A hypoechoic pattern of the thyroid at ultrasound does not indicate autoimmune thyroid diseases in patients with morbid obesity

Fifteen Years of Iodine Prophylaxis in Italy: Results of a Nationwide Surveillance (Period 2015-2019)

CONTEXT

In 2005, a nationwide program of iodine prophylaxis on a voluntary basis was implemented in Italy by law. However, recent data on iodine status are lacking.

OBJECTIVE

The aim of this study was to evaluate efficiency, effectiveness, and possible adverse effects (increased occurrence of thyroid autoimmunity and hyperthyroidism) of the Italian iodine prophylaxis program.

METHODS

From 2015 to 2019, a nationwide survey was performed. The use of iodized salt was evaluated in a sample of 164 593 adults and in 998 school canteens. A sample of 4233 schoolchildren (aged 11-13 years) was recruited to assess urinary iodine concentration, prevalence of goiter, and thyroid hypoechogenicity on ultrasound, with the latter being an indirect indicator of thyroid autoimmunity. Neonatal TSH values of 197 677 infants screened in regions representative of Northern, Central, and Southern Italy were analyzed to investigate the percentage of TSH values >5.0 mIU/L. Data on methimazole prescriptions were analyzed as indirect indicators of new cases of hyperthyroidism.

RESULTS

The prevalence of the use of iodized salt was 71.5% in adult population and 78% in school canteens. A median urinary iodine concentration of 124 μg/L, a prevalence of goiter of 2.2%, and a prevalence of thyroid hypoechogenicity of 5.7% were observed in schoolchildren. The percentage of neonatal TSH values >5.0 mIU/L resulted still higher (5.1%) than the World Health Organization threshold of 3.0%, whereas the prescriptions of methimazole showed a reduction of 13.5%.

CONCLUSION

Fifteen years of iodine prophylaxis have led to iodine sufficiency in Italy, although there still is concern about iodine nutritional status during pregnancy.

Subclinical Hypothyroidism in Patients with Obesity and Metabolic Syndrome: A Narrative Review

The literature on the connection between obesity, metabolic syndrome, and subclinical hypothyroidism is critically analyzed in this narrative review. These conditions are frequently observed among adult populations and various studies and meta-analyses have assessed their association. The prevalence of subclinical hypothyroidism in obese individuals is higher than in non-obese subjects and this trend is more pronounced in unhealthy obesity phenotypes. However, the diagnosis and treatment of subclinical hypothyroidism can be difficult in obese patients. Exaggerated body fat is linked to thyroid hypoechogenicity as evident through ultrasonography and euthyroid obese people have greater TSH, FT3, and FT3/FT4 ratios than non-obese individuals in a euthyroid condition. Moreover, a reduced expression of the TSH receptor and altered function of deiodinases has been found in the adipose tissue of obese patients. Current data do not support the necessity of a pharmacological correction of the isolated hyperthyrotropinemia in euthyroid obese patients because treatment with thyroid hormone does not significantly improve weight loss and the increase in serum TSH can be reversible after hypocaloric diet or bariatric surgery. On the other hand, obesity is linked to elevated leptin levels. Inflammation can raise the risk of Hashimoto thyroiditis, which increases the likelihood that obese patients will experience overt or subclinical hypothyroidism. Both metabolic syndrome and subclinical hypothyroidism are associated with atherosclerosis, liver and kidney disease. Hence, the association of these two illnesses may potentiate the adverse effects noted in each of them. Subclinical hypothyroidism should be identified in patients with obesity and treated with appropriate doses of L-thyroxine according to the lean body mass and body weight. Randomized controlled trials are necessary to verify whether treatment of thyroid deficiency could counteract the expected risks.

Normal thyroid volume in subjects evaluated in a primary ambulatory setting in Liguria

BACKGROUND

Ultrasonography (US) is the simplest method of evaluating thyroid volume (TV). The current normal TV in Liguria is not known. The aim of this study was to obtain normative data on TV in Liguria, Italy.

METHODS

From 3552 files of endocrine evaluations registered in a primary outpatient setting, we selected 483 files on euthyroid subjects (383 females and 100 males) with a normal echoic pattern on US. The inclusion criterion was the absence of thyroperoxidase autoantibodies and drugs known to interfere with thyroid hormone secretion or metabolism. TV was calculated by means of US. Anthropometric characteristics, smoking habits and the district where subjects lived were registered.

RESULTS

Less than 50% of patients were not taking any drug. The percentage of obesity was similar in both sexes. TSH levels were similar in males and females. Median TV was 8.0 mL (IQR: 6.7-9.8 mL) in females and 11.8 mL (9.3-15.6 mL) in males (P<0.0001). In females, TV was greater (P=0.01) in smokers than in non-smokers. In both sexes, the right lobe was significantly (P<0.0001) larger in volume than the left. Post-hoc analysis did not show any differences among age-groups in either females or males. In females, but not in males, TV differed significantly (P=0.0002) according to the district of residence. A significant positive correlation was found in both groups between TV and weight, height, BMI and BSA.

CONCLUSIONS

Reference values of TV in the Ligurian population are now available. TV in the general population could be compared with these normative data.

A first-trimester serum TSH in the 4-10 mIU/L range is associated with obstetric complications in thyroid peroxidase antibody-negative women

PURPOSE

The impact of mild subclinical hypothyroidism on pregnancy outcomes in TPOAb-negative women is poorly explored. The aim of the present study was the evaluation in a wide cohort of TPOAb-negative pregnant women the role of subclinical hypothyroidism (SCH) on several pregnancy outcomes.

METHODS

The study included women aged ≥ 18 years with a singleton pregnancy without known thyroid disease with serum TSH concentration between 0.4 and 10 mIU/L and TPOAb negative. Data about clinical and demographic features were collected. A blood sample was drown to test TSH, TPOAb, ANA and ENA concentration. The mean uterine artery pulsatility index was measured. Risk of adverse obstetric and fetal outcomes was collected.

RESULTS

The cohort included 2135 pregnant women. Pregnant women with TSH 4-10 mUI/L had a significantly higher frequency of family history of thyroid diseases, and personal history of celiac disease diseases, type 1 diabetes mellitus, rheumatic disease, antinuclear antibody (ANA) and anti-extractable nuclear antigen (ENA) positive tests. The risk for pre-eclampsia and small for gestational age (SGA) was significantly higher in pregnant women with first-trimester TSH 4-10 mIU/L. A first-trimester TSH serum level greater than 4 mIU/L was associated with a significant increase in the occurrence of abnormal uterine artery pulsatility index, with a more than threefold increase in the risk of developing pre-eclampsia and with the risk of SGA.

