Free Thyroxine Levels Research Articles

Cadmium Exposure was Associated with Sex-Specific Thyroid Dysfunction: Consistent Evidence from Two Independent Cross-Sectional Studies Based on Urinary and Blood Cadmium Measurements.

Population-based studies on the association between cadmium (Cd) exposure and thyroid function are limited and have shown conflicting results. Two independent cross-sectional studies using different Cd biomarkers were carried out in six rural areas with different soil Cd levels in China. Thyroid dysfunction was defined based on levels of thyroid stimulating hormone (TSH) and free thyroxine (FT4). Multivariable linear regression, multiple logistic regression, and restrictive cubic splines models were used to estimate the association between Cd and thyroid dysfunction. For both of the two independent studies, higher Cd levels were observed to be associated with lower TSH levels and higher risk of thyroid dysfunction. The negative relationship between urinary Cd and TSH was found in both total participants (β = - 0.072, p = 0.008) and males (β = - 0.119, p = 0.020) but not in females; however, the negative relationship between blood Cd and TSH was only found in females (β = - 0.104, p = 0.024). Higher urinary Cd was associated with higher risk of thyroid dysfunction (OR = 1.77, p = 0.031), while higher blood Cd was associated with higher risk of thyroid dysfunction (OR = 1.95, p = 0.011). Results from the two independent cross-sectional studies consistently suggested that higher Cd levels were associated with sex-specific thyroid dysfunction.

Thyroid dysfunction due to trace element deficiency-not only selenium but also zinc.

Levels of serum selenium (Se) and zinc (Zn) decrease when total parental nutrition (TPN) is administered without trace element supplementation for just a few weeks. These trace elements are involved in thyroid hormone metabolism and their deficiencies cause thyroid dysfunction. However, there have been few reports on the details of its clinical course. A 50-year-old man presented with thyroid dysfunction due to Se and Zn deficiency. He had an approximately 70-cm residual small intestine after undergoing intestinal resection and he received TPN without trace element supplementation for one and a half months. Blood tests revealed high levels of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) and low levels of free triiodothyronine (FT3). An abnormal pattern of thyroid function led to suspicion of Se deficiency. Se supplementation raised FT3 levels and lowered FT4 levels to within their respective reference ranges; however, subclinical hypothyroidism persisted with transient TSH elevation. We suspected that Zn deficiency also contributed to the hypothyroidism and, therefore, initiated Zn supplementation, which resulted in normalization of thyroid function. Although thyroid dysfunction has been reported in many studies conducted on Se and Zn deficiencies, hormonal patterns vary between reports. Further accumulation of cases, including detailed data on nutritional status, would be of benefit to elucidate the clinical reality. It is important to consider Se and Zn deficiencies when TSH and FT4 levels are elevated. It should also be noted that transient TSH elevation may be observed with Se supplementation.

Protective effect of higher free thyroxine levels within the reference range on biliary tract cancer risk: a multivariable mendelian randomization and mediation analysis.

Hepatobiliary cancer (HBC), including hepatocellular carcinoma (HCC) and biliary tract cancer (BTC), is currently one of the malignant tumors that mainly cause human death. Many HBCs are diagnosed in the late stage, which increases the disease burden, indicating that effective prevention strategies and identification of risk factors are urgent. Many studies have reported the role of thyroid hormones on HBC. Our research aims to assess the causal effects and investigate the mediation effects between thyroid function and HBC. Utilizing the Mendelian randomization (MR) approach, the study employs single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) to explore causal links between thyroid function [free thyroxine (FT4), thyroid stimulating hormone (TSH), hyperthyroidism and hypothyroidism] and HBC. Data were sourced from the ThyroidOmic consortium and FinnGen consortium. The analysis included univariable and multivariable MR analysis, followed by mediation analysis. The study found a significant causal association between high FT4 levels and the reduced risk of BTC, but not HCC. However, TSH, hyperthyroidism and hypothyroidism had no causal associations with the risk of HBC. Notably, we also demonstrated that only higher FT4 levels with the reference range (FT4-RR) could reduce the risk of BTC because this protective effect no longer existed under the conditions of hyperthyroidism or hypothyroidism. Finally, we found that the protective effect of FT4-RR on BTC was mediated partially by decreasing the risk of metabolic syndrome (MetS) and reducing the waist circumference (WC). The findings suggest that higher FT4-RR may have a protective effect against BTC, which is partially mediated by decreased risk of MetS and a reduction in WC. This study highlights the potential role of FT4 in the pathogenesis of BTC and underscores that MetS and WC may play mediation effects as two mediators in this process.

