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

Increased thyroid stimulating hormone (TSH) as a possible risk factor for atherosclerosis in subclinical hypothyroidism

Primary hypothyroidism (PHT) is associated with an increased risk for the development of atherosclerosis (AS) and other cardiovascular disorders. PHT induces atherosclerosis (AS) through the induction of endothelial dysfunction, and insulin resistance (IR). PHT promotes vasoconstriction and the development of hypertension. However, patients with subclinical PHT with normal thyroid hormones (THs) are also at risk for cardiovascular complications. In subclinical PHT, increasing thyroid stimulating hormone (TSH) levels could be one of the causative factors intricate in the progression of cardiovascular complications including AS. Nevertheless, the mechanistic role of PHT in AS has not been fully clarified in relation to increased TSH. Therefore, in this review, we discuss the association between increased TSH and AS, and how increased TSH may be involved in the pathogenesis of AS. In addition, we also discuss how L-thyroxine treatment affects the development of AS.

The Relationship between Subclinical Hypothyroidism and Carotid Intima-Media Thickness as a Potential Marker of Cardiovascular Risk: A Systematic Review and a Meta-Analysis

BACKGROUND AND OBJECTIVES

Thyroid dysfunction is known to have significant consequences on the cardiovascular system. The correlation between carotid intima-media thickness (CIMT) and subclinical hypothyroidism (SCH) has been frequently evaluated in clinical studies in recent years. This study aimed to evaluate the significance of this association through a meta-analysis.

METHODS

We conducted a systematic search of PubMed, MedLine, Scopus, and Web of Science databases using the keywords 'subclinical hypothyroidism and carotid intima-media thickness', from the beginning of each database until January 2023. We established the inclusion and exclusion criteria and considered studies that met the inclusion criteria. We used Jamovi for statistical analysis of the data.

RESULTS

We identified 39 observational studies that met the inclusion criteria, with 3430 subjects: 1545 SCH and 1885 EU. Compared to euthyroid subjects (EU), subjects with subclinical hypothyroidism (SCH) had significantly increased carotid intima-media thickness (CIMT) values; the estimated average mean difference was 0.08 (95% CI 0.05 to 0.10), p < 0.01, I2 = 93.82%. After the sensitivity analysis, a total of 19 from the 39 abovementioned studies were analyzed, with most studies showing a positive association between SCH and thickening of the carotid wall; the estimated average mean difference was 0.04 (95% CI 0.02 to 0.07), p = 0.03, I2 = 77.7. In addition, female sex, advanced age, and high cholesterol levels statistically significantly influenced this association.

CONCLUSIONS

Our meta-analysis indicates a significant positive association between SCH and increased CIMT, but with some limitations.

Obesity is associated with subclinical hypothyroidism in the presence of thyroid autoantibodies: a cross-sectional study

BACKGROUND

Both obesity and subclinical hypothyroidism (SCH) have adverse effects on human body, but the relationship between these two conditions remains inconsistent. The presence of thyroid autoantibodies influences thyroid hormone levels, and may further mediate the interaction between obesity and SCH. This study aimed to explore the association among obesity, SCH and thyroid autoantibodies.

METHODS

This study was a cross-sectional survey of 2505 subjects. Obesity was defined as a body mass index ≥28 kg/m². Serum concentrations of thyroid hormones, thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (Tg-Ab) were examined. Logistic analysis was used to explore the relation among obesity, SCH and thyroid autoantibodies.

RESULTS

A proportion of 11.54% (289/2505) subjects were obese, and 165 subjects had SCH. The positive rates of thyroid autoantibodies, TPO-Ab and Tg-Ab were 17.64% (442/2505), 11.02% (276/2505) and 14.13% (354/2505), respectively. The proportion of SCH was significantly higher in obese than nonobese subjects among those with positive thyroid autoantibodies [22.41% (13/58) vs. 11.72% (45/384), p = 0.025, χ2 test]. Moreover, obesity was significantly associated with SCH in the presence of thyroid autoantibodies after adjusting for confounding factors (OR 2.212, 95% CI 1.103 to 4.433, p = 0.025). A higher proportion of subjects with obesity had Tg-Ab positivity [17.99% (52/289) vs. 13.63% (302/2216), p = 0.045, χ2 test], and obesity remained significantly associated with Tg-Ab positivity by multiple logistic analysis (OR 1.504, 95% CI 1.077 to 2.101, p = 0.017).

CONCLUSIONS

Obesity was associated with SCH in the presence of thyroid autoantibodies. Examination of SCH is recommended in obese subjects with thyroid autoantibody positivity.

Update on dyslipidemia in hypothyroidism: the mechanism of dyslipidemia in hypothyroidism

Hypothyroidism is often associated with elevated serum levels of total cholesterol, LDL-C and triglycerides. Thyroid hormone (TH) affects the production, clearance and transformation of cholesterol, but current research shows that thyroid-stimulating hormone (TSH) also participates in lipid metabolism independently of TH. Therefore, the mechanism of hypothyroidism-related dyslipidemia is associated with the decrease of TH and the increase of TSH levels. Some newly identified regulatory factors, such as proprotein convertase subtilisin/kexin type 9, angiogenin-like proteins and fibroblast growth factors are the underlying causes of dyslipidemia in hypothyroidism. HDL serum concentration changes were not consistent, and its function was reportedly impaired. The current review focuses on the updated understanding of the mechanism of hypothyroidism-related dyslipidemia.

Anabolic hormones and heart failure with preserved ejection fraction: looking for Ariadne's thread

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome that accounts for more than half of all heart failure patients. Identification, early diagnosis and management of patients are still complex, and no targeted treatment is available, since all tested drugs were not able to lower hard clinical outcomes. A multi-hormonal deficiency syndrome has been described in HFpEF patients suggesting that different hormones may represent new biomarkers of the disease, but their clinical utility is still debated. The natriuretic peptides are the cornerstone biomarker in heart failure, predicting cardiovascular death and heart failure hospitalization. Testosterone and DHEA-S deficiencies have been reported in HFpEF and associated with right ventricular impairment and diastolic dysfunction. IGFBP-1/IGF-1 axis correlates with echocardiographic parameters of HFpEF patients and with several prognostic biomarkers including NT-proBNP and C reactive protein. Low triiodothyronine syndrome is frequently found in HFpEF and thyroid hormones should represent a potential biomarker of risk stratification and prognosis.

