Bone health in children with long-term idiopathic subclinical hypothyroidism

Subclinical hypothyroidism in children and adolescents as mild dysfunction of the thyroid gland: a single-center study

INTRODUCTION

Subclinical hypothyroidism (SH) is a biochemical diagnosis made when a serum thyroid-stimulating hormone (TSH) is ele-vated with circulating thyroid hormone levels within their reference ranges.

AIM OF THE STUDY

Aim of our prospective non-randomized study was to evaluate the course of SH.

MATERIAL AND METHODS

All patients with suspicion of SH referred to the Endocrinology Outpatient Clinic between 2014 and 2018 were recruited to prospective study.

RESULTS

A total of 130 patients with SH were recruited for this study. Thirty-five (26.9%) patients were followed up without levothy-roxine (L-T4) (SH-T0 group) and therapy with L-T4 was randomly introduced in 95/130 (73.1%) SH children (SH-T1 group). We did not find statistical differences in hSDS and BMI Z-score between the SH-T0 and SH-T1 groups (p = 0.761 and p = 0.843, respectively). Introducing L-T4 in patients with short stature did not affect the linear growth at the end of FU ex-pressed as hSDS. OH developed in six children (6.3%) in the SH-T1 group. After conducting a multivariate logistic regres-sion, we found that the baseline TSH concentration and BMI Z-score are possible predictors of OH.

CONSLUSIONS

Our study confirmed a low risk of progression of SH to overt hypothyroidism. The majority of patients remains SH or resolved for nor-mal thyroid function. The L-T4 therapy did not effect on linear growth and body weight. The main predictor of worsening to hypothyroidism were a higher TSH level and Z-score BMI.

The use of quantitative ultrasound in a tertiary-level children hospital: role in the follow-up of chronically ill patients

PURPOSE

To evaluate the use of QUS for the bone status assessment in children cared because of a chronic disease such as: inherited metabolic disorder, kidney disease and endocrine defect and considered by the attending physician as at specific risk.

METHODS

QUS outputs were calculated for each disorder and compared to: sex, age, Tanner stage, Z-score for height, weight and BMI (body mass index).

RESULTS

One-hundred-sixty-eight subjects aged between 3.5 and 18 years met the inclusion criteria. The overall bone quality indexes were under the normal range in all the groups considered. Impairment of bone quality parameters was more evident in the group of patients with inherited metabolic disorders, in which 65% of patients in charge were studied by QUS. Older age and sexual development were associated with less pronounced bone quality impairment, as measured by QUS, in the vast majority of conditions. Overall, the diseases for which the prediction of outcome was the strongest were: hyperphenylalaninemia, nephrotic syndrome and insulin dependent diabetes mellitus.

CONCLUSIONS

QUS is capable to provide information on skeletal status in children. Initial evaluation by QUS may allow defining patients with chronic disorders who deserve further, more invasive diagnostic studies. Inherited metabolic disorders warrant specific attention and strict monitoring for their potential effect on bone.

Endocrine Regulation on Bone by Thyroid

BACKGROUND

As an endocrine organ, the thyroid acts on the entire body by secreting a series of hormones, and bone is one of the main target organs of the thyroid.

SUMMARY

This review highlights the roles of thyroid hormones and thyroid diseases in bone homeostasis.

CONCLUSION

Thyroid hormones play significant roles in the growth and development of bone, and imbalance of thyroid hormones can impair bone homeostasis.

Post-Treatment Thyroid Diseases in Children with Brain Tumors: A Single-Center Experience at "Prof. Dr. Ion Chiricuță" Institute of Oncology, Cluj-Napoca

Aim of study: The purpose of the study was to evaluate the association of thyroid dysfunction occurring in pediatric patients treated for brain tumors. Patients and methods: A total of 255 patients with brain tumors were treated between 2001 and 2018 at the “Prof. Dr. Ion Chiricuță” Institute of Oncology, Cluj-Napoca. Due to a minimum follow-up of 4 years, we studied 184 out of the 255 patients. The cohort included 69 girls (37.5%) and 109 boys (62.5%), with a median age of 8.4 years. The evaluated tumors included medulloblastomas (47 patients), astrocytomas (44 patients), ependymomas (22 patients), gliomas (20 patients), germ cell tumors (12 patients), primitive neuroectodermal tumors (4 patients), as well as other types of tumors (15 patients); in 20 of the cases, biopsy could not be performed. Results: There was a 60% overall survival rate; among the 120 surviving patients, 11 (9.1%) were diagnosed with iatrogenic thyroid disease. We observed an important number of iatrogenic thyroid disease cases in this group of patients, thus revealing the importance of long-term thyroid function evaluation in all children who finalized their treatment for brain tumors. Through this study, we aimed to provide an accurate image of the methodology of monitoring for thyroid dysfunction in childhood brain tumor survivors. Conclusion: Given the fact that the probability of developing thyroid dysfunction in the pediatric population treated for brain tumors is not rare, we recommend that childhood brain tumor survivors be monitored for iatrogenic thyroid disease, in order to provide early diagnosis and treatment.

