Hypothyroidism

A causal relationship between hypothyroidism and rheumatoid arthritis, but not hyperthyroidism: evidence from the mendelian randomization study

OBJECTIVE

To investigate the genetic level causal association among hyperthyroidism, hypothyroidism, and rheumatoid arthritis (RA).

METHODS

We utilized the genome-wide association studies (GWAS) summary data for exposure (hyperthyroidism and hypothyroidism) and outcome (RA) from the IEU OpenGWAS database. We used two different sets of data (test cohort and validation cohort) for causal assessment of exposure and outcome. To establish a causal relationship between these conditions, we conducted a two-sample Mendelian randomization (MR) analysis. Subsequently, we evaluated the MR analysis results for heterogeneity, horizontal pleiotropy, and outliers, aiming to assess the validity and reliability of the findings. Moreover, we conducted additional analyses to examine the robustness of the MR results, including a "Leave one out" analysis and the MR robust adjusted profile score (MR-RAPS) method, ensuring the robustness and adherence to normal distribution assumptions.

RESULTS

The findings from the test cohort indicated that hyperthyroidism did not exhibit a genetic causal association with RA (P = 0.702, odds ratio [OR] 95% confidence interval [CI] = 1.021 [0.918-1.135]). Conversely, hypothyroidism displayed a positive genetic causal relationship with RA (P < 0.001, OR 95% CI = 1.239 [1.140-1.347]). The analysis results of the validation cohort are consistent with those of the test cohort. Notably, our MR analysis results demonstrated no evidence of heterogeneity, horizontal pleiotropy, or outliers. Furthermore, our MR analysis results remained unaffected by any single nucleotide polymorphism (SNP) and exhibited a normal distribution.

CONCLUSION

The results of this study showed that hypothyroidism was positively correlated with RA, while hyperthyroidism was not causally correlated with RA. Hypothyroidism may as a risk factor of RA should be paid attention to in clinical work. Future studies are needed to further confirm this finding.

Nonlinear association of TSH with pulmonary ventilation: insights from bidirectional Mendelian randomization and cross-sectional study

BACKGROUND

Thyroid hormones play a crucial role in numerous physiological processes, including pulmonary function. However, the relationship between thyroid function and different patterns of pulmonary ventilation remains unclear.

METHODS

This study employed a bidirectional two-sample Mendelian randomization (MR) approach combined with a cross-sectional study from the National Health and Nutrition Examination Survey (NHANES) to explore the relationship between thyroid function and pulmonary ventilation indicators. We used genomic data from the ThyroidOmics Consortium and the UK Biobank to derive instrumental variables for thyroid and pulmonary functions. Adults from the NHANES 2007-2012 were included to validate the MR findings through weighted generalized linear model (GLM) regression and restricted cubic spline (RCS) analysis.

RESULTS

Genetically predicted thyroid-stimulating hormone (TSH) was associated with pulmonary ventilatory function (forced expiratory volume in 1 s (FEV1): β = 0.0223, 95% confidence interval (CI) 0.0040-0.0406, p-value = 0.0170), particularly with a restrictive ventilatory pattern (forced vital capacity (FVC): β = 0.0237, 95% CI 0.0047-0.0427, p-value = 0.0143). This association was more robust in the low TSH subgroup. Additionally, the NHANES data revealed a nonlinear relationship between both FEV1% predicted and FVC% predicted and TSH, characterized by a positive relationship at lower TSH ranges and a negative relationship at higher TSH ranges.

CONCLUSIONS

Our findings highlight a significant association between TSH levels and a restrictive ventilatory pattern, underscoring the importance of thyroid health in the clinical evaluation of certain pulmonary diseases. These insights may guide more personalized interventions in respiratory medicine.

Subclinical hypothyroidism: a new predictor of heart failure with improved ejection fraction in HFrEF patients

Heart failure (HF) with improved ejection fraction (HFimpEF) has gradually attracted widespread attention in recent years for its better clinical prognosis. In this study, we attempted to investigate the relationship between subclinical hypothyroidism (SCH) and HFimpEF. This study retrospectively collected clinical data on patients with HF with reduced ejection fraction (HFrEF) hospitalized at the First Affiliated Hospital of USTC from March 2015 to September 2023, and divided into two groups as euthyroidism or SCH according to the baseline thyroid function. Then patients were further categorized into HFimpEF (follow-up LVEF > 40% and absolute increase ≥ 10%) and persistent HFrEF based on their LVEF on the echocardiograms during the follow-up period. Afterward, logistic regression was used to estimate the effect of SCH on HFimpEF. A total of 916 patients with HFrEF met the inclusion and exclusion criteria, and 396 patients (43.2%) progressed to HFimpEF status during the follow-up period. Compared with HFrEF patients, the prevalence of SCH is lower in HFimpEF patients (9.3% vs. 14.4%, P = 0.020). Univariate logistic regression analysis indicates that SCH was a potential predictor for HFimpEF (OR: 0.612 [95% CI 0.403-0.928], P = 0.021). After adjusting for multiple factors in logistic regression, the odds ratios of HFrEF patients with SCH progressing to HFimpEF decreased by 37.8% (OR: 0.622 [95% CI 0.397-0.974], P = 0.038) compared with patients with euthyroidism. This study suggests that thyroid function affects the improvement of cardiac function in patients with HFrEF and SCH is an independent predictor for HFimpEF.

Parameters associated with the development of autoimmune diseases in pediatric onset celiac disease

Patients with celiac disease (CeD) have an increased risk of developing other autoimmune diseases (ADs); however, risk factors and predictors for ADs remain unclear. The study objective is to assess predictors for development of ADs among pediatric onset CeD patients. The study included pediatric onset CeD patients, evaluated at Emek Medical Center, and followed for at least 2 years from April 2008 to April 2022. Data were collected from medical records and included baseline and follow-up data of demographics, clinical manifestations, laboratory variables, and subsequent development of ADs. Then, 930 children with CeD were included, and 790 fulfilled inclusion criteria. Patients were followed for a median of 4.9 years (range 2-16 years). During follow-up, 45%, 68%, and 80% normalized their tissue transglutaminase (TTG) levels by 6, 12, and 24 months, respectively. Among the entire cohort, 16 patients (2%) developed type 1 diabetes mellitus, 35 (4.4%) developed Hashimoto's thyroiditis, and 11 (1.3%) developed other ADs. Of 510 patients with sustained serological remission, 39 (7.6%) patients developed ADs compared to 23 (11.5%) of patients without sustained serological remission. In multivariate Cox models, shorter time to TTG normalization (hazard ratio (HR) 0.94 CI 95% 0.88-0.99) and sustained TTG levels less than three times the upper limit of normal (HR 0.87 CI 95% 0.72-0.96) were significantly associated with reduced risk of developing ADs.

CONCLUSION

Effective management of celiac disease, including timely TTG normalization and sustained lower TTG levels, may be important for reducing the risk of subsequent development of ADs in pediatric-onset CeD.

