Iodine and thyroid status during pregnancy and risk of stillbirth: A population-based nested case-control study

Prior research suggests that severe iodine deficiency in pregnancy may be associated with stillbirth. However, the relationship between mild to moderate iodine insufficiency, which is prevalent even in developed countries, and risk of stillbirth is unclear. We thus examined associations of iodine status and risk of stillbirth in a prospective population‐based nested case–control study in Finland, a mild to moderately iodine insufficient population. Stillbirth cases (n = 199) and unaffected controls (n = 249) were randomly selected from among all singleton births in Finland from 2012 to 2013. Serum samples were collected between 10 and 14 weeks gestation and analysed for iodide, thyroglobulin (Tg) and thyroid‐stimulating hormone (TSH). Odds ratios (ORs) and 95% confidence intervals (CIs) for stillbirth were estimated using logistic regression. After adjusting for maternal age, prepregnancy body mass index, socio‐economic status and other factors, neither high nor low serum iodide was associated with risk of stillbirth (Q1 vs. Q2–Q3 OR = 0.92, 95% CI = 0.78–1.09; Q4 vs. Q2–Q3 OR = 0.78; 95% CI = 0.45–1.33). Tg and TSH were also not associated with risk of stillbirth in adjusted models. Maternal iodine status was not associated with stillbirth risk in this mildly to moderately iodine‐deficient population. Tg and TSH, which reflect functional iodine status, were also not associated with stillbirth risk. The lack of associations observed between serum iodide, TSH and Tg and risk of stillbirth is reassuring, given that iodine deficiency in pregnancy is prevalent in developed countries.

Functions of the Thyroid-Stimulating Hormone on Key Developmental Features Revealed in a Series of Zebrafish Dyshormonogenesis Models

The hypothalamic–pituitary–thyroid (HPT) axis regulates many critical features in vertebrates. Utilizing TALENs and CRISPR/Cas9 techniques, thyroid-stimulating hormone subunit beta a (tshba), thyroglobulin (tg), and solute carrier family 16 member 2 (slc16a2) mutant zebrafish lines were generated. Among the three mutants, the earliest time point for the significantly altered T3 contents was observed in tshba mutants, which resulted in the most severe defects, including typical defects such as the retardation of inflated anterior swimming bladder (aSB), proper formation of fin ray and posterior squamation (SP), the larval-to-juvenile transition (LTJT) process, juvenile growth retardation, and mating failure. In tg mutants, which are actually compensated with an alternative splicing form, growth retardation was observed in the juvenile stage without LTJT and reproductive defects. The evident goiter phenotype was only observed in tg- and slc16a2 mutants, but not in tshba mutants. Other than goiters being observed, no other significant developmental defects were found in the slc16a2 mutants. Regarding the reproductive defects observed in tshba mutants, the defective formation of the secondary sex characteristics (SSCs) was observed, while no obvious alterations during gonad development were found. Based on our analyses, zebrafish at the 6–12 mm standard length or 16–35 days post-fertilization (dpf) should be considered to be in their LTJT phase. Using a series of zebrafish dyshormonogenesis models, this study demonstrated that the TSH function is critical for the proper promotion of zebrafish LTJT and SSC formation. In addition, the elevation of TSH levels appears to be essential for goiter appearance in zebrafish.

Serum TSH levels are associated with postoperative recurrence and lymph node metastasis of papillary thyroid carcinoma

OBJECTIVE

To explore the relationship between thyroid-stimulating hormone (TSH) levels in the serum and postoperative recurrence and lymph node metastasis (LNM) in papillary thyroid cancer (PTC) patients after surgery.

METHODS

We selected 272 patients diagnosed with PTC from June 2011 to July 2014. The clinical and pathological data of 272 PTC patients were collected at the First Affiliated Hospital of Wenzhou Medical University and analysed retrospectively. All PTC patients were tested for the BRAF^V600E gene mutation before surgery by fine-needle aspiration (FNA) cytology, and TSH levels in the serum were determined one month after surgery. The optimal cut-off value of thyroid-stimulating hormone (TSH) for predicting the recurrence or metastasis of PTC after surgery was determined by the establishment of a receiver operating characteristic (ROC) curve. Kaplan-Meier and Cox regression analyses were used to evaluate the correlation between the optimal cut-off value of TSH and disease-free survival rate and prognosis.

RESULTS

Of 272 patients, only 182 (73 BRAF^V600E+, 109 BRAF^V600E-) met the final study criteria. Among them, 60 cases had recurrence or metastasis, and 122 cases were controls. The optimal cut-off value of TSH for the prediction of recurrence or metastasis of PTC after surgery was 2.615 mlU/L. In our study, a high TSH level (> 2.615 mlU/L) was correlated with the BRAF^V600E mutation, multifocality, lymph node metastasis, recurrence, and metastasis. In all 182 patients, those with high TSH levels had worse disease-free survival. This result was more obvious in the 73 BRAF^V600E+ patients. The univariate analysis showed that lymph node metastasis, multifocality, lymph node dissection, tumour size, sex, BRAF^V600E mutation, and a high postoperative TSH level were all significantly correlated with recurrence or metastasis in PTC patients (all P < 0.05). In addition, the Cox multivariate analysis showed that lymph node metastasis, BRAF^V600E mutation, and high postoperative TSH levels were independent risk factors for PTC recurrence or metastasis (all P < 0.05).

