Thyroid Hormone Levels In Children Research Articles

Alterations of Thyroid Hormone Levels in Children with Intellectual Disability.

The aim of this article was to study the thyroid hormone levels in children with intellectual disabilities and determine the relationship between the thyroid hormone levels and intellectual disability. Participants included 60 children with intellectual disabilities (the study group) and 56 without (the control group). Nuclear medicine in vitro analysis techniques were used in this study. All the controls and patients underwent in vitro analysis, and their serum levels of thyroid hormone, including thyroid-stimulating hormone, total thyroxine (T4), free T4 (FT4), total triiodothyronine (T3), and free T3 (FT3), were tested. The levels of FT4 were lower in the study group than in the control group (p < 0.001). The levels of FT3 were higher in the study group than in the control group (p = 0.003). The levels of TSH were higher in the study group than in the control group, but the difference was not statistically significant (p = 0.363). The total T4 and total T3 levels were lower in the study group than in the control group, but the difference was not statistically significant (p = 0.642, p = 0.124, respectively). The levels of thyroid hormones in the study group differed from the control group. The differences may not be clinically significant beyond their statistical significance. Thyroid hormone levels may affect intellectual disability in children.

Thyroid status in children with severe acute malnutrition

Objectives: The objective of the study is to study thyroid hormone levels in children with severe acute malnutrition (SAM) and its correlation with serum total protein and albumin levels. Materials and Methods: A prospective cross-sectional study was carried out at Nutritional Rehabilitation Centre, Hubli, from Dec 2018 to Nov 2019. Inclusion criteria: All children in the age group of 6–59 months with SAM. Exclusion criteria: (i) Children suffering from metabolic disorders, tuberculosis, urinary tract infection, malabsorption syndrome (celiac disease), protein losing enteropathy, and nephrotic syndrome; (ii) Children with major congenital anomalies; and (iii) Children with chronic liver and kidney diseases. All enrolled children’s details of demography, clinical history, and examination were entered in a predesigned pro forma. Total triiodothyronine (TT3), total thyroxine (TT4), thyroid-stimulating hormone (TSH), and serum total protein and albumin were estimated. Data were analyzed using SPSS Version 16. Results: Total of 50 children fulfilled criteria during study period. Mean age of presentation was 18 ± 2.1 months with male-to-female ratio 0.8:1. The mean TT3 (ng/dl), TT4 (mcdg/l), and TSH (mIU/L) were 109.8 ± 50.6, 8.36 ± 3.7, and 2.5 ± 1.8, respectively. Mean total protein and albumin were 5.5 ± 1.4 g/dl and 2.97 ± 0.9 g/dl. Overall, 18 (36%) children had low total protein and 17 (34%) have low serum albumin. Low serum TT3, and TT4 levels were found in 11 (22%) and 14 (28%), respectively, and elevated TSH in 4 (8%) children. Low T3 was significantly associated with low albumin (P &lt; 0.01). Conclusion: The impaired thyroid function and low serum T3 levels seen in SAM children were probably an adaptive change to malnutrition.

THYROID STATUS IN CHILDREN WITH TYPE 1 DIABETES MELLITUS

The mutually aggravating effect of comorbid diseases of diabetes mellitus (DM) and autoimmune thyroiditis (AIT) is of scientific interest to researchers. Timely assessment of the thyroid status in children with DM and correction of thyroid pathology (TP) will improve metabolic control in these patients. Аmong 972 children with DM, 478 (49.2%) were assessed for thyroid status. It is noted that every year the determination of thyroid hormone levels in children increased from 7.6% (in 2014) to 92.1% (in 2019). Among 478 examined children, 319 (66.7%) had significantly revealed thyroid dysfunction. In the structure of thyroid pathologies, the frequency of hypothyroidism was 12.5% (in 11.3% - subclinical form), hyperthyroidism - 4%. functional changes in the concentration of thyroid hormones as Euthyroid sick syndrome were observed in 23.8%. The most common type of dysfunction was an isolated increase in free T3 (isolated T3 toxicosis) – in 43.3% of cases. In 2 cases out of 18 (0.6%), a complete picture of AIT was presented, and in the remaining 16 (5.1%), signs of AIT were observed only on ultrasound of the thyroid gland, and were not confirmed by the concentrations of anti-TPO Ab, anti-TG Ab. In 47 (14.7%) children, laboratory data on thyroid hormone levels showed elevated values of TSH, free T3, free T4. Keywords: children, diabetes mellitus, thyroid status, autoimmune thyroiditis