Can pulse wave velocity (PWV) alone express arterial stiffness? A neglected tool for vascular function assessment

Arterial stiffness, defined as the rigidity of the arterial wall, is the consequence of vascular aging and is associated with the full spectrum of cardiovascular diseases. Carotid-femoral pulse wave velocity (cf-PWV) is the gold standard method for arterial stiffness evaluation: it measures the velocity of the arterial pulse along the thoracic and abdominal aorta alongside arterial distensibility. Its value rises as stiffness progresses. Cf-PWV is helpful to assess residual cardiovascular risk (CVR) in hypertension (HT). In fact, an increase in pulsatility and arterial stiffness predicts CVR in patients affected by arterial HT, independently of other risk factors. Arterial stiffness can predict cardiovascular events in several other clinical conditions such as heart failure, diabetes, and pulmonary HT. However, cf-PWV has not been yet included in routine clinical practice so far. A possible reason might be its methodological and theoretical limitations (inaccuracy in the traveled distance, intra and interindividual variability, lack of well-defined references values, and age- and blood pressure-independent cutoff). To exceed these limits a strict adherence to guidelines, use of analytical approaches, and possibility of integrating the results with other stiffness examinations are essential approaches.

Altered methylarginine levels after surgery in subjects with multinodular goiter

OBJECTIVES

Thyroid disorders are important risk factor for cardiovascular diseases. Levels of methylarginines such as asymmetric dimethyl arginine (ADMA), L-monomethyl arginine (L-NMMA), symmetric dimethyl arginine (SDMA) are increase in cardiovascular diseases. Multinodular goiter (MNG) is the most common type of goiter in adults. To date, no study has been conducted to determine the levels of methylarginine in euthyroid MNG patients. Our aim in this study is to compare levels of methylarginines and related metabolites in the preoperative, postoperative MNG patients and controls.

METHODS

Serum ADMA, SDMA, L-NMMA, homoarginine (hArg), arginine and citrulline concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

ADMA (p<0.001), L-NMMA (p=0.002), l-arginine (p=0.006) and citrulline (p<0.001) levels were statistically significantly higher in preop group than postop group. ADMA (p=0.003), L-NMMA (p=0.003) levels were statistically significantly higher and SDMA/ADMA (p<0.001), hArg/ADMA (p<0.001) levels were statistically significantly lower in preop group than control group.

CONCLUSIONS

The levels of methylarginines and related metabolites altered in the euthyroid MNG patients compared to the control group, and more importantly, there were significant differences between the preop and postop groups. Therefore, these metabolites can be useful in the diagnosis and prognosis of thyroid disorders, even if thyroid hormone levels are normal.

Decreased Physiological Serum Total Bile Acid Concentrations in Patients with Type 2 Diabetic Peripheral Neuropathy

PURPOSE

Bile acids, amphipathic cholesterol metabolites, have been reported to have cytoprotective and neuroprotective effects in humans and animal models. The relationship of physiological serum total bile acid (TBA) levels with diabetic peripheral neuropathy (DPN), however, has not been determined. The purpose of this study was to investigate the relationship between physiological serum TBA and DPN.

PATIENTS AND METHODS

In total, 856 patients with type 2 diabetes mellitus (T2DM) aged 20-89 years were enrolled in this cross-sectional study. Serum TBA was measured, and its relationship with DPN and other parameters was analyzed.

RESULTS

T2DM patients with DPN had significantly lower serum TBA compared with those without (P<0.01). Serum TBA was negatively associated with glycated hemoglobin A1C, plateletcrit, fibrinogen, urine albumin-to-creatinine ratio, vibration perception thresholds, and prevalence of DPN, peripheral arterial disease, and diabetic foot ulceration after adjustment for age, sex, and body mass index (P<0.01 or P<0.05). A graded association with prevalence of DPN and increase in serum TBA quartiles was observed (P for trend <0.01), and there was an 48.2% decreased risk of DPN in the highest quartile of serum TBA versus the lowest quartile (95% CI 0.299-0.617; P=0.000) after multivariate adjustment. Receiver-operating characteristic analysis revealed that the optimal cutoff point of serum TBA to indicate DPN was 2.85 μmol/L (sensitivity 77.6% and specificity 45.6%).

CONCLUSION

These findings suggest that lower physiological serum TBA level may be associated with the prevalence of DPN in T2DM patients and may be a potential biomarker for DPN.

Subclinical Hypothyroidism as the Most Common Thyroid Dysfunction Status in Children With Down's Syndrome

INTRODUCTION

Thyroid dysfunctions are one of the most common abnormalities coexisting in children with Down's syndrome (DS) and have been reported in up to 54% of cases.

AIM OF THE STUDY

The purposes of this retrospective study were to investigate the course of subclinical hypothyroidism in children with DS, to evaluate the thyroid function of these subjects in relation to the risk of developing overt thyroid disease and autoimmunity, and to identify clinical and biochemical characteristics of patients prescribed L-T4 therapy in children and adolescents with DS and SH.

MATERIAL AND METHODS

The records of DS patients referred to the Endocrinology Outpatient Clinic between 2010 and 2015 for screening of thyroid function were observed till the end of 2019 June and analyzed retrospectively. The children diagnosed with congenital hypothyroidism, acute lymphoblastic leukemia, and seizures and treated with drugs that may have interfered with thyroid function like lithium, antiepileptic, or iodinated drugs and glucocorticoids were excluded from the study.