CONCLUSION

PTC patients with high TSH levels (> 2.615 mlU/L) have worse disease-free survival, which is more obvious in the BRAF^V600E+ population.

Patterns of Bodyweight Changes in Patients With Hypothyroidism, a Retrospective Study From Basrah, Southern Iraq

Background

Weight gain is one of the most important hypothyroidism-related concerns in patients with hypothyroidism. However, unexpectedly, levothyroxine replacement does not necessarily result in body weight (BWT) reduction among those patients. The study aimed to assess the patterns of BWT changes through time in patients with hypothyroidism.

Method

In a retrospective database study from Faiha Specialized Diabetes, Endocrine, and Metabolism Center, a total of 346 adult patients with hypothyroidism (192 newly diagnosed and 154 known hypothyroidism patients) who had one visit every three months, five visits in one year were included. Of these, 116 new and 69 known hypothyroidism patients had completed nine visits in two years. Each visit involved thyroid-stimulating hormone (TSH) and BWT measurements. Patients with chronic liver or renal disease, diabetes mellitus, thyroid cancer, or other malignancies, pregnancy, and steroid or hormonal therapies were excluded. The patients were further subdivided based on average TSH levels into controlled (TSH ≤ 4.2 μIU/ml) and uncontrolled (TSH > 4.2 μIU/ml). Repeated measures analysis of variance (ANOVA) with a Greenhouse-Geisser correction and post hoc tests using the Bonferroni correction were used to evaluate TSH and BWT changes through the study.

Results

Both in newly diagnosed and known hypothyroidism patients with an average TSH > 4.2 μIU/mL, BWT increased significantly through visits over one and two years. For newly diagnosed patients assessed over one year (F(2.41, 321.60) = 3.28, p = 0.03), the mean BWT increase was 1.4 ± 0.38 kg from 3rd to 12th month visits (p = 0.004). For newly diagnosed patients assessed over two years (F(3.10, 263.89) = 9.08, P < 0.0005), the mean BWT increase was 3.02 ± 0.77 kg from 3rd to 24th month visits (p = 0.007). For patients with known hypothyroidism assessed over one year (F(2.56, 187.47) = 7.11, p = 0.0003), the mean BWT increase was 1.97 ± 0.64 kg at 12th month visit, and over two years (F(2.35, 77.56) = 4.67, P = 0.009), the mean BWT increase was 3.78 ± 1.26 kg at 24th month visit. While in all other patients with an average TSH ≤ 4.2 μIU/mL, the BWT changed non-significantly through the visits for newly diagnosed patients over one year and two years (p = 0.10, 0.34, respectively), and known patients over one year and two years (p = 0.47, 0.34, respectively).

Conclusion

Contrary to what is believed, adequate treatment with levothyroxine does not associate with weight reduction. Instead, either the patient kept on the same weight or continued to gain more weight.

Changes in serum thyroid hormone levels in psychiatric patients treated with second-generation antipsychotics

INTRODUCTION

The objective of the study was to evaluate changes in serum thyroid hormone levels in psychiatric patients after second-generation antipsychotic (SGA) treatment, and to determine differences between monotherapy and polytherapy with SGAs, as well as differences between patients with and without a history of antipsychotics.

MATERIAL AND METHODS

A total of 71 patients with baseline thyroid hormone levels within the normal reference ranges were included in this retrospectively study.

RESULTS

After SGAs treatment, the serum levels of free triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine (TT3), and total thyroxine (TT4) significantly decreased, and serum thyroid-stimulating hormone (TSH) levels significantly increased (changes from baseline: FT3: -0.31 pmol/L, p < 0.001; FT4: -2.71 pmol/L, p < 0.001; TT3: -0.05 nmol/L, p = 0.024, TT4: -12.36 nmol/L, p < 0.001; TSH: 0.46 mIU/L, p < 0.001). One (1.4%) patient had TSH levels higher than 7 mIU/L. Changes in serum levels of TSH and TT3 between patients with or without a history of antipsychotic drugs were significantly different (changes from baseline: TSH: p < 0.001 vs. p = 0.089; TT3: p = 0.013 vs. p = 0.553). Changes in serum TSH levels had a moderate positive correlation with the average daily dose of SGAs (p = 0.007, r = 0.318).

CONCLUSIONS

After SGA treatment, patients seemed to have a trend of hypothyroidism, but the incidence was low. The preliminary results of this study did not show the necessity of regular monitoring of serum thyroid hormone levels in patients with baseline thyroid hormone levels within the normal reference ranges.

The relationships between thyroid-stimulating hormone level and insulin resistance, glucose effectiveness, first- and second-phase insulin secretion in Chinese populations