CONCLUSIONS

In TPOAb-negative pregnant women, a first-trimester serum TSH level ranging from 4 to 10 mIU/L is significantly and independently linked to an increased uterine artery pulsatility index as well as to negative pregnancy outcomes such as pre-eclampsia, SGA and gestational diabetes.

Possible added value of thyroglobulin antibody (TgAb) testing in the evaluation of thyroidal status of subjects with overweight or obesity

PURPOSE

An increase in serum TSH concentrations in the absence of thyroid disease, named isolated hyperthyrotropinemia, is frequently observed in subjects with obesity. It is directly associated with body mass index, and it is reversible following weight loss. Autoimmune hypothyroidism is frequently associated with obesity, it is usually progressive and needs replacement treatment with L-thyroxine. The aim of this study was to investigate the role of thyroglobulin antibodies (TgAb) to define the thyroidal status in subjects with overweight or obesity.

METHODS

This is a retrospective study including 749 consecutive adult patients with overweight or obesity. Of those, 76 were excluded from the analysis due to hyperthyroidism, previous thyroidectomy or radioiodine therapy for hyperthyroidism, hemiagenesis or drug-induced hypothyroidism. Serum thyrotropin (TSH), free thyroxine (FT4), free 3,5,3'-triiodothyronine (FT3), TgAb and thyroperoxidase antibodies (TPOAb) were measured in all patients.

RESULTS

Out of 673 patients, 408 did not have thyroid disease. Among patients with thyroid disease (n = 265), 130 had nodular disease with no humoral signs of thyroid autoimmunity and 135 (20%) had autoimmune thyroiditis, defined by the presence of TPOAb and/or TgAb. The prevalence of hyperthyrotropinemia, either directly measured or presumed based on L-thyroxine treatment at the time of data collection, was 63.9% in patients with both TgAb and TPOAb, 47.1% in those with isolated positivity of TPOAb, 42.8% in patients with isolated positivity of TgAb, and 14.5% in those with no detectable TgAb or TPOAb.

CONCLUSIONS

Our results confirm a high prevalence of autoimmune thyroiditis (20%) in patients with obesity. TgAb may be associated with hypothyroidism in the absence of TPOAb. TgAb measurement may turn helpful to unravel a proportion of subjects that may have or may develop primary hypothyroidism requiring specific substitutive treatment.

Association between High Normal TSH Levels and Obesity in Women with Anti-Thyroid Autoantibodies (ATAs)

A positive correlation between Thyroid-Stimulating Hormone (TSH) and Body Mass Index (BMI) has been reported in many studies, but data on this topic remain controversial, especially when TSH values are in the normal range. Moreover, few studies have evaluated the co-existence of thyroid autoimmunity. This study investigated the role of thyroid autoimmunity in the interconnection between TSH, BMI, and waist circumference (WC) in euthyroid patients with overweight or obesity. We enrolled 902 patients (213 males; mean age ± SD: 45 ± 14 years; mean BMI ± SD: 35.8 ± 6.5 kg/m²), with normal serum TSH concentration; anti-thyroid autoantibodies (ATAs) were evaluated in 752 patients (186 males). Patients were divided into four BMI classes, based on WHO criteria, and the relationship between BMI, WC, and TSH was evaluated in the whole sample and compared to ATAs positivity, observed in 235 patients (44 males). No significant difference was found between TSH levels in the BMI classes. A statistically significant correlation between TSH and BMI was found only in ATAs-positive females (N = 191, Spearman rho: 0.149; p-value: 0.040). However, this finding was not confirmed when considering the WC. Our study shows a positive correlation only between TSH and BMI in obese women with positive ATAs, suggesting that in these patients, the high normal levels of TSH could be attributed to a mild thyroid failure with a possible worsening obesity-related effect, and both need a careful evaluation.

Seronegative autoimmune diseases: A challenging diagnosis

Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.

Is There a Relationship Between Vascularity and Echogenicity of Thyroid Lobes in Ultrasonography With BMI? A Large Retrospective Cohort Study

Objective:

The aim of this study was to investigate the relationship between sonographic vascularity and echogenicity of the thyroid lobes, compared with a participant’s body mass index (BMI).

Materials and Methods:

A total of 3722 participations, with varied BMI, were included in the study. For all the participants, the thyroid-stimulating hormone (TSH) was measured, as well as thyroid volume, sonographic echogenicity, and vascularity were recorded. A multiple regression analysis was performed to assess the relationship between the sonographic vascularity and echogenicity, of thyroid lobes, compared with the participants’ BMI.

Results:

The serum TSH values were significantly higher in patients with a BMI > 25 kg/m². The sonographic vascularity and volume of thyroid lobes were positively correlated the participants’ BMI ( P < .005). Sonographic heterogenicity of the left thyroid lobe, right thyroid lobe, and the isthmus were positively associated with BMI ( P < .005). However, the hyper/hypoechogenicity did not demonstrate any significant correlation with BMI ( P > .005).

Conclusion:

Based on the findings of this study, it was concluded that thyroid volumes may have a significant positive relationship with BMI. In overweight participants (i.e., BMI more than 25), thyroid echogenicity was more heterogeneous and their thyroid lobes were more hypovascular.

Histological pattern and gene expression profiling of thyroid tissue in subjects with obesity

PURPOSE

Subjects with obesity may exhibit an increase in serum TSH concentrations. Several mechanisms have been proposed to explain this association, including the presence of a compensatory mechanism to counterbalance an accelerated turnover of thyroid hormones in subjects with obesity. This study aimed at evaluating whether the thyroids of subjects with obesity differs from those of normal-weight individuals regarding histology and gene expression profiling.

METHODS

Ninety-eight patients were selected among those scheduled for thyroidectomy. At histology, thyroid tissue samples were investigated for the presence of adipocytes and/or lymphocyte infiltration. In a subset of patients, the expression at mRNA level of several genes involved in metabolic pathways and immune cell-related mechanisms was quantified by NanoString Technology.

RESULTS

The presence of adipose cells was documented in thyroid specimens from 40% normal weight, 52.9% overweight and 73.5% patients with obesity. The number of infiltrating adipocytes was greater in specimens of patients with overweight or obesity compared to normal weight. The lymphocytes common antigen (CD45) and mast cell (MC) scores, and the number of CD3+ and CD8+ lymphocytes were higher in patients with overweight and obesity than in normal-weight subjects. Several genes involved in metabolic pathways were differently expressed in patients with overweight or obesity compared to normal weight, with upregulation of Leptin receptor and downregulation of Fatty Acid-Binding Protein 5.