Lipid Profile Perturbations Associated With Subclinical Hypothyroidism: A Descriptive Study.

Background Hypothyroidism is a prevalent endocrine disorder associated with dyslipidemia, which increases cardiovascular risk. Our study aimed to estimate the prevalence of dyslipidemia and subclinical hypothyroidism (SCH) and their correlation in a diverse population. Methods A descriptive cross-sectional retrospective analysis was conducted to assess the prevalence of dyslipidemia in patients with SCH. Data were collected over 19 months from the Clinical Biochemistry Department of a Moroccan university hospital. A total of 447 patients were included based on comprehensive lipid profile andthyroid-stimulating hormone (TSH) assessments, and normal free thyroxine (FT4) levels. Lipid profile and TSHmeasurements followed standardized procedures using the Cobas Roche® 6000 system (Roche Diagnostics Corporation,Indianapolis,USA). Dyslipidemia and SCH were defined according to established thresholds recommended by reputable organizations. Statistical analyses were performed using SPSS version 23.0 (IBM Corp., Armonk, USA)and Microsoft Excel (Microsoft Corporation, Redmond, USA), with significance set at p <0.05. Results In the total population (447 individuals), the prevalence of dyslipidemia was approximately 42.05% (N = 188), with hypoHDLemia being most prevalent at approximately 31.31% (N = 140). The prevalence of SCHwas approximately 12.75% (N = 57), with women constituting approximately 7.6% and men approximately 5.15%. In the euthyroid group 1 (N = 390), the prevalence of dyslipidemia was approximately 40.76% (159 individuals), while in the hypothyroid group 2 (N = 57), it increased to approximately 50.87% (N = 29). Hypertriglyceridemia was more prevalent in Group 2, with a prevalence of approximately 21.05% (N = 12), compared to Group 1, which had a prevalence of approximately 13.84% (N = 54). Additionally, hypoHDLemia was notably higher in Group 2, with a prevalence of approximately 38.59% (N = 22), compared to Group 1, which had a prevalence of approximately 30.25% ( N = 118). The chi-square test revealed a significant association between SCH and dyslipidemia (χ2 = 1.427, p <0.05). The calculated odds ratio (OR) of 1.5 (p <0.05) indicates that individuals with SCHare 1.5 times more likely to have dyslipidemia compared to those without SCH. Conclusion In conclusion, our study provides valuable insights into the prevalence of dyslipidemia and its association with SCHin our patient population. We observed a notable prevalence of dyslipidemia among individuals with SCH, characterized by elevated levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Importantly, while chi-square tests revealed a significant association between SCH and dyslipidemia, logistic regression analyses did not confirm a statistically significant correlation after adjusting for potential confounders.

Impending thyroid storm caused by hydatidiform mole

Introduction: Thyroid storm is a rare but life-threatening endocrine emergency. It is an acute exaggerated clinical manifestation of thyrotoxic state. We report an impending thyroid storm caused by a hydatidiform mole in a 14-year-old girl. This paper intends to describe hyperthyroidism secondary to molar pregnancy highlighting the rare but essential evaluation of hyperthyroidism. Case: A 14-year-old girl was consulted by the obstetric division to evaluate and manage hydatidiform mole with suspected hyperthyroidism. She had frequent palpitations and tremors for 1 week ago. She also complained of nausea and vomiting 1 week before admission to the hospital. We found a Burch-Wartofsky score of 25, which was categorized as an impending thyroid storm. Laboratory results showed mild anemia, low thyroid stimulating hormone (TSH) levels, high free thyroxine (T4) levels, and markedly elevated beta-human chorionic gonadotropin (beta-hCG) levels, normal Thyroid-stimulating hormone receptor antibodies (TRAb). Other laboratory parameters are mediocre. The ECG results showed sinus tachycardia. A mole tissue biopsy of the uterus confirms the morphology of the hydatidiform mole. These findings established the diagnosis of Impending Thyroid Storm caused by a hydatidiform mole. Conclusion: A hydatidiform mole can cause thyroid storm because the hormone hCG has similar structure to TSH. Doctors should always estimate the possibility of hyperthyroidism in a molar pregnancy.

Reference intervals for thyroid function from the fifth to seventh day of life in twin-pregnancy preterm neonates: an 8-year retrospective study.