Increased insulin resistance (IR); decreased glucose effectiveness (GE); and both first-and second phase of insulin secretion (FPIS, SPIS) have always been important factors for the development of type 2 diabetes. Therefore, in this study, we evaluated the relationships between thyroid-stimulating hormone (TSH) and these 4 factors in adult Chinese. We randomly enrolled 24,407 men and 24,889 women between 30 and 59 years old. IR, FPIS, SPIS and GE were measured with the equations built by our group. IR = log (1.439 + 0.018 × sex - 0.003 × age + 0.029 × BMI - 0.001 × SBP + 0.006 × DBP + 0.049 × TG - 0.046 × HDLC - 0.0116 × FPG) × 10 ^3.333. FPIS = 10 [1.477 - 0.119 × FPG + 0.079 × BMI - 0.523 × HDLC]. SPIS = 10 [-2.4 - 0.088 × FPG + 0.072 × BMI]. GE = (29.196 - 0.103 × age - 2.722 × TG - 0.592 × FPG) ×10 ^−3. The t test was performed to evaluate the differences between normal and diabetic groups. To evaluate the differences of the mean values of the 4 groups, from the highest to the lowest levels of TSH, we used a one-way analysis of variance. Age, high density lipoprotein-cholesterol and GE were higher in women. On the other hand, body mass index, blood pressure, low density lipoprotein-cholesterol, triglyceride, FPIS, SPIS and IR were higher in men. TSH was positively related to IR, FPIS, and SPIS and negatively related to GE. According to the r values, the tightest relationship was between TSH and IR, followed by GE, FPIS and SPIS. In conclusion, our data showed that IR, FPIS, and SPIS were positively related to the TSH level in middle-aged Chinese, whereas GE was negatively related. In both genders, IR had the tightest association followed by GE, FPIS, and SPIS.

A 33-year-old man with COVID-19 presented with subacute thyroiditis: A rare case report and literature review

We report the first case of the novel coronavirus disease 2019 (COVID-19) presenting with subacute thyroiditis in Ghaemshar, Mazandaran Province, Iran. In our patient, with the initiation of corticosteroid therapy, the symptoms of subacute thyroiditis gradually disappeared with a slow increase in thyroid-stimulating hormone (TSH) and the gradual elimination of thyrotoxicosis. This case shows that decreased TSH and persistent thyrotoxicosis may make the patient's condition worse. Managing this complication can take several weeks and can be complicated.

Thyroid-Stimulating Hormone and Free Thyroxine Alterations in Subjects with Occupational Hearing Loss

Context and Aim:

Occupational hearing loss (OHL) is caused by exposure to industrial noise. Alterations in the thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels are related to hearing loss. The purpose of this study is to investigate the TSH and FT4 level alterations in OHL.

Methods and Material:

Among 428 subjects, 144 male workers with normal hearing (NH), noise-induced hearing loss (NIHL), and high tone loss (HTL) (N = 48 in each group) were included in this study. All the subjects had normal TSH and FT4 levels.

Results:

The TSH level is higher in the HTL and NIHL groups in comparison to NH, but it is only significant in the HTL group. The FT4 level is significantly lower in the NIHL group; however, the lower FT4 level in the HTL group is not significant when compared to the NH group.

Discussion:

The NIHL group may turn into the HTL group over time. This process could be monitored by alteration in their TSH and FT4 levels.

Conclusions:

Alterations in the TSH and FT4 levels could be considered as a pathophysiology for OHL. More research is required to investigate the electrophysiological, physiological, and histological correlations of TSH and FT4 and different types of hearing loss caused by noise exposure.

A Novel Approach to Improve Newborn Screening for Congenital Hypothyroidism by Integrating Covariate-Adjusted Results of Different Tests into CLIR Customized Interpretive Tools

Newborn screening for congenital hypothyroidism remains challenging decades after broad implementation worldwide. Testing protocols are not uniform in terms of targets (TSH and/or T4) and protocols (parallel vs. sequential testing; one or two specimen collection times), and specificity (with or without collection of a second specimen) is overall poor. The purpose of this retrospective study is to investigate the potential impact of multivariate pattern recognition software (CLIR) to improve the post-analytical interpretation of screening results. Seven programs contributed reference data (N = 1,970,536) and two sets of true (TP, N = 1369 combined) and false (FP, N = 15,201) positive cases for validation and verification purposes, respectively. Data were adjusted for age at collection, birth weight, and location using polynomial regression models of the fifth degree to create three-dimensional regression surfaces. Customized Single Condition Tools and Dual Scatter Plots were created using CLIR to optimize the differential diagnosis between TP and FP cases in the validation set. Verification testing correctly identified 446/454 (98%) of the TP cases, and could have prevented 1931/5447 (35%) of the FP cases, with variable impact among locations (range 4% to 50%). CLIR tools either as made here or preferably standardized to the recommended uniform screening panel could improve performance of newborn screening for congenital hypothyroidism.

Thyroid-stimulating hormone level is negatively associated with fertilization rate in patients with polycystic ovary syndrome undergoing in vitro fertilization

OBJECTIVE

In this study, we investigated the effect of thyroid-stimulating hormone (TSH) level on the outcomes of in vitro fertilization (IVF) in patients with polycystic ovary syndrome (PCOS).

METHODS

Data pertaining to 60 patients who underwent IVF between May 2017 and May 2018 were included in the study. Thirty-two patients were diagnosed as PCOS (PCOS group) and 28 patients had tubal infertility (control group). Serum and follicular fluid TSH levels and follicular cyclic AMP (cAMP) level were detected by ELISA. TSH receptor (TSHR) expression level in granulosa cells was quantified by RT-PCR and Western blot.

RESULTS

In the PCOS group, oocyte maturation rate and fertilization rate were significantly lower than in the control group. Serum and follicular fluid TSH levels and ovarian cAMP level were higher in the PCOS group with an upregulation of ovarian TSHR. On multivariate linear regression analysis, fertilization rate showed a negative correlation with TSH levels in serum (B = -0.106, P = 0.005) and follicular fluid (B = -0.107, P = 0.001).

