The clinical use of thyroid function tests

Increased interleukin-9 and Th9 cells in patients with refractory Graves' disease and interleukin-9 polymorphisms are associated with autoimmune thyroid diseases

Introduction

Autoimmune thyroid diseases (AITDs) are prevalent disorders, primarily encompassing Graves' disease (GD) and Hashimoto's thyroiditis (HT). Despite their common occurrence, the etiology of AITDs remains elusive. Th9 cells, a new subset of CD4+T cells with immunomodulatory properties, have been linked to the development of various autoimmune diseases. However, research on the role of Th9 cells in AITDs is limited.

Methods

We investigated the expression of Th9 cells,their functional cytokine IL-9, and transcription factor IRF4 in peripheral blood mononuclear cells (PBMCs) and plasma of AITD patients and healthy controls. Additionally, we explored the genetic association between four loci polymorphisms (rs31564, rs2069879, rs1859430, and rs2069868) of the IL-9 gene and AITDs.

Results

We reported, for the first time, that refractory GD patients exhibited elevated mRNA levels of IL-9 and IRF4 in PBMCs, increased IL-9 protein levels in plasma, and a higher proportion of Th9 cells in peripheral blood when compared to normal controls. Furthermore, human recombinant IL-9 protein was found to enhance IFN-g secretion in PBMCs from both GD patients and normal controls. At the genetic association level, after adjusting for age and sex, the rs2069879 polymorphism exhibited a significant association with AITDs under an additive model (P<0.001, OR= 0.05, 95% CI=0.03-0.08).

Discussion

Our results reveal that Th9 cells may exert a pivotal role in the pathogenesis and progression of refractory GD and HT, and IL-9 holds promise as a novel therapeutic target for the management of AITDs.

Alteration in kynurenine pathway metabolites in young women with autoimmune thyroiditis

The kynurenine pathway (KP) of tryptophan degradation includes several compounds that reveal immunomodulatory properties. The present study aimed to investigate the alteration in KP metabolites in young women with autoimmune thyroiditis (AIT) and their associations with thyroid function. The thyroid function tests, antithyroid antibodies measurement and ultrasonography of the thyroid gland have been performed in 57 young women with AIT and 38 age-matched healthy controls. The serum levels of tryptophan, kynurenine (KYN) and its metabolites were determined, and the activity of KP enzymes was calculated indirectly as product-to-substrate ratios. KP was activated and dysregulated in AIT, along with significantly elevated levels of KYN and anthranilic acid (AA), at the expense of the reduction of kynurenic acid (KYNA), which was reflected by the increase in the AA/KYNA ratio (p < 0.001). In univariate and multiple regression analyses, peripheral deiodinase (SPINA-GD) activity in AIT was positively associated with KYNA, AA, and quinolinic acid (QA). The merger of AA, AA/KYNA ratio, QA and SPINA-GD exhibited the highest sensitivity and specificity to predict AIT (p < 0.001) in receiver operating characteristic (ROC) analysis. In conclusion, the serum KYN metabolite profile is dysregulated in young women with AIT and could serve as a new predictor of AIT risk.

Atypical Clinical Courses of Graves' Disease Confound Differential Diagnosis of Hyperthyroidism

BACKGROUND

This study examined the appropriateness of the current paradigm for differential diagnosis of painless thyroiditis and Graves' disease (GD) in patients with thyrotoxicosis.

METHODS

We retrospectively evaluated the clinical course of 343 consecutive patients with hyperthyroidism diagnosed by Tc-99m pertechnetate thyroid uptake (TcTU) testing at our hospital from January 2011 to December 2017.

RESULTS

Of the 263 patients with normal or high TcTU levels (≥1.0%), 255 (97%) had unequivocal GD and 5 had spontaneous remission GD or atypical GD. Of the 10 patients with low TcTU levels (<1.0% and ≥0.5%), 7 had GD, while others had subclinical GD, spontaneous remission GD with later relapse, and painless thyroiditis. Of those with very low TcTU levels (<0.5%), most had thyroiditis (painless thyroiditis, 33/67 [49%]; subacute thyroiditis, 29/67 [43%]), and some were positive for anti-TSH receptor antibodies.

CONCLUSION

Given that atypical GD may confound the diagnosis of thyrotoxicosis, it is essential to follow the patient as a tentative diagnosis, whatever the diagnosis. This is the first report clearly demonstrating that so far there is no gold standard for the diagnosis of GD. It is therefore urgent to establish a consensus on the definition of GD so that the specificity and sensitivity of future diagnostic tests can be determined.

The effects of metabolic indicators and immune biomarkers on pregnancy outcomes in women with recurrent spontaneous abortion: a retrospective study

Background

The etiology of recurrent spontaneous abortion (RSA) remains elusive despite specific investigations affirming the association between RSA and thyroid autoimmunity (TAI). This study explores the immunological and metabolic profiles of RSA patients exhibiting positive thyroid antibodies and their connection with the rates of first-trimester miscarriage and live births. The aim is to provide further guidance for clinical interventions.

Methods

A retrospective analysis included 478 women with RSA. Thyroid profile, thyroid peroxidase antibodies, and anti-thyroglobulin antibodies were measured in all participants. The clinical characteristics and pregnancy outcomes of RSA women were compared between thyroid autoimmunity (TAI)-positive and TAI-negative patients. Significant factors associated with adverse pregnancy outcomes and risk prediction models were explored in TAI-positive patients. Correlation analysis was used to identify specific metabolic or immune biomarkers associated with thyroid autoantibodies.

Results

The prevalence of TAI was 18.6%. Compared with women without TAI, the thyroid-stimulating hormone (TSH) concentration of TAI-positive RSA was significantly higher (2.80 ± 2.98 vs 1.89 ± 1.17, p=0.006). After 28 weeks, the live birth rate of the TAI-positive group was lower than that of the TAI-negative group, with statistical significance (p<0.05). The immune biomarkers that differed between RSA women with live births and those with first-trimester miscarriages were complement C4 and interleukin-6, respectively, in TAI-negative and TAI-positive women. Then, a risk prediction model for first-trimester miscarriage was constructed for TAI-positive women with an AUC of 0.81. Finally, some factors related to thyroid peroxidase antibody (TPO-Ab) levels were explored, and it was found that TPO-Ab levels were positively correlated with free thyroxine and negatively correlated with 25 hydroxyvitamin D, interleukin-4, and fasting blood glucose in RSA patients.

Conclusion

TAI-positive RSA patients have higher first-trimester miscarriage rates and a lower live birth rate, which may be related to metabolic immune shifts in TAI-positive RSA patients.

Simultaneous Identification of Major Thyroid Hormones by a Nickel Immobilized Biological Nanopore

Thyroid hormones (THs) are a variety of iodine-containing hormones that demonstrate critical physiological impacts on cellular activities. The assessment of thyroid function and the diagnosis of thyroid disorders require accurate measurement of TH levels. However, largely due to their structural similarities, the simultaneous discrimination of different THs is challenging. Nanopores, single-molecule sensors with a high resolution, are suitable for this task. In this paper, a hetero-octameric Mycobacterium smegmatis porin A (MspA) nanopore containing a single nickel ion immobilized to the pore constriction has enabled simultaneous identification of five representative THs including l-thyroxine (T4), 3,3',5-triiodo-l-thyronine (T3), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (3,5-T2) and 3,3'-diiodo-l-thyronine (3,3'-T2). To automate event classification and avoid human bias, a machine learning algorithm was also developed, reporting an accuracy of 99.0%. This sensing strategy is also applied in the analysis of TH in a real human serum environment, suggesting its potential use in a clinical diagnosis.

Distinct patterns of auto-reactive antibodies associated with organ-specific immune-related adverse events

The roles of preexisting auto-reactive antibodies in immune-related adverse events (irAEs) associated with immune checkpoint inhibitor therapy are not well defined. Here, we analyzed plasma samples longitudinally collected at predefined time points and at the time of irAEs from 58 patients with immunotherapy naïve metastatic non-small cell lung cancer treated on clinical protocol with ipilimumab and nivolumab. We used a proteomic microarray system capable of assaying antibody reactivity for IgG and IgM fractions against 120 antigens for systemically evaluating the correlations between auto-reactive antibodies and certain organ-specific irAEs. We found that distinct patterns of auto-reactive antibodies at baseline were associated with the subsequent development of organ-specific irAEs. Notably, ACHRG IgM was associated with pneumonitis, anti-cytokeratin 19 IgM with dermatitis, and anti-thyroglobulin IgG with hepatitis. These antibodies merit further investigation as potential biomarkers for identifying high-risk populations for irAEs and/or monitoring irAEs during immunotherapy treatment.

Trial registration

ClinicalTrials.gov identifier: NCT03391869.

Effects of aerobic, resistance, and combined training on thyroid function and quality of life in hypothyroidism. A randomized controlled trial

PURPOSE

This study aimed to compare the effects of aerobic, resistance, and combined exercises on thyroid function, lipid profile, exercise capacity, and quality of life (QoL) in hypothyroid women.

METHODS

Sixty women aged 35 to 45 with clinical hypothyroidism were randomized to four equal groups: aerobic training (AT), resistance training (RT), combined AT/RT, and control groups. All exercises were performed at low to moderate intensity, three days per week, and for 12 weeks. Patients in all groups were on levothyroxine therapy. Outcome measures were free thyroxin (T4), thyroid stimulating hormone (TSH), lipid profile, estimated maximal oxygen consumption (VO2 max) and QoL assessed by the 12-item Short Form (SF-12) Health Survey.