An Adolescent Female with Bipolar Disorder Presenting with Lithium-Induced Hyperthyroidism

Lithium therapy has been associated with several endocrine disorders including thyroid dysfunction, diabetes insipidus, and hyperparathyroidism. While its suppressive effect on thyroid function is well known, it is very rare to observe lithium-induced hyperthyroidism especially in the pediatric population. Here, we describe a case of lithium-induced hyperthyroidism in an adolescent female with bipolar disorder. The patient is a 17-year-old female who was treated with lithium for bipolar disorder and presented with symptoms and laboratory findings consistent with hyperthyroidism. Since thyroid autoantibodies were negative, thyroid dysfunction was attributed to lithium toxicity. Indeed, her clinical and biochemical hyperthyroid state resolved after stopping lithium therapy. Lithium-associated hyperthyroidism can occur in the pediatric population. We propose close monitoring of thyroid hormone levels in children on lithium therapy.

Thyroid Hormone Levels in Children Receiving Antiepileptic Drugs

Thyroid Hormone Levels in Children Receiving Antiepileptic Drugs

Lipid and thyroid hormone levels in children with epilepsy treated with levetiracetam or carbamazepine: A prospective observational study

Although previous studies have investigated the influence of antiepileptic drugs (AEDs) on lipid profiles and thyroid hormone levels, there is little evidence regarding the effects of levetiracetam (LEV). Therefore, we conducted a prospective longitudinal study to evaluate the effects of LEV and carbamazepine (CBZ) treatment on lipid profile and thyroid hormone levels in patients newly diagnosed with epilepsy. Inclusion criteria were as follows: (a) age between 4 and 15 years, (b) diagnosis of epilepsy with at least two focal seizures within a year, and (c) newly treated with LEV or CBZ monotherapy. Serum lipid profile and thyroid hormone levels were measured before and after 1 and 6 months of AED initiation. Among the 21 included patients (LEV: 13 patients, CBZ: 8 patients), all but one patient in the LEV group continued AED monotherapy during the study period. Although triglyceride (TG) levels tended to be increased in the CBZ group (baseline: 58.3 ± 22.0 mg/dl, 1 month: 63.8 ± 21.6 mg/dl, 6 months: 92.3 ± 63.6 mg/dl, p = 0.22, analyses of variance (ANOVA)), there were no significant changes in total cholesterol (TC), TG levels, high-density lipoprotein cholesterol (HDL-C), or low-density lipoprotein cholesterol (LDL-C) in either group. Serum free thyroxine (fT4) levels were significantly decreased in the CBZ group (baseline: 1.15 ± 0.06 ng/dl, 1 month: 1.00 ± 0.16 ng/dl, 6 months: 0.98 ± 0.14 ng/dl, p = 0.03, ANOVA). In contrast, there were no significant changes in fT4 or thyroid-stimulating hormone (TSH) levels in the LEV group. The results of the present study suggest that LEV monotherapy does not affect lipid profile or thyroid function while CBZ monotherapy may cause thyroid dysfunction.

Is It Necessary to Measure Thyroid Hormone Levels in Children Receiving Antiepileptic Drugs?

