Serum Thyrotropin Concentrations Research Articles

Total thyroxine, triiodothyronine, and thyrotropin concentrations during acute nonthyroidal illness and recovery in dogs.

Acute illness can result in changes in serum total thyroxine (tT4), total triiodothyronine (tT3), and thyrotropin (TSH) concentrations in euthyroid dogs defined as nonthyroidal illness syndrome, but longitudinal evaluation of these hormones during the recovery phase is lacking. To longitudinally evaluate serum tT4, tT3, and TSH concentrations during the acute phase and recovery from acute illness in dogs. Nineteen euthyroid client-owned dogs hospitalized for acute illness at a veterinary teaching hospital. Prospective longitudinal study. Serum tT4, tT3, and TSH concentrations were measured at the admission (T0), at last day of hospitalization (T1), and during the recovery phase at 3, 7, 14, and 21 days after the discharge (T2, T3, T4, and T5), respectively. tT4 and tT3 were below the reference interval (RI) at T0 in 3 (16%) and 18 (95%) dogs, respectively; tT4 normalized in all dogs early in the recovery phase, while low tT3 persisted at the end of the study in 16 (83%) dogs. Median TSH concentrations were increased at T5 compared with T1 (0.19 ng/mL [range 0.03-0.65] vs 0.11 ng/mL [range (0.05-0.26)], mean difference = 0.09 ng/mL; P = .03). Five (26%) dogs had TSH above the RI at least at 1 time point during the recovery phase. None of the dogs had concurrent low tT4 and high TSH during the study. In euthyroid dogs acute illness can interfere with evaluation of thyroid function up to 21 days during the recovery phase. Thyroid testing should be avoided or postponed in these dogs.

Analysis of Serum Free Thyroxine Concentrations in Healthy Term Neonates Underlines Need for Local and Laboratory-Specific Reference Interval: A Systematic Review and Meta-Analysis of Individual Participant Data.

Background: Initial evaluation of the hypothalamus-pituitary-thyroid axis is done by measuring serum free thyroxine (fT4) and thyrotropin concentrations. For correct interpretation of these measurements, reliable age-specific reference intervals (RIs) are fundamental. Since neonatal fT4 RIs conforming to the Clinical and Laboratory Standards Institute guidelines are not available for all assays, we set out to create literature-based uniform age-specific neonatal fT4 RIs that may be used for every assay. Methods: For meta-analysis of individual participant fT4 concentrations, we systematically searched MEDLINE and Embase (search date December 6, 2023; PROSPERO registration CRD42016041871). We searched for studies reporting fT4 concentrations in healthy term newborns aged 2-27 days, born to mothers without thyroid disease in iodine-sufficient regions. Authors were invited to supply data. Due to standardization differences between assays, data could not be combined for meta-analysis directly, and we attempted to normalize the data using two distinct methods. Results: We obtained 4206 fT4 concentrations from 20 studies that used 13 different assays from 6 manufacturers. First, we set out to normalize fT4 data using the mean and standard deviation of (assay-specific) adult RIs. fT4 concentrations were transformed into Z-scores, assuming a normal distribution. Using a linear mixed-effects model (LMM), we still found a significant difference between fT4 concentration across studies (p < 0.001), after this normalization. As a second approach, we normalized the fT4 concentrations using data from a method/assay comparison study. We used the relationship between the Cobas assay and the other assays as a reference point to convert all values to Cobas values. However, this method also failed to produce consistent results, with significant differences between the normalized data (LMM p < 0.001). Conclusions: We conclude that our attempts at normalizing fT4 assay results were unsuccessful. Confounders related to our unsuccessful analysis may be assay related and/or biological. These findings have significant implications for patient care, since relying on RIs from literature may result in erroneous interpretation of results. Therefore, we strongly recommend to establish local RIs for accurate interpretation of serum fT4 concentrations in neonates.