Drugs Causing Bone Loss

Drugs may cause bone loss by lowering sex steroid levels (e.g., aromatase inhibitors in breast cancer, GnRH agonists in prostate cancer, or depot medroxyprogestone acetate - DMPA), interfere with vitamin D levels (liver inducing anti-epileptic drugs), or directly by toxic effects on bone cells (chemotherapy, phenytoin, or thiazolidinedions, which diverts mesenchymal stem cells from forming osteoblasts to forming adipocytes). However, besides effects on the mineralized matrix, interactions with collagen and other parts of the unmineralized matrix may decrease bone biomechanical competence in a manner that may not correlate with bone mineral density (BMD) measured by dual energy absorptiometry (DXA).Some drugs and drug classes may decrease BMD like the thiazolidinediones and consequently increase fracture risk. Other drugs such as glucocorticoids may decrease BMD, and thus increase fracture risk. However, glucocorticoids may also interfere with the unmineralized matrix leading to an increase in fracture risk, not mirrored in BMD changes. Some drugs such as selective serotonin reuptake inhibitors (SSRI), paracetamol, and non-steroidal anti-inflammatory drugs (NSAIDs) may not per se be associated with bone loss, but fracture risk may be increased, possibly stemming from an increased risk of falls stemming from effects on postural balance mediated by effects on the central nervous system or cardiovascular system.This paper performs a systematic review of drugs inducing bone loss or associated with fracture risk. The chapter is organized by the Anatomical Therapeutic Chemical (ATC) classification.

Prevalence of subclinical hypothyroidism in obese children or adolescents and association between thyroid hormone and the components of metabolic syndrome

AIM

Subclinical hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) levels with the normal concentrations of thyroxine (T4) or free thyroxine (fT4), and its clinical significance is unclear. The purpose of this study is to investigate the prevalence of subclinical hypothyroidism in children and adolescents and determine the relationship between lipid profiles, insulin resistance and thyroid hormones.

METHODS

A retrospective, cross-sectional study was performed using data from a subset of the KNHANES VI. The subjects whose ages were in the range of 10-19 years were enrolled when their thyroid function tests were available (n = 1104), and their laboratory and anthropometric data were analysed.

RESULTS

Subclinical hypothyroidism was more commonly identified in the obese group (27 of 111) compared to the other groups (127 of 993) (24.3 vs. 12.8%, P = 0.002). Total cholesterol and triglyceride levels were higher in a group with subclinical hypothyroidism. Body mass index (BMI) was positively correlated with serum concentrations of the TSH and negatively correlated with serum concentrations of fT4 after adjusting for age. The concentrations of total cholesterol and triglyceride were positively correlated with the TSH concentrations following adjustment for age and BMI standard deviation scores. The fT4 concentrations were negatively linked with total cholesterol after adjusting for age and BMI standard deviation scores. No significant correlation was found between insulin resistance index and TSH and fT4.

CONCLUSIONS

Subclinical hypothyroidism was common in the obese group, and the concentrations of TSH were linked with the lipid profile. Subclinical hypothyroidism in obese children or adolescents should be closely monitored while also evaluating metabolic risk factors.

Mild Hypothyroidism in Childhood: Who, When, and How Should Be Treated?

Mild hypothyroidism, also known as subclinical hypothyroidism (SH), is biochemically defined as serum TSH levels above the upper limit of the reference range, in the presence of normal serum concentrations of total T4 and free T4 (FT4). In the neonatal period, mild hypothyroidism can be defined by the presence of a TSH value between 6 and 20 mIU/L and normal FT4 levels. After the neonatal period, SH can be defined mild if TSH ranges between 4.5 and 10 mIU/L. The management of mild hypothyroidism in childhood is challenging. The major concern is to establish whether this condition should always be considered an expression of mild thyroid dysfunction. Indeed, the effects of untreated mild hypothyroidism are still not completely defined. In the neonatal period, concern exists about neurocognitive outcome; in children, although there is no clear evidence of alterations in growth or neurocognitive development, subtle cardiovascular abnormalities have been documented. Therefore, there is still uncertainty about the need of treatment across all ages, and the management should be based on the age of the child, the etiology, and the degree of TSH elevation, as well as on other patient factors. This review updates current evidences on diagnosis and management of mild hypothyroidism in childhood.