RESULTS

The data of 77 DS patients were collected, evaluated, and analyzed. The study group consisted of 73 patients (32 girls and 41 boys with the mean age at baseline of 3.0 ± 4.5 years). A total of 63/73 (87%) children were diagnosed with SH. The 16/63 (25.4%) patients were followed-up without the treatment (group SH-T0), and therapy with levothyroxine (L-T4) was introduced in 47/63 (74.6%) SH children with a mean dosage of 1.8 ± 1.0 μg/kg/day (group SH-T1). Thyroxine supplementation did not improve growth expressed as ΔhSDS (0.1 ± 1.3, ranged -2.1 to 3.8 in SH-T0 vs. 0.0 ± 0.7, ranged -1.7 to 1.4 in SH-T1, p = 0.96) and ΔBMI Z-score (0.3 ± 0.9, ranged -0.9 to 2.6 in SH-T0 vs. 0.3 ± 1.1, ranged -2.1 to 2.9 in SH-T1, p = 0.65). Positive anti-TPO and anti-TG antibodies were detected in 7/63 (11.1%) DS cases.

CONCLUSIONS

SH is the most frequent presentation of thyroid gland dysfunction in DS children. A small percentage of patients develop an overt hypothyroidism, particularly in females with mostly positive titer of antithyroid autoantibodies.

Evolution of Hashimoto thyroiditis in children with type 1 diabetes mellitus (TIDM)

OBJECTIVES

Treatment of children with Hashimoto thyroiditis (HT) and particularly of those with coexistent diabetes mellitus type 1 (TIDM) and normal/mildly elevated serum TSH is controversial. The aim of the study was to evaluate the natural course of HT in children with TIDM compared with children with no other coexistent autoimmunity and investigate for possible predictive factors of thyroid function deterioration.

METHODS

Data from 96 children with HT, 32 with T1DM (23 girls, nine boys) mean (sd) age: 10.6 (2.3) years, and 64 age and sex-matched without T1DΜ (46 girls, 18 boys), mean (sd) age: 10.2 (2.9) years were evaluated retrospectively. They all had fT4 and TSH values within normal ranges and available data for at least three years' follow-up.

RESULTS

During the follow-up period, 11 children (34.4%) with TIDM exhibited subclinical hypothyroidism and two children (6.2%) progressed to overt hypothyroidism compared to 12 (18.8%) and two (3.1%) among children without TIDM, respectively. Among children with HT, a higher percentage (40.6%) of children with T1DM progressed to subclinical or overt hypothyroidism, compared with children (21.9%) with similar characteristics but without TIDM or other coexistent autoimmunity.

CONCLUSIONS

The annual conversion rate from euthyroidism to hypothyroidism in children with T1DM was significantly higher compared to sex and age-matched children without TIDM. Prospective randomized trials are needed to support the view of an earlier intervention therapy even in milder degrees of thyroid failure in these children.

Osteoprotegerin levels in children with subclinical hypothyroidism

AIM

In this study, we investigated the osteoprotegerin (OPG) and soluble receptor activator of nuclear factor-kappa Β ligand (sRANKL) serum levels in association with thyroid function in children with subclinical hypothyroidism.

METHODS

In 143 children and adolescents with subclinical hypothyroidism and 343 with normal thyroid function, age, height, weight and pubertal status were recorded and TSH, free thyroxine (FT4), anti-thyroid antibodies, OPG and sRANKL were measured in serum. Multiple linear regression was used for the statistical analysis with P < .05.

RESULTS

Children with subclinical hypothyroidism had higher TSH and lower FT4 serum levels than the control group (P < .05). Both groups had similar BMI Z-score, OPG and sRANKL serum levels. After multiple regression analysis, in children with subclinical hypothyroidism, OPG was negatively associated with FT4 (P < .05) whilst no association was observed between OPG and sRANKL, as well as between FT4 serum levels and RANKL.

CONCLUSION

Osteoprotegerin levels in children with subclinical hypothyroidism do not differ from those of euthyroid children. However, there is a negative association between FT4 and OPG levels observed only in the SH group. Considering the link between vascular dysfunction and alterations in osteoprotegerin levels, further research is needed to establish the role of childhood subclinical hypothyroidism in the long-term cardiovascular risk.

Diagnosis and Management of Endocrine Hypertension in Children and Adolescents

Hypertension in childhood and adolescence has increased in prevalence. Interest in the disease was raised after the 2017 clinical practice guidelines of the American Academy of Paediatrics on the definition and classification of paediatric hypertension. Among the secondary causes of paediatric hypertension, endocrine causes are relatively rare but important due to their unique treatment options. Excess of catecholamine, glucocorticoids and mineralocorticoids, congenital adrenal hyperplasia, hyperaldosteronism, hyperthyroidism and other rare syndromes with specific genetic defects are endocrine disorders leading to paediatric and adolescent hypertension. Adipose tissue is currently considered the major endocrine gland. Obesity-related hypertension constitutes a distinct clinical entity leading to an endocrine disorder. The dramatic increase in the rates of obesity during childhood has resulted in a rise in obesity-related hypertension among children, leading to increased cardiovascular risk and associated increased morbidity and mortality. This review presents an overview of pathophysiology and diagnosis of hypertension resulting from hormonal excess, as well as obesity-related hypertension during childhood and adolescence, with a special focus on management.

The effect of subclinical hypothyroidism on body composition parameters in children

BACKGROUND

It's known that overt hypothyroidism increases body fat content and weight. There's limited research about the effect of subclinical hypothyroidism (SH) on body composition in children and the effect of LT4 treatment. We aimed to evaluate body composition parameters in healthy subjects and in children with mild SH (MSH) and determine the effect of LT4 treatment.

METHODS

Sixty-four healthy children and 32 children with MSH were included. Anthropometric measurements and hormonal parameters were evaluated. Body composition was evaluated using bioelectric impedance analysis (BIA). Patients were put on LT4 treatment. BIA was performed again after 12 months of therapy.