The Predictive Value of Conventional Ultrasound Signs Plus Serological Indices for Neck Lymph Node Metastasis in Papillary Thyroid Cancer

The present study aimed to evaluate the predictive value of conventional ultrasound signs and serological indices in the detection of neck lymph node metastasis in papillary thyroid cancer (PTC). A total of 80 patients with PTC scheduled for surgery in our hospital between August 2019 and December 2022 were recruited. Patients with neck lymph node metastasis were categorized as the experimental group, and patients without neck lymph node metastasis were included in the control group. Patients’ ultrasound signs were analyzed, and serological indices were determined. Logistic analysis was performed to determine the risk factors for the development of postoperative neck lymph node metastasis in papillary thyroid cancer, and the receiver operating characteristic (ROC) curve was employed to assess their diagnostic efficiency. Significant differences were observed in the number of lesions, nodule size, calcification, blood flow RI, and PI values comparison between the two arms (P &lt; 0.05), while no significant differences were found in other ultrasound signs (P &gt; 0.05). Patients with neck lymph node metastasis exhibited significantly higher serum concentrations of thyroid stimulating hormone (TSH) and anti-thyroglobulin antibodies (TG-Ab) versus those without metastasis (P &lt; 0.05). Nodule size, number of lesions, and serum TSH level were independent risk factors for metastasis in neck lymph nodes in patients with papillary thyroid cancer (P &lt;0.05). Conventional ultrasound signs, combined with serologic indices, demonstrated the highest diagnostic efficiency for predicting neck lymph node metastasis in patients with papillary thyroid cancer. These findings showed a sensitivity of 0.868, specificity of 0.894, and an area under the ROC curve (AUC) of 0.918. Additionally, the Jorden index was calculated to be 0.761. Analysis revealed that nodule size, number of lesions, and serum TSH concentration were independent risk factors for neck lymph node metastasis in papillary thyroid cancer patients. The combination of conventional ultrasound signs and serologic indices provided a higher diagnostic value compared to using a single diagnostic modality, thus indicating promising clinical benefits.

Changes in thyroid function levels in female patients with first-episode bipolar disorder.

The identification of molecular biomarkers for bipolar disorder is anticipated to greatly improve the diagnosis and treatment of this disease. The objective of this case-control study is to determine whether the blood thyroid hormone levels in bipolar disorder patients are associated with different types of first onset. From August 1, 2020 to July 31, 2021 a total of 120 female patients diagnosed with bipolar disorder and hospitalized at Qingdao Mental Health Center were recruited as the case group, including 60 patients with depression as their first onset (depression first-episode group, DF) and 60 with mania/hypomania as their first onset (mania/hypomania first-episode group, M/HF). A group of 60 healthy adult females matching general demographic data, such as race and age, were selected as the control group. Blood samples were taken from both groups to measure serum triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) concentrations. The duration of current onset in the M/HF group was significantly less than that in the DF group (23.1 ± 20.2 vs. 125.2 ± 41.0 days). About 27% of patients in the M/HF group had thyroid abnormalities, in contrast to 60% in the DF group. The blood T3 and T4 levels in both the M/HF group and the DF group, as well as the TF3 levels in the DF group, were significantly lower as compared to control. The M/HF group had significantly higher T3 and FT3 levels than the DF group. The blood T3 levels were inversely correlated with the Young's Mania Scale score and the Hamilton Depression Scale score in both the M/HF and DF groups. Thyroid dysfunction resulting in reduced levels of blood thyroid levels may be involved in the disease progression of bipolar disorder, and correlated with the clinical symptoms in patients with depression or mania as the first episode.

The effect of metformin therapy on serum thyrotropin and free thyroxine concentrations in patients with type 2 diabetes: a meta-analysis

Type 2 diabetes and thyroid function disorders are two common chronic endocrine disorders with the high prevalence in various populations. Metformin is well established as the first-line drug therapy for managing diabetes mellitus. In this meta-analysis, we aimed to determine the effect of metformin on serum TSH and FT4 concentrations in patients with type 2 diabetes. We searched PubMed, Scopus, web of science, Cochrane library, and google scholar to collect information on the effect of metformin on serum TSH and FT4 levels. Demographic and clinical information and serum TSH and FT4 concentrations before and after metformin treatment were extracted. Studies on patients over 18 years of age were included. A total of 11 studies including 1147 patients were selected for the final analysis. In hypothyroid patients, the TSH level decreased significantly after treatment with metformin (Hedges’s g:1.55, 95%CI 0.93–2.16, p-value < 0.001); FT4 level increased slightly after taking metformin, but the increase was not significant (Heddges’s g: − 0.30, 95%CI − 0.90,0.31, p-value = 0.34). In euthyroid subjects, the slight decrease found in TSH and FT4 concentrations was not statistically significant. Metformin reduces TSH levels in hypothyroid patients; however, it has no effect on TSH levels in euthyroid patients. Metformin does not affect serum FT4 levels in euthyroid and hypothyroid patients.

The Relationship between Thyrotropin Serum Concentrations and Thyroid Carcinoma.