The immature and developing hypothalamic-pituitary-thyroid axis leads to different levels of thyroid function in twin neonates, including free thyroxine (FT4), free triiodothyronine (FT3), and thyroid stimulating hormone (TSH) levels. No reference intervals for twins have been established until now. To compensate for this lack, we collected data and established this standard across different gestational ages (GAs) and sexes. A total of 273 pairs of neonates admitted to the NICU in Southeast China from 2015 to 2022 were included. Each pair was divided into Neonate A (relatively heavy birth weight (BW)) and Neonate B (relatively light BW). Their thyroid functions were analyzed to establish reference intervals and comparisons were made stratified by GA and sex. The FT3, FT4, and TSH reference intervals in twin neonates with a GA of 26-36 weeks were as follows: Neonate A and B: 3.59 ± 0.99 and 3.57 ± 1.00 pmol/L; Neonate A and B: 17.03 ± 5.16 and 16.77 ± 5.29 pmol/L; and Neonate A and B: 4.097 ± 3.688 and 4.674 ± 4.850 mlU/L, respectively. There were significant differences between serum FT3 and FT4 reference intervals and GA (p < 0.05). The serum FT3 and FT4 reference intervals for male neonates were lower than those for female neonates in the 29-32-week group (p < 0.05). This was the first study, to our knowledge, to establish reference intervals for thyroid function in twin neonates from the fifth to seventh day of life, which will be beneficial for the diagnosis and management of congenital hypothyroidism.

Thyroid dysfunction in Egyptian patients with liver cirrhosis: a cross-sectional study

Background Owing to the liver’s important role in thyroid hormone metabolism. Concerns were raised about the effect of the degree of liver cirrhosis on thyroid functions. This study aimed to assess the effect of liver cirrhosis on thyroid functions and the relation between thyroid dysfunctions and both the severity of liver disease and associated clinical presentations. Aim To assess the effect of liver cirrhosis on thyroid function and its relation to the severity of liver disease. Patients and methods This was a cross-sectional study conducted on 70 patients with liver cirrhosis (35 cirrhotic compensated patients and 35 decompensated patients) in addition to 20 healthy control subjects. Serum free triiodothyronine (FT3), free thyroxine, and thyroid stimulating hormone (TSH) levels were measured. The severity of liver cirrhosis was assessed by Child-Turcotte-Pugh (CTP) and Model for End-Stage Liver Disease (MELD) scores. Statistical analysis was done to compare groups and evaluate the association of thyroid function tests with CTP and MELD scores. Results FT3 and free thyroxine levels showed significant differences among studied groups (P=0.013 and &lt;0.001, respectively) as both were decreased in decompensated patients compared with control group, while only FT3 was significantly decreased in compensated patients than the control group. While TSH levels showed no significant difference (P=0.062). FT3 and TSH levels showed a significant negative correlation to CTP and MELD scores. Conclusion Liver cirrhosis was associated with abnormalities in thyroid function tests that may be an additive cause to complaints in those patients. Being inversely related to the severity of the liver condition both TSH and FT3 needed to be followed-up as the liver condition deteriorated.

Thyroid psychosis: when your hormones take over your mind: a case report

IntroductionHyperthyroidism, characterized by excessive production of thyroid hormones, is a common endocrine disorder that affects various body systems. While most commonly recognized for its classic symptoms such as weight loss, tremors, and palpitations, it is important to acknowledge that hyperthyroidism can also lead to a rare but significant complication: psychosis. Psychosis in the context of hyperthyroidism refers to the presence of delusions, hallucinations, and disordered thinking, which can significantly impact an individual’s mental health and overall well-being.ObjectivesThis case report aims to describe a rare case of hyperthyroidism-related psychosis in a patient including the clinical presentation, diagnosis, and management. Additionally, we aim to increase awareness of and promote further research into this condition.MethodsWe present a comprehensive case report detailing the clinical course of a 29-year-old male patient with no previous medical or psychiatric history, who sought urgent psychiatric evaluation at the Razi Hospital La Manouba’s emergency department due to escalating symptoms of agitation and paranoia persisting for three days. The patient, identified as Mr. S.O., a Tunisian male, presented with severe agitation and paranoia necessitating the use of restraints upon admission to the psychiatric emergency department. The initial physical examination revealed no notable abnormalities, except for the presence of tachycardia, which was subsequently confirmed on an electrocardiogram, arousing suspicion of a primary psychiatric illness.ResultsWhile the standard blood workup yielded unremarkable findings, the endocrine workup revealed decreased levels of thyroid-stimulating hormone (TSH) and elevated free thyroxine (FT4). Further laboratory investigations demonstrated elevated anti-thyroid-stimulating hormone receptor antibodies, leading to the diagnosis of Graves’ disease. Collaborative consultation with an endocrinologist resulted in the initiation of a treatment regimen consisting of methimazole, propranolol, and risperidone. Notably, within three days of the initiated therapy, the patient exhibited significant improvement in terms of reduced agitation, coherent speech, and the development of self-reflection regarding the episode, ultimately leading to his discharge on the seventh day of hospitalization. This case report serves to highlight the complexity of psychiatric presentations associated with underlying endocrine disorders and underscores the importance of interdisciplinary collaboration in achieving optimal patient outcomes.ConclusionsWhile mental health factors play a significant role in the development of psychosis, it is essential to recognize that underlying medical conditions may also contribute to its onset or exacerbation.Disclosure of InterestNone Declared

Deciphering thyroid function and CIMT: a Mendelian randomization study of the U-shaped influence mediated by apolipoproteins.