WHAT IS KNOWN

• Pediatric patients with celiac disease (CeD) are at an increased risk of developing autoimmune diseases (ADs). Risk factors contributing to the development of ADs in CeD patients are not well established, particularly in the pediatric population.

WHAT IS NEW

• Timely TTG normalization and sustained low TTG levels (<3 times ULN) during follow-up are associated with a reduced risk of developing additional ADs in pediatric CeD patients.

FT4 is a novel indicator for risk assessment of severe hypocalcemia following parathyroidectomy

OBJECTIVE

To analyze the risk factors associated with the development of severe hypocalcemia (SH) in patients who have undergone parathyroidectomy (PTX).

METHODS

This research involved patients with chronic kidney disease-secondary hyperparathyroidism who underwent PTX between June 1, 2021, and May 31, 2023. SH was characterized by a serum total calcium (tCa) level below 1.8 mmol/L. This study aimed to analyze differences in preoperative laboratory findings and clinical manifestations between patients with and without SH. Logistic regression analysis was used to identify potential risk factors associated with the development of SH.

RESULTS

The incidence of SH was 23% (n = 176). Significant differences were observed in free thyroxine (FT4), free triiodothyronine, alanine aminotransferase, osteocalcin, tCa, alkaline phosphatase (ALP), C-terminal cross-linked telopeptide of type I collagen, and parathyroid hormone between the SH and non-SH groups. The three independent risk factors for SH were tCa [odds ratio (OR) 0.063, 95% confidence interval (95% CI) 0.006-0.663], ALP (OR 1.003, 95% CI 1.001-1.005), and FT4 (OR 0.439, 95%CI 0.310-0.621). The area under the curve, sensitivity, specificity, and overall accuracy of this model were 0.904 (95% CI 0.856-0.952), 46.3%(95% CI 32.0%-61.3%), 94.8% (95% CI 89.7%-97.5%), and 83.5% (95% CI 77.3%-88.3%), respectively.

CONCLUSION

The preoperative level of FT4 plays a crucial role in predicting the risk of SH after PTX. The combined FT4-ALP-tCa model demonstrates the ability to predict SH risk, providing valuable insights for customizing calcium supplementation strategies and improving clinical decision-making.

Thyroid function, autoimmunity, thyroid volume, and metabolic profile in people with Hashimoto thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is associated with high cardiovascular risk. Thyroid volume has a notable dispersion of values in these patients. This study aims to clarify the association between thyroid antibodies, thyroid morphology, insulin resistance, and lipid profile in patients with HT.

METHODS

Cross-sectional study that includes 409 subjects diagnosed with HT. We assessed thyroid function, markers of autoimmunity, and markers of cardiovascular risk. We also evaluated thyroid ultrasound and studied the correlation between all factors.

RESULTS

Among the study population, 9.8% were male, the mean age was 56.4 ± 17.4 years, 63.7% had dyslipidemia, and 29.5% had diabetes. Patients with hypothyroidism had higher levels of anti-thyroperoxidase antibodies (TPOab), and the decreased thyroid dimensions subgroup had a higher percentage of patients taking levothyroxine (98.7%). Positive correlations were found between TPOab and volume, and negative correlations were observed between thyroid-stimulating hormone (TSH) and volume.

CONCLUSION

The current study reveals a complex interrelationship between cardiovascular disease risk factors, thyroid function, autoimmunity, and thyroid volume in HT. These associations may be of clinical relevance, and further studies are needed to elucidate how these findings may be used clinically to reduce the cardiovascular risk in patients with HT.

The causal effects of inflammatory and autoimmune skin diseases on thyroid diseases: evidence from Mendelian randomization study

Background

To clarify the controversy between inflammatory or autoimmune skin diseases and thyroid diseases, we performed two-sample Mendelian randomization (MR) analyses.

Participants

Genetic data on factors associated with atopic dermatitis (AD, n=40,835), seborrheic dermatitis (SD, n=339,277), acne (n=363,927), rosacea (n=299,421), urticaria (n=374,758), psoriasis (n=373,338), psoriasis vulgaris (n=369,830), systemic lupus erythematosus (SLE, n=14,267), vitiligo (n=353,348), alopecia areata (AA, n=361,822), pemphigus (n=375,929), bullous pemphigoid (BP, n=376,274), systemic sclerosis (SSc, n=376,864), localized scleroderma (LS, n=353,449), hypothyroidism (n=314,995 or n=337,159), and hyperthyroidism (n=281,683 or n=337,159) were derived from genome-wide association summary statistics of European ancestry.

Main measures

The inverse variance weighted method was employed to obtain the causal estimates of inflammatory or autoimmune skin diseases on the risk of thyroid diseases, complemented by MR-Egger, weighted median, and MR-pleiotropy residual sum and outlier (MR-PRESSO).

Key results

AD, SLE, SD, and psoriasis vulgaris were associated with an increased risk of hypothyroidism, whereas BP was associated with a lower risk of hypothyroidism (all with p < 0.05). The multivariable MR analyses showed that AD (OR = 1.053; 95%CI: 1.015-1.092; p = 0.006), SLE (OR = 1.093; 95%CI: 1.059-1.127; p < 0.001), and SD (OR = 1.006; 95%CI: 1.002-1.010; p = 0.006) independently and predominately contributed to the genetic causal effect on hypothyroidism after adjusting for smoking. The results showed no causal effects of inflammatory or autoimmune skin diseases on hyperthyroidism.

Conclusion

The findings showed a causal effect of AD, SLE, SD on hypothyroidism, but further investigations should be conducted to explore the pathogenic mechanisms underlying these relationships.

LncRNA MALAT1-miR-339-5p-NIS axis is involved in the increased level of thyroid stimulating hormone (TSH) induced by combined exposure of high iodine and hyperlipidemia

Hypothyroidism and subclinical hypothyroidism were both characterized by elevated levels of thyroid stimulating hormone (TSH). Previous studies had found that high iodine or hyperlipidemia alone was associated with increased TSH level. However, their combined effects on TSH have not been elucidated. In this study, combination of high iodine and hyperlipidemia was established through the combined exposure of high-water iodine and high fat diet in Wistar rats. The results showed that combined exposure of high iodine and high fat can induce higher TSH level. The mRNA and protein levels of sodium iodide transporters (NIS) and type 1 deiodinase (D1) in thyroid tissues, which were crucial genes in the synthesis of thyroid hormones, decreased remarkably in combined exposure group. Mechanistically, down-regulated long non-coding RNA (lncRNA) metastasis associated in lung denocarcinoma transcript 1 (MALAT1) may regulate the expression of NIS by increasing miR-339-5p, and regulating D1 by increasing miR-224-5p. Then, the above findings were explored in subjects exposed to high water iodine and hyperlipidemia. The results indicated that in population combined with high iodine and hyperlipidemia, TSH level increased to higher level and lncRNA MALAT1-miR-339-5p-NIS axis was obviously activated. Collectively, this study found that combined exposure of high iodine and hyperlipidemia induced a higher level of TSH, and lncRNA MALAT1-miR-339-5p-NIS axis may play important role.