Thyroid Stimulating Hormone (TSH) is a hormone secreted by the pituitary gland and plays a role in regulating the production and secretion of thyroid hormones by the thyroid gland. This precise feedback loop is essential for maintaining a harmonious balance of thyroid hormones in the body, which are vital for numerous physiological processes. Consequently, TSH serves as a significant marker in assessing thyroid function, and deviations from normal TSH levels may indicate the presence of a thyroid disorder. Thyroid cancer (TC) is the malignant tumor within the endocrine system. In recent years, numerous experts have dedicated their efforts to discovering efficacious biomarkers for TC. These biomarkers aim to improve the accurate identification of tumors with a poor prognosis, as well as facilitate active monitoring of tumors with a more favorable prognosis. The role of TSH in the thyroid gland underscores its potential influence on the occurrence and progression of TC, which has garnered attention in the scientific community. However, due to the limited scope of clinical research and the dearth of high-quality foundational studies, the precise impact of TSH on TC remains unclear. Consequently, we present a comprehensive review of this subject, aiming to offer a valuable reference for future research endeavors.

Effects of the abdominal fat distribution on the relationship between exposure to air pollutants and thyroid hormones among Korean adult males

BackgroundSeveral significant associations between air pollution and thyroid function have been reported, but few studies have identified whether these associations differ by obesity, particularly its regional distribution. We assessed the relationship between ambient air pollution and thyroid hormone, and whether this relationship is modified by abdominal adiposity, as indicated by the waist circumference, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and visceral-to-subcutaneous fat ratio (VSR) in Korean men.MethodsWe included 2440 male adults in the final analysis and used each person’s annual average exposure to four air pollutants: particulate matter with an aerodynamic diameter ≤ 10 μm (PM10), nitrogen dioxide, sulfur dioxide (SO2), and carbon monoxide (CO). Abdominal fat deposition was quantified by computed tomography. Serum thyrotropin (TSH) and free thyroxine (FT4) concentrations were measured for thyroid hormone. To evaluate the relationship between air pollution and thyroid hormone according to adiposity, we performed multiple linear regression analysis on the two subgroups stratified by abdominal fat level.ResultsAbdominal adiposity was significantly related to FT4 concentration. The exposures to air pollutants were associated with increased TSH and decreased FT4 concentrations. In stratified analysis using abdominal fat traits, ambient air pollution except for SO2 was significantly related to increased TSH and decreased FT4 concentrations in the high adiposity group (all p < 0.05), but not in the normal adiposity group. Among the air pollutants, PM10 showed an association with an increase of TSH concentration in all group with high adiposity, including high VAT, high SAT, and high VSR groups (all p < 0.05). In case of FT4, CO showed a similar pattern. Among the abdominal fat-related traits, the VSR in the high adiposity group had the largest effect on the relationship between exposure to air pollutants and thyroid hormone.ConclusionsThis study suggests the first clue that the relationship between air pollution exposure and thyroid hormone differs according to abdominal fat distribution among Korean adult males.

A-338 TSH Reference Range in the First Trimester in a Iodine Sufficient Population of Pregnant Women Attended by the Public Health System in Curitiba South of Brazil

Abstract Background Thyroid diseases are common among women of reproductive age, and the serum concentration of thyroid-stimulating hormone (TSH) is the most used index to assess thyroid function during pregnancy. Changes in thyroid function during pregnancy can have a clinical impact on a woman's health and pregnancy outcome, as well as interfere with fetal health and child development. An adequate thyroid function is essential for normal intrauterine development. When comparing the levels of TSH between pregnant and non-pregnant women, TSH levels are lower in pregnancy, mainly in the first trimester, with gradual increase during pregnancy. Although some guidelines propose fixed TSH reference values in pregnancy according to the gestational trimester, the main recommendation is to carry out a study of their local population due to the significant variation in TSH reference range levels in different populations and different assays. Therefore, it is necessary to determine values of a reference interval for TSH for the local population of pregnant women. This study aims to determine the normal reference range of TSH in the first trimester of gestation in the public health system pregnant women from Curitiba. Methods This is an ongoing prospective cohort study, with the population sample from the pregnant women using the public health system, with age &amp;gt;18 years old in Curitiba, South of Brazil. 383 pregnant women were invited to participate. After evaluate the exclusion criteria (gestational age more than 13 weeks, twin pregnancy, thyroid disease, iodine ingestion, identification of the samples in the laboratory), 225 pregnant women had the TSH measured by chemiluminescent immunoassay on Atellica IM Analyzer (Siemens Healthineers), as well as the TPO-ab presence, FreeT4 and Total T4. The 2.5, 50 end 97,5 TSH percentiles were estimated for the normal pregnant population. Results The mean gestational age was 8,6 weeks (standard deviation 2.33). From 225 pregnant women, 22 (9.8%) had TPO-ab positive. The 2.5 and 97.5 percentiles of TSH were 0.12 and 5.28 μIU/mL after using de exclusion criteria. The populational iodine status was sufficient. In the TPO-ab positive population was found a higher level of TSH. The proportion of TPO-ab positive was significantly higher in the population with TSH &amp;gt;2.5 μIU/mL. Conclusions This preliminary data shows the TSH reference range with levels higher than other regions, reinforcing to do not use fixed values of TSH from other populations to evaluate the thyroid function in pregnancy. Comparing to the laboratory reference for non-pregnant adult (0.48 to 5.60 μIU/mL), the recommended reduction of 0.5 μIU/mL on upper limit and 0.4 μIU/mL on the lower limit found similar values to our findings.