RESULTS

All exercise groups showed significant improvements in all outcome measures compared to the baseline and the controls (p < 0.05). The combined AT/RT group showed more significant improvements in TSH and the mental component summary score of the SF-12 compared to the AT and RT groups (p < 0.05). The AT group showed the most significant improvement in estimated VO2 max, followed by the combined AT/RT and then the RT group. Non-significant differences were found between exercise groups in T4, blood lipids, and the physical component summary score of the SF-12 (p > 0.05).

CONCLUSION

In women with hypothyroidism on levothyroxine treatment, all AT, RT, and combined AT/RT could equally improve T4 levels, lipid profile, and physical health-related QoL. However, the combined AT/RT could induce the greatest improvements in TSH and mental health-related QoL, while the AT could have the greatest impact on exercise capacity in these patients.

TRIAL REGISTRATION

Pan African Clinical Trial Registry (PACTR), retrospective, PACTR202305810673587.

Structural and functional differences in auto-antibody positive compared to auto-antibody negative hypothyroid patients with chronic thyroiditis

Most primary hypothyroidism in adults is caused by chronic thyroiditis. Autoantibodies such as anti-thyroglobulin antibody (TgAb) and anti-thyroid peroxidase antibody (TPOAb) are involved in the pathogenesis of chronic thyroiditis. On the other hand, the clinical features of antibody-negative hypothyroidism are not clear. In this study, we aimed to determine the prevalence of thyroid-related autoantibodies in patients with primary hypothyroidism and to evaluate the differences in thyroid structure between antibody-positive and antibody-negative hypothyroidism. Among 804 patients who attended Kawasaki Medical School Hospital for thyroid hormone abnormalities or thyroid gland enlargement between January 1, 2010 and December 31, 2021, 237 patients with primary hypothyroidism who underwent thyroid antibody measurement and thyroid ultrasound examination were included. Participants were divided into groups according to antibody positivity/negativity, and differences in antibody positivity and thyroid structure were evaluated. In this study, 34.6% of patients had antibody-negative hypothyroidism. The positive rate of each antibody was 62.0% for TgAb and 49.4% for TPOAb. The participants with antibody-positive hypothyroidism had significantly larger thyroid gland on thyroid ultrasound examination (p < 0.05). Thyroid-stimulating hormone was significantly higher in participants with antibody-positive compared to antibody-negative hypothyroidism. The present study reveals a positive rate of thyroid-related autoantibodies in patients with hypothyroidism and the differences in thyroid structure between patients with and without antibodies. This study clearly show that the prevalence of antibody-negative chronic thyroiditis is quite high among hypothyroid patients, although this point needs confirmation by further investigations. The data in this study would be useful for the treatment of antibody-negative hypothyroid patients.

Exposure of Akwesasne Mohawk women to polychlorinated biphenyls and hexachlorobenzene is associated with increased serum levels of thyroid peroxidase autoantibodies

Persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorodiphenyltrichloroethane (p,p'-DDT) were reported to influence immunological activity. As endocrine-disrupting chemicals (EDC), these pollutants may disrupt normal thyroid function and act as catalysts for development of autoimmune thyroid disease by directly and indirectly affecting levels of thyroid peroxidase antibodies (TPOAbs). Native American communities are disproportionately exposed to harmful toxicants and are at an increased risk of developing an autoimmune disease. The aim of this study was to determine the association between POPs and TPOAbs in serum obtained from Native American women. This assessment was used to measure whether increased risk of autoimmune thyroid disease occurred as a result of exposure to POPs. Data were collected from 183 Akwesasne Mohawk women, 21-38 years of age, between 2009 and 2013. Multivariate analyses were conducted to determine the association between toxicant exposure and levels of TPOAbs. In multiple logistic regression analyses, exposure to PCB congener 33 was related to elevated risk of individuals possessing above normal levels of TPOAbs. Further, HCB was associated with more than 2-fold higher risk of possessing above normal levels of TPOAbs compared to women with normal levels of TPOAbs. p,p'-DDE was not associated with TPOAb levels within this study. Exposure to PCB congener 33 and HCB was correlated with above normal levels of TPOAbs, a marker of autoimmune thyroid disease. Additional investigations are needed to establish the causes and factors surrounding autoimmune thyroid disease which are multiple and complex.

Evaluation of the diagnostic performance of thyroid-stimulating immunoglobulin and thyrotropin receptor antibodies for Graves' disease

OBJECTIVE

To evaluate thyroid-stimulating immunoglobulin (TSI) and thyrotropin receptor antibodies (TRAb) diagnostic performance for Graves' disease (GD) and determine clinical cut-off value for diagnosing GD.

METHODS

Of 1369 retrospectively enrolled subjects, 1364 had a definitive diagnosis of untreated GD (GD-UT, n = 87); treated GD (GD-T, n = 206); autoimmune thyroid disease (AIT, n = 241); thyroid nodules (TN, n = 677); subacute thyroiditis (ST, n = 28); healthy subjects (HS, n = 125); other diseases with serological hyperthyroidism (n = 5) and were grouped into the following: UT-GD and control groups (AIT, TN, ST, and HS); and UT-GD and non-GD hyperthyroidism groups. Diagnostic performance of TSI and TRAb was evaluated using area under the curve (AUC) of receiver-operating characteristic (ROC) curve, and optimal clinical cut-off value was determined using maximization of Youden index.

RESULTS

TRAb AUC and clinical cut-off value for diagnosing GD were 0.981 and 1.245 IU/L (sensitivity, 96.6%; specificity, 97.1%; positive predictive value [PPV], 71.8%; negative predictive value [NPV], 99.9%; positive likelihood ratio [PLR], 33.31; negative likelihood ratio [NLR, 0.035), respectively, for the GD-UT and control groups. Those for TSI were 0.992 and 0.467 IU/L (sensitivity 98.8%; specificity, 96.4%; PPV, 68.8%; NPV, 99.9%; PLR, 27.472; NLR, 0.011). Those for TRAb in GD-UT and non-GD hyperthyroidism groups were 0.923 and 1.78 IU/L (sensitivity, 92.0%; specificity, 89.1%; PPV, 93%; NPV, 87.5%; PLR, 8.44; NLR, 0.089), respectively. For TSI, these were 0.92 and 0.545 IU/L (sensitivity, 97.7%; specificity, 83.6%; PPV, 90.4%; NPV, 95.8%; PLR27.472, NLR, 0.011), respectively.

CONCLUSION

TSI diagnostic performance for GD was excellent and had better sensitivity than TRAb.

The Clinical Implications of Anti-thyroid Peroxidase Antibodies in Graves’ Disease in Basrah

Background Graves' disease (GD) is an autoimmune disease, with thyrotropin receptor antibodies (TRAbs) being the most important cause in the pathogenesis. The aim of this study is to assess the clinical significance of anti-TPO Abs in GD. Methods A retrospective study was conducted at the Faiha specialized Diabetes, Endocrine, and Metabolism Center (FDEMC) in Basrah during the period between December 2021 and December 2022. A total of 141 patients with GD were involved in this study, and of them, 97 (68.8%) were women. They were divided into two groups: patients with positive and negative anti-TPO Abs groups. Results Positive anti-TPO Abs were seen in 83 patients (58.9%) with GD. Pretreatment-free thyroxine level (ng/dL) was higher in the anti-TPO Abs positive GD patients than in those with negative antibodies (3.7±0.2 versus 3.0±0.2 with a p=0.021). Similarly, higher TRAb titers (IU/ml) at baseline were also seen in patients with positive anti-TPO Abs (9.8±0.7 versus 6.8±0.8) with a p=0.008. Giraffe appearance on thyroid ultrasound was more common in the group with positive anti-TPO Abs as compared to patients with negative anti-TPO Abs: 20 (87.0%) versus 3 (13.0%) with a p=0.005. A higher anti-TPO Abs titer (IU/mL) was associated with a baseline TRAb level of more than 6.4 IU/mL, and giraffe appearance on thyroid ultrasound (206.5±20.0 p-value<0.0001 and 228.0±35.3 p value=0.007, respectively). Conclusion A positive anti-TPO Abs in GD is associated with a high TRAb titer and free T4 level at baseline, as well as a giraffe appearance on thyroid ultrasound.

Choosing which in-hospital laboratory tests to target for intervention: a scoping review

INTRODUCTION

Some laboratory testing practices may be of low value, leading to wasted resources and potential patient harm. Our scoping review investigated factors and processes that developers report using to inform decisions about what tests to target for practice improvement.

METHODS

We searched Medline on May 30th, 2019 and June 28th, 2021 and included guidelines, recommendation statements, or empirical studies related to test ordering practices. Studies were included if they were conducted in a tertiary care setting, reported making a choice about a specific test requiring intervention, and reported at least one factor informing that choice. We extracted descriptive details, tests chosen, processes used to make the choice, and factors guiding test choice.

RESULTS

From 114 eligible studies, we identified 30 factors related to test choice including clinical value, cost, prevalence of test, quality of test, and actionability of test results. We identified nine different processes used to inform decisions regarding where to spend intervention resources.

CONCLUSIONS

Intervention developers face difficult choices when deciding where to put scarce resources intended to improve test utilization. Factors and processes identified here can be used to inform a framework to help intervention developers make choices relevant to improving testing practices.