Multi-regulatory potency of USP1 on inflammasome components promotes pyroptosis in thyroid follicular cells and contributes to the progression of Hashimoto's thyroiditis

BACKGROUND

Inflammatory diseases are often initiated by the activation of inflammasomes triggered by pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs), which mediate pyroptosis. Although pyroptosis resulting from aberrant inflammasome triggering in thyroid follicular cells (TFCs) has been observed in Hashimoto's thyroiditis (HT) patients, the underlying mechanisms remain largely unknown. Given the extensive involvement of protein ubiquitination and deubiquitination in inflammatory diseases, we aimed to investigate how deubiquitinating enzymes regulate thyroid follicular cell pyroptosis and HT pathogenesis.

METHODS

Our study specifically investigated the role of Ubiquitin-specific peptidase 1 (USP1), a deubiquitinase (DUB), in regulating the inflammasome components NLRP3 and AIM2, which are crucial in pyroptosis. We conducted a series of experiments to elucidate the function of USP1 in promoting pyroptosis associated with inflammasomes and the progression of HT. These experiments involved techniques such as USP1 knockdown or inhibition, measurement of key pyroptosis indicators including caspase-1, caspase-1 p20, and GSDMD-N, and examination of the effects of USP1 abrogation on HT using a mouse model. Furthermore, we explored the impact of USP1 on NLRP3 transcription and its potential interaction with p65 nuclear transportation.

RESULTS

Our findings provide compelling evidence indicating that USP1 plays a pivotal role in promoting inflammasome-mediated pyroptosis and HT progression by stabilizing NLRP3 and AIM2 through deubiquitination. Furthermore, we discovered that USP1 modulates the transcription of NLRP3 by facilitating p65 nuclear transportation. Knockdown or inhibition of USP1 resulted in weakened cell pyroptosis, as evidenced by reduced levels of caspase-1 p20 and GSDMD-N, which could be restored upon AIM2 overexpression. Remarkably, USP1 abrogation significantly ameliorated HT in the mice model, likely to that treating mice with pyroptosis inhibitors VX-765 and disulfiram.

CONCLUSIONS

Our study highlights a regulatory mechanism of USP1 on inflammasome activation and pyroptosis in TFCs during HT pathogenesis. These findings expand our understanding of HT and suggest that inhibiting USP1 may be a potential treatment strategy for managing HT.

Traditional Chinese Medicine for Hashimoto's Thyroiditis: Focus on Selenium and Antioxidant Phytochemicals

Hashimoto's thyroiditis (HT) is not only the most frequent autoimmune thyroid disease (AITD), but it also has a significant impact on patients' health-related quality of life (HRQoL), and it has been variably associated with differentiated thyroid carcinoma. Even though its pathogenesis is still incompletely understood, oxidative stress is believed to play an important role. Hypothyroidism related to later stages of HT can be treated with levothyroxine substitution therapy; various approaches such as selenium supplementation and iodine-restricted diets have been proposed as disease-modifying treatments for earlier stages, and even thyroidectomy has been suggested for refractory cases of painful HT. Nevertheless, many patients still report suboptimal HRQoL, highlighting an unmet medical need in this area. The concepts and approaches of traditional Chinese medicine (TCM) in treating HT are not broadly known in the West. Here, we provide an overview of TCM for HT, including combinations of TCM with selenium. We encompass evidence from clinical trials and other studies related to complex TCM prescriptions, single herbs used in TCM, and phytochemicals; wherever possible, we delineate the probable underlying molecular mechanisms. The findings show that the main active components of TCM for HT have commonly known or presumed antioxidant and anti-inflammatory activities, which may account for their potential utility in HT. Further exploring the practices of TCM for HT and combining them with evidence- and mechanism-based approaches according to Western standards may help to identify new strategies to alter the clinical course of the disease and/or to treat patients' symptoms better and improve their HRQoL.

Evaluating the effectiveness of combined T4 and T3 therapy or desiccated thyroid versus T4 monotherapy in hypothyroidism: a systematic review and meta-analysis

BACKGROUND

Persistent symptoms in hypothyroid patients despite normalized TSH levels suggest the need for alternative treatments. This study aims to evaluate the effectiveness of combined T4 and T3 therapy or desiccated thyroid (DTE) compared to T4 monotherapy, with a focus on thyroid profile, lipid profile, and quality of life metrics.

METHODS

We conducted a systematic review in Embase, Medline/PubMed, and Web of Science up to 11/23/2023. We used the following keywords: "Armour Thyroid," OR "Thyroid extract," OR "Natural desiccated thyroid," OR "Nature-Throid," "desiccated thyroid," OR "np thyroid," OR "Synthroid," OR "levothyroxine," OR "Liothyronine," "Cytomel," OR "Thyroid USP," OR "Unithroid." AND "hypothyroidism. " We only included RCTs and excluded non-RCT, case-control studies, and non-English articles.

RESULTS

From 6,394 identified records, 16 studies qualified after screening and eligibility checks. We included two studies on desiccated thyroid and 15 studies on combined therapy. In this meta-analysis, combination therapy with T4 + T3 revealed significantly lower Free T4 levels (mean difference (MD): -0.34; 95% CI: -0.47, -0.20), Total T4 levels (mean difference: -2.20; 95% CI: -3.03, -1.37), and GHQ-28 scores (MD: -2.89; 95% CI: -3.16, -2.63), compared to T4 monotherapy. Total T3 levels were significantly higher in combined therapy (MD: 29.82; 95% CI: 22.40, 37.25). The analyses demonstrated moderate to high heterogeneity. There was no significant difference in Heart Rate, SHBG, TSH, Lipid profile, TSQ-36, and BDI Score. Subjects on DTE had significantly higher serum Total T3 levels (MD: 50.90; 95% CI: 42.39, 59.42) and significantly lower serum Total T4 (MD: -3.11; 95% CI: -3.64, -2.58) and Free T4 levels (MD: -0.50; 95% CI: -0.57, -0.43) compared to T4 monotherapy. Moreover, DTE treatment showed modestly higher TSH levels (MD: 0.49; 95% CI: 0.17, 0.80). The analyses indicated low heterogeneity. There was no significant difference in Heart Rate, SHBG, Lipid profile, TSQ-36, GHQ-28, and BDI Score.

CONCLUSIONS

Our study revealed that combined therapy and DTE lead to higher T3 and lower T4 levels, compared to T4 monotherapy in hypothyroidism. However, no significant effects on heart rate, lipid profile, or quality of life were noted. Given the heterogeneity of results, personalized treatment approaches are recommended.

Drug-induced hypothyroidism in tuberculosis

INTRODUCTION

Adverse reactions to tuberculosis treatment can impact patient adherence and prognosis. Hypothyroidism is a frequent adverse reaction caused using ethionamide, prothionamide, and para-aminosalicylic acid and is often underdiagnosed.