RESULTS

There was no significant difference between the anthropometric parameters and basal metabolic rate of the healthy children and the MSH group. The percentage of trunk muscle mass (TMM) in the MSH group was lower than in the control group (P < .05). After 12 months of LT4 treatment, the percentage of total fat-free mass (FFM), TMM and trunk fat-free mass (TFFM) were increased and percentage of total body fat mass and trunk fat mass were decreased (P < .05). The difference between the percentage of TMM in the MSH group and control group was insignificant after LT4 treatment (P > .05).

CONCLUSIONS

The percentage of TMM in children with MSH was found lower than healthy control group. After LT4 treatment, the percentage of the FFM, TMM and TFFM were increased and the difference between percentage of TMM in children with MSH and healthy controls was insignificant. Our data indicated that MSH might be associated with early changes in body composition parameters.

Epicardial Fat Thickness in Children with Subclinical Hypothyroidism and Its Relationship to Subclinical Atherosclerosis: A Pilot Study

BACKGROUND/AIMS

Thyroid hormones (TSH) play a key role in the working of the cardiovascular system, with direct effects on cardiac function, vascular system, and atherosclerotic factors. Epicardial adipose tissue, the visceral fat of the heart, has emerged as a new cardiometabolic risk marker because of its close anatomical proximity to the myocardium and coronary artery. This study aimed to evaluate epicardial fat thickness (EFT) in children with subclinical hypothyroidism (SH) and its relation to early atherosclerotic changes.

METHODS

The study included 32 children with SH due to autoimmune thyroiditis and 32 healthy children matched for age and gender as control group. Patients and controls underwent anthropometric evaluation and measurement of fasting lipids, glucose, insulin, homeostasis model assessment for insulin resistance and high-sensitivity C-reactive protein (hs-CRP). TSH, free thyroxine (FT4 and FT3) and antithyroid autoantibodies (antithyroid peroxidase and thyroglobulin antibodies) were also measured. Conventional echo-cardiography was used to assess EFT. Noninvasive ultrasound was used to measure carotid intima-media thickness and brachial artery flow-mediated dilation (FMD) responses.

RESULTS

Compared to controls, patients had higher atherogenic index (AI) and hs-CRP (p = 0.001 for each). Conventional echocardiography revealed that patients with SH had higher EFT (p = 01) and significantly lower FMD response compared with the control (p = 0.001). In multivariate analysis, EFT values were significantly correlated with TSH (OR 1.2; 95% CI 1.04-1.34; p = 0.01), hs-CRP (OR 1.1; 95% CI 1.09-1.14; p = 0.001, AI (OR 1.6; 95% CI 1.17-2.03; p = 0.001), and FMD response (OR 2.4; 95% CI 1.14-2.53; p = 0.01).

CONCLUSIONS

Our study demonstrated that EFT is higher in children with SH compared with controls and associated with FMD responses. Measurement of EFT by echocardiography in children with SH may help to identify those at high risk of developing subclinical atherosclerosis.

Cognitive Function in Children With Idiopathic Subclinical Hypothyroidism: Effects of 2 Years of Levothyroxine Therapy

BACKGROUND

Long-term consequences of mild subclinical hypothyroidism (SH) in children are still unclear, and the need for levothyroxine (L-T4) supplementation remains controversial. We designed a 2-year, case-control, prospective study of a cohort of children with SH to evaluate the effects of L-T4 therapy on neurocognitive outcome.

METHODS

Thirty-four children, age 9.1 ± 2.6 years, with long-lasting, idiopathic, and mild SH, and 34 healthy matched controls, were enrolled. Twenty SH children underwent a 2-year L-T4 treatment (group A), whereas 14 refused treatment and were reevaluated after a 2-year-follow-up (group B). IQ and specific cognitive domains were evaluated in all children at study entry and after 2 years of therapy (group A) or observation (group B) in SH individuals.

RESULTS

In SH children baseline IQ scores were normal and comparable to controls (full-scale IQ [FSIQ] 100.4 ± 11.3 vs 101.8 ± 14.2, verbal IQ [VIQ] 99.7 ± 13.7 vs 98.3 ± 14.9 and performance IQ [PIQ] 101.2 ± 10.4 vs 105 ± 10.4).In group A, L-T4 treatment was associated with normalization of thyrotropin (6.3 ± 1.0 mIU/L at baseline vs 2.8 ± 1.4 mIU/L at 2 years, P < .001). However, 2-year L-T4 therapy was not associated with a change in IQ scores (FSIQ 104.4 ± 13.8 vs 102.7 ± 11.0; VIQ 101.8 ± 14.9 vs 102.3 ± 11.9; and PIQ 106.5 ± 13.9 vs 102.7 ± 10.7) or in verbal or performance subtest scores. No significant differences were found in IQ scores after 2 years of treatment in group A compared to group B after a 2-year follow-up.

CONCLUSIONS

Our data suggest neurocognitive function in children is not impaired by persistent, mild, untreated SH and is not significantly modified by 2-year L-T4 supplementation.

Long-Term Follow-Up and Outcomes of Autoimmune Thyroiditis in Childhood

Background: Autoimmune thyroiditis (AIT) is the most common cause of acquired hypothyroidism in children. The natural outcome of AIT in childhood has been reported previously however follow-up duration is generally short and results variable. Objectives: To characterize clinical and biochemical findings at presentation of AIT, evaluate long-term outcomes and assess which factors at presentation predict evolution over time. Study cohort: 201 children under 18 years of age at presentation (82% female) were enrolled. Subjects were divided into five subgroups according to thyroid stimulating hormone (TSH) level at referral. Results: Mean follow-up was 8.1 years (range 0-29 years). At presentation, 34% of patients had overt hypothyroidism, 32% subclinical hypothyroidism (SCH), 16% compensated hypothyroidism, 14% were euthyroid, and 3.7% had Hashitoxicosis. Children with overt hypothyroidism were younger (10.6 vs. 13.2 years) and had higher thyroid peroxidase antibody titers. At the time of the study, levothyroxine (LT₄) therapy was required in 26% of children who were euthyroid at presentation, 56% of SCH patients, 83-84% of those with TSH above 10 mIU/L, and 57% of those with Hashitoxicosis. Over the years, 16% of children presenting with overt hypothyroidism stopped therapy. Free T₄ at presentation was the only predictor of outcome over time. Conclusions: Our findings suggest that only 26% children who were euthyroid at presentation developed hypothyroidism, whereas over 50% of those with SCH went on to require treatment. Of those presenting with overt hypothyroidism, 16% recovered with time. The only predictive parameter for LT₄ therapy at the end of the study was free T₄ levels at presentation. Long-term follow-up is required to determine ongoing therapy needs and screen for additional autoimmune diseases.