CONCLUSION

In PCOS patients, TSH levels, both in serum and follicular fluid, were negatively correlated with IVF oocyte maturation rate and fertilization rate. The effect of TSH on controlled ovarian hyperstimulated oocyte growth was likely mediated by the TSHR/cAMP signaling pathway.

Thyroid function modifications in women undergoing controlled ovarian hyperstimulation for in vitro fertilization: a systematic review and meta-analysis

OBJECTIVE

To investigate the impact of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF) on thyroid function.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile women undergoing conventional IVF or intracytoplasmic sperm injection.

INTERVENTION(S)

Systematic search of PubMed, MEDLINE, Embase, Scopus, and Web of Science from inception until November 2020. Studies could be included only if they met the following criteria: subjects were classified as euthyroid or hypothyroid; serum thyroid-stimulating hormone (TSH) and/or free thyroxine (FT4) levels were evaluated before COH; and the same thyroid function test was reassessed after COH (i.e., at the time of trigger for final follicle maturation and/or at pregnancy test).

MAIN OUTCOME MEASURE(S)

Mean difference (MD) between the serum TSH or FT4 levels assessed after COH and before COH.

RESULT(S)

In euthyroid women, the serum TSH levels assessed at the time of trigger and at the time of pregnancy test were significantly higher than those at baseline (MD: 0.69 mIU/L, 95% confidence interval [CI]: 0.30-1.08, I² = 93% and MD: 0.67, 95% CI: 0.49-0.85, I² = 72%, respectively). The serum FT4 levels did not undergo significant changes. Subanalysis confirmed an increase in the TSH level after restricting the analysis to women treated with gonadotropin-releasing hormone agonist protocols and to those who achieved pregnancy. A pronounced increase in the TSH level was observed in women treated for hypothyroidism (MD: 1.50 mIU/L, 95% CI: 1.10-1.89, I² = 0%).

CONCLUSION(S)

Pooling of the results showed a significant increase in serum TSH level in women undergoing COH for IVF. This change was particularly pronounced in women treated for hypothyroidism. New thyroid function screening strategies for women undergoing COH are warranted.

Correlations between neck circumference and serum thyroid hormones levels in postmenopausal women with euthyroid and subclinical hypothyroidism

Middle-aged and elderly women are at a higher risk of subclinical hypothyroidism (SHypo). Menopause is an important period of metabolic change in women and thyroid hormones are closely related to metabolic status. Neck circumference (NC) is a simple anthropometric index that reflects upper body fat accumulation. Therefore, this study aimed to explore the relationship between NC and thyroid hormones in postmenopausal women. A total of 1050 postmenopausal women were enrolled from Shanghai Zhabei communities (888 euthyroid subjects and 162 SHypo patients). Anthropometric parameters, including NC, were measured. The measurements of serum thyroid hormones were performed by electrochemical luminescence immunoassay. The results showed NC was positively correlated with thyroid-stimulating hormone (TSH) (r = .064, P = .039). TSH and the proportion of SHypo patients increased significantly in those with elevated NC (both P < .05). In logistic regression analysis, the risk of SHypo increased by 46.4% in those with elevated NC (OR = 1.464 [1.035-2.071], P = .031). After adjusting for metabolic confounding factors, the positive association disappeared (P = .112). Multiple linear regression analysis showed there were no significant correlations between NC and TSH in either univariate or multivariate model in the total population (both P > .05). And in the subgroup analysis of euthyroid and SHypo individuals, NC was also not related to TSH (all P > .05). In conclusion, there was no independent association between NC, a simple anthropometric index for upper body fat accumulation, and serum TSH levels in Chinese euthyroid and SHypo postmenopausal women.

Lipidomic Perturbations in Cynomolgus Monkeys are Regulated by Thyroid Stimulating Hormone

Thyroid disease affects an estimated 200 million people worldwide, and is commonly associated with increased blood lipid levels. However, the mechanism by which thyroid-stimulating hormone (TSH) affects lipid profiles is not clear. Twenty-four cynomolgus monkeys were treated with a novel exogenous recombinant human TSH (rhTSH) (SNA001) at 9 μg kg⁻¹, 22 μg kg⁻¹, or 54 μg kg⁻¹, and reference rhTSH (Thyrogen^®) at 22 μg kg⁻¹. The primary TSH (SNA001) pharmacokinetic (PK) parameters increased in a dose-dependent manner across the dose range of 9 μg kg⁻¹, 22 μg kg⁻¹, or 54 μg kg⁻¹. Peak triiodothyronine (T3) and thyroxine (T4) levels were reached within 24 h after rhTSH administration, which was delayed by approximately 20 h. In total, 420 lipid species were detected and quantified by ultra-performance liquid chromatography high resolution spectrometry (UPLC-HR-MS)-based lipidomics. Notably, peak levels of lipid accumulation, particularly sphingomyelin (SM) and triglycerides (TG), appeared at 4 and 24 h, which was consistent with the pattern of TSH and T3/T4 levels, respectively. According to weighted correlation network analysis (WGCNA), perturbations of many lipid species were strongly correlated with TSH and T3/T4 levels. TSH and the stimulated T3/T4 levels and lipid profiles following SNA001 administration were comparable to those after administration of the reference rhTSH (Thyrogen^®). The plasma lipidome and changes in lipid levels after rhTSH stimulation were associated with TSH and T3/T4 concentrations. T3/T4 and lipid profiles were delayed after TSH stimulation. Such phenomena require further exploration.