CONCLUSIONS

Increased BMI is associated with adipocyte and lymphocyte infiltration of the thyroid, not related to an autoimmune process, which might affect thyroid function in subjects with obesity. A differential gene expression profiling of metabolic and immune pathways in thyroid tissues of patients with obesity was also observed.

Impaired Glucose Metabolism, Anti-Diabetes Medications, and Risk of Thyroid Cancer

Simple Summary

An epidemiologic link exists between obesity, insulin resistance, diabetes, and some cancers, such as breast cancer and colon cancer. The prevalence of obesity and diabetes is increasing, and additional epidemiologic data suggest that there may be a link between obesity and risk of thyroid abnormalities. Factors that may link obesity and diabetes with thyroid proliferative disorders include elevated circulating levels of insulin, increased body fat, high blood sugars, and exogenous insulin use. However, mechanisms underlying associations of obesity, diabetes, and thyroid proliferative disorders are not yet fully understood. The present manuscript reviews and summarizes current evidence of mechanisms and epidemiologic associations of obesity, insulin resistance, and use of anti-diabetes medications with benign and malignant proliferative disorders of the thyroid.

Abstract

The prevalence of obesity is progressively increasing along with the potential high risk for insulin resistance and development of type 2 diabetes mellitus. Obesity is associated with increased risk of many malignancies, and hyperinsulinemia has been proposed to be a link between obesity and cancer development. The incidence of thyroid cancer is also increasing, making this cancer the most common endocrine malignancy. There is some evidence of associations between obesity, insulin resistance and/or diabetes with thyroid proliferative disorders, including thyroid cancer. However, the etiology of such an association has not been fully elucidated. The goal of the present work is to review the current knowledge on crosstalk between thyroid and glucose metabolic pathways and the effects of obesity, insulin resistance, diabetes, and anti-hyperglycemic medications on the risk of thyroid cancer development.

Nutritional iodine status and obesity

Iodine is an essential component of the thyroid hormones, thyroxine and triiodothyronine. Its availability strictly depends on iodine content of foods, which may vary from very low to very high. Inadequate iodine intake (deficiency or excess) may affect thyroid function resulting in hypothyroidism or hyperthyroidism. Based on median urinary iodine concentrations, epidemiological criteria have been established for the categorization and monitoring of nutritional iodine status of a population (or subgroups of populations). Additional methods for iodine intake assessment include measurement of thyroid size (by thyroid palpation or ultrasonography) and of biochemical parameters, such as neonatal thyroid stimulating hormone, thyroglobulin and thyroid hormones.

Recent studies carried out in overweight/obese children and adults provide evidence that body mass index (BMI) may significantly influence the above indicators, thus theoretically affecting the epidemiological evaluation of nutritional iodine status in populations.

In this short review, we analyze current knowledge on the effects of overweight and obesity on indicators of adequacy and monitoring of iodine status, namely urinary iodine excretion and thyroid volume and echogenicity.

Data on urinary iodine excretion in overweight/obese children are divergent, as both increased and reduced levels have been reported in overweight/obese children compared to normal-weight controls.

Whether gastrointestinal surgery may affect iodine absorption and lead to iodine deficiency in patients undergoing bariatric surgery has been evaluated in a limited number of studies, which excluded iodine deficiency, thus suggesting that supplements usually recommended after bariatric surgery do not need to include iodine.

Albeit limited, evidence on thyroid volume and obesity is consistent with a direct relationship between thyroid volume and BMI, irrespective of nutritional iodine status. Finally, a higher frequency of thyroid hypoechoic pattern has been described in overweight/obese children. This finding has been recently related to an increased adipocyte infiltration and thyroid parenchyma imbibition mediated by inflammatory cytokines and should be considered when the frequency of thyroid hypoechoic pattern is used as non-invasive marker to indirectly assess thyroid autoimmunity in monitoring Universal Salt Iodization programs. Further studies, specifically addressing the role of schoolchildren body mass index as a factor potentially influencing iodine intake indicators are needed.

Obesity and Monitoring Iodine Nutritional Status in Schoolchildren: is Body Mass Index a Factor to Consider?

Background: The frequency of overweight (OW) and obese (OB) children has increased worldwide, particularly in economically developed countries. No studies have been conducted to verify whether the increasing frequency of OW and obesity in schoolchildren may affect the evaluation of iodine nutritional status in populations. The aim of this study was to verify whether urinary iodine concentration (UIC), thyroid volume (TV), and thyroid hypoechoic pattern may be affected by body mass index (BMI) in schoolchildren. Methods: The children included in this study (aged 11-13 years) were a part of the schoolchildren recruited in the second nationwide survey (period 2015-2019) conducted in Italy to monitor by law (Atto di Intesa Stato-Regioni February 26, 2009) the nationwide iodine prophylaxis program. Specifically, 1281 schoolchildren residing in iodine-sufficient areas (IS group) and 384 children residing in a still mildly iodine-deficient area (ID group) were recruited between January and March 2015 in the first-degree secondary state schools. In all the children, spot UIC was measured, thyroid ultrasound was performed to evaluate TV, and hypoechogenicity was assessed to indirectly evaluate iodine-associated thyroid autoimmunity. Results: The frequency of OW, OB, and adequate weight (AW) children was similar in the IS and ID groups at any age. After adjusting for sex and age, the regression analysis showed lower UIC values in OB children than in AW children of the IS group (beta coefficient = -34.09 [95% confidence interval -65.3 to -2.8]), whereas no significant differences were observed in the ID group. In both the IS and ID groups, the distribution of TV in AW children was significantly shifted toward lower values in comparison to the distribution of OB children (p < 0.001 in the IS group; p = 0.012 in the ID group). Furthermore, the frequency of thyroid hypoechogenicity was higher in the ID group than in the IS group (10.9% vs. 6.6%, p = 0.005); however, in both groups, it was significantly lower in AW children than in OB children (p < 0.01). Conclusions: This study for the first time demonstrates that BMI may be a confounding factor in monitoring iodine nutritional status in schoolchildren. Since in Italy as in other Western countries the number of OW and OB children is high, BMI is a factor to consider in monitoring salt iodization programs worldwide.