Report on advances for pediatricians in 2018: allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery

This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient care.

Thyroid hormone therapy for subclinical hypothyroidism

Subclinical Hypothyroidism (SCH) is defined as a raised level of serum TSH level in the presence of normal circulating free thyroid hormones. SCH is a highly prevalent condition displaying some peculiarities, both in terms of the diagnostic and therapeutic approach, when specific population and/or concomitant diseases are taken into account. The debate upon whether LT4 therapy should be initiated or not in patients with SCH is a long lasting one and still it remains controversial. Current evidence supports the concept that the clinical consequences of SCH may be profoundly different in relation to several patient-specific characteristics. Aim of the present review is to provide updated indications for SCH treatment in specific clinical settings. These will include the management of SCH in obese and diabetic patients, in pregnant women, and in specific age groups. Treatment modalities, including LT4 doses and recommended follow-up strategy will also be discussed. In the era of "precision medicine" the decision to-treat-not-to-treat SCH should be individualized taking into account risks and beneficial outcomes of LT4 therapy. With this in mind, we reviewed the most relevant studies in the recent literature in order to provide evidence for or against LT4 replacement therapy for SCH in specific clinical settings.

Evaluation of the relationship of subclinical hypothyroidism with metabolic syndrome and its components in adolescents: a population-based study

PURPOSE

This study investigated the association of subclinical hypothyroidism (SCH) with metabolic syndrome (MetS) and its components in adolescents.

METHODS

The study population included 1006 adolescents (aged 10-18 years) from the Korea National Health and Nutrition Examination Surveys; SCH subjects were compared with euthyroid subjects. MetS was defined using the International Diabetes Federation criteria. The risks of MetS and its components in SCH and euthyroid subjects were calculated using binary logistic regression analyses.

RESULTS

Study subjects had a mean age of 14.2 ± 2.5 years, and 53% were male. The prevalence of MetS was 2.5% in the overall study population (3.2% of males and 1.7% of females). Among the 1006 subjects, 143 (14.2%) had SCH. The risk of MetS was not higher in SCH subjects than in euthyroid subjects (odds ratio [OR], 1.50; 95% confidence interval [CI], 0.54-4.11); however, among the components of MetS, the risk of abdominal obesity was higher in SCH subjects than in euthyroid subjects (OR, 2.08; 95% CI, 1.04-4.15) after adjusting for age, sex, and body mass index (BMI). Although not statistically significant, a trend toward increased risk of elevated blood pressure (BP) was observed in SCH subjects relative to euthyroid subjects after further adjusting for age, sex, and BMI (OR, 2.01; 95% CI, 0.89-4.52). Furthermore, non-obese SCH subjects had higher systolic BP compared with non-obese euthyroid subjects after adjusting for age, sex, and BMI (P = 0.014).

CONCLUSIONS

SCH was not associated with the presence of MetS. However, SCH may be associated with abdominal obesity and possibly elevated BP in adolescents.

Association between mild hyperthyrotropinemia and hypercholesterolemia in children with severe obesity

Background Severe obesity is associated with a number of cardiometabolic risk factors. Thyroid-stimulating hormone (TSH) levels are often slightly increased in children with obesity. The clinical significance of the mild elevation in TSH in children with obesity is unclear. Objective To examine the association between TSH and lipids in children with severe obesity. Methods We performed a retrospective analysis of records of children with severe obesity with simultaneous measurements of TSH and lipids. Children with TSH <0.3 mIU/L and ≥10 mIU/L were excluded. The relationship between TSH and lipids was evaluated using univariate/multiple variable linear and logistic regression. Results The study included 834 children (age 13.8 ± 4.1 years, males 46%, body mass index [BMI]: 36.9 ± 7.6 kg/m2; BMI z-score 2.6 ± 0.4). Seventy-four (8.9%) children had TSH between 5 and <10 mIU/L (high TSH [HTSH]). TSH was positively associated with non-high-density lipoprotein (HDL) cholesterol (β: 1.74; 95% confidence interval [CI] 0.29-3.20, p = 0.02). Total cholesterol and non-HDL cholesterol were higher in males with HTSH compared to those with normal TSH (175.5 vs. 163.5 mg/dL, p = 0.02 and 133.7 vs. 121.4 mg/dL, p = 0.02, respectively). The odds of elevated non-HDL cholesterol (≥145 mg/dL) was higher in males with HTSH relative to those with normal TSH (odds ratio [OR]: 2.78; 95% CI 1.35-5.69, p = 0.005). Conclusions TSH levels were positively associated with non-HDL cholesterol in children with severe obesity. Males with mildly elevated TSH had higher total cholesterol and non-HDL cholesterol compared to males with normal TSH. Further studies are warranted to determine if levothyroxine therapy would result in improvement in total cholesterol or non-HDL cholesterol in children with severe obesity with mildly elevated TSH.