AREAS COVERED

We searched Scielo, Scopus, and EMBASE databases, including 67 articles. Antitubercular drug-induced hypothyroidism has a prevalence of 17%. It occurs after 2 to 3 months of treatment and resolves within 4 to 6 weeks after discontinuation. It is postulated to result from the inhibition of thyroperoxidase function, blocking thyroid hormone synthesis. Symptoms are nonspecific, necessitating individualized thyroid-stimulating hormone measurement for detection. Specific guidelines for management are lacking, but initiation of treatment with levothyroxine, as is customary for primary hypothyroidism, is recommended. Discontinuation of antitubercular drugs is discouraged, as it may lead to unfavorable consequences.

EXPERT OPINION

Antitubercular drug-induced hypothyroidism is more common than previously thought, affecting one in six MDR-TB patients. Despite diagnostic and treatment recommendations, implementation is hindered in low-income countries due to the lack of certified laboratories. New drugs for tuberculosis treatment may affect thyroid function, requiring vigilant monitoring for complications, including hypothyroidism.

Causal association between obesity and hypothyroidism: a two-sample bidirectional Mendelian randomization study

Introduction

Previous observational studies have reported a positive correlation between obesity and susceptibility to hypothyroidism; however, there is limited evidence from alternative methodologies to establish a causal link.

Methods

We investigated the causal relationship between obesity and hypothyroidism using a two-sample bidirectional Mendelian randomization (MR) analysis. Single-nucleotide polymorphisms (SNPs) associated with obesity-related traits were extracted from a published genome-wide association study (GWAS) of European individuals. Summarized diagnostic data of hypothyroidism were obtained from the UK Biobank. Primary analyses were conducted using the inverse variance-weighted (IVW) method with a random-effects model as well as three complementary approaches. Sensitivity analyses were performed to ascertain the correlation between obesity and hypothyroidism.

Results

MR analyses of the IVW method and the analyses of hypothyroidism/myxedema indicated that body mass index (BMI) and waist circumference (WC) were significantly associated with higher odds and risk of hypothyroidism. Reverse MR analysis demonstrated that a genetic predisposition to hypothyroidism was associated with an increased risk of elevated BMI and WC, which was not observed between WC adjusted for BMI (WCadjBMI) and hypothyroidism.

Discussion

Our current study indicates that obesity is a risk factor for hypothyroidism, suggesting that individuals with higher BMI/WC have an increased risk of developing hypothyroidism and indicating the importance of weight loss in reducing the risk of hypothyroidism.

Replacement Dose for Overt Hypothyroidism Induced by Programmed Cell Death Protein 1 Antibodies May Be Higher than Recommended

BACKGROUND

The present recommendations, consensus, or guidelines for the replacement dosage for hypothyroidism induced by programmed cell death protein 1 (PD-1) therapy are not uniform, and there are very few special clinical trials that have examined the replacement dosage for it.

OBJECTIVES

This article illustrates the clinical characteristics of hypothyroidism induced by PD-1 antibodies (Abs) and reports the recommended replacement dosage for hypothyroidism.

METHODS

Eighteen patients with overt primary hypothyroidism induced by PD-1 Abs (group 1) were selected from 655 patients with different tumor types. Retrospective analysis was performed on patients in group 1 and 18 patients with natural courses of overt primary hypothyroidism who were age- and sex-matched with the patients in group 1 (group 2). The replacement dosages required for the patients in the two groups were compared.

RESULTS

Thyroid dysfunction occurred in group 1 after approximately 3.0 ± 1.4 cycles of PD-1 therapy (1-6 stages), with a median time of 61.5 days. The median time of onset of hypothyroidism among all patients was 87.5 days (30-240 days). Most of the patients with hypothyroidism were asymptomatic, and the onset of hypothyroidism was independent of age, sex, TPOAb, TgAb and TSH in group 1 (P>0.05). The average replacement dosage for patients in group 1 was 1.8 ± 0.6 μg/kg/d (0.6-3.2 μg/kg/d). Multiple linear regression analysis showed that sex, age, TPOAb, TgAb and TSH were not correlated with drug dosage.

CONCLUSION

It seemed that the average maintenance dosage of levothyroxine might need to be 1.8 μg/kg/day for patients with overt hypothyroidism induced by PD-1 Abs.

Diagnosis and Long-term Treatment of Suspected Congenital Hypothyroidism in a Pigeon (Columba livia domestica)

An approximately 6-month-old domestic pigeon (Columba livia domestica) was presented for lethargy and an inability to perform its first molt. The pigeon was obese, had anatomical characteristics of a chick, including cere and plumage, and had a ventral coelomic soft tissue mass. Initial blood work was unremarkable. A computed tomographic scan confirmed excessive fat deposition in the coelom and a mass adherent to the liver. A fine-needle aspirate of the mass indicated fat accumulation. A thyroid-stimulating hormone (TSH) test was planned for this pigeon and 3 presumed euthyroid pigeons. Each pigeon was administered 80 µg (∼230 µg/kg) of recombinant human TSH. Blood was drawn at time 0 and 3 and 6 hours after administration of recombinant human TSH. Plasma total thyroxine (TT4) was measured in duplicate with an in-house analyzer and a reference laboratory. After recombinant human TSH administration, healthy pigeons showed a 4- to 21-fold increase in TT4, whereas the hypothyroid pigeon had all values <0.12 µg/dL. The pigeon was prescribed 20 µg of compounded levothyroxine twice daily. In the following months, the pigeon molted and developed adult features. The ventral coelomic soft tissue mass disappeared and repeated computed tomography scans showed a decreased amount of body fat and a reduction in the size of the coelomic mass. Levothyroxine was further adjusted multiple times according to additional TT4 testing to a dose of 2.5 µg once daily. The pigeon has been under treatment with levothyroxine for more than 2 years. Here we present the first reported case of confirmed hypothyroidism in a pigeon. Diagnosis with a TSH stimulation test was unequivocal, even when only considering the results of the in-house analyzer. Levothyroxine treatment resolved clinical signs and could be titrated to an appropriate dose.

Interference or Noninterference Between Soy and Levothyroxine: That Is the Question. A Narrative Review of Literature

OBJECTIVE

To evaluate the effect of soy intake on levothyroxine (L-T4) absorption among different L-T4 formulations.

METHODS

A PubMed/MEDLINE, Web of Science, and Scopus research was performed. Case reports, case series, and original studies written in English and published online up to November 30, 2022, were selected and reviewed. The final reference list was defined based on the relevance of each study to the scope of this review.

RESULTS

Few data, mainly case reports, seemed to suggest a possible interference of soy products on L-T4 tablets absorption. However, the only prospective randomized cross-over study showed no differences in L-T4 absorption when L-T4 and soy isoflavones were assumed concomitantly. The very little data available on liquid L-T4 formulations did not allow for any conclusions to be made, even if a double-blind placebo-controlled trial showed no impaired L-T4 absorption.