Thyroid autoantibodies

Thyroid-stimulating hormone (TSH) receptor antibody (TSH-R-Ab or TRAb) testing plays a pivotal role in arriving at the aetiological diagnosis in patients with thyrotoxicosis. A positive test establishes the diagnosis of Graves' disease (GD) while a negative result in conjunction with imaging studies supports other possible aetiologies. In patients with GD, TRAb levels at diagnosis and at the time of withdrawal of antithyroid drugs can identify patients who are unlikely to achieve remission and guide clinical management decisions. We provide an algorithm that incorporates TRAb in the decision-making process for the management of thyrotoxicosis. The utility of TRAb in predicting the risk of fetal and neonatal thyroid dysfunction is established and widely accepted in guidelines. TRAb may also help in the diagnosis of Graves' orbitopathy, especially in euthyroid or hypothyroid patients and its role in guiding its management is evolving as a useful adjunct to the clinical parameters used in making therapeutic decisions.Anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) indicate thyroid autoimmunity. The most common use of TPOAb is to identify patients at a higher risk of progression to treatment-requiring hypothyroidism. They also aid the diagnosis of immune thyroiditis and Hashimoto's encephalopathy. Thyroglobulin measurement is used to help guide differentiated thyroid cancer treatment. TgAb is used as an accompanying test with thyroglobulin measurement as its presence can interfere with the thyroglobulin assay. A negative TgAb result reduces the likelihood of, but does not exclude, interference with thyroglobulin assay.

Oxidative stress in Hashimoto's thyroiditis: possible adjuvant therapies to attenuate deleterious effects

A number of studies have shown that oxidative stress is related to the pathogenesis of several immunological diseases, such as Hashimoto's thyroiditis (HT), although there is no plausible mechanism to explain it. Thus, we aimed at hypothesizing and providing some possible mechanisms linking oxidative stress to autoimmunity aspects and its implications for HT, as well as adjuvant therapeutic proposals to mitigate the deleterious effects. Our hypothesis is that deficient eating habits, autoimmune regulator gene predisposing gene, dysbiosis and molecular mimicry, unfolded proteins and stress in the endoplasmic reticulum, and thymus involution appear to be the main potential factors leading to HT oxidative stress. Likewise, we show that the use of minerals selenium and zinc, vitamins D and C, as well as probiotics, can be interesting adjuvant therapies for the control of oxidative damage and poor prognosis of HT. Further clinical trials are needed to understand the real beneficial and side effects of these supplements.

Minor perturbations of thyroid homeostasis and major cardiovascular endpoints—Physiological mechanisms and clinical evidence

It is well established that thyroid dysfunction is linked to an increased risk of cardiovascular morbidity and mortality. The pleiotropic action of thyroid hormones strongly impacts the cardiovascular system and affects both the generation of the normal heart rhythm and arrhythmia. A meta-analysis of published evidence suggests a positive association of FT4 concentration with major adverse cardiovascular end points (MACE), but this association only partially extends to TSH. The risk for cardiovascular death is increased in both subclinical hypothyroidism and subclinical thyrotoxicosis. Several published studies found associations of TSH and FT4 concentrations, respectively, with major cardiovascular endpoints. Both reduced and elevated TSH concentrations predict the cardiovascular risk, and this association extends to TSH gradients within the reference range. Likewise, increased FT4 concentrations, but high-normal FT4 within its reference range as well, herald a poor outcome. These observations translate to a monotonic and sensitive effect of FT4 and a U-shaped relationship between TSH and cardiovascular risk. Up to now, the pathophysiological mechanism of this complex pattern of association is poorly understood. Integrating the available evidence suggests a dual etiology of elevated FT4 concentration, comprising both ensuing primary hypothyroidism and a raised set point of thyroid function, e. g. in the context of psychiatric disease, chronic stress and type 2 allostatic load. Addressing the association between thyroid homeostasis and cardiovascular diseases from a systems perspective could pave the way to new directions of research and a more personalized approach to the treatment of patients with cardiovascular risk.

Relationship Between Thyroid Autoantibodies and Recurrence of Papillary Thyroid Carcinoma in Children and Adolescents

Background

Numerous studies reported connection between papillary thyroid carcinoma (PTC) and thyroid autoantibody in adults, but few of them have investigated whether there is a similar link in children and adolescents. The purpose of this research was to explore the relationship between clinicopathological features, prognosis and preoperative thyroid peroxidase antibody (TPOAb) as well as thyroglobulin antibody (TgAb) status in children and adolescents with PTC.

Methods

This study retrospectively reviewed 179 patients of PTC who underwent a thyroidectomy from January 2000 to June 2021 at Tianjin Medical University Cancer Hospital. We compared preoperative TgAb and TPOAb status with the clinicopathological features and prognosis of children and adolescents with PTC in different age groups.

Results

Patients with positive preoperative TPOAb and TgAb had lower recurrence rate in the younger group (P = 0.006, 0.047, respectively). Patients with positive TPOAb preoperatively had normal level of preoperative Tg and less cervical LNM than patients with negative TPOAb in children and adolescents (P < 0.05). Positive TPOAb preoperatively of PTC patients had a longer median DFS (113.4 months) than negative TPOAb (64.9 months) (P = 0.009, log-rank). Univariate analyses showed age, maximal tumor size, T stage, multifocality, lateral LNM and N staging were predictors for cancer recurrence in children and adolescents (P<0.05). Cox regression analysis found younger age (HR 0.224, P < 0.001), lateral LNM (HR 0.137, P = 0.010), N stage (HR 30.356, P < 0.001) were independent risk factors for recurrence.

Conclusions

Our study found that presence of preoperative TPOAb and TgAb could serve as novel prognostic factors for predicting recurrence of PTC in children.

A U-shaped association between serum albumin with total triiodothyronine in adults

BACKGROUND

Thyroid dysfunction is a common thyroid disorder in our life and its symptoms are non-specific, therefore the diagnosis of thyroid dysfunction is important for patients. Albumin (ALB) can carry thyroid hormones to their sites of action as a way to achieve rapid delivery of thyroid hormones to the tissues. The purpose of this study was to investigate the relationship between serum ALB levels and total triiodothyronine (TT3) in adults.

METHODS

Data from the 2007-2012 National Health and Nutrition Examination Survey (NHANES) were used to examine the association between ALB and TT3 using multivariate logistic regression models. Fitting smoothed curves and generalized weighted models were also used.

RESULTS

The analysis included a total of 7933 participants that we found an independent positive relationship between ALB and TT3 among participants [0.006 (0.003, 0.009)]. In men, there was a significant positive correlation between ALB and TT3, whereas in women ALB and TT3 suggested a significant negative correlation. Moreover, our study revealed that the independent association between the levels of ALB and TT3 was significant in Non-Hispanic White, but not in Non-Hispanic Black. Notably, we found a U-shaped association between ALB and serum TT3 in total participants (inflection point for ALB: 41 g/L) and females after adjusted covariates (inflection point for ALB: 46 g/L).

CONCLUSIONS

We found a U-shaped relationship between serum ALB and TT3 with infection point at 41 g/L for ALB, which may provide a reference for future screening in adults with thyroid dysfunction.

Spectrum of thyroid function test among type 2 diabetic patients attending a rural health facility, southwest Nigeria: A hospital-based study

Objectives:

The thyroid gland produces hormones that have significant influence on carbohydrate metabolism; its disorders may affect carbohydrate metabolism in type 2 diabetic patients (T2DM) more than the non-diabetic (NDM) patients as reported in various studies. We determined the spectrum of thyroid function tests (TFTs) profile among T2DM in our rural health facility.

Methods:

T2DM patients and NDM patients were recruited for the study. The age, educational level, occupation, marital status, and duration of diabetes were extracted from interviewer’s administered questionnaire. The weight, height, body mass indices (BMIs), and the waist and hip circumferences were measured. Waist-hip ratios (WHR) were calculated for all participants. Venous blood was collected and assayed for free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) using a Chemiluminescence Immunoassay (CLIA) 2nd Generation Autoanalyzer. The mean, standard deviation, frequencies, and percentages were calculated for the variables. The student’s t-test and chi-square test were also determined as appropriate.

Results:

Seventy-eight patients made up of 56 T2DM and 22 NDM were evaluated in this study. Fifty-one were males while 27 were females; 67.9% and 59.1% of the female participants were T2DM and NDM, respectively. The WHR was significantly higher in T2DM than NDM (0.92 ± 0.05 versus 0.88 ± 0.06). The TSH was higher in T2DM than the NDM. Forty-four (78.6%) of the T2DM had euthyroid (normal) biochemical pattern; 12 (21.4%) showed abnormal biochemical pattern of euthyroid sick syndrome, subclinical hyperthyroid, and subclinical hypothyroid. Thirty (53.6%) of the T2DM were diagnosed less than five years ago. The value of TSH was increasing with the duration of diabetes but not in a statistically significant way. None of the T2DM showed overt hypothyroid or hyperthyroid test result.

Conclusion:

Thyroid function test may identify diabetics with altered thyroid hormone status that may impact on their metabolic control. Knowledge of the functional state of the thyroid gland can help in achieving a better metabolic control and attenuate the development of complications in T2DM.

Preoperative Thyroid Peroxidase Antibody Predicts Recurrence in Papillary Thyroid Carcinoma: A Consecutive Study With 5,770 Cases

Background

Thyroid autoimmunity is common in papillary thyroid carcinoma (PTC) and was believed to confer a better prognosis; however, controversy still remains. This study aimed to investigate the prognostic value of chronic lymphocytic thyroiditis (CLT) and preoperative thyroid peroxidase antibody (TPOAb) in PTC patients.