Management of Subclinical and Overt Hypothyroidism Following Hemithyroidectomy in Children and Adolescents: A Pilot Study

Background: To reduce surgical complications and avoid lifelong thyroid hormone replacement, hemithyroidectomy is preferred in children and adolescents with benign nodular thyroid disease. However, hypothyroidism following hemithyroidectomy may occur, and postoperative thyroid hormone replacement for hypothyroidism following hemithyroidectomy is usually administered without a full understanding of the clinical characteristics of hypothyroidism. Methods: To investigate the incidence and risk factors of hypothyroidism after hemithyroidectomy in children and adolescents, and to identify whether postoperative thyroid hormone replacement is necessary, a retrospective review of 43 patients under 18 years of age who underwent hemithyroidectomy from January 2009 to October 2016 was conducted. All hypothyroid patients were retrospectively analyzed to determine the incidence and predisposing factor(s) of postoperative hypothyroidism. All patients were measured regarding age, sex, serum thyrotropin (TSH), anti-thyroid antibody, and histological evidence of lymphocytic infiltration. Hypothyroid patients were measured for symptoms, timing of diagnosis, and thyroid hormone replacement. Results: The mean age at the time of surgery was 13.65 ± 3.04 years. Of the cohort, 34 patients were female (79.07%), and the mean follow-up time was 28 ± 9 months. Hypothyroidism was diagnosed in 11 of the 43 patients. The mean postoperative TSH level was 7.17 ± 2.13 μIU/ml. The mean preoperative TSH level was 3.11 ± 0.59 μIU/ml in hypothyroid patients compared with 1.92 ± 0.72 μIU/ml in euthyroid patients (P < 0.05). A preoperative TSH level >2.2 μIU/l and lymphocytic infiltration graded 3 or 4 were found to be independent risk factors for the development of hypothyroidism. There were no significant differences between groups in terms of patient age or sex. Conclusions: In the pediatric and adolescent population, patients with elevated preoperative TSH levels or the presence of lymphocytic infiltration may increase the risk of risk of hypothyroidism. In our study, postoperative levothyroxine (L-T4) treatment was necessary in 16.28% of cases after hemithyroidectomy. Patients with mild postoperative hypothyroidism should be followed up, without the need for immediate L-T4 replacement, so as to expect patients to recover spontaneously.

Hashimoto Thyroiditis and Dyslipidemia in Childhood: A Review

Hashimoto autoimmune thyroiditis (AIT) is the most common cause of acquired hypothyroidism in the pediatric population. Development of AIT is mediated mainly by cellular immune response directed toward thyroid autoantigens, leading to inflammation and impaired function of thyroid gland. Both thyroid dysfunction and inflammation affect the metabolism of plasma lipoproteins. The alterations in lipid profile worsen with the advancement of hypothyroidism, ranging from discrete changes in euthyroid AIT patients, to atherogenic dyslipidemia in the overt hypothyroidism. In this review, characteristics of dyslipidemia in pediatric AIT patients, and the consequences in respect to the risk for cardiovascular disease (CVD) development are discussed. Additionally, benefit of L-thyroxine treatment on serum lipid profile in pediatric AIT patients is addressed. Finally, potential usefulness of novel lipid biomarkers, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), non-cholesterol sterols, low-density lipoprotein particle size and number, and high-density lipoprotein structure and functionality in AIT patients is also covered. Further longitudinal studies are needed in order to elucidate the long-term cardiovascular outcomes of dyslipidemia in pediatric patients with Hashimoto AIT.

Subclinical Hypothyroidism in Children: When a Replacement Hormonal Treatment Might Be Advisable

Aim of this mini review was to analyze the main variables which should be taken into account when the decision regarding a possible treatment with L-T4 has to be considered for a child with subclinical hypothyroidism (SH). The indications of periodical monitoring and vigilance have been also discussed. It was inferred that therapy should be recommended for children with underlying Hashimoto's thyroiditis and progressive deterioration of thyroid status over time, particularly in the cases with goiter and hypothyroid symptoms and in those with associated Turner syndrome or Down's syndrome and/or other autoimmune diseases. Treatment might also be recommended for children with proatherogenic metabolic abnormalities. Treatment is not advisable in children with idiopathic and mild SH, no goiter, no hypothyroid symptoms and negative anti-thyroid autoantibodies. In the absence of any therapeutic intervention, clinical status and thyroid function tests should be periodically monitored, in order to individuate the children who might benefit from treatment. It has been suggested that children with a persistent mild elevation of TSH, who are not treated with L-T4, should undergo biochemical monitoring of thyroid function and re-assessment of clinical status every 6 months. After 2 years with stable thyroid function tests, the interval between monitoring can be extended.

Mild subclinical hypothyroidism is associated with paediatric dyslipidaemia

BACKGROUND

There is a lack of consensus on the cardiometabolic consequences of mild subclinical hypothyroidism (SCH) among children. The objective of the current study was to compare lipid profiles in children with mild SCH with those of euthyroid children.

STUDY DESIGN

Retrospective medical record review.

PATIENTS

Children (ages 2-18 years) who had undergone simultaneous measurement of TSH, free thyroxine (T4) and lipids. Lipids in children with mild SCH (TSH 5-<10 mIU/L and normal free T4, n = 228) were compared with those in euthyroid children (n = 1215).

RESULTS

TSH level was positively associated with total cholesterol and nonhigh density lipoprotein (non-HDL) cholesterol [β 0.05(0.03-0.08), P < .0001 and β 0.05(0.03-0.08), P < .0001, respectively]. Total cholesterol was significantly higher in children and adolescents with mild SCH compared with euthyroid children (4.43 ± 1.14 mmol/L vs 4.2 ± 0.85 mmol/L, P = .0005). Similarly, non-HDL cholesterol level was also higher in children with mild SCH relative to euthyroid children (3.08 ± 1.14 mmol/L vs 2.91 ± 0.8 mmol/L, P = .001). The adjusted odds ratio of having elevated total cholesterol and elevated non-HDL cholesterol was greater in children with mild SCH compared with euthyroid children (OR 1.88, 95% CI; 1.28-2.73; P = .001 and 1.72, 95% CI 1.2-2.5; P = .003, respectively). The presence of thyroid autoimmunity was not associated with higher rates of dyslipidaemia.

CONCLUSIONS

Mild SCH in children and adolescents was associated with higher rates of elevated total cholesterol and elevated non-HDL cholesterol. Randomized placebo controlled studies are warranted to determine if treatment of mild SCH in children leads to improvement in lipid profile.

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.