CONCLUSION

The inference of soy products on L-T4 absorption, if present, seems to have little clinical impact. Considering this fact, the Hamlet-like question whether soy milk interferes with L-T4 absorption remains unanswered.

A Patient with Hypothyroidism in Need of Periodontal Connective Tissue Graft Surgery

Hypothyroidism is a condition characterized by thyroid hormone deficiency and can be caused by a variety of factors. Untreated or chronic hypothyroidism can present in adult patients as myxedema, which is characterized by symptoms including fatigue, generalized slower metabolism, weight gain, depressed mood, dry skin, and brittle hair. Hypothyroidism can have various oral manifestations, particularly in children, in whom it can delay the eruption of the dentition. Dental management of patients with hypothyroidism depends on the etiology and status of the disease and requires the consideration of other organ systems affected.

Impact of thyroid-stimulating hormone levels after controlled ovarian hyperstimulation on in vitro fertilization/intracytoplasmic sperm injection outcomes in women with fresh embryo transfer: a prospective cohort study

Objective

Maternal hypothyroidism before and during pregnancy is associated with an increased risk of adverse pregnancy outcomes; many studies have evidenced that controlled ovarian hyperstimulation (COH) triggers a significant increase in the levels of TSH; however, no large-scale prospective studies have evaluated the impact of TSH levels after COH on assisted reproductive technology outcomes. The aim of this prospective study was to investigate whether in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes are affected by TSH levels after COH in women with fresh embryo transfer (ET).

Methods

A total of 664 patients who underwent IVF/ICSI treatment and received fresh ET at the Peking University Third Hospital were included in this study. The rates of clinical pregnancy, miscarriage, live birth, and preterm delivery were analyzed.

Results

The patients were categorized into two groups based on serum TSH levels after COH (0.55 mIU/L < TSH < 2.5 mIU/L: n= 449, 2.5 mIU/L ≤ TSH ≤ 4.78 mIU/L: n= 215). There were no significant differences in the rates of clinical pregnancy, miscarriage, and live birth between the two groups, even after adjusting for age, body mass index (BMI), thyroid antibody positivity, and COH protocols. However, the preterm delivery rate was significantly higher in women with TSH < 2.5 mIU/L than in those with TSH ≥ 2.5 mIU/L, even after adjusting for relevant confounding factors. There was no significant difference in live birth weight between the two groups.

Discussion

Mildly elevated TSH levels (TSH ≥ 2.5 mIU/L) after COH did not affect IVF/ICSI outcomes, and strict control of TSH levels within 2.5 mIU/L after COH might not be necessary. Additionally, strictly controlled TSH levels (TSH < 2.5 mIU/L) may increase preterm delivery risk.

Computer-Assisted Levothyroxine Dose Selection for the Treatment of Postoperative Hypothyroidism

Background: Thyroid hormone replacement with levothyroxine (LT4) is a recommended treatment for patients undergoing thyroidectomy. The starting LT4 dose is frequently calculated based on the patient's weight. However, the weight-based LT4 dosing performs poorly in clinical practice, with only ∼30% of patients achieving target thyrotropin (TSH) levels at the first thyroid function testing after treatment initiation. A better way to calculate the LT4 dose for patients with postoperative hypothyroidism is needed. Methods: In this retrospective cohort study we used demographic, clinical, and laboratory data for 951 patients after thyroidectomy and several regression and classification machine learning methods to develop an LT4 dose calculator for treating postoperative hypothyroidism targeting the desired TSH level. We compared the accuracy with the current standard-of-care practice and other published algorithms and evaluated generalizability with fivefold cross-validation and out-of-sample testing. Results: The retrospective clinical chart review showed that only 285/951 (30%) patients met their postoperative TSH goal. Obese patients were overtreated with LT4. An ordinary least squares regression based on weight, height, age, sex, calcium supplementation, and height:sex interaction predicted prescribed LT4 dose in 43.5% of all patients and 45.3% of patients with normal postoperative TSH (0.45-4.5 mIU/L). The ordinal logistic regression, artificial neural networks regression/classification, and random forest methods achieved comparable performance. LT4 calculator recommended lower LT4 doses to obese patients. Conclusions: The standard-of-care LT4 dosing does not achieve the target TSH in most thyroidectomy patients. Computer-assisted LT4 dose calculation performs better by considering multiple relevant patient characteristics and providing personalized and equitable care to patients with postoperative hypothyroidism. Prospective validation of LT4 calculator performance in patients with various TSH goals is needed.

Systemic lupus erythematosus is causally associated with hypothyroidism, but not hyperthyroidism: A Mendelian randomization study

Background

The relationship between systemic lupus erythematosus (SLE) and thyroid diseases is still controversial. Due to confounders and reverse causation, previous studies were not convincing. We aimed to investigate the relationship between SLE and hyperthyroidism or hypothyroidism by Mendelian randomization (MR) analysis.

Methods

We performed a two-step analysis using bidirectional two-sample univariable and multivariable MR (MVMR) to explore the causality of SLE and hyperthyroidism or hypothyroidism in three genome-wide association studies (GWAS) datasets, including 402,195 samples and 39,831,813 single-nucleotide polymorphisms (SNPs). In the first step analysis, with SLE as exposure and thyroid diseases as outcomes, 38 and 37 independent SNPs strongly (P < 5*10^-8) associated with SLE on hyperthyroidism or SLE on hypothyroidism were extracted as valid instrumental variables (IVs). In the second step analysis, with thyroid diseases as exposures and SLE as outcome, 5 and 37 independent SNPs strongly associated with hyperthyroidism on SLE or hypothyroidism on SLE were extracted as valid IVs. In addition, MVMR analysis was performed in the second step analysis to eliminate the interference of SNPs that were strongly associated with both hyperthyroidism and hypothyroidism. 2 and 35 valid IVs for hyperthyroidism on SLE and hypothyroidism on SLE were obtained in MVMR analysis. MR results of two steps analysis were estimated respectively by multiplicative random effects-inverse variance weighted (MRE-IVW), simple mode (SM), weighted median (WME) and MR-Egger regression methods. Sensitivity analysis and visualization of MR results were performed by heterogeneity test, pleiotropy test, leave-one-out test, scatter plots, forest plots and funnel plots.

Results

The MRE-IVW method in the first step of MR analysis revealed that SLE was causally associated with hypothyroidism (OR = 1.049, 95% CI = 1.020-1.079, P < 0.001), but not causally associated with hyperthyroidism (OR = 1.045, 95% CI = 0.987-1.107, P = 0.130). In the inverse MR analysis, the MRE-IVW method revealed that both hyperthyroidism (OR = 1.920, 95% CI = 1.310-2.814, P < 0.001) and hypothyroidism (OR = 1.630, 95% CI = 1.125-2.362, P = 0.010) were causally associated with SLE. Results from other MR methods were consistent with MRE-IVW. However, when MVMR analysis was performed, there was no longer a causal relationship of hyperthyroidism on SLE (OR = 1.395, 95% CI = 0.984-1.978, P = 0.061), nor was there a causal relationship of hypothyroidism on SLE (OR = 1.290, 95% CI = 0.823-2.022, P = 0.266). The stability and reliability of the results were confirmed by sensitivity analysis and visualization.