Urine concentrating ability in cats with hyperthyroidism: Influence of radioiodine treatment, masked azotemia, and iatrogenic hypothyroidism.

Hyperthyroid cats often have urine specific gravity (USG) values <1.035. It remains unclear how USG changes after treatment, if USG can be used to predict azotemia after treatment, or how iatrogenic hypothyroidism influences USG values. To determine the proportion of hyperthyroid cats with USG <1.035 vs ≥1.035; if USG changes after treatment; and whether USG <1.035 correlated with unmasking of azotemia or hypothyroidism. Six hundred fifty-five hyperthyroid cats treated with radioiodine; 190 clinically normal cats. Prospective, before-and-after study. Hyperthyroid cats had serum thyroxine, thyroid-stimulating hormone, and creatinine concentrations, and USG measured before and 6 months after successful treatment with radioiodine. Of untreated hyperthyroid cats, USG was ≥1.035 in 346 (52.8%) and <1.035 in 309 (47.2%). After treatment, 279/346 (80.6%) maintained USG ≥1.035, whereas 67/346 (19.4%) became <1.035; 272/309 (88%) maintained USG <1.035, whereas 37/309 (12%) became ≥1.035. Only 22/346 (6.4%) with USG ≥1.035 developed azotemia after treatment, compared with 136/309 (44%) with <1.035 (P < .001). Of cats remaining nonazotemic, 38% had USG <1.035, compared with 20% of normal cats (P < .001). The 137 cats with iatrogenic hypothyroidism had lower USG after treatment than did 508 euthyroid cats (1.024 vs 1.035), but USGs did not change after levothyroxine supplementation. USG <1.035 had high sensitivity (86.1%) but moderate specificity (65.2%) in predicting azotemia after treatment. Hyperthyroidism appears not to affect USG in cats. However, cats with evidence of sub-optimal concentrating ability before radioiodine treatment (USG < 1.035) are more likely to develop azotemia and unmask previously occult chronic kidney disease. Iatrogenic hypothyroidism itself did not appear to affect USG values.

Clinical study to evaluate the efficacy of Commiphora muku (Muqil) on thyroid function in hypothyroidism

Background: Hypothyroidism is a common endocrine disorder in which there is deficient production of thyroid hormone. Even though hormone replacement therapy is the mainstay treatment of hypothyroidism, but due to adverse effects on long term use, safe and effective Unani herbal drugs need to be researched. A decrease in serum concentrations of thyroid hormone causes an increased secretion of thyroid stimulating hormone (TSH), thus resulting in elevated serum TSH concentration. Methods: The methods used to determine thyroid dysfunction are still serum thyroid stimulating hormone and the main circulating thyroid hormones thyroxine and triiodothyronine either as total or estimated free concentrations, and it is indeed the improved assay sensitivities and specificities that have made it possible to diagnose these milder forms. TSH, T3 and T4 with safety parameters tests were done before treatment and after completion of treatment in both the groups in order to make the proper diagnosis, to exclude other systemic ailments and to assess the efficacy/safety of the proposed herbal drug. Results: The effects of test drug on lowering the raised serum TSH are attributed to the thyroid activities of the test drug which shoes highly significance p&lt;0.01 before and after intervention. In respect of thyroxin there were no significant results between the test and control group. Conclusions: The study concluded that the efficacy of Commiphora mukul (Muqil) on thyroid function was designed to explore the role of Unani herbal drugs in the management of hypothyroidism on Unani principles is effective, safe and cost effective.