Shear-Wave Elastography-Diagnostic Value in Children with Chronic Autoimmune Thyroiditis

Chronic autoimmune thyroiditis (CAT) is the most common thyroid disorder in the pediatric population. Ultrasound evaluation may suggest the diagnosis. Additionally, shear-wave elastography (SWE) proved to be a valuable additional diagnosis tool in adults with CAT by assessing thyroid stiffness (TS). This study aims to assess its use also in detecting children with CAT. The study group consisted of 50 children with confirmed diagnosis of CAT, who were compared to the control group, consisting of 50 children with no thyroid pathology and with an adult group of 50 subjects with CAT. The evaluation included, besides bioimmunochemical evaluation, also thyroid ultrasound evaluation and elastography measurements in the same session (Aixplorer Mach 30, Supersonic imagine, France). The mean TS values were significantly lower for children in the CAT group compared to adults with CAT (15.51 ± 4.76 kPa vs. 20.96 ± 6.31 kPa; p < 0.0001) and higher compared to the healthy aged matched controls (15.51 ± 4.76 kPa vs. 10.41 ± 2.01 kPa; p < 0.0001). SWE elastography definitely seems a promising technique in the evaluation of children with autoimmune thyroid pathology.

Compared with classic Hashimoto's thyroiditis, chronic autoimmune serum-negative thyroiditis requires a lower substitution dose of L-thyroxine to correct hypothyroidism

PURPOSE

Serum-negative-chronic-autoimmune-thyroiditis (SN-CAT) is considered a milder variant of classic Hashimoto's thyroiditis (CHT). However, its prevalence remains unknown and it is still unclear whether SN-CAT behaves differently in terms of L-thyroxine (LT4) substitution treatment of hypothyroidism. Aims of this study were to estimate the prevalence of SN-CAT in a large series of hypothyroid patients and to compare LT4 requirements in hypothyroid patients with SN-CAT and CHT.

METHODS

Five-hundred-eighty-one consecutive patients with primary-autoimmune-hypothyroidism were enrolled in a cross-sectional study. LT4 requirements and thyroid-volume changes were longitudinally evaluated in 49 hypothyroid patients with SN-CAT and in 98 sex and age-matched hypothyroid patients with CHT.

RESULTS

In our series the prevalence of SN-CAT was 20.8%. At diagnosis, patients in the CHT and SN-CAT groups had similar male/female ratio, age and BMI, while serum TSH and thyroid-volume were significantly greater in the CHT group. In the longitudinal study, during a follow-up of 8.9 ± 4.6 years, 8 out of 49 (16.3%) SN-CAT patients developed positive tests for of circulating TPO-Ab and/or Tg-Ab. Thyroid-volume significantly decreased in CHT patients, but not in those with SN-CAT. The maximum daily substitution dose of LT4 was smaller in SN-CAT patients as compared with the CHT ones. Multivariate analysis showed that age, BMI, basal TSH and thyroid antibody status independently and significantly predicted the maximum daily substitution dose of LT4.

CONCLUSIONS

SN-CAT accounts for a significant proportion of patients with autoimmune hypothyroidism. Compared with hypothyroid patients diagnosed with CHT, the SN-CAT ones require smaller doses of LT4 to correct their hypothyroidism.

Thyroid Nodules in Severely Obese Patients: Frequency and Risk of Malignancy on Ultrasonography

Background: We aimed to compare the thyroid ultrasonographic findings of severely obese versus nonobese individuals, and the frequency, characteristics, and risk of malignancy in detected nodules.Design: Case-control study including 67 adults with severe obesity (body mass index [BMI] ≥ 35 kg/m²) and 67 nonobese controls (BMI < 30 kg/m²). The participants underwent ultrasound evaluation of the thyroid and cervical subcutaneous tissue. The risk of malignancy in detected nodules was determined using the American Thyroid Association (ATA) 2015 and the Thyroid Imaging Reporting and Data System (TI-RADS) classifications. Fine-needle aspiration biopsy (FNAB) was performed in nodules for which the procedure was recommended according to the ATA-2015 or TI-RADS criteria, and the cytological evaluation followed the Bethesda classification.Results: The mean BMI values in the case and control groups were 47.0 ± 6.1 kg/m² and 22.8 ± 2.7 kg/m², respectively. There were no differences between groups regarding sex, age, total T3, and antiperoxidase (antiTPO) antibody positivity. When compared with controls, severely obese individuals showed a greater frequency of parenchymal hypoechogenicity (p = 0.042), cervical subcutaneous tissue thickness (p < 0.001), overall frequency of thyroid nodules (p = 0.038), and frequency of multiple nodules (p = 0.013). No significant differences were observed in terms of risk of nodular malignancy according to both the ATA-2015 and TI-RADS classifications in severely obese compared with nonobese individuals.Conclusions: Severely obese individuals (versus nonobese controls) presented increased parenchymal hypoechogenicity and frequency of thyroid nodules on ultrasonographic evaluation. However, no significant differences were observed in terms of risk of nodular malignancy between both groups according to the ATA-2015 and TI-RADS criteria. Thus, ultrasonographic thyroid screening of severely obese individuals is not justified.

The Association of Obesity with Autoimmune Thyroiditis and Thyroid Function-Possible Mechanisms of Bilateral Interaction

A growing number of patients suffer from autoimmune diseases, including autoimmune thyroid disease. There has simultaneously been a significant increase in the prevalence of obesity worldwide. It is still an open question whether adiposity can directly influence activation of inflammatory processes affecting the thyroid in genetically predisposed individuals. Adipokines, biologically active substances derived from the adipocytes, belong to a heterogenic group of compounds involved in numerous physiological functions, including the maintenance of metabolism, hormonal balance, and immune response. Notably, the presence of obesity worsens the course of selected autoimmune diseases and impairs response to treatment. Moreover, the excess of body fat may result in the progression of autoimmune diseases. Nutritional status, body weight, and energy expenditure may influence thyroid hormone secretion. Interestingly, thyroid hormones might influence the activity of adipose tissue as metabolic alterations related to fat tissue are observed under pathological conditions in which there are deficits or overproduction of thyroid hormones. Functioning TSH receptors are expressed on adipocytes. Thermogenesis may presumably be stimulated by TSH binding to its receptor on brown adipocytes. There could be a bilateral interaction between the thyroid and adipose. Obesity may influence the onset and course of autoimmune disease.

Altered Thyroid Function and Structure in Children and Adolescents Who Are Overweight and Obese: Reversal After Weight Loss

CONTEXT

Obesity is associated with hypothyroidism and goiter.

OBJECTIVE

The aim of the study was to verify whether thyroid structure and function would improve after weight loss.