Subclinical hypothyroidism in children: is it always subclinical?

Aim of this commentary is to report current knowledges on the main clinical and metabolic abnormalities which might be observed in children with longstanding and untreated subclinical hypothyroidism (SH) and to comment the most recent views about natural evolution of thyroid function in the cases with either idiopathic or Hashimoto’s thyroiditis-related SH. On the basis of these preliminary remarks, the essential guidelines for an appropriate and tailored management of SH children are also proposed.

Evaluation of bone mineralization in former preterm born children: Phalangeal quantitative ultrasound cannot replace dual-energy X-ray absorptiometry

Background

Preterm infants are at risk of impaired bone health in later life. Dual-energy X-ray absorptiometry-scan (DXA) is the gold standard to determine bone mineralization. Phalangeal quantitative ultrasound (pQUS) is an alternative technique that is inexpensive, easy to use and radiation-free. The aim of this study was to investigate whether both techniques reveal equivalent results.

Materials and methods

Sixty former preterm infants (31 boys; 29 girls) received a DXA and pQUS at age 9 to 10 years. DXA measured bone mineral content (BMC) and bone mineral density (BMD) for total body and lumbar spine (L1-4), while pQUS measured the amplitude dependent speed of sound (AD-SoS) and bone transit time (BTT) at metacarpals II-IV providing continuous values and Z-scores based on age and sex. Four statistical methods evaluated the association between both techniques: Pearson's correlation coefficients, partial correlation coefficients adjusted for gestational age, height and BMI, Bland-Altman analysis and cross tabulation.

Results

Both techniques showed a statistically significant weak correlation for continuous values as well as Z-scores (0.291–0.462, p < 0.05). Boys had significant and relatively high correlations (0.468–0.585, p < 0.05). In comparison, the correlations for girls were not significant. Correlation coefficients further decreased while calculating the partial correlations. The Bland-Altman plots showed poor agreement. Sensitivity ranged from 33% to 92% and specificity from 16% to 68%. Positive and negative predictive values ranged from 4% to 38% and 82% to 97%, respectively.

Conclusions

We found statistically significant weak correlations and poor agreement between DXA and pQUS measurements. DXA is not equivalent to pQUS and therefore not replaceable by this technique in former preterm born children at the age of 9 to 10 years.

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DXA is the golden standard to determine bone mineralization, while Quantitative ultrasound is a radiation-free alternative.

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Four statistical tests were used to investigate the equivalence of both methods.

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Comparison of results of 60 preterm born children at age 9 to 10 years found poor agreement between both methods.

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There was a discrepancy in differentiating the same children with normal or reduced bone mineralization.

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Quantitative ultrasound cannot replace the DXA scan for determination of bone mineralization in preterm born children.

Effect of subclinical hypothyroidism on the skeletal system and improvement with short-term thyroxine therapy

The purpose of the study was to observe changes in the skeletal system of rats with subclinical hypothyroidism (SCH) and to determine whether L-thyroxine (L-T4) administration suppresses those changes. Sixty male Wistar rats were randomly divided into control, SCH, and SCH+T4 groups. SCH was induced in rats by administration of methimazole (MMI), and rats in the SCH+T4 group were treated with L-T4 after 45 days of MMI administration. The SCH group had higher thyroid-stimulating hormone (TSH) level than the control and SCH+T4 groups. There were no differences in serum thyroid hormone (FT4 and FT3) levels among the three groups. Bone mineral density; serum levels of BALP and TRACP-5b, two bone metabolic markers; and the biomechanical properties of the femurs were lower in the SCH group than in the control group. After L-T4 treatment, serum BALP and TRACP-5b levels and the femur biomechanical properties were higher in the SCH+T4 than the SCH group. Histopathological examination revealed damage to the structure of the femur trabecular bone network in rats with SCH, and L-T4 treatment improved this condition to some extent. These findings demonstrate that L-T4 treatment ameliorates the destructive effects of SCH on the skeletal system in rats.