Biological variation of serum thyrotropin and thyroid hormones concentrations determined at 8-week intervals for 1 year in clinically healthy cats.

Cats commonly develop thyroid disease but little is known about the long-term biological variability of serum thyroid hormone and thyrotropin (thyroid-stimulating hormone; TSH) concentrations. We aimed to determine the long-term biological variation of thyroid hormones and TSH in clinically healthy cats. A prospective, observational study was carried out. Serum samples for analysis of total thyroxine (T4, by radioimmunoassay [RIA] and homogenous enzyme immunoassay [EIA]), triiodothyronine (T3 ), free T4 (by dialysis), and TSH were obtained every 8 weeks for 1 year from 15 healthy cats, then frozen until single-batch analysis. Coefficients of variation (CV) within individual cats ( ) and among individual cats ( ), as well as the variation between duplicates (ie, analytical variation [ ]) were determined with restricted maximum likelihood estimation. The indices of individuality (IoI) and reference change values (RCVs) for each hormone were calculated. Some thyroid hormones showed similar (total T4 by EIA) or greater (TSH) interindividual relative to intraindividual variation resulting in intermediate to high IoI, consistent with previous studies evaluating the biological variation of these hormones weekly for 5-6 weeks. By contrast, total T4 (by RIA) and free T4 had a low IoI. Total T3 had a high ratio of to ; therefore, interindividual variation could not be distinguished from analytical variation. No seasonal variability in the hormones could be demonstrated. Clinicians might improve the diagnosis of feline thyroid disease by establishing baseline concentrations for analytes with intermediate-high IoI (total T4, TSH) for individual cats and applying RCVs to subsequent measurements.

Evaluation of the therapeutic effect of Descurainia sophia (L.) Webb ex Prantl seed extract on hyperthyroidism: A double-blind placebo-controlled pilot clinical trial.

The seeds of Descurainia sophia (L.) Webb ex Prantl contain goitrogenic glucosinolates, such as gluconapin (3-butenyl glucosinolate). Because of the important role of iodine in the synthesis of thyroid hormones and the inhibitory activity of D. sophia on iodine uptake by the thyroid gland, this study aimed to determine the effects of D. sophia syrup on clinical and biochemical variables of thyrotoxicosis in hyperthyroid patients. In this randomized, double-blind trial, 10 newly diagnosed hyperthyroid female patients were randomly assigned to treatment with (1) methimazole (MMI) plus D. sophia capsules (350 mg/d) or (2) MMI plus placebo capsules. The primary outcomes were clinical and biochemical manifestations of hyperthyroidism after 60 days. Serum levels of FT3 and FT4 significantly decreased (5.9 ± 2.5 vs. 9.4 ± 5.9 and 29.1 ± 3.1 vs. 31.77 ± 3.7, respectively) and the serum thyroid-stimulating hormone (TSH) concentration significantly increased in the D. sophia group contrasted to the placebo group (4.7 ± 0.1 vs. 0.05 ± 0.02). Significant improvement in the thyrotoxicosis clinical symptoms was reported in the D. sophia group contrasted to the placebo group (p < .05). D. sophia can suppress plasma levels of FT3 and FT4 and may be useful as adjunctive therapy for hyperthyroidism.

Reference intervals for serum TSH concentrations of healthy children from the Central Region of Brazil.

The objective of this study was to determine the serum thyroid-stimulating hormone (TSH) concentration reference intervals (RIs) of healthy children aged 1 to 10 years of both sexes, living in the Central Region of Brazil. 1,735 children [869 (50.1%) female; 866 (49.9%) male] enrolled in the morning shift of 47 pre- and 83 public elementary schools in the municipality of Cuiabá, Mato Grosso, were studied by gathering anthropometric and social data and their medical history. A blood sample was collected from each child to determine the TSH concentration using the electrochemiluminescence method on a Cobas® 6000 modular analyzer (Analyzer series, Roche Diagnostics). The RIs were determined using the 2.5 and 97.5 percentile and the mean ± 2 standard deviations methods. After identifying the homoscedastic groups by age and sex, outliers higher or lower than three standard deviations were excluded. The distribution of serum TSH concentrations showed no significant age or sex differences. Based on the percentile method, TSH RI ranged from 0.93 to 5.86 μIU/mL. Based on the mean ± 2 standard deviations, TSH RI ranged from 0.30 to 5.29 μIU/mL. The normal serum TSH concentration of the Brazilian children evaluated in this study differ from those of populations from other countries. Other regional population studies may validate the RIs found in this study and enable its safer use in pediatric clinical practice.