Methods

A retrospective analysis was performed on 5,770 PTC patients who underwent surgical treatment with pathologically confirmed PTC in our institution between 2012 to 2016. The patients were divided into groups with respect to the coexistence of CLT or preoperative TPOAb levels. The clinicopathological characteristics and disease-free survival (DFS) rates were compared between the groups.

Results

The coexistence of CLT was likely to have bilateral, multifocal tumors. Particularly, PTC patients with TPOAb++ (&gt;1,000 IU/L) had a larger tumor size (p = 0.007) and higher rates of bilaterality and multifocality than those with TPOAb− (TPOAb&lt; 100 IU/L), while for lymph node metastasis and extrathyroidal extension, there is no statistical difference. Tumor recurrence was found in 15 of 425 (3.5%), 9 of 436 (2.1%), and 56 of 3,519 (1.6%) patients with TPOAb++, TPOAb+, and TPOAb−, respectively (p = 0.017). On univariate analysis, TPOAb++ was correlated with tumor recurrence, with a hazard ratio of 2.20 [95% confidence interval (CI), 1.25–3.89], which remained as an independent risk factor at 1.98 (95% CI, 1.10–3.55) on multivariate analysis. PTC patients with TPOAb++ had the lowest DFS rates (96.5 vs. 97.9 vs. 98.4%, p = 0.020).

Conclusion

CLT is not a protective factor in PTC patients. We provide initial evidence that the preoperative TPOAb instead predicts recurrence in papillary thyroid carcinoma.

Effect of occupational cadmium exposure on the thyroid gland and associated inflammatory markers among workers of the electroplating industry

Cadmium (Cd) is widespread throughout the environment and is used in the electroplating industry. It has been found to have an effect on the endocrine system. However, its effects and their underlying mechanisms are still not clear. The aim of this study was to evaluate how cadmium exposure at work affected the levels of thyroid hormones and the associated inflammatory and oxidative markers. This study was conducted in an electroplating industry in Cairo, Egypt. Ninety male cadmium-exposed workers were matched with 90 male unexposed participants. A detailed questionnaire was designed and given to every participant in the study, and full clinical examinations were carried out. Blood samples were collected from all participants for determination of levels of serum cadmium, thyroid hormones, anti-thyroid peroxidase antibody (anti-TPO), interleukin-6 (IL-6), malondialdehyde (MDA), and tumor necrosis factor-alpha (TNF-α). Morning midstream urine samples were obtained to measure urine cadmium levels. Results showed that the total blood and urinary cadmium levels were significantly higher in the exposed group (2.38 ± 0.94 μg/L and 5.45 ± 1.92 μg/g creatinine, respectively) than in the unexposed group. The serum levels of anti-TPO antibody, TSH, MDA, IL-6, and TNF-α also were significantly higher in the cadmium-exposed group than in the unexposed group. Significant direct relationships were seen between the biological indices of cadmium exposure and anti-TPO antibodies, TSH, IL-6, TNF-α, and MDA. It was concluded that there is a link between occupational cadmium exposure and autoimmune hypothyroidism, inflammatory, and oxidative stress markers.

Epidemiological survey of the status of iodine nutrition and thyroid diseases in Guangxi, China

OBJECTIVE

To survey the status of iodine nutrition and the prevalence of thyroid diseases in Guangxi, China, and to explore the risk factors for positive thyroid antibody.

METHODS

We used the multistage stratified cluster random sampling method to select a total of 2488 subjects from an urban and a rural location. All the subjects completed a questionnaire survey, blood and urine samples were also collected, and B-mode thyroid ultrasound was used to determine thyroid function and detect thyroid antibodies.

RESULTS

1) The median level of urinary iodine was 148.53 μg/L in school-age children in Guangxi, China. 2) The prevalence rates for thyroid diseases were as follows: hyperthyroidism, 0.89 %; subclinical hyperthyroidism, 1.05 %; hypothyroidism, 0.69 %; and subclinical hypothyroidism, 8.87 %. The rates of thyroid antibody positivity were as follows: thyroid peroxidase antibody (TPOAb), 13.60 %; thyroglobulin antibody (TGAb), 13.60 %; thyroid antibodies, 18.2 %; and thyroid nodules, 16.94 %. 3) The rate of TPOAb positivity was significantly higher in women aged 18-29, 30-39, 40-49, or 60-69 years than in men in the same age groups (P < 0.05), and the TGAb positivity rate was significantly higher in women than in men of the same age group (P < 0.05). 4) The rate of thyroid antibody positivity was significantly higher in individuals with iodine deficiency than in individuals with adequate iodine (21.6 % vs 18.4 %) or excess iodine (21.6 % vs 15.5 %) (both P < 0.05). 5) The female sex and a family history of thyroid diseases were the major risk factors for thyroid antibody positivity (odds ratio [OR] 3.010, P <0.05; OR 2.486, P <0.05).

CONCLUSION

The overall level of iodine is adequate in Guangxi, China; this level should be maintained to prevent the thyroid diseases related with iodine deficiency or excess of iodine. Female sex and a family history of thyroid diseases are independent risk factors for thyroid antibody positivity.

Mistaken Identity: The Role of Autoantibodies in Endocrine Disease

BACKGROUND

Autoimmune endocrine diseases can be thought of as a case of mistaken identity. The immune system mistakenly attacks one's own cells, as if they were foreign, which typically results in endocrine gland hypofunction and inadequate hormone production. Type 1 diabetes mellitus and autoimmune thyroid disorders (Hashimoto and Graves diseases) are the most common autoimmune endocrine disorders, while conditions such as Addison disease are encountered less frequently. Autoantibody production can precede clinical presentation, and their measurement may aid verification of an autoimmune process and guide appropriate treatment modalities.

CONTENT

In this review, we discuss type 1 diabetes mellitus, autoimmune thyroid disorders, and Addison disease, emphasizing their associated autoantibodies and methods for clinical detection. We will also discuss efforts to standardize measurement of autoantibodies.

CONCLUSIONS

Autoimmune endocrine disease progression may take months to years and detection of associated autoantibodies may precede clinical onset of disease. Although detection of autoantibodies is not necessary for diagnosis, they may be useful to verify an autoimmune process.

IgG Subclass Analysis in Patients with Chagas Disease 4 Years After Benznidazole Treatment

BACKGROUND

In humans, Trypanosoma cruzi infection is controlled by a complex immune response. Immunoglobulin G (IgG) is important for opsonizing blood trypomastigotes, activating the classic complement pathway, and reducing parasitemia. The trypanocidal activity of benznidazole is recognized, but its effects on the prevention and progression of Chagas disease is not well understood OBJECTIVE: We aimed to evaluate the levels of total IgG and cross-specific IgG subclasses in patients with chronic Chagas disease of different clinical forms before and after 4 years of benznidazole treatment.

METHODS

Eight individuals with the indeterminate form and nine with the cardiac form who completed the treatment protocol were evaluated. The levels of total IgG and IgG1, IgG2, IgG3, and IgG4 isotypes were quantified in the serum of each individual using the fluorescent immunosorbent assay. The results are expressed as relative fluorescence unit.

RESULTS

Patients with chronic Chagas disease presented decreased levels of total IgG at 48 months after benznidazole treatment. Increased IgG1 and decreased IgG3 levels were observed in patients with the cardiac form and those with exacerbated clinical forms. In addition, a decrease in the IgG3/IgG1 ratio was observed in individuals with the cardiac form of Chagas disease.

CONCLUSIONS

Benznidazole administration in the chronic phase differentially changes IgG subclasses in patients with cardiac and indeterminate forms, and monitoring the IgG3 level may indicate the possible prognosis to the cardiac form or worsening of the already established clinical form.

Relation Between Zinc and Thyroid Hormones in Humans: a Systematic Review

The aim of this study was to systematically evaluate the relation between zinc and the thyroid hormones in humans. The search for articles was conducted using the Pubmed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and ScienceDirect databases on October 21 and 22, 2019, by two authors independently. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed in the conduct of this review. The Cochrane Collaboration tool was used to assess the risk of bias of the trials included in this review. After the screening of the articles, eight studies that assessed the effects of zinc supplementation on thyroid hormone concentrations and ten studies that assessed the relationship between blood zinc concentrations and thyroid hormones were included in this systematic review. Although cross-sectional and case-control studies have shown a relationship between zinc deficiency and thyroid, the data from this systematic review provides inconclusive evidence with respect to the effects of zinc supplementation on thyroid hormone concentrations due to the divergence of the research found by the authors that only reports findings in patients suffering from some kind of disease, which cannot be generalized to the average human population.

Antithyroid Peroxidase Antibodies and Histopathological Outcomes in Egyptian Patients Subjected to Total Thyroidectomy for Non-Malignant Nodular Goiter

Objective

The study aimed to assess antithyroid antibodies in patients with benign thyroid masses and the effect of total thyroidectomy on the antibodies titers.

Patients and Methods

This is a retrospective work of 112 cases managed with total thyroidectomy with positive antithyroid peroxidase antibodies (TPO-Ab), anti-thyroglobulin antibodies (Tg-Ab), or both. All patients were euthyroid before surgery. Thyroid function tests and thyroid antibodies levels were measured before and 6 and 12 months after surgery.