Non-invasive markers of cardiovascular risk in patients with subclinical hypothyroidism: A systematic review and meta-analysis of 27 case control studies

It has been reported that subclinical hypothyroidism (SCH) is closely related to subclinical atherosclerosis. According to the impact of SCH on noninvasive markers of cardiovascular risk, we fulfilled a meta-analysis of included studies to provide an integrated overview. We searched electronic databases and included all relevant studies involving SCH and epicardial adipose tissue (EAT), carotid intima-media thickness (CIMT), pulse wave velocity (PWV), flow-mediated dilation (FMD) and glyceryl trinitrate-induced dilation (GNT- induced dilation). The result was calculated in a meta-analysis to assess the impact of SCH on these markers. A total of 27 studies were entered in the final analysis. Compared with euthyroid subjects, SCH patients exhibited a significantly increased CIMT (SMD: 0.369 mm; 95%CI: 0.038, 0.700; P = 0.029) and EAT (SMD: 1.167 mm; 95%CI: 0.869, 1.466; P = 0.000) and increased PWV (SMD: 3.574 m/s; 95%CI: 0.935, 6.213, P = 0.008). We also found significantly lower FMD (SMD: −1.525%, 95%CI: −2.156, −0.894, P = 0.000) and lower GNT-induced dilation (SMD: −0.384%, 95%CI: −0.625, −0.142, P = 0.002). Sensitivity analysis and subgroup analysis confirmed the above results. Our meta-analysis confirmed a significant association of SCH and cardiovascular risk with arterial wall thickening and stiffening and endothelial dysfunction. These findings will help to establish detailed cardiovascular prevention strategies for SCH patients.

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.

The relationship between hyperthyrotropinemia and metabolic and cardiovascular risk factors in a large group of overweight and obese children and adolescents

PURPOSE

Mild TSH elevations are frequently observed in obese patients, in the absence of any detectable thyroid disease. Our objective is to evaluate the relationship between the raised TSH levels and the biochemical and clinical consequences of obesity.

METHODS

This is a retrospective cross-sectional study of a large population of obese children and adolescents. We evaluated 833 subjects (340 m, 493 f), aged 14.4 ± 2.5 (range 5.2-18.5) years, height SDS 0.27 ± 1.04 (-3.49-4.35), and BMI SDS 2.94 ± 0.59 (1.60-4.68). Body composition, free T4, TSH, anti-TPO antibodies, anti-TG antibodies, inflammation markers (total WBC and the subtypes, ultrasensitive C-reactive protein), and metabolic parameters [AST, ALT, γGT, ALP, glycaemia, insulin, total cholesterol (TC), HDL-cholesterol (HDL-C), and LDL-cholesterol (LDL-C), triglycerides (TG)] were measured, and oral disposition index (ODI) and cardiovascular risk factors (TC/HDL-C and TG/HDL-C) were calculated. After exclusion of the subjects showing anti-thyroid antibodies, the remaining 779 (325 m, 454 f) were then subdivided into two subgroups according to a TSH value below (group A) or above (group B) 4.5 mU/L.

RESULTS

Clinical characteristics and hematological markers of patients with and without positive anti-thyroid antibodies were similar, with the exception of higher TSH levels in the latter group. Using analysis of covariance, the subjects of group B had significantly higher values of TC (170.3 ± 28.7 vs 163.3 ± 32.9 mg/dL; p < 0.05), systolic (125.8 ± 13.5 vs 124.5 ± 13.1 mm/Hg), and diastolic blood pressure (79.2 ± 8.0 vs 77.9 ± 8.2 mm/Hg) than subjects of group A. No difference was observed in body composition, ODI, and the cardiovascular risk factors between these two groups.

CONCLUSION

TSH elevation in overweight and obese children and adolescents, being associated with a higher TC and blood pressure, might negatively influence the cardiac status. Longitudinal studies are requested, however, to confirm this hypothesis and, therefore, to conclude whether a substitutive treatment with l-thyroxine is really needed in these patients.

Cardiovascular Risk Factors in Children and Adolescents with Subclinical Hypothyroidism

BACKGROUND

Subclinical hypothyroidism (SCH) is a commonly encountered entity in day-to-day clinical practice and has been associated with adverse cardiovascular risk profile in adults and children. Data on children and adolescents with SCH, from India, are limited.

MATERIALS AND METHODS

This study was a cross-sectional case-control study, conducted at a tertiary care center in Northeast India. Twenty-seven children and adolescents aged 11 ± 2.4 years with SCH and thyroid-stimulating hormone >7.5 mIU/L were included in the study along with 20 age-, gender-, and height-matched controls. Multiple clinical, biochemical, and radiological cardiovascular risk factors were assessed and compared between the two groups.

RESULTS

Body mass index (BMI) (P = 0.048), waist circumference (P = 0.008), waist to height ratio (P = 0.007), low-density lipoprotein cholesterol (P = 0.04), triglycerides (TGs) (P = 0.038), TGs to high-density lipoprotein (HDL) cholesterol ratio (P = 0.005), non-HDL cholesterol (P = 0.019), fasting insulin (P = 0.006), and homeostasis model assessment of insulin resistance (P = 0.007) were found to be significantly higher while free T4 (P = 0.002) and HDL cholesterol (P = 0.019) were found to be significantly lower in SCH subjects compared to controls. On multiple regression analysis, BMI was found to have significant association with multiple cardiovascular risk factors.

CONCLUSION

Children and adolescents with SCH were found to have adverse cardiovascular risk profile. Long-term follow-up studies are required to assess the clinical significance of these findings and requirement for therapy.

Subclinical hypothyroidism in paediatric population treated with levothyroxine: a real-world study on 2001-2014 Italian administrative data

OBJECTIVE

To estimate the prevalence of subclinical hypothyroidism (SH) among children, by using levothyroxine low dosage as disease proxy, and to describe prescription pattern.

DESIGN

An historical cohort study was performed through administrative databases of 12 Italian Local Health Units covering 3,079,141 inhabitants. A cohort of children (aged 0-13 years) was selected in the period 2001-2014. A subgroup of new users (aged 0-9 years) was identified and followed up for 5 years.