The debate on treating subclinical hypothyroidism

Subclinical hypothyroidism (SCH) represents a mild or compensated form of primary hypothyroidism. The diagnosis of SCH is controversial, as its symptoms are non-specific and its biochemical diagnosis is arbitrary. The treatment of SCH was examined among non-pregnant adults, pregnant adults and children. In non-pregnant adults, treatment of SCH may prevent its progression to overt hypothyroidism, reduce the occurrence of coronary heart disease, and improve neuropsychiatric and musculoskeletal symptoms associated with hypothyroidism. These benefits are counteracted by cardiovascular, neuropsychiatric and musculoskeletal side effects. SCH is associated with adverse maternal and fetal outcomes that may improve with treatment. Treating SCH in children is safe and may improve growth. Importantly, the evidence in this field is largely from retrospective and prospective studies with design limitations, which precludes a conclusive recommendation for the treatment of SCH.

Subclinical hypothyroidism in childhood - current knowledge and open issues

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range, in the presence of normal concentrations of total T₄ or free T₄. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease recorded among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.

Effects of L-thyroxine treatment on early markers of atherosclerotic disease in children with subclinical hypothyroidism

OBJECTIVE

To investigate the effect of levothyroxine (L-T4) treatment on early markers of atherosclerotic disease in children with mild idiopathic subclinical hypothyroidism (SH).

DESIGN

Two-year, open, case-control prospective study.

METHODS

A total of 39 children, aged 9.18±3.56 years, with SH and 39 healthy controls were enrolled in the study. Waist-to-height ratio (WHtR), blood pressure, triglycerides, total cholesterol (total-C), HDL-C, LDL-C, non-HDL-C, triglycerides/HDL-C, atherogenic index (AI), homocysteine (Hcy), asymmetric dimethylarginine (ADMA), flow-mediated dilation (FMD) and intima-media thickness (IMT) were evaluated at baseline and after 2 years of L-T4 treatment in SH children and after 2 years of follow-up in controls.

RESULTS

At study entry WHtR was higher in SH subjects compared with controls (0.56±0.08 vs 0.49±0.07, P=0.04) and significantly decreased after 2 years of treatment (0.50±0.06, P<0.0001). Mean HDL-C levels (50.47±11.43 vs 61.06±13.83mg/dL, P=0.002) were lower, while triglycerides/HDL-C (1.63±1.07 vs 1.19±0.69, P=0.05), AI (3.32±0.90 vs 2.78±0.68, P=0.005), and Hcy (9.35±2.61 vs 7.71±1.94μmol/L, P=0.01) were higher in SH subjects compared with controls and improved after 2 years of treatment (HDL-C 56.26±13.76mg/dL, P<0.0001; triglycerides/HDL-C 1.23±0.78, P=0.006; AI 2.82±0.68, P<0.0001; and Hcy 8.25±2.09μmol/L, P=0.06). ADMA concentrations at baseline were higher in SH subjects compared with controls (0.77±0.21 vs 0.60±0.16μmol/L, P=0.001) and decreased after therapy (0.58±0.13μmol/L, P<0.0001). FMD, IMT and other metabolic parameters were not different among SH subjects and controls at baseline and after 2 years.

CONCLUSIONS

Children with SH may have subtle pro-atherogenic abnormalities. Although L-T4 treatment exerts some beneficial effects, the long-term impact of therapy on metabolic outcomes in SH children still remains unclear.

Evaluation of impact of steroid replacement treatment on bone health in children with 21-hydroxylase deficiency

There are conflicting data regarding the potential impact of chronic glucocorticoid (GC) therapy on the bone mineral density of patients with congenital adrenal hyperplasia (CAH). Previous studies performed by dual-energy X-ray absorptiometry reported conflicting results. The purpose of this study was to assess the impact of chronic GC replacement treatment in children with classical and non classical CAH due to 21-hydroxylase deficiency (21-OHD) by quantitative ultrasonometry (QUS), an easy, cheap, and radiation-free technique. The study population consisted of nineteen 21-OHD patients (nine males) on lifelong GC treatment. Anthropometric, hormonal, and treatment data were recorded for each patient, and bone quality was assessed by QUS measurements. QUS findings (amplitude-dependent speed of sound and bone transmission time) were normal in 21-OHD patients and did not correlate with duration of treatment, daily, total, and yearly hydrocortisone dose. Furthermore, no significant correlation was found between QUS findings and 17α-hydroxy progesterone, Δ4-androstenedione, and testosterone levels. In conclusion, our results provide reassurance that currently used replacement doses of GC do not have a major impact on bone in patients with CAH. QUS seems to be a reliable tool for screening of bone health in children with 21-OHD.