Thyroid-stimulating hormone and free thyroxine fail to predict the severity and clinical course of hyperemesis gravidarum: A prospective cohort study

Introduction

Little is known about the pathophysiology of hyperemesis gravidarum (HG). Proposed underlying causes are multifactorial and thyroid function is hypothesized to be causally involved. In this study, we aimed to assess the utility of thyroid‐stimulating hormone (TSH) and free thyroxine (FT4) as a marker and predictor for the severity and clinical course of HG.

Material and methods

We conducted a prospective cohort study including women admitted for HG between 5 and 20 weeks of gestation in 19 hospitals in the Netherlands. Women with a medical history of thyroid disease were excluded. TSH and FT4 were measured at study entry. To adjust for gestational age, we calculated TSH multiples of the median (MoM). We assessed HG severity at study entry as severity of nausea and vomiting (by the Pregnancy Unique Quantification of Emesis and nausea score), weight change compared with prepregnancy weight, and quality of life. We assessed the clinical course of HG as severity of nausea and vomiting and quality of life 1 week after inclusion, duration of hospital admissions, and readmissions. We performed multivariable regression analysis with absolute TSH, TSH MoMs, and FT4.

Results

Between 2013 and 2016, 215 women participated in the cohort. TSH, TSH MoM, and FT4 were available for, respectively, 150, 126, and 106 of these women. Multivariable linear regression analysis showed that lower TSH MoM was significantly associated with increased weight loss or lower weight gain at study entry (ΔKg; β = 2.00, 95% CI 0.47‐3.53), whereas absolute TSH and FT4 were not. Lower TSH, not lower TSH MoM or FT4, was significantly associated with lower nausea and vomiting scores 1 week after inclusion (β = 1.74, 95% CI 0.36‐3.11). TSH and FT4 showed no association with any of the other markers of the severity or clinical course of HG. Twenty‐one out of 215 (9.8%) women had gestational transient thyrotoxicosis. Women with gestational transient thyrotoxicosis had a lower quality of life 1 week after inclusion than women with no gestational transient thyrotoxicosis (p = 0.03).

Conclusions

Our findings show an inconsistent role for TSH, TSH MoM, or FT4 at time of admission and provide little guidance on the severity and clinical course of HG.

Supplement therapy with apelin for improving the TSH level and lipid disorders in PTU-induced hypothyroid rats

Hyperlipidemia is a common metabolic disorder in the general population, which may arise in hypothyroidism. Apelin is an endogenous ligand that acts as an adiponectin, and is involved in energy storage and metabolism. This study evaluated the effects of apelin administration per se or in combination with T4 on the serum level of thyroid-stimulating hormone (TSH), body weight, and lipid profile, along with the serum level of apelin, and its mRNA expression in heart, in 6-propyl-2-thiouracil (PTU)-induced hypothyroid rats. Male Wistar rats were assigned to five different groups: control, H (hypothyroid), H+A, H+T, and H+A+T. All groups except the control one received PTU (0.05%) in the drinking water for 6 weeks. In addition to PTU, the H+A, H+T, and H+A+T groups received apelin (200 μg/kg/day, i.p.), l-thyroxin (T4) (20 μg/kg/day, via gavage tube), and apelin+T4 during the last 14 days of the trial, respectively. A combined application of T4 and apelin in the H+A+T group effectively diminished mean TSH level, low-density-lipoprotein cholesterol/high-density-lipoprotein cholesterol ratio, and atherogenic index in these animals when compared with these values for the H group. Coadministration of apelin with T4 may offer valuable therapeutic benefits, specifically lowering blood plasma TSH, lipid disorder, and atherosclerosis biomarkers in PTU-induced hypothyroid rats.

Immediate postoperative measurement of thyroid-stimulating hormone as an early predictor of remission in thyroid-stimulating hormone-secreting pituitary adenomas

OBJECTIVE

Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is a rare type of pituitary adenoma; thus, little is known about TSHomas. The purpose of this study was to analyze clinical characteristics and therapeutic outcomes of TSHomas based on a single-center experience. The authors also searched for reliable preoperative and early postoperative factors that could predict long-term endocrinological remission.

METHODS

The clinical, radiological, and pathological characteristics and surgical and endocrinological outcomes of 31 consecutive cases of TSHomas that were surgically treated between 2005 and 2017 were reviewed retrospectively. Preoperative factors were evaluated for their ability to predict long-term remission by comparing remission and nonremission groups. TSH and free thyroxine levels were measured at 2, 6, 12, 18, and 24 hours after surgery to determine whether they could predict long-term remission.

RESULTS

Gross-total removal of tumor was achieved in 28 patients (90.3%), and 26 patients (83.9%) achieved endocrinological remission by surgery alone based on long-term endocrinological follow-up (median 50 months, range 32-81 months). The majority of the tumors were solid (21/31, 67.7%), and en bloc resection was possible in 16 patients (51.6%). Larger tumor size and tumor invasion into cavernous sinus and sphenoid sinus were strong predictors of lower rates of endocrinological remission. Immediate postoperative TSH level at 12 hours after surgery was the strongest predictor, with a 0.62 μIU/mL cutoff. Postoperative complications included CSF rhinorrhea in one patient and epistaxis in another patient, who underwent additional surgical treatment for the complications.

CONCLUSIONS

Tumor size and extent are major prognostic factors for both extent of resection and endocrinological remission. The consistency of TSHomas was more likely to be solid, which makes extracapsular dissection more feasible. Long-term remission of TSHomas could be predicted even during the early postoperative period.