Effect of morning versus night-time administration of proton pump inhibitor (pantoprazole) on thyroid function test in levothyroxine-treated primary hypothyroidism: a prospective cross-over study

BackgroundOne of the common causes of suboptimal control of thyroid stimulating hormone (TSH) in levothyroxine-treated hypothyroidism is coadministration of proton pump inhibitors (PPIs). Morning administration of pantoprazole has been shown to suppress intragastric pH to a greater extent. We therefore aimed to determine the effect of pantoprazole at different time points of the day on thyroid function test (TFT) in levothyroxine-treated overt primary hypothyroidism.MethodsIn this single centre, hospital based, prospective, two arm cross-over study (AB, BA), participants were randomized into 2 groups based on morning (6:00 am – 7:00 am simultaneously with the scheduled levothyroxine tablet) (group M) and evening (30 min before dinner) intake of 40 mg pantoprazole tablet (group N). After the initial 6 weeks (period 1), a washout period of 1 week for pantoprazole was given, and then both the groups crossed over for another 6 weeks (period 2). Patients were instructed to continue the same brand of levothyroxine tablet at empty stomach 1-hour before breakfast. Serum TSH was measured at baseline, week 6, and week 13.ResultsData from 30 patients, who completed the study with 100% compliance, were analysed. Mean TSH values of the study participants were significantly higher both at week 6 and week 13 compared to the baseline. Mean baseline serum TSH concentrations for groups M and N were 2.70 (± 1.36), and 2.20 (± 1.06) µlU/mL, respectively. Mean serum TSH concentrations at the end periods 1 and 2 for group M were 3.78 (± 4.29), and 3.76 (± 2.77) while the levels in group N were 3.30 (± 1.90), and 4.53 (± 4.590) µlU/mL, respectively. There was a significant rise in serum TSH concentration across periods 1 and 2 in both the groups (F2, 58 = 3.87, p = 0.03). Within group changes in TSH across periods 1 and 2 were not statistically significant. Similarly difference in TSH between the groups, either at 6 weeks or at 13 weeks, were also not statistically significant.ConclusionsConcomitant use of pantoprazole, even for 6 weeks, leads to significant elevation in serum TSH in levothyroxine-treated patients who are biochemically euthyroid, irrespective of timing of pantoprazole intake. Early morning and night-time administration of pantoprazole have similar effect on TFT in these patients.

The determinants of thyroid function among vegetable farmers with primary exposure to chlorpyrifos: A cross-sectional study in Central Java, Indonesia

ObjectivesOccupational pesticide exposure, chlorpyrifos (CPF) in particular, may adversely affect the thyroid. The purpose of this study was to evaluate the determinants of thyroid function as indicated by the serum concentration of thyroid-stimulating hormone (TSH) among Indonesian vegetable farmers with primary exposure to CPF. MethodsA total of 151 vegetable farmers participated in this study. The sociodemographic and occupational characteristics of the participants were obtained using a structured interviewer-administered questionnaire. A validated quantitative method was used to estimate the cumulative exposure level (CEL). Serum TSH, thyroglobulin (Tg), free thyroxine (FT4), and urinary iodine excretion (UIE) were measured in the laboratory. The difference in TSH concentrations according to CEL and other characteristics were analysed using the Mann-Whitney U test. A multiple linear regression model was used to evaluate the potential determinants of TSH. ResultsThe mean age was 50 (SD 9.4) years. The median concentrations of TSH, FT4, and Tg/FT4 ratio were 1.46 mIU/L, 1.17 ng/dL, and 6.23 × 102, respectively. We observed that higher TSH concentrations were found among those with a higher Tg/FT4 ratio, were classified as high CEL, and had lower UIE or FT4. ConclusionsOur findings show that Tg/FT4 ratio, CEL, FT4, UIE concentrations, and post-spraying days were determinants of TSH concentrations among farmers with primary exposure to CPF. These results indicate that farmers are exposed to agents with thyroid-disrupting properties, thus supporting previous evidence showing the potential for thyroid disorders in agricultural populations exposed to pesticides.

Iodine-Induced Hyperthyroidism and Long-term Risks of Incident Atrial Fibrillation and Flutter.