Conclusions

Our univariable and multivariable MR analysis revealed that systemic lupus erythematosus was causally associated with hypothyroidism, but did not provided evidence to support a causal relationship of hypothyroidism on SLE or between SLE and hyperthyroidism.

Preparation of Levothyroxine Transdermal Gels and Preliminary Pharmacokinetic Study in Hypothyroidism Rat Model

Background:

Hypothyroidism is a common disorder due to inadequate thyroid hormone secretion. In patients with hypothyroidism, levothyroxine (LT4) is the treatment of choice, and tablets are the most common dosage form. However, the main limitation of tablet LT4 is malabsorption.

Objective:

This study intends to develop a new dosage form of percutaneous drug delivery for levothyroxine. Absorption of levothyroxine sodium through the application of gel formulation was studied using a hypothyroidism rat model.

Methods:

A formulation of levothyroxine sodium gel was developed and selected. In-vitro transdermal experiments were performed using the vertical Franz diffusion pool method, and gel formulation was used for animal research (hypothyroidism rats model). Total 30 rats were randomly divided into 6 groups, and one was the normal control group. The other 5 groups were prepared as hypothyroidism models. After applying different doses of gel preparation to the rat model, we measured serum total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) using fluorescence determination of luminescence immunoassay.

Results:

The optimum formulation of levothyroxine gels comprised 20% polyvinyl alcohol (PVA), 5% glycerol, 2% azone, and 6% oleic acid. The application of levothyroxine sodium gel resulted in quick and smooth action so that the predicted level of the normal control group could be reached within 2 weeks, and it lasted steadily for 8 weeks.

Conclusion:

This research study successfully developed and tested an optimal formulation of levothyroxine gel with therapeutic benefit on hypothyroidism in rats.

Prevalence of Ménière's Disease in Syrian Patients with hypothyroidism: Cross-sectional study

Background

Ménière's Disease, a long-term debilitating disorder has been increasingly found among patients with hypothyroidism. Our study aims to evaluate the prevalence of ménière's disease among hypothyroid patients and assess the interrelationship between patients' symptomology and ménière's disease.

Materials and methods

A cross-sectional study was performed at the endocrinology clinics at Damascus Hospital and Syrian Red Crescent Hospital, Damascus, Syria between September 2021 and January 2022. Patients with hypothyroidism were interviewed using a questionnaire. The questionnaire contained questions about socio-demographic information, hypothyroid history, diagnostic criteria of ménière's disease, chief complaint, medical history, and lab test results. Patients, who reported ménière's disease symptoms, were referred to the otorhinolaryngology clinic for confirmation or exclusion of ménière's disease. At the clinic, patients underwent an otoscopy and a pure tone audiometry, probable and definite ménière's disease was diagnosed accordingly.

Results

Of 217 hypothyroid patients included in the sample, 17 (7.8%) were diagnosed with definite ménière's disease and 31 (14.3%) were diagnosed with probable ménière's disease. Hypothyroid symptoms reported among patients diagnosed with definite ménière's disease compared to no diagnosis differed by feeling low (χ2 (1, 217) = 4.014, p = 0.045), and depressive appearance (χ2 (1, 217) = 8.887, p = 0.003). Patients diagnosed with definite ménière's disease, probable ménière's disease, and both definite and probable ménière's disease were more likely to report that their symptoms affected their lifestyle compared to those that reported no effect (χ2 (3, 217) = 62.565, p < 0.001), (χ2 (3, 217) = 31.380, p < 0.001), and (χ2 (3, 217) = 35.542, p < 0.001), respectively.

Conclusion

A high number of hypothyroid patients were diagnosed with MD. Clinicians should consider clinically screening for MD among hypothyroid patients presenting to clinics.

•

This study shows a significant association between hypothyroidism and Ménière's disease.

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Rates of feeling low and depressive appearance increase in definite MD patients.

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Meniere's disease patients were predisposed to the disease's effect on their lifestyle.

The Prevalence of Thyroid Dysfunction in Korean Women Undergoing Routine Health Screening: A Cross-Sectional Study

Background: Women are more likely to experience thyroid diseases than men. However, thyroid dysfunction risk in women undergoing the menopausal transition remains largely unknown. We explored the prevalence of thyroid dysfunction across menopausal stages. Methods: We conducted a cross-sectional study of 53,230 women aged 40 years or older who underwent health screening between 2014 and 2018. Menopausal stages were categorized into 4 based on the Stages of Reproductive Aging Workshop +10 criteria. A multinomial logistic regression model was used to estimate the prevalence ratios (PRs) with confidence intervals [CIs] for thyroid dysfunction in menopausal stages compared with that in premenopause. Results: The prevalence of overt hypothyroidism was significantly increased during late transition and postmenopause; it remained significant after further adjustments for potential confounders (age, center, year of examination, age at menarche, parity, education level, smoking status, alcohol consumption, physical activity, and body mass index) with corresponding multivariable-adjusted PRs [CI] of 1.61 [1.12-2.30] and 1.66 [1.16-2.37] in the late transition and postmenopausal stages, respectively. A significant increase in the prevalence of subclinical hypothyroidism was also observed in the late transition and postmenopausal stage with multivariable-adjusted PRs [CI] of 1.22 [1.06-1.40] and 1.24 [1.07-1.44], respectively. In contrast, subclinical and overt hyperthyroidism were not significantly associated with menopausal stages. Conclusions: In this study of pre- and perimenopausal Korean women, the prevalence of overt and subclinical hypothyroidism was significantly elevated in the late menopausal transition. Future prospective studies are warranted to investigate the clinical and prognostic significance of thyroid dysfunction in women during menopausal transition.

Management of Hypothyroidism in Internal Medicine: Patient Profile and Effects of an Educational Programme in the Cluster-Randomized FADOI TIAMO Study

Background and aims

There is still limited knowledge regarding the clinical profile and appropriateness of treatment in patients with hypothyroidism hospitalized in Internal Medicine (IM) Departments in Italy. The aim of this study is to evaluate: 1) the characteristics of patients and possible deviations from national and international clinical practice recommendations (CPRs) in evidence-based guidelines (EBGs); 2) the improvement of patient management by means of a standardized educational programme (EP).

Methods

A nationwide multicentre study, comprising two replications of a retrospective survey (phases 1 and 3) with an intervening EP (phase 2) in half of the centres and no EP in the other half, was conducted. The EP was based on outreach visits. Centres were assigned to the two arms of the study, labelled the training group (TG) and control group (CG) respectively, by cluster randomization. Four EBGs and 39 CPRs provided the basis on which 22 treatment management indicators were identified (7 referring to the time of hospital admission, 15 to post-admission).