Carotid Intima-Media Thickness (CIMT) is a key marker for atherosclerosis, with its modulation being crucial for cardiovascular disease (CVD) risk assessment. While thyroid function's impact on cardiovascular health is recognized, the causal relationship and underlying mechanisms influencing CIMT remain to be elucidated. In this study, Mendelian Randomization (MR) was employed to assess the causal relationship between thyroid function and CIMT. Thyroid hormone data were sourced from the Thyroidomics Consortium, while lipid traits and CIMT measurements were obtained from the UK Biobank. The primary analysis method was a two-sample MR using multiplicative random effects inverse variance weighting (IVW-MRE). Additionally, the study explored the influence of thyroid hormones on lipid profiles and assessed their potential mediating role in the thyroid function-CIMT relationship through multivariate MR analysis. The study revealed that lower levels of Free Thyroxine (FT4) within the normal range are significantly associated with increased CIMT. This association was not observed with free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), or TPOAb. Additionally, mediation analysis suggested that apolipoprotein A-I and B are involved in the relationship between thyroid function and CIMT. The findings indicate a potential U-shaped curve relationship between FT4 levels and CIMT, with thyroid hormone supplementation in hypothyroid patients showing benefits in reducing CIMT. This research establishes a causal link between thyroid function and CIMT using MR methods, underscoring the importance of monitoring thyroid function for early cardiovascular risk assessment. The results advocate for the consideration of thyroid hormone supplementation in hypothyroid patients as a strategy to mitigate the risk of carotid atherosclerosis. These insights pave the way for more targeted approaches in managing patients with thyroid dysfunction to prevent cardiovascular complications.

Effect of Laparoscopic Sleeve Gastrectomy on Thyroid Function Tests and Levothyroxine Doses in People With Obesity.

We investigatedhow laparoscopic sleeve gastrectomy (LSG) affected serum levels of thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) in obese patients with hypothyroidism. We additionally examinedwhether the dose of levothyroxine decreases as a result of weight loss in this study. Fifty-one people with obesity who received levothyroxine treatment for hypothyroidism and underwent LSG between January 2017 and January 2023 were retrospectively examined. Weight, body mass index (BMI), TSH, FT4, FT3, weekly levothyroxine dose changes, and weight-adjusted levothyroxine doses before surgery and the sixth monthafter surgery were compared. Among the 51 patients included in this study, 50.98% ceased the use of levothyroxine, and nearly half (41.18%) required an adjustment of their levothyroxine dose during the follow-up period (sixthmonth). Notably, the total weekly dose of levothyroxine (mcg) decreased in the sixthmonth following surgery (p<0.001). The weekly weight-adjusted dose (mcg/kg) decreased during the same time frame (p<0.001). The preoperative total weekly dose of levothyroxine, EWL% and absence of hyperlipidemia were found to be the independent predictors of the weight-adjusted weekly levothyroxine dose change (p<0.001, p=0.038, and p=0.044, respectively). Thyroid function tests in people with obesity can show improvement after LSG. LSG may reduce the weight-adjusted dose of levothyroxine at six months postoperatively and therefore patients should be monitored for possible levothyroxine dose readjustments based on weight loss.

Microstructural alterations of the hypothalamus in Parkinson's disease and probable REM sleep behavior disorder