DESIGN AND PATIENTS

We evaluated 96 children who were overweight/obese who showed an altered parenchymal pattern at thyroid ultrasound without circulating antithyroid antibodies. At phase 1, body mass index (BMI), SD score (SDS), body composition, free T4 (fT4), TSH, high-sensitivity C reactive protein (CRPhs), white blood cells, metabolic profile, and a thyroid ultrasound were assessed. Thyroid volume was expressed as SDS on the basis of the references values for age. Alterations in echogenicity and homogeneity were graded from 0 to 5 (thyroid score). The same parameters were re-examined after a weight loss program (phase 2).

RESULTS

After a mean period of treatment of 0.8 ± 0.3 years, there was a significant decrease of BMI SDS, percentage fat mass, CRPhs, TSH, and thyroid volume SDS (all P < 0.0001), whereas fT4 remained unchanged. The thyroid score significantly improved (z = -9088; P < 0.0001) [i.e., it decreased in 82 individuals, was tied in 12, and worsened only in two subjects; the score completely normalized in 48 (50%) individuals]. BMI SDS reduction was a unique predictor of the decrease of TSH, thyroid volume, and structure, whereas CRPhs reduction was an independent predictor only for the TSH change. Moreover, CRPhs variations mediated the association between BMI SDS and TSH.

CONCLUSION

The alterations of thyroid function and structure in children with obesity are reversible after weight loss.

Influence of Body Mass Index on the Clinicopathologic Features of Papillary Thyroid Carcinoma

BACKGROUND

Epidemiologic studies have demonstrated an increased risk for papillary thyroid carcinoma (PTC) with increasing body mass index (BMI). However, the relationships between excess weight and the behavior of PTC are inconsistent. The aim of this study was to evaluate the impact of excess weight on clinicopathologic features of PTC and on patient outcomes.

METHODS

Data from 417 patients with PTC who underwent total thyroidectomy with cervical lymph node dissection were retrospectively analyzed. On the basis of World Health Organization standardized categories of BMI, patients were divided into 4 groups: underweight, normal weight, overweight, and obese. Histopathologic tumor features, stage at diagnosis, and disease status were determined by chart review. Logistic regression models were used to define associations between BMI and clinicopathologic features of PTC. Cox proportional-hazards models were used to assess associations between BMI and locoregional recurrence.

RESULTS

Overweight (odds ratio [OR], 3.90; P = .040) and obesity (OR, 9.19; P = .012) were independent predictors of vascular invasion. Furthermore, obesity (OR, 6.14; P = .004) was an independent predictor of extrathyroidal invasion. During follow-up (median, 29 months; range, 5-87 months), 48 patients (11.5%) experienced locoregional recurrence. There were no significant differences in locoregional recurrence of PTC among BMI groups. When adjusted for other confounding factors, extrathyroidal invasion (OR, 8.35; P < .001), vascular invasion (OR, 3.57; P < .001), cervical lymph node metastasis (OR, 3.71; P = .009), and advanced tumor-node-metastasis stage (OR, 3.81; P < .001) were identified as independent factors for locoregional recurrence.

CONCLUSIONS

Higher BMI was associated with extrathyroidal invasion and vascular invasion in patients with PTC, which suggests that excess weight is associated with aggressive clinicopathologic features of PTC. But patients with higher BMI did not have an increased risk for developing postoperative complications and locoregional recurrence.

Management of Subclinical Hypothyroidism in Pregnancy: A Comment from the Italian Society of Endocrinology and the Italian Thyroid Association to the 2017 American Thyroid Association Guidelines-"The Italian Way"

The 2017 American Thyroid Association guidelines for the diagnosis and management of thyroid disease during pregnancy and the postpartum were published six years after the previous ones. They provide comprehensive clinical recommendations for the whole spectrum of thyroid diseases, as well as for optimal iodine intake during pregnancy, postpartum, and lactation. The present position statement mainly regards the recommended flow chart for therapeutic decision making in pregnant women being diagnosed with subclinical hypothyroidism. Here, we comment on the major biochemical and clinical situations and the corresponding therapeutic recommendations. In particular, we welcome the critical revision of the thyrotropin (TSH) reference range in pregnancy, and we agree that there is no need to treat thyroid peroxidase antibody-negative women with a serum TSH ranging from 2.5 μIU/mL to the upper limit of the reference range. This recommendation will hopefully reduce the huge proportion of healthy pregnant women in whom, according to the previous guidelines, levothyroxine therapy had to be initiated. On the other hand, we are concerned with the recommendation to only "consider treatment" in thyroid peroxidase antibody-negative pregnant women with a serum TSH ranging from the upper limit of the reference range to 10.0 μIU/mL. This is because thyroid antibodies may be falsely negative during gestation, and serum negative chronic autoimmune thyroiditis is a well-known clinical entity even outside pregnancy. Based on these and other arguments, we recommend treatment with levothyroxine in pregnant women with TSH levels ranging between the upper limit of the reference range and 10.0 μIU/mL independently from their thyroid antibody status.

Is a Surgeon-performed Ultrasound Good Enough in Diagnosing Thyroid Malignancy?

BACKGROUND

The widespread availability of ultrasonography has facilitated the evaluation of thyroid nodules, to differentiate between malignant and benign nodules and between metastatic and reactive lymph nodes. From the radiologists' suite, ultrasound has moved into the surgeon's office.

AIM

The aim of the present study was to evaluate the relevance of surgeon-performed ultrasound (SPUS) in the diagnosis of malignancy of the thyroid.

METHODS

SPUS for 389 consecutive patients attending the outpatient department of endocrine surgery in a tertiary care institute in Chennai. The SPUS data of 350 patients who underwent total thyroidectomy were compared with the report of radiologist-performed ultrasonogram, fine-needle aspiration cytology, and histopathology examination.

RESULTS

SPUS ranked the maximum with a Spearman's correlation of 0.886 (P < 0.0001). The sensitivity and specificity of positive-predictive value and negative-predictive value of SPUS were 98.53%, 95.72%, 96.81%, and 98%, respectively.

CONCLUSION

SPUS is a very useful clinical adjunct in diagnosing malignancy of the thyroid and saves the patient time and resource in visiting another consultant. A surgeon who is more familiar with the anatomy and pathophysiology of thyroid disorders triages the nodule better.