Purpose This article evaluates the effect of antiepileptic drugs (AEDs) on thyroid function tests in children with epilepsy. Methodology One hundred twenty children were studied, with 40 patients taking older generation AEDs Na valproate (N = 20) and carbamazepine (N = 20), 40 patients taking newer generation AEDs levetiracetam (N = 20) and oxcarbazepine (N = 20), and 40 healthy children as controls. Serum T3, T4, FT4, and thyroid-stimulating hormone (TSH) were measured. Results Patients taking Na valproate had lower T3, T4, and a higher TSH level than controls. Patients taking carbamazepine had the lowest T3, T4, and FT4 serum levels among patients receiving AEDs. Conclusion The thyroid function tests were affected by the use of Na valproate and carbamazepine compared to both the control group and the group taking newer AEDs oxcarbazepine and levetiracetam. In addition, there was no effect of levetiracetam on thyroid function test results.

Longitudinal Change in Thyroid Hormone Levels in Children with Epilepsy on a Ketogenic Diet: Prevalence and Risk Factors.

Background and PurposeThe aim of this study is to evaluate the prevalence of hypothyroidism and the change of thyroid hormone level in the children with epilepsy on a ketogenic diet (KD).MethodsThe levels of serum free thyroxine (fT4) and thyroid-stimulation hormone (TSH) were measured at the start of the KD and at 6- to 12-month intervals in children with intractable epilepsy. Hypothyroidism was defined as fT4 level < 0.8 ng/dL and TSH level > 6.0 μIU/mL.ResultsA total of 28 children (17 boys and 11 girls) were enrolled in the study. The mean age of onset of seizure was 1.4 ± 1.6 years, the mean age of the start of the KD was 3.2 ± 2.4 years, and the mean duration of KD was 1.9 ± 1.5 years. Overall, there was no significant longitudinal change in the mean fT4 (0.99 ± 0.25 vs. 0.94 ± 0.71 ng/dL, p = 0.28) and TSH (2.94 ± 1.32 vs. 3.18 ± 1.21 μIU/mL, p = 0.44) levels from the start of the KD to last follow-up. The patients with a younger age of seizure onset, earlier initiation of KD, and higher serum levels of cholesterol and triglyceride had a significant decrease in fT4 levels and increase in TSH levels during the KD. Sex, duration of the seizure or KD therapy, seizure types, seizure frequency, seizure outcomes, brain lesion, ratio of KD, and being overweight did not affect the longitudinal change of fT4 and TSH levels during KD.ConclusionThyroid function had no significant longitudinal decrease in pediatric epilepsy during KD therapy. However, careful monitoring of the serum levels of fT4/TSH should be recommended in children on KDs, especially in those with earlier seizure onset, earlier start of KD, and higher levels of lipid profiles.

Is there any association between urinary metabolites of polycyclic aromatic hydrocarbons and thyroid hormone levels in children and adolescents?

Considering the possible effects of polycyclic aromatic hydrocarbons (PAHs) on thyroid function, the current study aims to investigate the association of PAH urinary metabolites with the level of thyroid hormones in a sample of Iranian children and adolescents. This cross-sectional study was conducted from September 2015 to July 2016 in Isfahan, Iran. Participants were 150 students, aged 6-18years, who were selected by multistage cluster random sampling from schools of Isfahan province. Blood and urine samples of participants were obtained for measurement of thyroid hormone levels (measured by immunoradiometric assay) and PAH urinary metabolites, including 1-hydroxynaphthalene, 2-hydroxynaphthalene, 9-hydroxyphenanthrene, and 1-hydroxypyrene. The association of serum thyroid-stimulating hormone (TSH) and PAH urinary metabolites was determined by correlation and regression analyses. Multivariate regression analysis revealed significant association between serum TSH and PAH urinary metabolites; this association remained significant after adjustment for gender and age. The corresponding figures were r=0.85 for 1-naphthol, r=0.86 for 2-naphthol, r=0.87 for 1-hydroxypyrene, and r=0.42 for 9-phenantrol, respectively, all p values<0.001. The mean levels of 1-hydroxypyrene and 9-phenanthrol were higher in boys than those in girls (p<0.05). The findings of this study indicated significant positive association between urinary PAH biomarkers and the TSH level in children and adolescents. It can be suggested that long-term exposure to PAHs might result in thyroid function impairment. The clinical implication of the current findings should be confirmed by future longitudinal studies.