Subclinical hypothyroidism in children and adolescents: is it clinically relevant?

Although subclinical hypothyroidism (SH) is a common clinical problem, its diagnosis tends to be incidental. According to the definition, it should be asymptomatic, only detectable by screening. The presence or coincidence of any symptoms leads to L-thyroxine treatment. The clinical presentation, especially in younger patients with subclinical hypothyroidism, is still under dispute. Accordingly, the aim of this paper was to review the literature from the past seven years. The literature search identified 1,594 potentially relevant articles, of which 24 met the inclusion criteria. Few studies focus on the symptomatology of subclinical hypothyroidism, and most of them analyzed a small number of subjects. A significant correlation was found by some authors between subclinical hypothyroidism and a higher risk of hypertension, dyslipidemia, and migraine. No evidence of the impact of subclinical hypothyroidism on weight, growth velocity, and puberty was revealed. As the quality of most studies is poor and no definite conclusions can be drawn, randomized, large-scale studies in children and adolescents are warranted to determine the best care for patients with SH.

Bone health in children and adolescents with steroid-sensitive nephrotic syndrome assessed by DXA and QUS

BACKGROUND

The management of steroid-sensitive nephrotic syndrome (SSNS) requires treatment with high-dose glucocorticoids (GCs), but GC usage causes the most frequent form of drug-induced osteoporosis. The aim of our study was to evaluate the impact of GCs on bone mineralization in patients with SSNS using two diagnostic tools, dual-energy X-ray densitometry (DXA) and quantitative ultrasound (QUS), and to compare the diagnostic efficacy of these two imaging tools.

METHODS

A total of 30 children with SSNS (age 5.20 ± 2.20 years) were evaluated at the start (T0) and after 1 (T1), 2.44 ± 0.75 (T2, 18 patients) and 5.96 ± 2.33 years (T4, 12 patients) of GC treatment. Patients who stopped at T2 were also evaluated at the 1-year timepoint after ceasing GC treatment (T3).

RESULTS

Of the patients assessed at T2, 11 had bone mineralization at the lower limit of normal versus those at T0 and T1, with bone mineralization rescue at the 1-year timepoint after GC discontinuation. At T4, 6/12 patients had densitometric parameters at the lower limit of normal values, and 3/12 patients showed reduced bone mineralization. The parameters derived from measurements of DXA and QUS were significantly related to each timepoint.

CONCLUSIONS

Patients with SSNS receiving GC therapy undergo bone status alteration related to the dosage and duration of the therapy. In terms of diagnostic efficacy, DXA and QUS were comparable, indicating that QUS is a reliable tool to evaluate bone health in children with SSNS.

Redistribution of body composition in patients with Graves' disease after iodine-131 treatment

OBJECTIVE

The objective of this study was to investigate body composition redistribution at 3 months after radioactive iodine therapy (RAI).

METHODS

Eighty patients with Graves' disease (GD) for RAI and 18 volunteers were recruited. All patients underwent thyroid status test and dual-energy x-ray absorptiometry at baseline and 3 months after RAI. According to the second thyroid status test, patients were divided into the following groups: A, with aggravated hyperthyroidism; B-1, with improved hyperthyroidism; B-2, with euthyroidism; and B-3, with hypothyroidism.

RESULTS

Total lean mass (LM) but fat mass (FM) and bone mineral content (BMC) of whole GD patients after RAI recovered to be not different with controls. Compared with baseline, in group A, FM in the left leg increased, and LM in left arm, right arm, trunk and total LM decreased (P<0.05). In B-2, FM in the head increased, and LM in the head, right arm, trunk and total LM increased (P<0.05). In B-3, FM in the right leg and total body fat percentage decreased, but FM in the head, android-to-gynoid fat ratio and body mass index increased (P<0.05); LM of all sites, weight and total mass increased (P<0.05); BMC in lumbar spine and left leg, and total BMC decreased (P<0.05). Body composition of unmentioned sites was retained after RAI in each group (P>0.05).

CONCLUSIONS

Replenishment of LM gets priority rather than FM and BMC during the first 3 months after RAI, and the increase in LM starts from the upper body; head is the regional site in which FM recovery occurs first.