Results

Histopathological evaluation revealed Hashimoto thyroiditis (47.3%), colloid nodules (22.3%), and lymphocytic thyroiditis (30.4%). All patients were TPO-Ab positive, while 96 patients (85.7%) were Tg-Ab positive before surgery. There was no considerable change in TPO-Ab and Tg-Ab after surgery (p = 0.817, and p=0.560, respectively). Also, there was no significant difference between the three histopathological diagnoses in the levels of TPO-Ab (p = 0.086) or Tg-Ab (p = 0.673).

Conclusion

Antithyroid antibodies are not valuable markers for diagnosis or prognosis of benign thyroid diseases subjected to total thyroidectomy. We do not recommend their use beyond supporting evidence of the possibility of the autoimmune nature of the illness if other criteria are confirmed.

Profiling retrospective thyroid function data in complete thyroidectomy patients to investigate the HPT axis set point (PREDICT-IT)

BACKGROUND

The homeostatic euthyroid set point of the hypothalamus-pituitary-thyroid axis of any given individual is unique and oscillates narrowly within substantially broader normal population ranges of circulating free thyroxine (FT4) and thyroid-stimulating hormone (TSH), otherwise termed 'thyroid function test (TFT)'. We developed a mathematical algorithm codenamed Thyroid-SPOT that effectively reconstructs the personalized set point in open-loop situations and evaluated its performance in a retrospective patient sample.

METHODS

We computed the set points of 101 patients who underwent total thyroidectomy for non-functioning thyroid disease using Thyroid-SPOT on each patient's own serial post-thyroidectomy TFT. Every predicted set point was compared against its respective healthy pre-operative euthyroid TFT per individual and their separation (i.e. predicted-observed TFT) quantified.

RESULTS

Bland-Altman analysis to measure the agreement between each pair of an individual's predicted and actual set points revealed a mean difference in FT4 and TSH of + 3.03 pmol/L (95% CI 2.64, 3.43) and - 0.03 mIU/L (95% CI - 0.25, 0.19), respectively. These differences are small compared to the width of the reference intervals. Thyroid-SPOT can predict the euthyroid set point remarkably well, especially for TSH with a 10-16-fold spread in magnitude between population normal limits.

CONCLUSION

Every individual's equilibrium euthyroid set point is unique. Thyroid-SPOT serves as an accurate, precise and reliable targeting system for optimal personalized restoration of euthyroidism. This algorithm can guide clinicians in L-thyroxine dose titrations to resolve persistent dysthyroid symptoms among challenging cases harbouring "normal TFT" within the laboratory ranges but differing significantly from their actual euthyroid set points.

Performance Evaluation of Thyroid Function Tests on a Novel Chemiluminescent Microparticle Immunoassay System

BACKGROUND

The Alinity i system (Abbott), a recently developed automated immunoassay analyzer, has a compact footprint and a throughput of 200 tests per hour. Here, we present the first performance evaluation of thyroid function test (TFT) on the Alinity i system.

METHODS

We performed precision, linearity, comparison, functional sensitivity, carryover, and reference interval verification of 4 hormones (Thyroid Stimulation Hormone; TSH, total T3, free T4, and total T4) using the reagents provided by the manufacturer following the guidelines of the Clinical Laboratory Standards Institute. The performance of Alinity i was compared to that of the Architect i2000 immunoassay analyzer (Abbott, US).

RESULTS

The within-laboratory coefficients of variation for all the hormones were 1.6-3.6%. Linearity was observed for all the hormones over the entire tested analytical range (R2 ≥ 0.99). The results for all the evaluated hormones using Alinity i system strongly correlated (r ≥ 0.978) with those from Architect i2000. Functional sensitivity was lower than the lower limit of the analytical measurement range. Sample carryover was less than 1.0%.

CONCLUSIONS

TFTs on the Alinity i system showed acceptable performance in terms of precision, linearity, comparison, functional sensitivity, and carryover. Therefore, this system could be a useful laboratory tool for performing TFTs.

Paraclinical serum markers as aids in the diagnosis of autoimmune encephalitis

Expert opinion suggests the presence ANA and thyroid antibodies may be helpful to diagnosis autoimmune encephalitis (AE). This study investigates the sensitivity of these serum markers in a cohort of 26 patients with AE. TPO-Ab, TG-Ab and ANA (titer ≥1:320) were present in 45%, 35% and 32% of patients tested, respectively. The prevalence of TPO-Ab (11.3%), TG-Ab (10.4%) and ANA ≥1:320 (3.3%) has been previously reported in disease-free populations. Although these antibodies represent non-specific markers of autoimmunity, this study demonstrated that TPO-Ab, TG-Ab and ANA were significantly elevated in AE compared to disease-free populations (p < .001, p = .003, p < .001, respectively).

Biochemical pattern of thyroid function test and clinical impression of thyroid disorder in a rural tertiary health institution in Nigeria

Background

Thyroid disorders are one of the most common endocrine disorders seen globally. Diagnostic challenge may arise both clinically and biochemically because of the multiple function of thyroid hormones (THs). Request for thyroid function test (TFT s) may be based on clinical impression that may suggest thyroid dysfunction or obvious symptoms and signs that are diagnostic of hyperthyroidism or hypothyroidism.

Materials and Methods

This retrospective study looks at the biochemical patterns of TFTs and the clinical impression of thyroid disorders in a rural tertiary institution. Information extracted from the laboratory register includes indication for the test, the hospital number, the gender, the age, and the THs assayed. The corresponding biochemical pattern of the TFT result was established.

Results

A total of 297 requests were submitted for TH assay; 34 were excluded from the present study because there were no clinical information. There were 239 females and 24 males giving a female-to-male ratio of 9.9:1. Majority of the requests (36.5%) were for goiters, followed by gynecological disorders (20.9%) and clinical thyroid disorders (17.9%). About 46% (45.8%) of the goiter cases were biochemically euthyroid, whereas 13.5% were biochemically primary hyperthyroid. Among the 47 cases of thyroid disorders by the physician's clinical impression, 27.7% were euthyroid, 17% were biochemically hyperthyroid, and 10.6% were hypothyroid. Of the 55 gynecological disorders assessed, only 7.3% show biochemical evidence of TH alteration with 56.4% being euthyroid. About 47% (46.6%) of those that did routine medical examination had altered TH level that includes hyperthyroidism and hypothyroidism.

Conclusion

Goiter is the most prevalent thyroid disorder in this environment. Biochemical pattern of thyroid function test in our environment was mostly euthyroid despites clinical features suggestive of thyroid disorders.

Thyroid Hormone Tests Ordering Practice and Cost-Effectiveness in Samples Referred to International Clinical Laboratories from Addis Ababa Health Facilities

Background

Thyroid dysfunction accounts for majority of endocrine disorders. In sub-Saharan Africa Graves' disease and hypothyroidism have accounted for 13.1% and 8.8% while the burden of thyroid disorder has ranged from 6.18 to47.34% among countries in the Arab world. The cost for a primary thyroid test done to evaluate the gland function constituted a large proportion of the public health budget. For instance, 10 million thyroid functions have been done each year by laboratories which cost 30 million UK pounds, and they represent 8% of laboratory charge in the US. When a TSH-only protocol (guideline) was used, 95% of the requests were sufficient for diagnosis without requiring further tests, thereby resulting in 50% savings on FT4 reagent and reducing the annual TFT reagent cost by 25%. This is an original study, and its objective was to assess the ordering pattern of TSH tests and their cost-effectiveness in patients' samples referred to ICL from Addis Ababa health facilities between July2015 to June 2016.

Method

An institution-based cross-sectional study design was utilized to study the ordering pattern of thyroid function tests using one-year retrospective data from ICL.

Results

Thyroid profiles were ordered more frequently (49.5%) compared to TSH only (24.3%). An additional 2625.70 USD was paid by patients for individual components in the profile tests that turned out normal.

Conclusion

Guidelines advocate TSH as the initial test for thyroid dysfunction, but the use of a combination of tests is more common.

A remarkable case of thyrotoxicosis initially caused by graves' disease followed by a probable TSHoma - a case report

BACKGROUND

Graves' disease is the commonest cause of thyrotoxicosis whilst thyrotropin (TSH)-producing pituitary adenomas (thyrotropinomas, TSHomas) are very rare and account for just 1-2% of all pituitary adenomas. Coexistence of a TSHoma and Graves' disease has been very rarely reported. Here, we report a case of a patient whose initial presentation with primary thyrotoxicosis due to Graves' disease, was subsequently followed by a relapse of thyrotoxicosis due to a probable TSHoma.

CASE

A sixty-eight year old woman was referred to our department with classical features of thyrotoxicosis. Initial biochemistry confirmed hyperthyroxinaemia [free thyroxine (fT4) 20.4 pmol/L (reference range 7.0-16.0)] and a suppressed TSH [< 0.02mIU/L (0.50-4.20)]. A technetium pertechnetate uptake scan was consistent with Graves' Disease. She was treated with carbimazole for 18 months and remained clinically and biochemically euthyroid. After stopping carbimazole her fT4 started to rise but TSH remained normal. Laboratory assay interference was excluded. A TRH stimulation test demonstrated a flat TSH response and pituitary MRI revealed a microadenoma. Remaining pituitary hormones were in the normal range other than a slightly raised IGF-1. An ¹¹C-methionine PET/CT scan coregistered with volumetric MRI (Met-PET-MRI^CR) demonstrated high tracer uptake in the left lateral sella region suggestive of a functioning adenoma. The patient declined surgery and was unable to tolerate cabergoline or octreotide. Thereafter, she has elected to pursue a conservative approach with periodic surveillance.