Analysis and functional characterization of sequence variations in ligand binding domain of thyroid hormone receptors in autism spectrum disorder (ASD) patients.

Thyroid hormone (T3) and thyroid receptors (TRα and TRβ) are the major components of the thyroid hormone pathway. The link between thyroid pathway and neuronal development is proven in clinical medicine. Since the thyroid hormone levels in Autistic children are normal, variations in their receptors needs to be explored. To achieve this objective, changes in THRA and THRB receptor genes was studied in 30 ASD and normal children from India. The impact of some of these mutations on receptor function was also studied.

Longitudinal change of Thyroid hormone levels in children with epilepsy on ketogenic diet

Longitudinal change of Thyroid hormone levels in children with epilepsy on ketogenic diet

Prenatal exposure to perfluorinated compounds affects thyroid hormone levels in newborn girls

Perfluorinated compounds (PFCs) are ubiquitous in the environment and have been detected in humans and wildlife. Exposure to PFCs has decreased in the United States recently, while exposure to PFCs continues in Asian countries, which represents a public health concern. Various mechanisms by which PFCs affect fetal growth have been proposed, such as activation of peroxisome proliferators, disruption of thyroid hormones and changes in lipid metabolism. However, the overall evidence for an association with thyroid hormones is not strong. Therefore, we examined the effect of various prenatal PFCs on cord blood thyroid hormones: triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) levels, and explored the endocrine disrupting effect of these PFCs on thyroid hormone levels in children according to gender. Two hundred and seventy-nine study participants were selected from among the enrolled participants in the Ewha Birth & Growth Retrospective Cohort, a retrospective birth cohort study conducted at Ewha Womans University Hospital, Seoul, Korea between 2006 and 2010. A generalized linear model was constructed to explore the association of PFCs and thyroid hormones. Further, an analysis stratified by gender was conducted. Our study shows that cord blood perfluoro n-pentanoic acid (PFPeA) was positively associated with cord blood T4 (p=0.01) level. Gender-specific analysis showed that prenatal PFCs: PFPeA and Perfluorohexane sulfonic acid (PFHxS) exposure significantly increased T4 (p<0.01) and T3 (p=0.03), respectively, while perfluorononanoic acid (PFNA) decreased TSH (p=0.04) concentration in newborn girls. Thus, prenatal PFC exposure may disrupt thyroid hormone homeostasis. Thyroid hormones play a crucial role in fetal development and may have gender specific action. Hence, these results are of utmost importance in high-risk groups, such as pregnant women and children.

Thyroid Functions and Trace Elements in Pediatric Patients with Exogenous Obesity

Obesity is a multifactorial disease developing following impairment of the energy balance. The endocrine system is known to be affected by the condition. Serum thyroid hormones and trace element levels have been shown to be affected in obese children. Changes in serum thyroid hormones may result from alterations occurring in serum trace element levels. The aim of this study was to evaluate whether or not changes in serum thyroid hormone levels in children with exogenous obesity are associated with changes in trace element levels. Eighty-five children diagnosed with exogenous obesity constituted the study group, and 24 age- and sex-matched healthy children made up the control group. Serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), thyroglobulin (TG), selenium (Se), zinc (Zn), copper (Cu), and manganese (Mn) levels in the study group were measured before and at the third and sixth months of treatment, and once only in the control group. Pretreatment fT4 levels in the study group rose significantly by the sixth month (p = 0.006). Zn levels in the patient group were significantly low compared to the control group (p = 0.009). Mn and Se levels in the obese children before and at the third and sixth months of treatment were significantly higher than those of the control group (p = 0.001, p = 0.001). In conclusion, fT4, Zn, Cu, Mn, and Se levels are significantly affected in children diagnosed with exogenous obesity. The change in serum fT4 levels is not associated with changes in trace element concentrations.