Although iodine-induced hyperthyroidism is a potential consequence of iodinated radiologic contrast administration, its association with long-term cardiovascular outcomes has not been previously studied. To investigate the relationships between hyperthyroidism observed after iodine contrast administration and incident atrial fibrillation/flutter. Retrospective cohort study of the U.S. Veterans Health Administration (1998-2021) of patients age ≥18 years with a normal baseline serum thyrotropin (TSH) concentration, subsequent TSH <1 year, and receipt of iodine contrast <60 days before the subsequent TSH. Cox proportional hazards regression was employed to ascertain the adjusted hazard ratio (HR) with 95% CI of incident atrial fibrillation/flutter following iodine-induced hyperthyroidism, compared with iodine-induced euthyroidism. Iodine-induced hyperthyroidism was observed in 2500 (5.6%) of 44 607 Veterans (mean ± SD age, 60.9 ± 14.1 years; 88% men) and atrial fibrillation/flutter in 10.4% over a median follow-up of 3.7 years (interquartile range 1.9-7.4). Adjusted for sociodemographic and cardiovascular risk factors, iodine-induced hyperthyroidism was associated with an increased risk of atrial fibrillation/flutter compared with those who remained euthyroid after iodine exposure (adjusted HR 1.19, 95% CI 1.06-1.33). Females were at greater risk for incident atrial fibrillation/flutter than males (females, HR 1.81, 95% CI 1.12-2.92; males, HR 1.15, 95% CI 1.03-1.30; P for interaction = .04). Hyperthyroidism following a high iodine load was associated with an increased risk of incident atrial fibrillation/flutter, particularly among females. The observed sex-based differences should be confirmed in a more sex-diverse study sample, and the cost-benefit analysis of long-term monitoring for cardiac arrhythmias following iodine-induced hyperthyroidism should be evaluated.

Lower thyroid stimulating hormone concentrations linked to suicidal ideations among individuals with anxiety and mood disorders

IntroductionSuicidal behavior is quite common in individuals with anxiety and mood disorders (AMD). One of the coexistence factors in suicidal behavior is thyroid dysfunction, however the results are still controversial (Shen et al. J Affect Disord 2019;(1)180-185; Zhou et al., Transl Psychiatry. 2021;11(1):97). The role of thyroid function in suicidal ideation among individuals with comorbid AMD have not been thoroughly investigated.ObjectivesThe aim of this cross-sectional study was to identify potential associations between thyroid function and suicidal ideation in a sample of individuals with anxiety and mood disorders.MethodsThis exploratory study comprised 77 consecutive individuals with AMD (age range 18-73 years, 76% were females) attending the Psychiatry Day care unit. All individuals have been evaluated for current psychiatric diagnoses, suicidal ideation using the Mini International Neuropsychiatric Interview [M.I.N.I. 7.0.2]) as well as for socio-demographic factors and for current psychotropic medication use. Severity of depression and anxiety symptoms have been evaluated using the Patient Health Questionnaire-9 (PHQ-9) and the General Anxiety Disorder-7 (GAD-7). The biochemical blood tests were performed for the concentrations of thyroxine (FT4), triiodothyronine (FT3) and thyroid stimulating hormone (TSH). The univariate and multivariable logistic regression analyses were used to assess the association between biochemical parameters and suicidal ideation.ResultsOf all study individuals with AMD – 56% have been identified as having current SI. There were not significant differences according to age, gender, education, BMI, smoking, depression and anxiety symptoms and current psychotropics use between SI and non-SI individuals. Serum FT4, FT3 and TSH concentrations were within normal range. However individuals with SI had significantly lower TSH concentrations in comparison to the non-SI (1.54 (0.77) vs. 2.04 (1.22) IU/L, respectively; p = 0.049), without significantly differences in FT4 and FT3 concentrations. A multiple logistic regression, adjusting for sociodemographic factors and severity of mental symptoms revealed, that non-SI individuals with AMD were likely to have higher TSH levels than SI (odds ratio = 2.15 (95% CI 1.10–4.22; p = 0.027).ConclusionsAmong individuals with AMD, lower levels of TSH concentrations have been associated with presence of suicidal ideation, independently of sociodemographic factors and severity of depression and anxiety.Disclosure of InterestV. Liaugaudaitė Grant / Research support from: European Union (project No P-PD-22-150) under the agreement with the Research Council of Lithuania (LMTLT)., A. Podlipskytė: None Declared, J. Burkauskas Consultant of: Cronos, N. Mickuvienė: None Declared, V. Adomaitienė: None Declared, E. Zauka: None Declared, V. Steiblienė: None Declared

Short-term Changes in Thyroid-Stimulating Hormone Level after Body Fat Reduction via Partial Meal Replacement.