CONCLUSION

This is a very unusual case of thyrotoxicosis caused by two different processes occurring in the same patient. It highlights the importance of considering dual pathology when previously concordant thyroid function tests become discordant. It also highlights a potential role of Met-PET-MRI^CR in the localisation of functioning pituitary tumours.

Predicting response and toxicity to PD-1 inhibition using serum autoantibodies identified from immuno-mass spectrometry

Background: Validated biomarkers are needed to identify patients at increased risk of immune-related adverse events (irAEs) to immune checkpoint blockade (ICB). Antibodies directed against endogenous antigens can change after exposure to ICB. Methods: Patients with different solid tumors stratified into cohorts received pembrolizumab every 3 weeks in a Phase II trial (INSPIRE study). Blood samples were collected prior to first pembrolizumab exposure (baseline) and approximately 7 weeks (pre-cycle 3) into treatment. In a discovery analysis, autoantibody target immuno-mass spectrometry was performed in baseline and pre-cycle 3 pooled sera of 24 INSPIRE patients based on clinical benefit (CBR) and irAEs. Results: Thyroglobulin (Tg) and thyroid peroxidase (TPO) were identified as the candidate autoantibody targets. In the overall cohort of 78 patients, the frequency of CBR and irAEs from pembrolizumab was 31% and 24%, respectively. Patients with an anti-Tg titer increase ≥1.5x from baseline to pre-cycle 3 were more likely to have irAEs relative to patients without this increase in unadjusted, cohort adjusted, and multivariable models (OR=17.4, 95% CI 1.8-173.8, p=0.015). Similarly, patients with an anti-TPO titer ≥ 1.5x from baseline to pre-cycle 3 were more likely to have irAEs relative to patients without the increase in unadjusted and cohort adjusted (OR=6.1, 95% CI 1.1-32.7, p=0.035) models. Further, the cohort adjusted analysis showed patients with anti-Tg titer greater than median (10.0 IU/mL) at pre-cycle 3 were more likely to have irAEs (OR=4.7, 95% CI 1.2-17.8, p=0.024). Patients with pre-cycle 3 anti-TPO titers greater than median (10.0 IU/mL) had a significant difference in overall survival (23.8 vs 11.5 months; HR=1.8, 95% CI 1.0-3.2, p=0.05). Conclusions: Patient increase ≥1.5x of anti-Tg and anti-TPO titers from baseline to pre-cycle 3 were associated with irAEs from pembrolizumab, and patients with elevated pre-cycle 3 anti-TPO titers had an improvement in overall survival.

Associations of Elevated Antithyroperoxidase Antibodies with Thyroid Function, Survival, Functioning, and Depressive Symptoms in the Oldest Old: The Leiden 85-plus Study

Background: Elevated levels of antithyroperoxidase antibodies (TPOAbs) have been associated with progression of subclinical thyroid dysfunction, extrathyroidal diseases, and decrease in functional status. However, TPOAb as determinant of future thyroid dysfunction and other clinical outcomes has not been studied well for adults aged 85 years and over. This study aimed to assess associations of TPOAb levels with thyroid function, survival, physical function, disability in activities of daily living (ADL), cognitive function, and depressive symptoms in the oldest old. Methods: Data from a population-based cohort study (Leiden 85-plus Study) of residents of Leiden, the Netherlands, aged 85 and older were used. Baseline serum TPOAb levels were available for 488 participants (82% of the total cohort). We considered levels ≥35 IU/mL as elevated. Thyroid function (thyrotropin [TSH] and free thyroxine) was assessed at age 85 (baseline), 87, and 88 years. Survival, physical function, disability in ADL, cognitive function, and depressive symptoms were assessed from age 85 through 90 years. Results: At baseline, 64 of the 85-year old participants (13.1%) had elevated TPOAb levels. They were more often female, had higher TSH levels, and a higher prevalence of overt or subclinical hypothyroidism than participants with normal TPOAb levels. Over time, elevated TPOAb levels were independently associated with a lower mortality risk (hazard ratio 0.72, [95% confidence interval 0.53-0.99]), but were not associated with changes in thyroid function, nor with physical function, disability in ADL, cognitive function, or depressive symptoms. Conclusions: In community-dwelling oldest old, elevated TPOAb levels are cross-sectionally associated with higher TSH levels. Over time, elevated TPOAb levels are associated with a survival benefit but are not associated with changes in thyroid function, functional status, or depressive symptoms in old age. The added clinical value of TPOAb tests in oldest old persons with thyroid dysfunction is limited.

Individualised requirements for optimum treatment of hypothyroidism: complex needs, limited options

Levothyroxine (LT4) therapy has a long history, a well-defined pharmacological profile and a favourable safety record in the alleviation of hypothyroidism. However, questions remain in defining the threshold for the requirement of treatment in patients with subclinical hypothyroidism, assessing the dose adequacy of the drug, and selecting the best treatment mode (LT4 monotherapy versus liothyronine [LT3]/LT4 combinations) for subpopulations with persisting complaints. Supplied as a prodrug, LT4 is enzymatically converted into the biologically more active thyroid hormone, triiodothyronine (T3). Importantly, tetraiodothyronine (T4) to T3 conversion efficiency may be impaired in patients receiving LT4, resulting in a loss of thyroid-stimulating hormone (TSH)-mediated feed-forward control of T3, alteration of the interlocking equilibria between serum concentrations of TSH, free thyroxine (FT4), and free triiodothyonine (FT3), and a decrease in FT3 to FT4 ratios. This downgrades the value of the TSH reference system derived in thyroid health for guiding the replacement dose in the treatment situation. Individualised conditionally defined setpoints may therefore provide appropriate biochemical targets to be clinically tested, together with a stronger focus on clinical presentation and future endpoint markers of tissue thyroid state. This cautionary note encompasses the use of aggregated statistical data from clinical trials which are not safely applicable to the individual level of patient care under these circumstances.

Antithyroid Peroxidase Antibodies in Multinodular Hashimoto's Thyroiditis Indicate a Variant Etiology

Introduction

Hashimoto's thyroiditis (HT) is a common autoimmune thyroid disorder, which predominantly presents as a diffuse goiter, with few studies which report HT presenting as multinodular goiter, with variable frequencies ranging from 59% to 78.6% especially from south Indian populations. This variant clinical presentation may have diagnostic challenges which require further analysis. Anti-TPO antibodies are more common (90-95%) in Hashimoto's thyroiditis than anti-TG antibodies in Hashimoto's thyroiditis. This study analyzes the clinical features and the correlation of anti-TPO levels with diffuse and multinodular forms of HT.

Material and Methods

This study was conducted in the Department of General Surgery in a tertiary care hospital in south Tamil Nadu. Patients presenting with clinical features of a thyroid disorder were interviewed and given a detailed clinical, radiological examination and guided FNAC. Those patients diagnosed by FNAC as HT were registered and a sample of 3cc of blood was drawn for T3, T4, TSH, and anti-TPO analysis. All the data were tabulated.

Results and Discussion

Of the 212 patients who presented with goiters, 96 were diagnosed by FNAC as having a cytological picture suggestive of Hashimoto's thyroiditis. Of these 96 patients with HT, 46 (47.9%) were multinodular (HT-MNG), 14 (14.58%) were solitary nodules (HT-SNT), and the remaining 36 (37.5%) were diffuse goiters (HT-D). Of the 46 patients who are HT-MNG, 36.9% had elevated anti-TPO-Ab (more than 35.0U/l) and 63.1% had normal/lower values (less than 35.0U/l). But of 36 patients with HT-D, 77.7% had elevated anti-TPO-Ab levels (>35U/l). Chi square statistics was 15.8346 and the p value is 0.0005 (<.05). Eight cases of HT-D and 3 cases of HT-MNG had hyperthyroidism and 3 cases of HT-D had hypothyroidism and all other cases were in euthyroid state.

Conclusion

Patients presenting as multinodular Hashimoto's thyroiditis have low prevalence of elevated anti-TPO-Ab than diffuse HT which suggests that multinodular form of Hashimoto's thyroiditis is a unique clinical entity with etiopathogenesis that is at variance with the diffuse form.

Effects of exposure to ethanolic extract from Achyrocline satureioides (Lam.) D.C. flowers on reproductive and developmental parameters in Wistar rats

Achyrocline satureioides (LAM) D.C. is a species plant used in folk medicine with several medicinal properties; however, few studies have focused on its potential adverse effects. The aim of this study was to examine the effects of ethanolic extract of A. satureioides flowers administered during pre-mating, mating, pregnancy and postpartum period on reproductive and developmental parameters in rats. Male and female rats received by gavage 0, 250, 500 or 750 mg/kg of extract. The animals were treated from pre-mating until 13 days post-partum. Phytochemical analysis revealed the presence of important flavonoids (quercetin, luteolin, caffeic acid, rutin, and ferulic acid). In females, biochemical, hematological or gestational parameters were not markedly altered by the extract. However, an increase in calcium and thyroid stimulating hormone (TSH) levels was found in treated-dams. Although TSH and T4 levels were not significantly altered in pups, there was a rise in body weight of pups whose mothers were treated with the extract. All males treated were able to successfully copulate with treated-females. However, rats exposed to 500 and 750 mg/kg of extract exhibited a significant decrease in daily testicular sperm production and delay in sperm transit time in the epididymis. The ethanolic extract of A. satureioides flowers produced adverse effects in the male reproductive system as evidenced by diminished sperm production and transport. In addition, the extract elevated TSH levels of exposed mothers which may consequently affect the development of pups but this requires further evaluation.