Long term exposure to organochlorine pesticides and thyroid function in children from Cidade dos Meninos, Rio de Janeiro, Brazil

A pesticide factory in Cidade dos Meninos village, Duque de Caxias County, Rio de Janeiro, Brazil, ended its activity in 1961, leading to widespread contamination of the environment by several organochlorine pesticides. The aim of this study was to investigate the effects of chronic exposure to organochlorine pesticides on thyroid hormone levels in children residing in Cidade dos Meninos. In a population-based survey carried out between 2003 and 2004, serum concentration of 19 pesticides and levels of free thyroxine (T4), total triiodothyronine (T3) and thyroid-stimulating hormone (TSH) were determined in 193 children younger than 15 years old. Multivariate linear regression was conducted to examine thyroid hormone levels according to quintiles of organochlorine exposure, controlling for age, gender and serum lipid content. Free T4 and TSH levels were within reference values (0.7–1.8ng/dl and 0.35–5.5mU/l), whereas total T3 was above the reference range (80–180ng/dl) in 28% of children. More than 60% of the children had detectable levels of most organochlorine pesticides. With the exception of heptachlor and methoxychlor, total T3 levels showed a significant increasing linear trend regardless of pesticide type to which children were exposed. Free T4 levels were positively and significantly associated only with exposure to p,p'-DDD, endosulfan 1, and dieldrin. No significant trend was found for TSH. Data showed that exposure of children to organochlorine pesticides produced a significant increase in serum total T3 concentrations. The clinical implications of such a total T3 elevation and subsequent development are uncertain and warrant the need for health monitoring of these children.

Thyroid Hormone Levels in Children Receiving Carbamazepine or Valproate

Antiepileptic therapy is associated with alteration of thyroid hormone levels. We evaluated the effect of valproate and carbamazepine therapy on the thyroid hormone profile of epileptic children. Subjects included children aged 2-12 years receiving therapy for at least 6 months. Free triiodothyronine, free thyroxine, and thyroid-stimulating hormone were measured by electrochemiluminescent assay in 30 children receiving carbamazepine, 34 children receiving valproate, and 30 age- and sex-matched control subjects. Groups were similar for age, body mass index, and duration of therapy. Thyroid-stimulating hormone (mean ± S.D.) was 2.67 ± 1.66, 4.53 ± 1.9, and 3.61 ± 1.75 μ IU/mL in the control, valproate, and carbamazepine group, respectively (P < 0.001). Free thyroxine was 1.39 ± 0.19, 1.40 ± 0.63, 1.11 ± 0.19 ng/dL (P = 0.009). Free triiodothyronine was 4.03 ± 0.74, 4.14 ± 0.94, 3.92 ± 0.68 pg/mL (P = 0.54). When groups were compared 2 at a time, there was no difference in free triiodothyronine (P > 0.05). Free thyroxine levels in the carbamazepine group were significantly different from valproate (P = 0.015) and control (P = 0.027). Thyroid-stimulating hormone increased with both valproate and carbamazepine compared to control but was significant with valproate (P < 0.001). We conclude that carbamazepine and valproate therapy alters thyroid functions by decreasing free thyroxine levels. Compensation by increase in thyroid-stimulating hormone is better with valproate. The need for monitoring and supplementation should be assessed further.

Effects of pre and postnatal exposure to low levels of polybromodiphenyl ethers on neurodevelopment and thyroid hormone levels at 4 years of age