BackgroundWhether there is hypothalamic degeneration in Parkinson's disease (PD) and its association with clinical symptoms and pathophysiological changes remains controversial. ObjectivesWe aimed to quantify microstructural changes in hypothalamus using a novel deep learning-based tool in patients with PD and those with probable rapid-eye-movement sleep behavior disorder (pRBD). We further assessed whether these microstructural changes associated with clinical symptoms and free thyroxine (FT4) levels. MethodsThis study included 186 PD, 67 pRBD, and 179 healthy controls. Multi-shell diffusion MRI were scanned and mean kurtosis (MK) in hypothalamic subunits were calculated. Participants were assessed using Unified Parkinson's Disease Rating Scale (UPDRS), RBD Questionnaire-Hong Kong (RBDQ-HK), Hamilton Depression Rating Scale (HAMD), and Activity of Daily Living (ADL) Scale. Additionally, a subgroup of PD (n = 31) underwent assessment of FT4. ResultsPD showed significant decreases of MK in anterior-superior (a-sHyp), anterior-inferior (a-iHyp), superior tubular (supTub), and inferior tubular hypothalamus when compared with healthy controls. Similarly, pRBD exhibited decreases of MK in a-iHyp and supTub. In PD group, MK in above four subunits were significantly correlated with UPDRS-I, HAMD, and ADL. Moreover, MK in a-iHyp and a-sHyp were significantly correlated with FT4 level. In pRBD group, correlations were observed between MK in a-iHyp and UPDRS-I. ConclusionsOur study reveals that microstructural changes in the hypothalamus are already significant at the early neurodegenerative stage. These changes are associated with emotional alterations, daily activity levels, and thyroid hormone levels.

Associations among thyroid hormone levels and mean corpuscular volume in adults in the US: A cross-sectional examination of the NHANES 2007-2012 dataset.

Mean corpuscular volume (MCV) is an important indicator used to determine the etiology of anemia and is associated with a variety of diseases. However, the link between thyroid function and MCV has yet to be clarified. This study was thus developed to assess relationships between thyroid function and MCV in a population of adults in the US. Results from the National Health and Nutrition Examination Survey study performed from 2007 to 2012 were used to conduct a cross-sectional analysis. Key thyroid-related variables included in this analysis were thyroid-stimulating hormone, total thyroxine (TT4), free triiodothyronine (FT3), total triiodothyronine (TT3), free thyroxine (FT4), antithyroglobulin, thyroglobulin, and antithyroid peroxidase levels. Generalized linear regression models were employed when estimating associations between MCV quartiles and thyroid parameters in 8104 adults 18 + years of age. In these participants, the weighted mean (SD) MCV was 89.36 (0.16) fL, with thyroid-stimulating hormone levels of 1.86 (0.03) mIU/mL, FT3 levels of 3.20 (0.01) pg/mL, FT4 levels of 0.80 (0.01) ng/dL, TT3 levels of 115.09 (0.64) ng/dL, and TT4 levels of 7.81 (0.04) μg/dL. When analyses were not adjusted, higher MCV values were related to reduced serum levels of FT3, TT3, or TT4. Following adjustment for possible confounding variables, this significant negative correlation between MCV and levels of FT3, TT3, and TT4 remained, and subgroup analysis revealed that this negative correlation was present in the male group and in the age group >50 years, but not in the female group and in the age group less than or equal to 50 years. These results suggest a significant negative correlation between MCV and FT3, TT3, and TT4, and this negative correlation originated more from the male population and those older than 50 years of age. The underlying mechanisms warrant additional investigation.

COMPARATIVE ANALYSIS OF THYROID FUNCTION PROFILES BETWEEN POLYCYSTIC OVARY SYNDROME PATIENTS AND HEALTHY CONTROLS: A COMPREHENSIVE STUDY

Objective: To assess the thyroid function status of patients with Polycystic Ovary Syndrome (PCOS) and to compare it with that of healthy women. Methods: This was a descriptive cross-sectional study conducted in the Department of Biochemistry in collaboration with the Department of Obstetrics and Gynecology of a tertiary care hospital in Northern India. 30 patients diagnosed to have polycystic ovarian syndrome on the basis of the Rotterdam criteria were included in this study as cases (Group P). 30 healthy women were enrolled as the control group (Group H). The mean age and marital status of the patients were assessed. The body mass index of all the patients was also determined and compared. Systolic blood pressure, diastolic blood pressure, and pulse rate were also compared. A thyroid function test was done in both groups. The mean triiodothyronine (T3), T4, and thyroid-stimulating hormone (TSH) levels were compared in both groups. p&lt;0.05 was taken as statistically significant. Results: The mean age of patients with PCOS and healthy individuals was 22.10±3.97 years and 23.76±3.97 years, respectively. The mean ages of both groups were found to be comparable in both studies (p=0.1108). The mean body mass index (BMI) of groups P and H was found to be 27.23±5.82 and 23.15±4.12, respectively. The women in group P were found to have a higher BMI as compared to women in group H, and the difference was found to be statistically significant (p=0.0027). The mean pulse rate, systolic blood pressure, and diastolic blood pressure values were found to be comparable. The mean FT3 levels in groups P and H were found to be 3.11±0.88 and 3.13±0.42 ng/mL, whereas the mean free thyroxine levels in groups P and H were found to be 0.96±0.16 and 0.89±0.15, respectively, μg/dL. The mean T3 and T4 levels of both groups were found to be comparable in both groups. However, the mean TSH level in groups P and H was found to be 4.95±2.24 and 2.50±1.19 0.3–4.5 μIU/ml, respectively. The mean TSH level in group P was found to be higher than group H, and the difference was found to be statistically significant (p&lt;0.001). Conclusion: The prevalence of subclinical hypothyroidism was found to be significantly high in women with PCOS, making it necessary to do periodic thyroid function tests in PCOS.