Time trends of thyroglobulin antibody in ablated papillary thyroid carcinoma patients: Can we predict the rate of negative conversion?

OBJECTIVES

Persistence of thyroglobulin antibody (TgAb) in patients with papillary thyroid carcinoma (PTC) years after total thyroidectomy (TT) followed by ablation occurs even without any evidence of structural disease. Few studies have studied the natural course of TgAb positivity and factors that may influence this course. The present study evaluated the time trends of TgAb in ablated PTC patients and aimed to identify the predictive factors for the rate of negative conversion of TgAb.

MATERIALS AND METHODS

Overall, 1279 patients who underwent TT and subsequent ablation for PTC, with available data on thyroid peroxidase Ab (TPOAb) and TgAb prior to surgery (preop-) and ablation (abl-) were enrolled. Patients with initial distant metastasis or recurrence during follow-up were excluded.

RESULTS AND CONCLUSION

Preop-TgAb was positive in 24.9% of patients (n = 319), whereas abl-TgAb positivity decreased to 12.8% (n = 164). In 164 patients positive for abl-TgAb, TgAb in patients with higher abl-TgAb levels decreased more gradually than those observed in patients with lower abl-TgAb levels (p < 0.001). Furthermore, in patients within the same range of abl-TgAb levels, patients positive for abl-TPOAb had a higher rate of negative conversion of TgAb compared with negative patients for abl-TPOAb (log rank p < 0.001). TPOAb significantly increased the rate of negative conversion in multivariate analysis adjusted for abl-TgAb (odds ratio 1.59, 95% confidence interval 1.11-2.28, p = 0.011). This study clearly showed that abl-TgAb titers and abl-TPOAb status can predict the rate of negative conversion. These findings can guide the optimal timing for additional examination in patients positive for TgAb during follow-up.

Subclinical Thyroid Dysfunction was not Associated with Cardiac Arrhythmias in a Cross-Sectional Analysis of the ELSA-Brasil Study

Background

The association of subclinical thyroid dysfunction (STD) with cardiac arrhythmias remains controversial, particularly in the non-elderly population.

Objective

To investigate whether STD was associated with cardiac arrhythmias in a cohort of middle-aged and older adults.

Methods

Baseline data of the Longitudinal Study of Adult Health, ELSA-Brasil (35-74 years) were collected from 2008 to 2010. After exclusion of clinical hypothyroidism and hyperthyroidism, participants were categorized as euthyroidism (TSH = 0.4-4.0 µU/mL), subclinical hypothyroidism (TSH > 4.0 µU/mL; FT4 = 0.8-1.9 ng/dL), and subclinical hyperthyroidism (TSH < 0.4 µU/mL; FT4 = 0.8-1.9 ng/dL). The prevalence rates of tachycardia (HR > 100) and bradycardia (HR < 60), atrial fibrillation/flutter, conduction disorders, extrasystoles, low QRS voltage, prolonged QT intervals, and persistent supraventricular rhythms were compared between groups after adjusting for age, sex, comorbidities, lifestyle, body mass index and medications.

Results

The HR data of 13,341 participants (52% female; median age, 51 years) and the electrocardiogram readings of 11,795 were analyzed; 698 participants (5.23%) were classified as subclinical hypothyroidism, 193 (1.45%) as subclinical hyperthyroidism, and 12,450 (93.32%) as euthyroidism. The prevalence of rhythm and conduction disorders was similar, as were HR medians, even in the subgroups with TSH < 0.01 UI/mL or > 10.0 UI/mL or in older adults. Conduction disorders were less prevalent in older adults with subclinical hypothyroidism (adjusted OR = 0.44; 95% CI 0.24 to 0.80).

Conclusion

In this large, multicenter and cross-sectional study, STD was not associated with cardiac arrhythmias, but a longitudinal assessment is necessary.

Selective screening for thyroid dysfunction in pregnant women: How often do low-risk women cease to be treated following the new guidelines of the American Thyroid Association?

OBJECTIVE

Universal screening for thyroid dysfunction in pregnant women is not recommended by the American Thyroid Association (ATA) or the American Association of Clinical Endocrinologists (AACE). This study evaluated the frequency of pregnant women that would have an indication for levothyroxine (L-T4) according to the new ATA/AACE guidelines among low-risk women without an indication for screening with TSH.

SUBJECTS AND METHODS

The sample consisted of 412 pregnant women ranging in age from 18 to 30 years. These women were considered to be at low risk for thyroid dysfunction according to ATA/AACE and would not be candidates for screening with TSH. Anti-thyroid peroxidase antibodies (TPOAb) and TSH were measured. Women who had TSH > 2.5 mIU/L or TPOAb in the first trimester were submitted to subsequent evaluations in the second and third trimester.

RESULTS

In the first trimester, none of the pregnant women would have L-T4 therapy "recommended" and treatment would be "considered" in only two. In the second trimester, pregnant women with positive TPOAb or TSH > 2.5 mIU/L in the first trimester (n = 30) were reevaluated. L-T4 treatment would be "recommended" in only one woman and would be "considered" in two others. The 28 women that were not treated in the second trimester were reevaluated in the third trimester, but none of them would have L-T4 "recommended".

CONCLUSION

The findings of the study suggest that selective screening, recommended by ATA/AACE does not result in a significant loss of pregnant women with an indication for L-T4 treatment.

Hypothyroidism as a Predictor of Surgical Outcomes in the Elderly

There is a high prevalence of hypothyroidism in the elderly population, mainly among women. The most important cause is autoimmune thyroiditis, but also iodine deficiency, radioiodine ablation, and surgery may be responsible for hypothyroidism in elderly hospitalized patients. Thyroid-related symptoms are sometimes comparable to physiological manifestations of the aging process, and hypothyroidism may be related with many symptoms which can be present in critical patients, such as cognitive impairment, cardiovascular, gastrointestinal, and hematological alterations, and eventually myxedema coma which is a severe and life-threatening condition in older adults. Adequate thyroid hormone levels are required to achieve optimal outcomes from any kind of surgical intervention. However, only few randomized clinical trials investigated the association between non-thyroidal illness (or low-T3 syndrome), and adverse surgical outcomes, so far. The goal of this review is to discuss the role of thyroid function as a predictor of surgical outcomes in the elderly.

Thyroid function test reference ranges in the first trimester of gestation and pregnancy outcomes: Protocol and preliminary results for cohort population-based study Isfahan, Iran

Background:

This paper presents the protocol and primary findings of pregnancy cohort population-based study in Isfahan, Iran.

Materials and Methods:

In this cohort, 418 pregnant and 438 nonpregnant women were enrolled. In the first phase, serum concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody, and urinary iodine concentration (UIC) were measured. Furthermore, the thyroid ultrasound was also performed. According to the results of thyroid function tests in the first phase, local reference range for TSH, FT4, and FT3 in pregnant and nonpregnant women are determined. The 2.5^th and 97.5^th percentiles are determined as limits of the reference ranges. In the second phase, all pregnant women underwent prenatal care visits in each trimester and they followed for 7 days after delivery and the pregnancy outcomes data are reported.

Results:

The mean ± standard deviation for TSH, FT4, FT3, and UIC in the first trimester of gestation was 1.84 ± 1.32 mIU/L, 1.01 ± 0.15 ng/dL, 4.50 ± 0.64 pmol/L, and 172.0 ± 90.29 μg/L, respectively. In nonpregnant women, these values for TSH, FT4, FT3, and UIC were 2.58 ± 1.77 mIU/L, 1.10 ± 0.21 ng/dL, 4.49 ± 0.57 pmol/L, and 190.0 ± 109.6 μg/L, respectively.

Conclusion:

The results of the present study could contribute to establish a local thyroid function tests reference ranges in the first trimester of pregnancy. It could possibly be effective on making a local reference value to prevent of thyroid disease misdiagnosis during pregnancy and adverse pregnancy outcomes.

Serum TSH level stability after 5 years in euthyroid adults at low risk for thyroid dysfunction

OBJECTIVE

To evaluate changes in thyroid function after 5 years, the interval proposed for new assessment, in initially euthyroid adults.

SUBJECTS AND METHODS

Initially, 1,426 apparently healthy adults considered low risk for thyroid dysfunction, were evaluated by measurement of TSH. After 5 years, 1,215 (85.2%) subjects were reevaluated.

RESULTS

After 5 years, four subjects were receiving levothyroxine (L-T4) replacement therapy and 25 others had TSH > 4 mIU/L, only two of them with TSH > 10 mIU/L. All of these subjects had TSH > 3 mIU/L in the initial evaluation. During reassessment, none of the subjects had been or was treated for hyperthyroidism and 22 had TSH < 0.4 mIU/L (none of them < 0.1 mIU/L). Nineteen of these subjects had TSH ≤ 0.6 mIU/L in the initial evaluation. Among the 1,098 subjects with TSH between 0.6 and 3 mIU/L in the initial evaluation, reassessment showed that none of the subjects was using L-T4; only three had TSH > 4 mIU/L (none of them > 10 mIU/L); none had been or was treated for hyperthyroidism, and only three had TSH < 0.4 mIU/L (none of them < 0.1 mIU/L). These results did not differ between men and women or between subjects ≤ 60 and > 60 years.