There are at present very few studies of the effects of polybromodiphenyl ethers (PBDEs), used as flame retardants in consumer products, on neurodevelopment or thyroid hormone levels in humans. The present study aims to examine the association between pre and postnatal PBDE concentrations and neurodevelopment and thyroid hormone levels in children at age 4years and isolate the effects of PBDEs from those of PCBs, DDT, DDE and HCB.A prospective birth cohort in Menorca (Spain) enrolled 482 pregnant mothers between 1997 and 1998. At 4years, children were assessed for motor and cognitive function (McCarthy Scales of Children's Abilities), attention-deficit, hyperactivity and impulsivity (ADHD-DSM-IV) and social competence (California Preschool Social Competence Scale). PBDE concentrations were measured in cord blood (N=88) and in serum of 4years olds (N=244). Among all congeners analyzed only PBDE 47 was quantified in a reasonable number of samples (LOQ=0.002ng/ml). Exposure to PBDE 47 was analyzed as a dichotomous variable: concentrations above the LOQ (exposed) and concentrations below (referents).Scores for cognitive and motor functions were always lower in children pre and postnatally exposed to PBDE47 than in referents, but none of these associations was statistically significant (β coefficient (95%CI) of the total cognition score: −2.7 (−7.0, 1.6) for postnatal exposure, and −1.4 (−9.2, 6.5) for prenatal exposure). Postnatal exposure to PBDE 47 was statistically significantly related to an increased risk of symptoms on the attention deficit subscale of ADHD symptoms (RR (95%CI)=1.8 (1.0, 3.2)) but not to hyperactivity symptoms. A statistically significant higher risk of poor social competence symptoms was observed as a consequence of postnatal PBDE 47 exposure (RR (95%CI)=2.6 (1.2, 5.9)). Adjustment for other organochlorine compounds did not influence the results. Levels of thyroid hormones were not associated to PBDE exposure.This study highlights the importance of assessing the effects of PBDE exposure not just prenatally but also during the early years of life. In the light of current evidence a precautionary approach towards PBDE exposure of both mothers and children seems warranted.

Thyroid hormone levels in children with Prader–Willi syndrome before and during growth hormone treatment

Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, obesity and short stature. Several endocrine abnormalities have been described, including GH deficiency and hypogonadotrophic hypogonadism. Published data on thyroid hormone levels in PWS children are very limited. To evaluate thyroid function in children with PWS, before and during GH treatment. At baseline, serum levels of T4, free T4 (fT4), T3, reverse T3 (rT3) and TSH were assessed in 75 PWS children. After 1 year, assessments were repeated in 57 of the them. These children participated in a randomized study with two groups: group A (n = 34) treated with 1 mg GH/m(2)/day and group B (n = 23) as controls. Median age (interquartile range, IQR) of the total group at baseline was 4.7 (2.7-7.6) years. Median (IQR) TSH level was -0.1 SDS (-0.5 to 0.5), T4 level -0.6 SDS (-1.7 to 0.0) and fT4 level -0.8 SDS (-1.3 to -0.3), the latter two being significantly lower than 0 SDS. T3 level, at 0.3 SDS (-0.3 to 0.9), was significantly higher than 0 SDS. After 1 year of GH treatment, fT4 decreased significantly from -0.8 SDS (-1.5 to -0.2) to -1.4 SDS (-1.6 to -0.7), compared to no change in untreated PWS children. However, T3 did not change, at 0.3 SDS (-0.1 to 0.8). We found normal fT4 levels in most PWS children. During GH treatment, fT4 decreased significantly to low-normal levels. TSH levels remained normal. T3 levels were relatively high or normal, both before and during GH treatment, indicating that PWS children have increased T4 to T3 conversion.

Thyroid function in children with different lipoprotein profiles: observations in a biracial (black/white) population--the Bogalusa Heart Study.