TSHR Variant Screening and Phenotype Analysis in 367 Chinese Patients With Congenital Hypothyroidism.

Genetic defects in the human thyroid-stimulating hormone (TSH) receptor (TSHR) gene can cause congenital hypothyroidism (CH). However, the biological functions and comprehensive genotype-phenotype relationships for most TSHR variants associated with CH remain unexplored. We aimed to identify TSHR variants in Chinese patients with CH, analyze the functions of the variants, and explore the relationships between TSHR genotypes and clinical phenotypes. In total, 367 patients with CH were recruited for TSHR variant screening using whole-exome sequencing. The effects of the variants were evaluated by in-silico programs such as SIFT and polyphen2. Furthermore, these variants were transfected into 293T cells to detect their Gs/cyclic AMP and Gq/11 signaling activity. Among the 367 patients with CH, 17 TSHR variants, including three novel variants, were identified in 45 patients, and 18 patients carried biallelic TSHR variants. In vitro experiments showed that 10 variants were associated with Gs/cyclic AMP and Gq/11 signaling pathway impairment to varying degrees. Patients with TSHR biallelic variants had lower serum TSH levels and higher free triiodothyronine and thyroxine levels at diagnosis than those with DUOX2 biallelic variants. We found a high frequency of TSHR variants in Chinese patients with CH (12.3%), and 4.9% of cases were caused by TSHR biallelic variants. Ten variants were identified as loss-of-function variants. The data suggest that the clinical phenotype of CH patients caused by TSHR biallelic variants is relatively mild. Our study expands the TSHR variant spectrum and provides further evidence for the elucidation of the genetic etiology of CH.

A Look at Thyroid Functions as a Predictor on Prognosis of Critically Ill Patients in İntensive Care Units from the Perspective of Covid-19.

Aim: Thyroid gland can be affected both by cytokine storm and through angiotensin-converting enzyme-2 receptors. A worse prognosis has been described in patients with low fT3 levels. The aim of this study is to evaluate the prognostic significance of thyroid function during COVID-ICU hospitalization. Methods: After ethical approval, 100 COVID-19 patients followed in the ICU between March 2020 and April 2021 was admitted to study. Patients with previous thyroid disease were excluded from study. Free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) levels at ICU admission were evaluated. Clinical, demographic, laboratory, treatment, and outcome data were obtained from the patient's electronic hospital records. Mann Whitney U, Spearman correlation, binary logistic, and linear regression tests were used for statistical analysis. Results: TSH was in 31 patients, fT3 was in 37 patients, and fT4 was in 54 patients, which were outside the normal ranges. fT3 were lower in non-survivors than the survivors (p: 0.036). However, the fT3 level was not the independent factor for mortality rate in linear regression analysis (p=0,652). APACHE II and procalcitonin levels as independent predictors of mortality (p: 0,017). fT3 remained an independent factor for the length of ICU stay (p=0,024) and the length of hospital stay (p=0,031). Conclusion: fT3 is a prognostic indicator that can predict hospital and ICU length of stay in critically ill patients with Covid-19. In the future, a broader panel of validated biochemical markers, including fT3 levels, may become a simple tool for stratified management of patients with severe COVID-19.

Energy-Related Hormones in Raw and Retail Cow’s Milk and Possible Risk for Consumers

Abstract The study aimed to determine the concentration of energy-related hormones in cow’s milk and to consider them from a public health perspective. Fourteen Holstein cows were subjected to milk and blood sampling on the following days in lactation (DIL): 10, 30, 60, 90, 150, 180, 210, 250 and 280 to determine milk hormones, fat and protein content and blood biochemical parameters. For the same purpose, bulk-tank milk was sampled and samples of retail m ilk with 1.5% (CM1.5) and 3.2% (CM3.2) fat was purchased. Milk insulin-like growth factor-1 (IGF-1) values were significantly lower at 90, 150, 180, 210 and 250 and significantly higher at 10, 30 and 60 DIL than lactation average (LA). Milk insulin concentrations were significantly lower at 30, 60 and 90 and higher at 210, 250 and 280 DIL than LA. Free thyroxine (fT4) level in the milk was higher at 250 DIL, while milk free triiodothyronine (fT3) concentrations were lower at 30, 60, 90 and 280 DIL, and significantly higher at 10 and 180 DIL than respective LA. Milk cortisol levels were lower at 60 and 280 DIL than LA. All measured milk hormones were significantly lower in CM1.5 compared to CM3.2, bulk-tank milk and LA. An exception was the LA of IGF-1, which was significantly lower than the IGF-1 content in CM1.5. Blood biochemical parameters fluctuated evenly during lactation and were within the reference range. Hormone concentrations in cow’s milk fluctuate during lactation, giving milk an important role in the context of public health.