Cardiovascular risk factors in children with long-standing untreated idiopathic subclinical hypothyroidism

CONTEXT

Subclinical hypothyroidism (SH), defined as increased TSH serum levels and normal serum free T4 concentrations, has been associated with an increased risk of coronary heart disease in adults. Data in children and adolescents are scanty.

OBJECTIVE

The objective of the study was to investigate the clinical and biochemical cardiovascular risk factors in children with mild SH (serum TSH concentrations 4.5-10 mU/L).

DESIGN AND SETTING

This is a cross-sectional and controlled study conducted at a tertiary referral center on patients with persistent idiopathic long-standing (3.2 ± 0.4 y) mild SH. At study entry patients and controls underwent a clinical and biochemical assessment for cardiovascular risk.

PARTICIPANTS

Forty-nine children aged 8.5 ± 0.5 years with SH and 49 controls were enrolled in the study.

MAIN OUTCOME MEASURE

Systolic and diastolic blood pressure, body mass index (BMI), waist to height ratio, lipid profile, homocysteine, high-sensitivity serum C-reactive protein, fibrinogen, adiponectin, insulin, and homeostasis model assessment index were measured.

RESULTS

Waist to height ratio (P < .0001), atherogenic index (P = .001), triglycerides to high-density lipoprotein-cholesterol ratio (P = .01), and homocysteine levels (P = .002) were significantly higher and high-density lipoprotein-cholesterol significantly lower (P = .003) in SH subjects compared with controls. No significant differences were found in the other clinical and biochemical cardiovascular risk factors analyzed. Multivariate regression model revealed that BMI and thyroid status were the main independent factors affecting dependent variables. Even after an adjustment for BMI, most of the variables still remained significantly associated with mean TSH levels or SH duration.

CONCLUSIONS

Mild long-lasting untreated idiopathic SH may be associated with subtle proatherogenic abnormalities. Although it is difficult to establish whether these mild abnormalities represent the early steps in the initiation of atherogenesis, these children need to be carefully monitored for metabolic complications.

2014 European thyroid association guidelines for the management of subclinical hypothyroidism in pregnancy and in children

This guideline has been produced as the official statement of the European Thyroid Association guideline committee. Subclinical hypothyroidism (SCH) in pregnancy is defined as a thyroid-stimulating hormone (TSH) level above the pregnancy-related reference range with a normal serum thyroxine concentration. Isolated hypothyroxinaemia (defined as a thyroxine level below the 2.5th centile of the pregnancy-related reference range with a normal TSH level) is also recognized in pregnancy. In the majority of SCH the cause is autoimmune thyroiditis but may also be due to iodine deficiency. The cause of isolated hypothyroxinaemia is usually not apparent, but iodine deficiency may be a factor. SCH and isolated hypothyroxinaemia are both associated with adverse obstetric outcomes. Levothyroxine therapy may ameliorate some of these with SCH but not in isolated hypothyroxinaemia. SCH and isolated hypothyroxinaemia are both associated with neuro-intellectual impairment of the child, but there is no evidence that maternal levothyroxine therapy improves this outcome. Targeted antenatal screening for thyroid function will miss a substantial percentage of women with thyroid dysfunction. In children SCH (serum TSH concentration >5.5-10 mU/l) normalizes in >70% and persists in the majority of the remaining patients over the subsequent 5 years, but rarely worsens. There is a lack of studies examining the impact of SCH on the neuropsychological development of children under the age of 3 years. In older children, the evidence for an association between SCH and impaired neuropsychological development is inconsistent. Good quality studies examining the effect of treatment of SCH in children are lacking.

Subclinical hypothyroidism: Controversies to consensus

Diagnoses of subclinicaal hypothyroidism (SCH) is biochemically made, when serum thyroid stimulating hormone (TSH) levels is elevated while free thyroid hormone levels are within normal reference range. SCH is diagnosed after excluding all other causes of elevated TSH levels. Symptoms of SCH may vary from being asymptomatic to having mild nonspecific symptoms. The risk of progression to overt hypothyroidism is related to number of factors including initial serum TSH concentration, presence of auto antibodies, family history and presence goiter. Various screening recommendations for thyroid function assessment are in practice. There are still controversies surrounding SCH and associated risk of various cardiovascular diseases (CVDs), pregnancy outcomes, neuropsychiatric issues, metabolic syndrome, and dyslipidemia. Consensus will require more large randomized clinical studies involving various age groups and medical condition, especially in developing countries. All these efforts will definitely improve our understanding of disease and ultimately patient outcomes.