CONCLUSION

Repeat TSH measurement within an interval of only 5 years would not be cost-effective in adults without known thyroid disease or risk factors for dysfunction who exhibit TSH between 0.6 and 3 mIU/L.

Subclinical Changes in Maternal Thyroid Function Parameters in Pregnancy and Fetal Growth

CONTEXT

Overt thyroid disease in pregnancy is a known risk factor for abnormal fetal growth and development. Data on the effects of milder forms of variation in maternal thyroid function on intrauterine growth are less well examined.

OBJECTIVE

We explored these associations using repeated thyroid hormone and ultrasound measurements.

DESIGN, SETTING, AND PARTICIPANTS

Data were obtained from 439 pregnant women without diagnosed thyroid disease who were participants in a case-control study of preterm birth nested within an ongoing prospective birth cohort in Boston, Massachusetts.

MAIN OUTCOME MEASURES

Ultrasound and delivery indices of fetal growth were standardized to those measured in a larger population.

RESULTS

At median 10, 18, and 26 weeks of gestation, we observed significant inverse associations between free thyroxine (FT4) and birth weight z scores, with the strongest association detected at median 10 weeks, at which time a 10% increase in FT4 was associated with a 0.02 z score decrease (∼8.5 g) in birth weight (β = -0.41 for ln-transformed FT4; 95% confidence interval, -0.64 to -0.18). FT4 was also inversely associated with repeated measurements of estimated fetal weight, head circumference, and abdominal circumference. We observed weaker inverse associations for total T4 and a positive relationship between total triiodothyronine and birth weight z scores. We did not observe any associations for thyroid-stimulating hormone.

CONCLUSION

In pregnant women without overt thyroid disease, subclinical changes in thyroid function parameters may influence fetal growth.

The effect of anti-thyroid antibodies positivity on children with primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is the most common cause of acquired thrombocytopenia in children. Anti-thyroid antibodies (aTA) have previously been found to be present in various autoimmune diseases. Our aim was to study the effect of aTA positivity (which are anti-thyroid peroxidase (aTPo) and/or anti-thyroglobulin (aTg)) on children with primary immune thrombocytopenia and their relation to treatment response. Sixty-one children with primary ITP were enrolled in the present study. They were further subdivided into: ND&P group (newly diagnosed and persistent) and chronic ITP group. Seventy-five apparently healthy children were enrolled as control group. aTPo and aTg antibodies were significantly higher and more frequently positive in all children with ITP and in each ITP group than the control group (P <.05 in all). But, there were no statistically significant differences between the two ITP subgroups (P >.05). aTA positive children with ITP had significantly lower platelet count: at the start of treatment (P =.009), after receiving methylprednisolone or intravenous immunoglobulin (P =.02) and at one month follow-up (P =.003) than aTA negative children with ITP. Lastly, aTA positive children had more relapses (P =.03), continued more frequently to have relapses after one year in the ND&P group (P =.02) and required immunosuppressive therapy more frequently in the chronic ITP group (P =.005).

Thyroid Autoimmunity: Role of Anti-thyroid Antibodies in Thyroid and Extra-Thyroidal Diseases

Autoimmune diseases have a high prevalence in the population, and autoimmune thyroid disease (AITD) is one of the most common representatives. Thyroid autoantibodies are not only frequently detected in patients with AITD but also in subjects without manifest thyroid dysfunction. The high prevalence raises questions regarding a potential role in extra-thyroidal diseases. This review summarizes the etiology and mechanism of AITD and addresses prevalence of antibodies against thyroid peroxidase, thyroid-stimulating hormone receptor (TSHR), and anti-thyroglobulin and their action outside the thyroid. The main issues limiting the reliability of the conclusions drawn here include problems with different specificities and sensitivities of the antibody detection assays employed, as well as potential confounding effects of altered thyroid hormone levels, and lack of prospective studies. In addition to the well-known effects of TSHR antibodies on fibroblasts in Graves' disease (GD), studies speculate on a role of anti-thyroid antibodies in cancer. All antibodies may have a tumor-promoting role in breast cancer carcinogenesis despite anti-thyroid peroxidase antibodies having a positive prognostic effect in patients with overt disease. Cross-reactivity with lactoperoxidase leading to induction of chronic inflammation might promote breast cancer, while anti-thyroid antibodies in manifest breast cancer might be an indication for a more active immune system. A better general health condition in older women with anti-thyroid peroxidase antibodies might support this hypothesis. The different actions of the anti-thyroid antibodies correspond to differences in cellular location of the antigens, titers of the circulating antibodies, duration of antibody exposure, and immunological mechanisms in GD and Hashimoto's thyroiditis.

Treatment of Thyroid Dysfunctions Decreases the Risk of Cerebrovascular Events in Men but Not in Women: Results of the MONICA/KORA Cohort Study

OBJECTIVE

Thyroid disorders are well known to be associated with cardiovascular diseases. Some studies have shown that the negative effects of thyroid disorders are partially reversible after adequate treatment. The aim of this analysis was to assess the risk of incident ischemic cerebrovascular diseases in study participants treated for thyroid dysfunctions in a population-based cohort study.

METHODS

For the presented analyses data from 8564 male and 8714 female individuals aged 25 to 74 years of the MONICA/KORA cohort were used (median follow-up 14.0 years). A combined binary variable "thyroid disorder" (TDC) was created utilizing data on self-reported physician-treated thyroid disorders and information about medication use. To examine the association between TDC and incident ischemic cerebrovascular events, we performed multiple adjusted Cox proportional hazard regression models and calculated hazard ratios and corresponding 95% confidence intervals (HR, 95%CI).

RESULTS

During follow-up between 1984 and 2008/2009, 514 incident fatal and non-fatal ischemic cerebrovascular events occurred in men and 323 in women. At baseline, 3.5% of men and 15.6% of women reported TDC. In the fully adjusted model, males who reported TDC had a significantly reduced risk of ischemic cerebrovascular events (HR = 0.52, 95%CI = 0.29-0.92). A similar result was obtained in men, when we utilized information on thyroid hormones use only. For the total study population and for women with TDC we found no association with ischemic cerebrovascular events.

CONCLUSIONS

In our longitudinal analyses subjects with treated thyroid diseases had no increased risk of incident ischemic cerebrovascular events. Surprisingly in males, even a significantly reduced risk of incident ischemic cerebrovascular events was found, a result that deserves further clarification.

Selenium and its relationship with selenoprotein P and glutathione peroxidase in children and adolescents with Hashimoto's thyroiditis and hypothyroidism

The essential trace element selenium (Se) is required for thyroid hormone synthesis and metabolism. Selenoproteins contain selenocysteine and are responsible for biological functions of selenium. Glutathione peroxidase (GPx) is one of the major selenoproteins which protects the thyroid cells from oxidative damage. Selenoprotein P (SePP) is considered as the plasma selenium transporter to tissues. The aim of this study was to evaluate serum Se and SePP levels, and GPx activity in erythrocytes of children and adolescents with treated Hashimoto's thyroiditis, hypothyroidism, and normal subjects. Blood samples were collected from 32 patients with Hashimoto's thyroiditis, 20 with hypothyroidism, and 25 matched normal subjects. All the patients were under treatment with levothyroxine and at the time of analysis all of the thyroid function tests were normal. GPx enzyme activity was measured by spectrophotometry at 340 nm. Serum selenium levels were measured by high-resolution continuum source graphite furnace atomic absorption. SePP, TPOAb (anti-thyroid peroxidase antibody), and TgAb (anti-thyroglobulin antibody) were determined by ELISA kits. T4, T3, T3 uptake and TSH were also measured. Neither GPx activity nor SePP levels were significantly different in patients with Hashimoto's thyroiditis or hypothyroidism compared to normal subjects. Although GPx and SePP were both lower in patients with hypothyroidism compared to those with Hashimoto's thyroiditis and normal subjects but the difference was not significant. Serum Se levels also did not differ significantly in patients and normal subjects. We did not find any correlation between GPx or SePP with TPOAb or TgAb but SePP was significantly correlated with Se. Results show that in patients with Hashimoto's thyroiditis or hypothyroidism who have been under treatment with levothyroxine and have normal thyroid function tests, the GPx, SePP and Se levels are not significantly different.

MECHANISMS IN ENDOCRINOLOGY: Impact of isolated TSH levels in and out of normal range on different tissues

Routine treatment of thyroid cancer (TC) includes long-term suppression of TSH. The necessity of this treatment in low- and intermediate-risk patients as well as the extent of TSH suppression is currently under discussion. A literature search was performed to illustrate the role of TSH in extrathyroidal cells and to identify potential reasons for different effects of exogenously suppressed and endogenously low TSH levels. Although adverse effects of subnormal and supranormal TSH blood levels on heart and brain have not been consistently found, studies show a clear negative effect of suppressed TSH levels on bone mineral density. Experimental data also support an important role of TSH in the immune system. The ability of levothyroxine (l-T4) to regulate TSH levels and triiodothyronine levels in a physiological manner is limited. Reduction of circadian changes in TSH levels, decrease of thyroid hormone-binding proteins, prevention of potential compensatory increases of TSH levels (e.g., in old age), and unresponsiveness of TSH-producing cells to TRH on l-T4 treatment might cause adverse effects of suppressed TSH levels. In view of the adverse effects of aggressive TSH suppression, achieving the suggested levels of TSH between 0.9 and 1 mU/l in the treatment of low-to-intermediate risk TC patients appears justified.