Serum levels of glucose, thyroid stimulating hormone, and free thyroxine in boys diagnosed with attention deficit hyperactivity disorder: a cross-sectional pilot study

BackgroundAlthough attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder, its aetiology remains unclear. We aimed to establish a relationship between ADHD diagnosis and serum levels of glucose, free thyroxine (FT4), and thyroid stimulating hormone (TSH) in primary school aged boys.MethodsIn a cross-sectional study, we enrolled 133 participants aged 6.5–12.5 years, 67 of whom met DSM-5 criteria for ADHD and 66 healthy age-matched boys. The ADHDT test (ADHDT) was used to assess ADHD symptoms and the Wechsler Intelligence Scale for Children – Revised was used to exclude participants with cognitive deficits. The ADHD participants were tested using the Iowa Conners’ Teacher Rating Scale.ResultsThe ADHD participants had lower glucose levels, higher TSH values, and significantly lower FT4 values than the control group. The multiple logistic regression analysis showed that TSH is a parameter that is 2.7% more likely to occur in the ADHD group. We found a significant correlation between the TSH level and the symptoms of hyperactivity (r = 0.318, p = 0.009) and impulsivity (r = 0.275, p = 0.024) as well as between the glucose level and the symptoms of hyperactivity (r = 0.312, p = 0.010).ConclusionsCertain ADHD symptoms may correlate with certain hormonal patterns. Our results suggest that the likelihood of suffering from ADHD was lower when FT4 levels were elevated. One biochemical parameter that was significantly and independently associated with the diagnosis of ADHD was the serum TSH level.Trial registrationOn June 26, 2018, at its VI session in 2018, the Ethics Committee of the Institute for Mental Health in Belgrade, Serbia, has considered and unanimously approved the conduct of the research, under the number 1704/1.

Correlation of serum ferritin and thyroid hormone levels: A matched case–control study

Introduction: Hypothyroidism is a common disorder of the endocrine system caused by insufficient biologically active hormones at the tissue level or the inability of the tissue to utilize thyroid hormones. Iron plays a crucial role in the synthesis and metabolism of thyroid hormones, and it is stored in the body as ferritin. We aimed to evaluate the correlation between serum ferritin (SF) levels and thyroid hormone panel levels in both hypothyroid and euthyroid subjects. Methods: In 2022, a matched case–control study was conducted. The study involved participants with hypothyroidism and a control group (n = 53). The levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), and SF were measured using the chemiluminescence immunoassay on a Mindray Cl 900-i analyzer (Shenzhen Mindray Bio-Medical Electronics Co., China). Results: The hypothyroid group had TSH levels that were significantly higher (10.76 [8.54-18.76] vs. 1.76 [1.26-2.58]; p &lt; 0.001) and SF concentrations that were significantly lower (39.08 [21.15-45.70] vs. 54.09 [41.41-71.82]; p &lt; 0.001) compared to the control group. In both male and female subjects of the hypothyroid group, a strong negative correlation was found between SF concentration and TSH levels ([Rho = −0.855,p &lt; 0.01]; [Rho = −0.747; p &lt; 0.01]). In female subjects of the hypothyroid group, a weak positive correlation was found between SF concentration and fT3 (Rho = 0.488; p &lt; 0.05). In the euthyroid group, a correlation of the same strength and direction was found for fT4 (Rho = 0.366; p &lt; 0.05). Conclusion: Research results indicate a correlation between lower SF concentrations and hypothyroidism, which is of particular importance for understanding the etiopathogenesis, diagnosis, monitoring, and treatment modalities of patients with hypothyroidism.