Assessment of the Thyroid Functions among Female Flight Attendants

Introduction: Epidemiological observations indicate that stewardesses are exposed to reproductive and endocrine system disturbances. The aim of the study was to assess of thyroid function disturbances as well as to identify factors affecting the thyroid function among stewardesses working both within one time zone and on long-distance flights. Material and methods: The cross-sectional study covered 103 women aged 23–46. The study group (I) was divided into two subgroups: group Ia comprising stewardesses flying within one flight zone and group Ib stewardesses working on long-distance flights. The control group (II) were women of reproductive age who sought medical assistance due to marital infertility in whom the male factor was found to be responsible for problems with conception in the course of the diagnostic process. The assessment included: age, BMI, menstrual cycle regularity, length of work, frequency of flying, thyroid stimulating hormone (TSH) concentration, level of free thyroxine (fT4), antibodies to thyroglobulin (aTG) and to thyroperoxidase (aTPO), prolactin concentration, sex hormone binding globulin (SHGB) concentration, total cholesterol, and low density lipoprotein (LDL) fraction. Descriptive methods and inferential statistics methods were used to compile the data. Results: The difference between the concentrations of TSH in the study group (2.59 mcIU/mL) and the control group (1.52 mcIU/mL) was statistically significant (p < 0.01). An elevated titer of thyroid antibodies (aTPO and/or aTG) was revealed in 46.3% of stewardesses and in 15.1% of patients from the control group (p < 0.001). Groups Ia and Ib in individual concentrations were not statistically significant. The frequency of occurrence of an elevated titer of thyroid antibodies depended on the length of work in the study group (p > 0.05). No statistically significant difference was found in patients spending up to 60 h a month flying and in patients spending more than 60 h flying, the percentage of the occurrence of thyroid antibodies was 50% and 43.5, respectively. Conclusions: The occurrence in stewardesses of a higher TSH concentration than in the control group can signify that stewardesses are burdened with a higher risk of the development of hypothyroidism in the future. The character of the work of stewardesses (frequency of flying as well as length of work) does not affect the immunological profile of the thyroid.

Predictive Value of Thyroid Hormones for Incident Hyperuricemia in Euthyroid Subjects: The Tianjin Chronic Low-Grade Systemic Inflammation and Health Cohort Study

OBJECTIVE

Thyroid hormones (THs) play an important role in both serum uric acid (SUA) excretion and purine nucleotide metabolism. Past research mainly focused on the relationships between thyroid dysfunction and hyperuricemia. Although most subjects at risk for hyperuricemia are euthyroid, few studies have investigated the predictive values of THs on incident hyperuricemia in euthyroid adults. This study aimed to examine how free triiodothyronine, thyroxine, and thyroid-stimulating hormone are related to incident hyperuricemia in euthyroid subjects.

METHODS

Participants without baseline hyperuricemia were recruited from Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study and followed up for ∼6 years. Thyroid function was determined by chemiluminescence immunoassay methods. Hyperuricemia was defined as SUA ≥416.5 μmol/L for males and ≥357.0 μmol/L for females. Thyroid function and SUA were assessed yearly during follow-up. Adjusted Cox proportional hazards regression models were used to assess the relationship between thyroid function and hyperuricemia.

RESULTS

The incidence rates of hyperuricemia were 109 and 50 per 1000 person-years in males and females, respectively. In males, compared with the lowest quartile, the multivariable-adjusted hazards ratios for hyperuricemia in the highest quartiles of triiodothyronine, thyroxine, and thyroid-stimulating hormone were 0.57 (0.50-0.66), 0.63 (0.54-0.73), and 1.03 (0.90-1.19) (P for trend < .0001, < .0001, and .51), respectively. However, no statistically significant correlations between thyroid function and incident hyperuricemia in females were found.

CONCLUSION

This cohort study is the first to demonstrate that higher THs are related to lower risk of incident hyperuricemia in a male population with euthyroid status.

Biochemical follow-up of nonfunctioning benign thyroid nodules

OBJECTIVE

For the biochemical follow-up of benign thyroid nodules, some authors recommend periodic lifelong measurement of thyroid-stimulating hormone (TSH) to assess for the development of toxic nodules over time. The purpose of this retrospective study was to assess the incidence of thyroid dysfunction over time in patients with benign thyroid nodule(s), with a normal TSH at diagnosis and to identify any factors that may predict biochemical dysfunction over time.

METHODS

Medical records of patients with the diagnosis of thyroid nodule(s) between January 2011 and August 2014 were reviewed. Patients who had TSH measurement within 1 year of initial diagnostic ultrasound (US) were included.

RESULTS

One-hundred fifty-seven patients identified with thyroid nodule(s) satisfied inclusion criteria. At a median follow-up of 45 (34-63) months, 13 (8.3%) patients developed thyroid dysfunction. The mean initial TSH in the group which developed subclinical hyperthyroidism (0.65 mIU/mL) was statistically different from the group that did not develop thyroid dysfunction (1.37 mIU/mL, P: 0.007). More patients with TSH <1 mIU/L developed thyroid dysfunction as compared to subjects with TSH ≥1 mIU/L (P: .022). There was no significant difference in the incidence of thyroid dysfunction on the basis of gender, race, smoking status, TPO Ab positivity and number of nodules at diagnosis.