Improved Thyroid Hypoechogenicity Following Bariatric-Induced Weight Loss in Euthyroid Adults With Severe Obesity-a Pilot Study

Background: Obesity may affect both biochemical thyroid function tests; and thyroid morphology, as assessed using ultrasound scans (US). The aim of the present pilot study was to explore whether weight loss achieved by bariatric surgery alters thyroid US morphology including gray-scale measurements; and/or function in euthyroid adults with severe obesity. Methods: Euthyroid adults (>18 years) with body mass index (BMI) ≥40 kg/m² and negative thyroid peroxidase antibodies were assessed at baseline (pre-surgery) and after achieving at least 5% weight loss of their baseline body weight following bariatric surgery. Anthropometric assessments, biochemical/hormonal measurements (TSH, free-T4, free-T3, reverse-T3, and leptin) and thyroid US with gray-scale histogram analysis were performed at the baseline and post-surgery follow-up. Results: Ten Caucasian, euthyroid patients (women/men: 8/2; age: 48.6 ± 3.1 years; BMI: 51.4 ± 1.8 kg/m²) successfully completed this study with significantly decreased body weight (>5% weight loss), waist circumference and serum leptin levels post-surgery (mean post-surgery follow-up duration: 16.5 ± 2.5 months). In parallel to the observed bariatric-induced weight loss, thyroid US echogenicity increased by 25% (p = 0.03), without significant changes in thyroid volume. No significant changes in thyroid function tests were detected. No significant correlations were observed between the increase in thyroid echogenicity and the decreases in anthropometric parameters and circulating leptin. Conclusion: Our results indicate that in euthyroid adults with severe obesity, marked weight loss achieved by bariatric surgery is associated with a parallel significant increase in the thyroid US echogenicity, suggesting that morphological changes of the thyroid in obesity are reversible with weight loss. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03048708.

The Association of Triiodothyronine-to-Thyroxine Ratio with Body Mass Index in Obese Nigerian Children and Adolescents

The interest in the relationship between thyroid dysfunction and obesity is on the increase. This study compares the triiodothyronine-to-thyroxine (T3/T4) ratio in obese and lean children and adolescents, and correlates thyroid hormones with body mass index (BMI) in obese Nigerian children. It is a retrospective study of records of 76 obese children and adolescents with a BMI of 31.7 ± 0.1 kg/m² (26 males aged 10.9 ± 0.35 years, and 50 females aged 10.8 ± 0.4 years) that were referred to the laboratory for thyroid hormone evaluation because of their obese status. The controls were 20 age-matched non-obese apparently healthy subjects, with a mean age of 11.0 ± 0.47 years and a BMI of 20.2 ± 0.2 kg/m². Serum T3, T4, and thyroid stimulating hormone (TSH) were determined using ELECSYS 1010 auto-analyzer (Roche Diagnostics, Penzberg, Germany). The BMI (p < 0.001), T3 (p < 0.01), TSH (p < 0.001) and T3/T4 ratio (p < 0.001) were significantly higher in obese than non-obese children and adolescents. Triiodothyronine (r = 0.230; p < 0.05), TSH (r = 0.272; p < 0.02), and T3/T4 ratio (r = 0.232; p < 0.05) correlated positively with BMI in obese children and adolescents. The T3/T4 ratio (p < 0.005) was significantly higher in obese boys than obese girls. Serum T3, TSH, and T3/T4 ratio correlated positive with BMI in obese Nigerian children and adolescents. Since thyroid dysfunction represents a continuum from asymptomatic to clinical symptomatic disease, it is suggested that obese children be counseled on the need to maintain ideal BMI in order to avoid the risks associated with obesity.

Ultrasound image of the thyroid gland in obese children

Obesity as a disease of affluence also affects younger children. Numerous observations suggest a link between excessive body weight and thyroid function disorders. Subclinical hypothyroidism has been diagnosed increasingly frequently in patients with obesity. A growing number of papers also point to morphological changes of the thyroid gland in the ultrasound examination in obese children. These reports mainly concern changes in echogenicity. The present paper discusses the most important aspects of this topic on the basis of the literature as well as containing a brief analysis based on own experiences.

Correlation of normal thyroid ultrasonography with thyroid tests

BACKGROUND

Thyroid disorders are frequently seen in the community. Thyroid ultrasonography (US) is commonly used in the diagnosis of thyroid diseases. The relationship between heterogeneous echogenicity of thyroid gland and thyroid tests are well known.

METHODS

The aim of this study is to evaluate the correlation of normal US with the thyroid tests. A total of 681 individuals were enrolled in the study. Individuals were separated into two groups as normal (group 1) and hypoechoic (group 2) according to the echogenicity in US. Subjects with nodular thyroid lesions were excluded from the study. Thyroid stimulating hormone (TSH), free T4 (fT4), thyroid peroxidase antibody (TPOAb) and anti-thyroglobulin antibody (TgAb) values were recorded in both groups and thyroid stimulating hormone receptor antibody (TRAb) was recorded in individuals with low TSH.

RESULTS

86.1% of individuals in group 1 had normal TSH, 93.7% had normal thyroid antibodies and in 77.6% of individuals, all thyroid tests performed were normal. In the 6.9% of the group 2, all reviewed thyroid tests were normal (P<0.001).

CONCLUSIONS

Our study shows that US is correlated with normal thyroid function tests and is a valuable tool in the prediction of normal thyroid function.

Changes in body weight after treatment of primary hypothyroidism with levothyroxine

OBJECTIVE

Surprisingly few studies have examined weight change in hypothyroid patients after initiation of levothyroxine (LT4) therapy. Our study aimed to investigate weight change after initiation of LT4 treatment for primary hypothyroidism.

METHODS

Using electronic medical records from Boston Medical Center, Boston, Massachusetts, we performed a retrospective cohort study between January 1, 2003, and February 1, 2011. Adults ≥18 years of age with newly diagnosed primary hypothyroidism with an initial thyroid-stimulating hormone (TSH) level ≥10 mIU/L were identified. Patients with postsurgical hypothyroidism, thyroid cancer, and a history of radioactive iodine or head/neck irradiation, congestive heart failure, anorexia nervosa, end-stage renal disease, cirrhosis, pregnancy, or use of prescription weight-loss medications were excluded. TSH and weight at diagnosis and up to 24 months after LT4 initiation were collected. Weight change was assessed at the first posttreatment serum TSH level <5 mIU/L.