Effects of Levothyroxine Treatment on Fertility and Pregnancy Outcomes in Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: Subclinical hypothyroidism, defined by elevated thyrotropin (TSH) and normal free thyroxine levels, is associated with adverse pregnancy outcomes, including preterm birth, pre-eclampsia, and small for gestational age. Despite the uncertainty regarding the effectiveness of levothyroxine (LT4) treatment on pregnancy outcomes in subclinical hypothyroidism, LT4 is widely administered with a pre-treatment threshold TSH level of 2.5 mU/L. The aim of this study is to investigate the efficacy of periconceptional LT4 treatment for subclinical hypothyroidism, including TSH levels >2.5 mU/L, and identify the characteristics of subclinical hypothyroidism that can benefit from LT4 treatment. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials from inception to February 2023. We analyzed the pooled effects of LT4 on subclinical hypothyroidism before and during pregnancy. The main outcomes before pregnancy were live birth, pregnancy, and miscarriage. The main outcomes during pregnancy were live birth, miscarriage, and preterm birth. We conducted subgroup analyses to compare the effects of LT4 on subclinical hypothyroidism with TSH levels of 2.5-4.0 and >4.0 mU/L. Results: Of the 888 studies identified, 27 full-text articles were screened for eligibility. Five studies on pre-conception treatment with 768 participants and eight studies on treatment during early pregnancy with 2622 participants were analyzed. One of the two studies on pre-conception treatment in subclinical hypothyroidism with TSH >4.0 mU/L had high risk of bias and the other was composed of 64 participants. Pre-conception LT4 treatment had no significant effect in improving rates of live births and pregnancies, or reducing miscarriages (risk ratio [RR], 95% confidence interval): 1.41 (0.84-2.36), 1.73 (0.88-3.39), and 0.46 (0.11-2.00), respectively. LT4 treatment during pregnancy was not significantly associated with higher rates of live births (RR 1.03, 0.98-1.09) nor decreased miscarriage rates (RR 1.01, 0.66-1.53). The effect of LT4 treatment on preterm birth during pregnancy was significantly different depending on the TSH values (p = 0.04); a positive effect was shown in the subclinical hypothyroidism subgroup with TSH >4.0 mU/L (RR 0.47, 0.20-1.10), while no significant effect was observed in the subgroup with TSH 2.5-4.0 mU/L (RR 1.35, 0.79-2.31). Conclusions: Pre-conceptional LT4 treatment for subclinical hypothyroidism does not improve fertility or decrease the incidence of miscarriages. However, further well-designed studies are needed for pre-conceptional treatment, especially in TSH >4.0 mU/L. LT4 treatment during pregnancy had a positive effect on preterm birth; nevertheless, this was only applicable to subclinical hypothyroidism with TSH >4.0 mU/L.

The association between per-/polyfluoroalkyl substances in serum and thyroid function parameters: A cross-sectional study on teenagers living near a Chinese fluorochemical industrial plant

Thyroid hormones (THs) play an important role in a wide range of crucial biological functions related to growth and development, and thyroid antibodies (TAs) can influence the biosynthesis of THs. Epidemiological studies have indicated that per- and polyfluoroalkyl substances (PFAS) could induce thyroid disruption, but studies on teenagers living in areas with high PFAS exposure are limited. This cross-sectional study focused on 836 teenagers (11– 15 years) living near a Chinese fluorochemical industrial plant. Decreased levels of free thyroxine (FT4, ﹤9.6 pmol/L, abnormal rate = 19.0 %) and elevated levels of free triiodothyronine (FT3, ﹥6.15 pmol/L, abnormal rate = 29.8 %) were observed. Correlations of serum PFAS concentrations and TAs/THs were analyzed. Increased PFOA was identified as a risk factor of decreased FT4 by using unadjusted (OR: 11.346; 95 % CI: 6.029, 21.352, p < 0.001) and adjusted (OR: 12.566; 95 % CI: 6.549, 24.115, p < 0.001) logistic regression models. In addition, significantly negative correlations were found between log10 transformed PFOA and FT4 levels using linear (unadjusted: β = −1.543, 95 % CI: −1.937, −1.148, p < 0.001; adjusted: β = −1.534, 95 % CI: −1.930, −1.137, p < 0.001) and BKMR models. For abnormal FT3, a significantly positive association between PFHxS and FT3 levels was observed in a regression model (unadjusted: β = −0.903, 95 % CI: −1.212, −0.595, p < 0.001; adjusted: β = −0.894, 95 % CI: −1.204, −0.583, p < 0.001), and PFHxS was identified as a risk factor (unadjusted: OR: 4.387; 95 % CI: 2.619, 7.346, p < 0.001; adjusted: OR: 4.527; 95 % CI: 2.665, 7.688, p < 0.001). Sensitivity analyses confirmed the robustness of the above results. This study reported the elevated PFAS exposure and thyroid function of teenagers living near a fluorochemical industrial plant from China.