METHODS

The prevalence was provided as mean value of the whole period, as annual trend, by patient gender and age. Demographic details, information on levothyroxine dosage, comorbidities and co-medications were provided. Therapy duration and medication persistence were evaluated among new users.

RESULTS

644 children treated with levothyroxine low dosage was selected, with a mean annual prevalence of 0.20 per 1000 children. The temporal trend of prevalence was stable, with a slight reduction in the 2005-2008. Prevalence by age showed an increase after 10 years. Patients were treated with an average annual dose of 4290 µg/year and 66.9% of children were affected by comorbidities. Among 197 new users, 62.9% received therapy only for one year, whereas out of those treated two or more years, 89.0% resulted persistent to the therapy.

CONCLUSIONS

This study provides real-world epidemiology of SH among children, and it depicts the clinical and therapeutic characteristics of these subjects. Its findings showed that the SH treatment of this disorder was widely variable, also due to lack of evidence concerning paediatric population.

Effect of Thyroxin Treatment on Carotid Intima-Media Thickness (CIMT) Reduction in Patients with Subclinical Hypothyroidism (SCH): a Meta-Analysis of Clinical Trials

Aim: Research shows that subclinical hypothyroidism (SCH) is related to an increased carotid intima –media thickness (CIMT), a surrogate marker of subclinical cardiovascular disease (CVD). It is controversial whether or not SCH should be treated to reduce CVD morbidity and mortality. This meta-analysis aimed to determine whether SCH is associated with an increase in CIMT as compared to Euthyroidism (EU) and whether thyroxin (T4) treatment in SCH can reverse the change in CIMT.

Methods: Two independent reviewers conducted an extensive database research up to December 2016. A total of 12 clinical trials discussed the effect of Thyroxin on CIMT values at pre- and post-treatment in subjects with SCH.

Results: CIMT was significantly higher among SCH (n = 280) as compared to EU controls (n = 263) at baseline; the pooled weighted mean difference (WMD) of CIMT was 0.44 mm [95% confidence interval (CI) 0.14, 0.74], p = 0.004; I² = 65%. After treatment with thyroxin in subjects with SCH (n = 314), there was a statistically significant decrease in CIMT from pre- to post-treatment; the pooled WMD of CIMT decrease was [WMD −0.32; 95% CI (−0.47, −0.16), p = < 0.0001; I² = 2%], and it was no longer different from EU controls [WMD 0.13 mm; 95% CI (−0.04, 0.30); p = 0.14; I² = 27%]. The total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL) were higher in SCH as compared to EU controls and decreased significantly after treatment with thyroxin.

Conclusion: This meta-analysis shows that thyroxin therapy in subjects with SCH significantly decreases CIMT and improves lipid profile, modifiable CVD risk factors. Thyroid hormone replacement in subjects with SCH may play a role in slowing down or preventing the progression of atherosclerosis.

Autoimmune thyroid diseases in children

Autoimmune thyroid diseases (AIT) are common in children and may present with a variety of signs and symptoms including: euthyroid goiter, hypothyroidism, or hyperthyroidism. The natural history of AIT may be different in children but in all age groups, there appear to be genetic risk factors and environmental triggers that initiate thyroid autoimmunity. Areas covered: In this review, we summarize recent studies that investigate the genetics and environmental triggers believed to be involved in thyroid autoimmunity. We also discuss the approach and controversies in the treatment of children with AIT. Expert commentary: Much has been learned about the major roles for genetics, cytokines, regulatory lymphocytes, and environmental triggers in CLT but controversies remain.

Pediatric TSH Reference Intervals and Prevalence of High Thyroid Antibodies in the Lebanese Population

The aims of this study are to establish reference values for TSH in Lebanese schoolchildren; to look at the relationship between TSH and age, gender, BMI, socioeconomic status (SES), and thyroid antibodies (TAb); and to investigate the prevalence of abnormal TAb in this population. 974 Lebanese schoolchildren aged 8-18 years were recruited from 10 schools of different SES. Third-generation TSH, TPO-Ab, and Tg-Ab measurements were performed using the IMMULITE chemiluminescent immunoassay. The mean TSH is 2.06 ± 1.05 μUI/ml. TSH values are inversely correlated with age (p < 0.0001), are higher in boys than in girls (resp., 2.14 ± 1.10 and 1.98 ± 0.99 μUI/ml, p = 0.017), and are positively correlated with BMI (p < 0.0001). They are also significantly higher in subjects from low-SES schools (p = 0.03) and in girls with positive TAb (p = 0.026). In boys, TSH is independently associated with age, BMI, and schools' SES (p = 0.01, p = 0.03, and p = 0.026, resp.) while in girls, the association is only significant for age and TAb (p = 0.0001 and p = 0.015, resp.). The prevalence of TAb is 4.3% (3% for TPO-Ab and 2.1% for Tg-Ab). Our results showed higher TSH values in the pediatric Lebanese population compared to western populations. TSH varies according to age, gender, BMI, and SES and is associated in girls with TAb.

Asymmetric Dimethylarginine and Its Relation As a Biomarker in Nephrologic Diseases

It is encouraging to observe that a search for publications on "asymmetric dimethylarginine (ADMA)" in PubMed, as updated on June 2016, yielded >2500 items, 24 years after a splendid paper published by Vallance et al in which the authors proposed that ADMA accumulation could be a cardiovascular risk factor in chronic kidney diseases. ADMA is the endogenous inhibitor of nitric oxide synthase and is related to endothelial dysfunction, which plays an important role in vascular damage elicited by various cardiometabolic risk factors. Although current knowledge suggests that ADMA has critical central roles in renal diseases, there are still unexplained details. The present article aims to provide a review on ADMA and its relation as a biomarker in nephrologic diseases. We aimed to systematize articles in which ADMA levels were assessed in order to clarify its role in many diseases and establish its reference values in different populations.

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.