RESULTS

A total of 101 patients (mean age, 48 ± 15 years; 71% women) were included. Initial median TSH was 18.3 mIU/L (range, 10.1 to 710.5 mIU/L) and initial median weight was 79.6 kg (range 41.5 to 167.5 kg). Posttreatment median TSH level was 2.3 mIU/L (range, 0.04 to 5 mIU/L), and weight change at a median of 5 months (range, 1.1 to 25.6 months) was -0.1 kg (range, -20.6 to 7.7 kg). Initial median body mass index (BMI) of 95 of the patients was 29.3 kg/m2 (range, 19.5 to 56.1 kg/m2), and the median change in BMI was -0.1 kg/m2 (range, -7.1 to 3.3 kg/m2). Only 52% of patients lost weight, with a mean weight loss of 3.8 ± 4.4 kg. Gender, race, education, insurance type, age, initial TSH level, time to normalization of TSH, and initial weight were not associated with changes in weight or BMI.

CONCLUSION

Contrary to popular belief, our study of 101 patients with primary hypothyroidism showed that no significant weight change occurs after initiation of LT4 treatment.

Mechanisms in endocrinology: the crosstalk between thyroid gland and adipose tissue: signal integration in health and disease

Obesity and thyroid diseases are common disorders in the general population and they frequently occur in single individuals. Alongside a chance association, a direct relationship between 'thyroid and obesity' has been hypothesized. Thyroid hormone is an important determinant of energy expenditure and contributes to appetite regulation, while hormones and cytokines from the adipose tissue act on the CNS to inform on the quantity of energy stores. A continuous interaction between the thyroid hormone and regulatory mechanisms localized in adipose tissue and brain is important for human body weight control and maintenance of optimal energy balance. Whether obesity has a pathogenic role in thyroid disease remains largely a matter of investigation. This review highlights the complexity in the identification of thyroid hormone deficiency in obese patients. Regardless of the importance of treating subclinical and overt hypothyroidism, at present there is no evidence to recommend pharmacological correction of the isolated hyperthyrotropinemia often encountered in obese patients. While thyroid hormones are not indicated as anti-obesity drugs, preclinical studies suggest that thyromimetic drugs, by targeting selected receptors, might be useful in the treatment of obesity and dyslipidemia.

Serum negative autoimmune thyroiditis displays a milder clinical picture compared with classic Hashimoto's thyroiditis

BACKGROUND

Despite high sensitivity of current assays for autoantibodies to thyroperoxidase (TPO) and to thyroglobulin (Tg), some hypothyroid patients still present with negative tests for circulating anti-thyroid Abs. These patients usually referred to as having seronegative autoimmune thyroiditis (seronegative CAT) have not been characterized, and definite proof that their clinical phenotype is similar to that of patients with classic chronic autoimmune thyroiditis (CAT) is lacking.

OBJECTIVE

To compare the clinical phenotype of seronegative CAT (SN-CAT) and CAT as diagnosed according to a raised serum level of TSH with negative and positive tests for anti-thyroid Abs respectively.

METHODS

A case-control retrospective study enrolling 55 patients with SN-CAT and 110 patients with CAT was performed. Serum free triiodothyronine (FT3), free thyroxine (FT4), TSH, Tg Abs, and TPO Abs were measured in all patients.

RESULTS

Patients with SN-CAT displayed significantly lower mean levels of TSH (6.6±3.4 vs 10.2±9.8 μU/ml; P=0.009), higher mean FT4 levels (1.1±0.2 vs 0.9±0.2 ng/dl; P=0.0002), and similar FT3 levels when compared with CAT patients. Mean thyroid volume was significantly greater in patients with CAT when compared with SN-CAT patients (11.2±6.5 vs 8.1±3.7 ml; P=0.001). Logistic regression demonstrated that FT4 (0.123 (0.019-0.775); (P=0.026)) and thyroid volume (1.243 (1.108-1.394); (P=0.0002)) were significantly and independently related to the diagnosis (CAT/SN-CAT). Patients with SN-CAT had a similar prevalence of thyroid nodules and female gender but a lower prevalence of overt hypothyroidism (5.4 vs 20.9%; P=0.012) as opposed to patients with CAT.

CONCLUSIONS

These results suggest an autoimmune etiology of SN-CAT, which, however, seems to have a milder clinical course when compared with CAT.

Raised serum TSH in morbid-obese and non-obese patients: effect on the circulating lipid profile

Morbid obesity is associated with a high rate of raised serum TSH associated with normal free thyroid hormones. The body repercussions of this thyroid abnormality, suggesting subclinical hypothyroidism, are still debated. In particular, it is unclear whether the raised serum TSH of obesity results in changes of circulating lipids typically observed in hypothyroidism. Aim of this study was to evaluate the impact of a raised serum TSH on the lipid profile in morbid-obese and non-obese patients. Serum TSH, FT4, FT3, Tg-Ab, TPO-Ab and lipids were measured in 55 morbid-obese (BMI > 40 kg/m(2)) and 55 non-obese (BMI < 30 kg/m(2)) patients with a raised serum TSH. Despite similar serum levels of TSH, FT4 and FT3, morbid-obese patients displayed significantly lower mean levels of total cholesterol (200.8 ± 35.6 vs. 226.9 ± 41.4 mg/dl, p < 0.001) and a significantly lower prevalence of hypercholesterolemia (50.9 vs. 72.7 %, p < 0.01) when compared with non-obese patients. Morbid-obese patients also had lower mean serum HDL cholesterol and higher serum triglycerides. The impact of a raised serum TSH on the lipid profile differs in morbid-obese compared to non-obese patients, suggesting that obese patients might not be truly hypothyroid. Measuring total cholesterol could be a helpful tool for deciding whether a morbid-obese patient with a raised serum TSH should be given levothyroxine treatment.

Prevalence of goiter and thyroid nodular disease in patients with class III obesity

OBJECTIVES: To evaluate the prevalence of goiter and nodular disease in patients with class III obesity, and to correlate results with serum leptin levels and insulin resistance (IR) parameters. SUBJECTS AND METHODS: A cross-sectional study was performed to assess thyroid ultrasound (US) patterns, HOMA-IR, serum leptin, and TSH levels in obese patients and controls. RESULTS: Thyroid volume was positively correlated with body mass index (BMI) (r = 0.240, p = 0.039) and with HOMA-IR (r = 0.329; p < 0.01). Thyroid US patterns were similar between groups. However, when data from the male group was considered, greater thyroid volume was detected in the obese group compared with controls (10.8 vs. 8.5 cm³; p = 0.04). Also, nodules were more frequently detected (67% vs. 18%), as were nodules requiring FNAB (33.3% vs. 0%, p ≥ 0.05-0.09), in this group. CONCLUSION: Although IR did not correlate directly with the presence of nodules, the results support the hypothesis of a direct association between insulin resistance and thyroid volume.