Results

The 21 participating centres recruited 587 hospitalized patients with hypothyroidism, 421 of which were females (71.7%, mean age 74.1 + 14.4 yrs): 318 in phase 1 and 269 in phase 3. The cause of hypothyroidism was unknown in 282 patients (48%). Evaluation at the time of admission identified satisfactory adherence to CPRs (>50%) for 63.6% of the indicators. In the phase 3, TG centres showed significant improvement vs CG in 4 of the 15 post-admission indicators, while 1 out of 15 was significantly worse.

Conclusions

The EP based on outreach visits significantly improved some indicators in the management of patients with hypothyroidism, with specific reference to appropriateness of TSH dosage and levothyroxine (LT4) treatment modality.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT05314790.

Increased Risk of Hypothyroidism in People with Asthma: Evidence from a Real-World Population-Based Study

BACKGROUND

Non-T2 asthma and hypothyroidism share several inflammatory mechanisms in common. However, large-scale, real-world studies evaluating the association between asthma and hypothyroidism are lacking. The objective of this study was to evaluate the risk for asthma patients of developing hypothyroidism.

METHODS

In the retrospective cohort study, people with asthma were recruited from the Longitudinal Health Insurance Database in Taiwan. After excluding ineligible patients with a previous history of hypothyroidism, 1:1 propensity matching was conducted to select a non-asthma control group. Based on the multivariate Cox regression model, the adjusted hazard ratio of asthma patients developing hypothyroidism was calculated.

RESULTS

In total, 95,321 asthma patients were selected as the asthma group and the same amount of people without asthma were selected as the control group. The incidence levels of new-onset hypothyroidism in asthma and non-asthma groups were 8.13 and 6.83 per 100,000 people per year, respectively. Compared with the non-asthma group, the adjusted hazard ratio of the asthma group developing hypothyroidism was 1.217 (95% confidence interval, 1.091-1.357).

CONCLUSIONS

We found having asthma to be associated with an increased risk of hypothyroidism. Clinicians should be concerned regarding the endocrinological and inflammatory interaction between the two diseases while caring for people with asthma.

Sex-specific Effect of Maternal Thyroid Hormone Trajectories on Preschoolers' Behavioral Development: A Birth Cohort Study

CONTEXT

Maternal thyroid hormone trajectories are a better predictor of offspring's neurodevelopment than hormone levels in single trimester of pregnancy. Programming effect of uterine hormonal environment on offspring's health is usually sex-specific.

OBJECTIVE

To examine the sex-specific effect of thyroid hormone trajectories on preschoolers' behavioral development.

DESIGN

Based on Ma' anshan Birth Cohort in China, pregnant women were recruited at their first antenatal checkup from May 2013 to September 2014.

SETTING

Ma' anshan Maternal and Child Health Hospital in China.

PATIENTS OR OTHER PARTICIPANTS

1860 mother-child pairs were included in the analysis. Children were followed up at age of 4.

MAIN OUTCOME MEASURES

Maternal thyroid hormones [thyroid-stimulating hormone (TSH), free thyroxine (FT4)] and thyroid peroxidase antibody in the first, second, and third trimesters of pregnancy were retrospectively assayed. Preschoolers' behavioral development was assessed by Achenbach Child Behavior Checklist/1.5~5.

RESULTS

Maternal TSH and FT4 levels were respectively fitted into high, moderate, and low trajectories. In boys, maternal high TSH trajectory was related to withdrawn [odds ratio (OR) = 2.01, 95% CI: 1.16, 3.50) and externalizing problems (OR = 2.69, 95% CI: 1.22, 5.92), and moderate TSH trajectory was associated with aggressive behavior (OR = 3.76, 95% CI: 1.16, 12.23). Maternal high FT4 trajectory was associated with anxious/depressed (OR = 2.22, 95% CI: 1.08, 4.56) and total problems (OR = 1.74, 95% CI: 1.13, 2.66), and low FT4 trajectory was associated with aggressive behavior (OR = 4.17, 95% CI: 1.22, 14.24).

CONCLUSIONS

Maternal thyroid hormone trajectories impact preschool boys' behavioral development.

Predicting Elevated TSH Levels in the Physical Examination Population With a Machine Learning Model

Objective

The purpose of this study was to predict elevated TSH levels by developing an effective machine learning model based on large-scale physical examination results.

Methods

Subjects who underwent general physical examinations from January 2015 to December 2019 were enrolled in this study. A total of 21 clinical parameters were analyzed, including six demographic parameters (sex, age, etc.) and 15 laboratory parameters (thyroid peroxidase antibody (TPO-Ab), thyroglobulin antibody (TG-Ab), etc.). The risk factors for elevated TSH levels in the univariate and multivariate Logistic analyses were used to construct machine learning models. Four machine learning models were trained to predict the outcome of elevated TSH levels one year/two years after patient enrollment, including decision tree (DT), linear regression (LR), eXtreme Gradient boosting (XGBoost), and support vector machine (SVM). Feature importance was calculated in the machine learning models to show which parameter plays a vital role in predicting elevated TSH levels.

Results

A total of 12,735 individuals were enrolled in this study. Univariate and multivariate Logistic regression analyses showed that elevated TSH levels were significantly correlated with gender, FT3/FT4, total cholesterol (TC), TPO-Ab, Tg-Ab, creatinine (Cr), and triglycerides (TG). Among the four machine learning models, XGBoost performed best in the one-year task of predicting elevated TSH levels (AUC (0.87(+/- 0.03))). The most critical feature in this model was FT3/FT4, followed by TPO-Ab and other clinical parameters. In the two-year task of predicting TSH levels, none of the four models performed well.

Conclusions

In this study, we trained an effective XGBoost model for predicting elevated TSH levels one year after patient enrollment. The measurement of FT3 and FT4 could provide an early warning of elevated TSH levels to prevent relative thyroid diseases.

Subclinical hypothyroidism in older individuals

Subclinical hypothyroidism, which is defined as a thyroid-stimulating hormone concentration higher than the reference range (generally 4·5 mIU/L or higher) with normal free thyroxine concentrations, is frequently found in older individuals. International guidelines differ in recommendations for management of subclinical hypothyroidism in older individuals. We assessed published data during the past decade on the clinical significance and treatment of subclinical hypothyroidism in individuals aged 65 years and older. Meta-analyses, randomised clinical trials, and cohort studies are discussed in this narrative Review. Studies showed no significantly increased incidence in adverse cardiovascular, musculoskeletal, or cognitive outcomes in individuals aged 65 years or older when serum thyroid-stimulating hormone concentration was 4·5-7·0 mIU/L versus a euthyroid group. Moreover, in older individuals with subclinical hypothyroidism, symptoms of hypothyroidism and cardiac and bone parameters did not improve after levothyroxine treatment. These data suggest that treatment with levothyroxine should be considered for individuals aged 65 years or older with subclinical hypothyroidism when thyroid-stimulating hormone concentration is persistently 7 mIU/L or higher and to not initiate treatment with thyroid-stimulating hormone concentrations of less than 7 mIU/L. Levothyroxine doses should be personalised according to age, comorbidities, and life expectancy.