Abnormalities of thyroid function are associated with hyperlipidemia, a risk factor for coronary artery disease that starts in childhood. We investigated the age-, race-, and sex-related differences in thyroid function and its relation to serum lipoprotein levels in children (n = 363) aged 6 to 18 years from the biracial (black/white) community of Bogalusa, Louisiana, using an ultrasensitive thyroid-stimulating hormone (TSH) assay. Serum levels of lipoprotein cholesterol fractions, triglycerides, triiodothyronine (T3), thyroxine (T4), and the Tanner stage of sexual development were determined. Serum T3 (P < 0.0001), T4 (P < 0.0001), and TSH (P < 0.0020) levels decreased significantly with Tanner stage. Serum T4 levels were significantly higher (P < 0.0001) in both black and white females than their male counterparts. An unexpected finding was a significantly increased mean serum TSH in whites (2.09 + 0.91; mean + standard error of mean) when compared to blacks (1.74 + 0.10; P = 0.0185). Overall, no significant correlation was noted between serum lipoprotein variables and TSH. However, those with the highest low-density lipoprotein to very low-density lipoprotein cholesterol fractions had a higher T4 and a T4/TSH ratio than those with the lowest low-density lipoprotein to very low-density lipoprotein cholesterol fractions. In summary, it is concluded that there is no simple relationship between lipoproteins and TSH or thyroid hormone levels in children.

Thyroid Function in Children With Different Lipoprotein Profiles: Observations in a Biracial (Black/White) Population- The Bogalusa Heart Study

AbstractAbnormalities of thyroid function are associated with hyperlipidemia, a risk factor for coronary artery disease that starts in childhood. We investigated the age-, race-, and sex-related differences in thyroid function and its relation to serum lipoprotein levels in children (n = 363) aged 6 to 18 years from the biracial (black/white) community of Bogalusa, Louisiana, using an ultrasensitive thyroid-stimulating hormone (TSH) assay. Serum levels of lipoprotein cholesterol fractions, triglycerides, triiodothyronine (T3), thyroxine (T4), and the Tanner stage of sexual development were determined. Serum T3 (P < 0.0001), T4 (P < 0.0001), and TSH (P < 0.0020) levels decreased significantly with Tanner stage. Serum T4 levels were significantly higher (P < 0.0001) in both black and white females than their male counterparts. An unexpected finding was a significantly increased mean serum TSH in whites (2.09 + 0.91; mean + standard error of mean) when compared to blacks (1.74 + 0.10; P = 0.0185). Overall, no significant correlation was noted between serum lipoprotein variables and TSH. However, those with the highest low-density lipoprotein to very low-density lipoprotein cholesterol fractions had a higher T4 and a T4frSH i'atio than those with the lowest low-density lipoprotein to very lowdensity lipoprotein cholesterol fractions. In summary, it is concluded that there is no simple relationship between lipoproteins and TSH or thyroid hormone levels in children.

Contributors

Perfluorinated compounds (PFCs) are ubiquitous in the environment and have been detected in humans and wildlife. Exposure to PFCs has decreased in the United States recently, while exposure to PFCs continues in Asian countries, which represents a public health concern. Various mechanisms by which PFCs affect fetal growth have been proposed, such as activation of peroxisome proliferators, disruption of thyroid hormones and changes in lipid metabolism. However, the overall evidence for an association with thyroid hormones is not strong. Therefore, we examined the effect of various prenatal PFCs on cord blood thyroid hormones: triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH) levels, and explored the endocrine disrupting effect of these PFCs on thyroid hormone levels in children according to gender. Two hundred and seventy-nine study participants were selected from among the enrolled participants in the Ewha Birth & Growth Retrospective Cohort, a retrospective birth cohort study conducted at Ewha Womans University Hospital, Seoul, Korea between 2006 and 2010. A generalized linear model was constructed to explore the association of PFCs and thyroid hormones. Further, an analysis stratified by gender was conducted. Our study shows that cord blood perfluoro n-pentanoic acid (PFPeA) was positively associated with cord blood T4 (p = 0.01) level. Gender-specific analysis showed that prenatal PFCs: PFPeA and Perfluorohexane sulfonic acid (PFHxS) exposure significantly increased T4 (p < 0.01) and T3 (p = 0.03), respectively, while perfluorononanoic acid (PFNA) decreased TSH (p = 0.04) concentration in newborn girls. Thus, prenatal PFC exposure may disrupt thyroid hormone homeostasis. Thyroid hormones play a crucial role in fetal development and may have gender specific action. Hence, these results are of utmost importance in high-risk groups, such as pregnant women and children.