBDE concentrations in human milk in Norway were comparable to concentrations reported from other European countries and Asia, but not the US and Canada where levels are approximately one order of magnitude higher. We observed no statistically significant associations between BDE-47, 99, 153, 154, 209 and HBCD in human milk and TSH in models adjusted for possible confounders and other environmental toxicants including polychlorinated biphenyls (PCBs). Conclusions We did not observe an association between TSH and exposure to HBCD and PBDEs within the exposure levels observed.

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Interpretation of thyroid function in children

Cited by 7 publications

References 9 publications

Serum polybrominated diphenyl ether concentrations and thyroid function in young children

Serum polybrominated diphenyl ether concentrations and thyroid function in young children

Serum Polybrominated Diphenyl Ether Concentrations And Thyroid Function In Young Children

Associations between brominated flame retardants in human milk and thyroid-stimulating hormone (TSH) in neonates

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