Serum thyroid-stimulating hormone (TSH) levels change during body weight reduction. However, the changes that occur during short-term body weight control interventions remain controversial. Thus, this study aimed to evaluate the changes in TSH levels according to body fat reduction. We performed a 3-month intervention study involving partial meal replacement. Forty-nine participants completed the study. Correlations between changes in TSH levels and other body composition parameters were determined. The subjects were divided into two groups according to their body fat reduction (>1 kg, n=20; <1 kg, n=29). The changes in metabolic parameters, including TSH levels, were compared. For significant values, a multivariate analysis was performed after adjustment to evaluate the relationship between TSH changes and body fat reduction. The 3-month intervention caused favorable changes in body proportions and metabolic parameters. TSH levels changed significantly only after changes in total body fat, showing a partial correlation. Changes in TSH levels were significantly different between groups (P=0.014). Moreover, the change in TSH levels was significantly different after adjustment (P=0.012). A body fat reduction, especially >1 kg, can reduce serum TSH concentrations in subjects with metabolic syndrome after short-term body weight intervention.

Reference Intervals of Thyroid Hormones During Pregnancy Established by Three Statistical Methods.

Monitoring the thyroid hormones during pregnancy is of great importance for fetal growth and development. Throughout the whole pregnancy, there is constant fluctuation in the thyroid hormone reference intervals (RIs). The purpose of this study is to determine method- and trimester-specific RIs for thyroid-stimulating hormone, free thyroxine, and free triiodothyronine in pregnant women in China. In this study, 2,167 women with normal pregnancies (first trimester, n = 299; second trimester, n = 1,032; third trimester, n = 836) and 4,231 healthy nonpregnant women subjects were recruited. Serum thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) concentrations were measured using electrochemiluminescence immunoassays in Abbott Alinity i analyzer. Following the exclusion of outliers, the RIs were determined using three statistical techniques: the non-parametric method, the Hoffmann method, and the Q-Q plot method. Pregnant women's levels of these three thyroid hormones differ markedly from those of healthy non-pregnant women. In addition, the concentrations of these three hormones change considerably over the course of the three phases of pregnancy. The Q-Q plot method offered more comparable RIs with the non-parametric method in healthy non-pregnant women than the Hoffmann method. Three statistical techniques were used to construct the trimester-specific RIs of thyroid hormones in pregnant women, and there was little difference between them all. The RIs by the non-parametric and Q-Q plot methods indicated closer RIs, and the RIs by the Hoffmann approach were higher and wider than those by the other two methods. For thyroid hormones, trimester-specific RIs are required. The RIs determined by non-parametric and Q⁃Q plot indirect calculation could be used as the alternative method.

A cross-sectional study of lipid profile among school-going children with subclinical hypothyroidism in rural Telangana

Abstract Background: Subclinical hypothyroidism (SCH) is defined as serum thyroid-stimulating hormone (TSH) concentration above the statistically defined upper limit of the reference range and serum-free thyroxine (fT4) concentration within its reference range. The correlation of higher levels of TSH and dyslipidaemia in children is controversial. This study was done among school children to document the prevalence of SCH and to investigate the association between the lipid profile and TSH in children with SCH. Methods: A cross-sectional study among 982 school-going children (6-12 years) was conducted and 91 children with SCH were included. Their weight, height, body mass index (BMI), fasting lipid profile (serum total cholesterol [TC], triglycerides [TG] and high-density lipoprotein [HDL]) were converted to z scores and compared with the reference population data. Results: The prevalence of SCH was 11%. Mean TC, TG and HDL levels (mg/dL) were 169 ± 8.8, 66.4 ± 7.7 and 40.5 ± 4.1, respectively. The mean HDL value in the study population was significantly lower, whereas the mean TC levels were significantly higher than the population mean. There was no correlation between TC z scores and TSH (ρ = 0.071) and HDL z scores and TSH (ρ = −0.01371). Multiple linear regression showed a statistically significant association between TSH and HDL z scores (P = 0.006) and TSH and TC z scores (P = 0.008) after adjusting for age and BMI z scores. Conclusions: Children with SCH have an abnormal lipid profile. There is association between TSH and dyslipidaemia (decreased HDL and increased TC) in SCH.