CONCLUSIONS

We recommend re-examining the current practice and clinical utility of frequent TSH monitoring in all patients with thyroid nodules, particularly if initial TSH level is ≥1 mIU/L.

Thyroid function control among pregnant women following a therapeutic thyroidectomy

OBJECTIVES

The aim of this study was to assess the extent of thyroid function control among pregnant women who had previously undergone a therapeutic thyroidectomy.

DESIGN

Retrospective cohort study.

SETTING

The largest health maintenance organization in Israel.

PARTICIPANTS

All female patients who were pregnant between May, 2001 and September, 2012 and had a medical history of thyroid surgery.

MAIN OUTCOME MEASURE

The thyroid-stimulating hormone (TSH) levels throughout the pregnancy were compared to recommended trimestral values. A multivariate analysis was performed to determine risk factors for not attaining TSH recommended range.

RESULTS

A total of 477 females with a history of thyroid surgery had given 701 births during the study period. Forty-three percent (n = 203), had thyroidal malignancy. Nearly half of the women underwent total thyroidectomy (43.4%, n = 207). The women's TSH values were within the recommended range in only 60% (n = 350) of the pregnancies during the first trimester (0.1-2.5 mIU/L), in 61% (n = 335) during the second trimester (0.2-3 mIU/L), and in 70% (n = 338) during the third trimester (0.3-3 mIU/L). In multivariate analysis, women that underwent a total thyroidectomy due to a benign thyroid disease, were at the highest risk for not attaining target TSH levels.

CONCLUSIONS

This very large cohort of pregnant women with a past history of thyroid surgery demonstrated a significant percentage of pregnancies with TSH values above the recommended range. Women that underwent a total thyroidectomy due to benign thyroid disease were at the highest risk for gestational hypothyroidism.

Follicular GH and IGF1 Levels Are Associated With Oocyte Cohort Quality: A Pilot Study

INTRODUCTION

Oocyte quality contributes to the development of an optimal embryo and thus a successful pregnancy. The objective of this study was to analyse the association between oocyte cohort quality and the follicular levels of growth hormone (GH), insulin-like growth factor 1 (IGF1), 25-hydroxy vitamin D (25OHD), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4) and antithyroid antibodies, as a function of intracytoplasmic sperm injection (ICSI) outcomes.

MATERIAL AND METHODS

We conducted a prospective comparative pilot study from January 2013 to December 2017. 59 ICSI cycles constituted an abnormal oocyte cohort (n=34 cycles, in which more than 50% of oocytes presented at least one morphological abnormality) and a normal oocyte cohort (n=25 cycles, in which 50% or less of the oocytes presented at least one morphological abnormality). GH, IGF1, 25OHD, TSH, fT3, fT4 and antithyroid antibodies were measured in follicular fluid.

RESULTS

The fertilisation rate was lower in the abnormal oocyte cohort (65.5% vs. 80%, respectively, p=0.012). Oocytes' proportion with at least one abnormality was 79.4% in the abnormal oocyte cohort and 29.0% in the normal oocyte cohort. The mean number of morphological abnormalities per oocyte was significantly higher in the abnormal oocyte cohort. The follicular levels of GH (4.98 vs. 2.75 mIU/L, respectively; p <0.01) and IGF1 (72.1 vs. 54.2 ng/mL, respectively; p=0.05) were higher in the normal oocyte cohort. There was no association with follicular levels of TSH, fT3, fT4, antithyroid antibodies, or 25OHD.

CONCLUSION

Oocyte cohort quality appears to be associated with follicular levels of GH and IGF1.

Within-Person Variation in Serum Thyrotropin Concentrations: Main Sources, Potential Underlying Biological Mechanisms, and Clinical Implications

BACKGROUND

Individuals exhibit fluctuations in the concentration of serum thyroid-stimulating hormone (TSH) over time. The scale of these variations ranges from minutes to hours, and from months to years. The main factors contributing to the observed within-person fluctuations in serum TSH comprise pulsatile secretion, circadian rhythm, seasonality, and ageing. In clinical practice and clinical research however, such within-person biological variation in serum TSH concentrations is often not considered. The aim of this review is to present an overview of the main sources of within-person variation in TSH levels, as well as the potential underlying biological mechanisms, and the clinical implications.

SUMMARY

In euthyroid individuals, the circadian rhythm, with a nocturnal surge around 02:00-04:00 h and a nadir during daytime has the greatest impact on variations in serum TSH concentrations. Another source of within-person variation in TSH levels is seasonality, with generally higher levels during the cold winter months. Since TSH is secreted in a pulsatile manner, TSH levels also fluctuate over minutes. Furthermore, elevated TSH levels have been observed with ageing. Other factors that affect TSH levels include thyroid peroxidase (TPO)-antibody positivity, BMI, obesity, smoking, critical illness, and many xenobiotics, including environmental pollutants and drugs. Potential underlying biological mechanisms of within-person variation in TSH levels can be safely concluded from the ability of TSH to respond quickly to changes in cues from the internal or external environment in order to maintain homeostasis. Such cues include the biological clock, environmental temperature, and length of day. The observed increase in TSH level with ageing can be explained at a population level and at an organism level. In clinical practice, the season for thyroid testing can influence a patient's test result and it occurs frequently that subclinical hypothyroid patients normalize to euthyroid levels over time without intervention.