Thyroid function and obesity

Nowadays, childhood obesity is one of the biggest health emergencies in the developed countries. Obesity leads to multiple metabolic alterations which increase the risk of developing diabetes and cardiovascular diseases. Thyroid function has been often described as altered in obese children, however, it is not clear whether the altered thyroid function is the cause or the consequence of fat excess. On the other hand, thyroid structure seems also to be affected. Nevertheless, both functional and structural alterations seem to improve after weight loss and therefore no treatment is needed.

Prevalence of hyperthyrotropinemia in obese children before and after weight loss

BACKGROUND

Obesity is a worldwide epidemic. In recent years, increasing attention has been focused on thyroid function in obesity.

OBJECTIVES

To establish the prevalence of elevated thyroid-stimulating hormone (TSH) levels in obese children and adolescents, and identify the relationship between TSH levels and other metabolic and hormonal variables before and after weight reduction.

MATERIALS AND METHODS

We evaluated 150 obese subjects (aged 3-17 years) for anthropometric, biochemical, metabolic and hormonal variables. Measurements were taken at baseline and, in a subgroup of children with hyperthyrotropinemia, after a 6-month intervention program based on exercise, behavior therapy, and nutrition education.

RESULTS

At baseline, 23 participants (15.3 %) had hyperthyrotropinemia, and 21 of these patients completed the weight reduction intervention. Among these 21 patients, 14 had substantial weight loss and a significant decrease in TSH and free T3 levels.

CONCLUSION

We conclude that TSH and T3 levels are significantly increased in childhood obesity; in most cases, however, these increases cannot be elucidated by thyroid autoimmunity or iodine deficiency. If thyroid disorders are excluded beforehand, an elevated TSH with normal thyroid hormone levels in obese children seems rather a consequence than a cause of obesity since weight loss leads to a normalization of elevated TSH levels. In this context, thyroid hormone alterations in obesity suggest an adaptation process.

Morbid obesity in women is associated to a lower prevalence of thyroid nodules

BACKGROUND

Few studies have recently showed functional and morphological changes of the thyroid gland in relation to obesity. To our knowledge, no data are available about the prevalence of thyroid nodules in female obese patients. The aim of this study was to investigate the prevalence of thyroid nodules in morbidly obese women.

METHODS

One hundred eight consecutive female obese patients were selected from those referred to our medical and surgery outpatients providing that following criteria were satisfied: (1) affected by morbid obesity (body mass index (BMI) >40 kg/m(2)); (2) no previous diagnosis of thyroid disease; (3) biochemically proven euthyroid state at the time of recruitment. Ninety-seven control subjects, constituted by normo-weight and/or slightly overweight (BMI ≤ 30 kg/m(2)) women, should satisfy the above criteria 2 and 3. All the subjects were submitted to ultrasound investigation.

RESULTS

The two groups of patients displayed no differences for age and fT4 levels. Obese patients clearly showed a lower prevalence of thyroid nodules [odds ratio 0.294, 95% confidence interval 0.206-0.382]. A single nodule was found in 23% of obese patients as compared to 65% of control subjects (p < 0.0001). No difference for age (year) was found between obese and non-obese subjects with nodules (40.5 ± 8.2 vs. 44.2 ± 8.9, respectively, p = 0.07).

CONCLUSIONS

Our data clearly show a significantly lower prevalence of thyroid nodules in morbidly obese patients. Further studies are needed to confirm and to understand this first observation.

Shear wave elastography in the diagnosis of thyroid nodules: feasibility in the case of coexistent chronic autoimmune Hashimoto's thyroiditis

OBJECTIVE

ShearWave™ Elastography (SWE) is real-time, quantitative and user-independent technique, recently introduced in the diagnostic work-up of thyroid nodules. Hashimoto's thyroiditis (HT), characterized by variable degrees of lymphocytic infiltration and fibrosis, might affect shear wave propagation. The aim of this study was to assess the feasibility of SWE in cytologically benign thyroid nodules within both Hashimoto's and nonautoimmune thyroid glands. The effect of autoimmunity on the gland stiffness was also evaluated.

DESIGN

longitudinal study in a single centre.

PATIENTS

SWE was performed in 75 patients with a benign thyroid nodule at cytology: 33 with Hashimoto's thyroiditis (HT group) and 42 with uni- or multi-nodular goitre, negative for thyroid autoimmunity (non-HT group).

RESULTS

The elasticity index (EI) of the extra-nodular tissue was greater, though not statistically significant, in the HT than in the non-HT group (24·0 ± 10·5 kPa vs 20·8 ± 10·4 kPa; P = 0·206). However, the EI of extra-nodular tissue was related to the TPOAb titre in the HT group (P = 0·02) and was significantly higher in patients with HT receiving L-thyroxine than in the euthyroid subjects (P = 0·02). The EI of thyroid nodules was similar in HT and non-HT groups. In both groups, the stiffness of nodules was significantly higher than that of the embedding tissue.

CONCLUSIONS

Our data indicate that SWE correctly defines the elasticity of thyroid nodules independently from the coexistence of autoimmune thyroiditis, always being able to differentiate nodular tissue from the surrounding parenchyma. In HT, the stiffness of extra-nodular tissue increases in relation to both the thyroid antibody titre and the degree of impairment of thyroid function.

Thyroid function in childhood obesity and metabolic comorbidity

Childhood obesity is a worldwide health problem and its prevalence is increasing steadily and dramatically all over the world. Obese subjects have a much greater likelihood than normal-weight children of acquiring dyslipidemia, elevated blood pressure, and impaired glucose metabolism, which significantly increase their risk of cardiovascular and metabolic diseases. Elevated TSH concentrations in association with normal or slightly elevated free T4 and/or free T3 levels have been consistently found in obese subjects, but the mechanisms underlying these thyroid hormonal changes are still unclear. Whether higher TSH in childhood obesity is adaptive, increasing metabolic rate in an attempt to reduce further weight gain, or indicates subclinical hypothyroidism or resistance and thereby contributes to lipid and/or glucose dysmetabolism, remains controversial. This review highlights current evidence on thyroid involvement in obese children and discusses the current controversy regarding the relationship between thyroid hormonal derangements and obesity-related metabolic changes (hypertension, dyslipidemia, hyperglycemia and insulin resistance, nonalcoholic fatty liver disease) in such population. Moreover, the possible mechanisms linking thyroid dysfunction and pediatric obesity are reviewed. Finally, the potential role of lifestyle intervention as well as of therapy with thyroid hormone in the treatment of thyroid abnormalities in childhood obesity is discussed.