CONCLUSIONS

Serum TSH concentrations vary over time within an individual, which is caused by multiple different internal and external factors. It is important to take the within-person variations in serum TSH concentrations into account when testing a patient in clinical practice, but also in performing clinical research.

Case Report: A Case of Pituitary Adenoma Producing Growth Hormone and Thyroid-Stimulating Hormone Simultaneously

BACKGROUND

Pituitary adenoma producing growth hormone (GH) or thyroid-stimulating hormone (TSH) is characterized by various specific symptoms and/or findings. However, the frequency of pituitary adenoma producing both hormones is relatively low. In this report, we show a case of pituitary adenoma producing both GH and TSH simultaneously.

CASE PRESENTATION

A 27-year-old woman was diagnosed as acromegaly based on various symptoms and clinical findings. For further examination and treatment, she was hospitalized in our institution. It was likely that this subject had pituitary adenoma producing both GH and TSH. In brain magnetic resonance imaging, there was a giant tumor around pituitary fossa. After the diagnosis of GH- and TSH-producing pituitary adenoma, pituitary tumor resection and cyber knife therapy were performed. In addition, we started additional treatment with somatostatin analog and GH receptor antagonist. After then, GH and insulin-like growth factor (IGF-1) levels were suppressed. After the operation, since thyroid function was not sufficiently suppressed, we started anti-thyroid drug thiamazole. After then, thyroid function was normalized and we stopped thiamazole. In GH and TSH staining, many GH-positive and TSH-positive cells were observed. These findings further confirmed our diagnosis that the pituitary adenoma in this subject produced both GH and TSH simultaneously.

CONCLUSIONS

We should bear in mind the possibility of pituitary adenoma producing both GH and TSH at the same time.

Statin Use and Benefits of Thyroid Function: A Retrospective Cohort Study

PURPOSE

Previous studies have suggested that cholesterol may influence thyroid function. Since statins are widely used for their cholesterol-lowering effect, we aimed to assess the association between statin use and thyroid function, and also to explore the role of the cholesterol-lowering effect in it.

METHODS

We performed a retrospective cohort study derived from REACTION study. Eligible subjects receiving statin therapy were included in the statin group, and sex-, age-, total cholesterol (TC)-, and thyroid function-matched participants without lipid-lowering therapy were included in the control group. The median follow-up time was three years. Outcomes of thyroid function were evaluated at the end of follow-up. We used multivariable regression models to assess the association between statin use and outcomes of thyroid function, and also performed mediation analyses to explore the role of cholesterol in it.

RESULTS

A total of 5,146 participants were screened, and 201 eligible subjects in the statin group and 201 well-matched subjects in the control group were analyzed. At the end of follow-up, TC and thyroid-stimulating hormone (TSH) levels in the statin group were lower than those in the control group (both p < 0.05), and the percentage of euthyroid subjects was higher in the statin group (88.06% vs. 76.12%, p = 0.002). The incidence rate of subclinical hypothyroidism (SCH) in euthyroid subjects was lower in the statin group (6.29% vs. 14.86%, p = 0.009), and the remission rate among subjects with SCH was higher in the statin group (50.00% vs. 15.38%, p = 0.008). In multivariable regression analyses, statin use was independently associated with lower TSH levels and higher odds to be euthyroid (OR 2.335, p = 0.004) at the end of follow-up. Mediation analyses showed the association between statin use and TSH levels were mediated by TC changes during follow-up.

CONCLUSION

Statin use was associated with benefits of thyroid function, and TC changes serve as a mediator of the association between statin use and TSH levels. Further studies are needed to clarify the possible underlying mechanism.

Low TSH Levels Within Euthyroid Range Could Play a Negative Role on Bone Mineral Density in Postmenopausal Women with Type 2 Diabetes

OBJECTIVE

We aimed to evaluate the relationship between thyroid-stimulating hormone (TSH) and bone mineral density (BMD) in euthyroid type 2 diabetes (T2D).

METHODS

This retrospective analysis enrolled 439 T2D patients with normal thyroid function, including 226 males and 213 females. All the female patients were postmenopausal. Serum glycosylated hemoglobin A1c (HbA1c), TSH, free triiodothyronine (FT₃), and free thyroxine (FT₄) concentrations were analyzed. BMD of the lumbar spine (L₁-L₄), femoral neck, and hip joint was determined using dual-energy X-ray absorptiometry.

RESULTS

The patients were grouped based on tri-sectional quantiles of the TSH levels: 0.55~1.70mIU/L (Group 1), 1.71~2.58mIU/L (Group 2), and 2.59~4.74mIU/L (Group 3). Our data showed that, in male patients, no difference in BMD was identified among groups. In postmenopausal women, unlike at the lumbar spine (P = 0.459), the mean BMD at the femoral neck (P = 0.014) and hip joint (P = 0.014) had a statistical difference among groups and increased with TSH level. In addition, our analysis demonstrated that TSH levels shown no correlation with BMD at all sites in males. However, in females, BMD at the femoral neck (r = 0.156, P = 0.023) and hip joint (r = 0.172, P = 0.012) had a positive correlation with TSH levels. After adjusting for age and BMI, multiple regression analysis showed that TSH levels influenced BMD at the femoral neck (β = 0.188, P = 0.001) and hip joint (β = 0.204, P = 0.001) in female patients.

CONCLUSION

In summary, our data demonstrates that low TSH levels are associated with decreased BMD at the femoral neck and hip joint in postmenopausal T2D women with euthyroidism.