High-TSH Subclinical Hypothyroidism Is Associated With Postoperative Mortality in Acute Type A Aortic Dissection

BACKGROUND

Subclinical hypothyroidism can negatively affect the cardiovascular system and increase the risk of mortality, especially for individuals with thyroid-stimulating hormone (TSH) levels above 10 mU/L. We investigated the relationship between high-TSH subclinical hypothyroidism and postoperative mortality in acute type A aortic dissection (ATAAD) patients.

METHOD

We enrolled 146 patients with ATAAD who underwent aortic surgery in Beijing Anzhen Hospital from July 2016 to November 2018. Thyroid hormone levels were obtained before surgery, and participants were divided into a ≥10mU/L TSH level group and a <10mU/L level group. Cox proportional hazard regression and subgroup analysis were conducted to examine the association of preoperative high-TSH subclinical hypothyroidism with postoperative mortality.

RESULT

Participants with preoperative high-TSH (≥10mU/L) subclinical hypothyroidism tended to have longer hospitalization stays after surgery [16.0 (IQR 11.0-21.0) days vs 12.5 (IQR 8.0-16.0) days, P=0.001]. During the first 30 days after operation, 15 of 146 patients died (10.3%); during a median of 3.16 (IQR 1.76-4.56) years of follow-up, 24 patients died (16.4%). Cox proportional hazard regression showed that preoperative high-TSH subclinical hypothyroidism was independently associated with 30-day mortality (HR=6.2, 95% CI, 1.7-22.0, P=0.005) and postoperative mortality after adjusting for age, sex, BMI, hypertension, ejection fraction, diabetes and history of PCI (HR=3.4, 95% CI, 1.4-8.0, P=0.005).

CONCLUSION

This study showed that preoperative high-TSH subclinical hypothyroidism was an independent predictor of postoperative mortality in ATAAD patients who underwent aortic surgery.

Relatively Lower FT3 Levels Are Associated with Impaired Quality of Life in Levothyroxine-Treated Patients with Hashimoto Thyroiditis

OBJECTIVE

Patients with Hashimoto thyroiditis (HT) frequently have some complaints despite achieving euthyroidism after levothyroxine (LT4) treatment. This study aimed to investigate the relevant factors affecting the quality of life (QoL) in euthyroid HT patients after LT4 treatment.

METHODS

In this case-control study, 133 participants with HT were included. They were divided into two groups: 64 euthyroid HT subjects (control group) and 69 HT patients were rendered euthyroid by LT4 treatment (well-controlled group). QoL was measured with the Thyroid-Related Patient-Reported Outcome (ThyPRO-39) questionnaire.

RESULTS

Both study groups were well matched with respect to gender, age, BMI, euthyroidism, and thyroid antibodies (TPOAb and TGAb). Compared with the control group, the well-controlled group had lower FT3 (P < 0.01) levels. Of note, QoL was impaired on all scales in the well-controlled group. Moreover, ThyPRO-39 scores among the well-controlled group were significantly higher (worse) than the control group in all scales. Regarding the composite scale, its score was related to FT3 (r = -0.176, P=0.043) but not to FT4 and TSH levels. Further logistic regression analysis revealed FT3 was significantly associated with elevated composite QoL [0.128 (0.029-0.577), P < 0.01] after adjustment of potential confounders.

CONCLUSION

Relatively lower FT3 concentrations, even within the normal reference range, were related to impaired QoL in HT patients treated with LT4. This finding supports the great value of FT3 in clinical decision-making on dose adequacy.

Genetically Determined TSH Level Within Reference Range Is Inversely Associated With Alzheimer Disease

CONTEXT

Contradictory findings were reported in observational studies on the association of thyroid function (thyrotropin [TSH] and free thyroxine [FT4] levels) with Alzheimer disease (AD).

OBJECTIVE

This work aims to determine whether genetically determined TSH/FT4 levels within reference range are causally associated with AD.

METHODS

A bidirectional, 2-sample mendelian randomization (MR) study was conducted. With summary statistics from the largest genome-wide association studies (GWAS)/GWAS meta-analysis of TSH level(n ≥ 54 288), FT4 level(n = 49 269), and AD (71 880 cases; 383 378 controls), we used an MR approach to evaluate the bidirectional causal relationship between TSH/FT4 levels and AD. The inverse-variance weighted method was adopted as the main analysis.

RESULTS

One SD increase in genetically determined TSH level within reference range was causally associated with a reduced risk of AD (odds ratio: 0.988; 95% CI, 0.977-0.998). A similar inverse association was observed in sex-specific analysis. The causal association was attenuated after adjustment for atrial fibrillation and blood pressure, suggesting they may mediate the causal pathway. A positive causal effect of AD on TSH level was detected only in male participants. This male-specific feedback loop may explain why the largest cohort study to date (Rotterdam Study) demonstrated a null observational association in men. Null association was observed between FT4 level and AD in both directions.

CONCLUSION

Genetic predisposition to increased TSH level, even within reference range, may lower the risk of AD, with atrial fibrillation, systolic, and diastolic blood pressure as possible mediators. Given the higher magnitude of risk reduction observed in the Rotterdam Study, whether the causal estimates derived from this MR study are underestimated warrants further investigation.

Common Pitfalls in the Interpretation of Endocrine Tests

Endocrine tests are the cornerstone of diagnosing multiple diseases that primary care physicians are frequently faced with. Some of these tests can be affected by situations that affect the proper interpretation, leading to incorrect diagnoses and unnecessary treatment, such as the interference of biotin with thyroid function test, falsely elevated prolactin values in presence of macroprolactinemia or falsely normal due to the "hook effect" in macroprolactinomas. Recognizing these situations is essential for the clinician to make an adequate interpretation of these tests as well as an accurate diagnosis that guarantees the best outcomes for the patient.

Комплаєнс до лікування левотироксином хворих на гіпотиреоз під час пандемічної ери SARS-CoV-2

Актуальність. Гіпотиреоз потребує замісної терапії левотироксином (L-T4), щоб підтримувати в пацієнтів стан еутиреозу. Кількість госпіталізацій з приводу хронічних захворювань зменшилась протягом ери COVID-19. Мета дослідження— встановити частоту госпіталізацій пацієнтів з гіпотиреозом під час пандемії COVID-19 порівняно з аналогічним періодом часу в 2019 році. Матеріали та методи. Дослідження було проведене серед пацієнтів, які звернулись у відділення внутрішньої медицини університетської лікарні Abant Izzet Baysal та отримували замісну терапію L-T4 внаслідок гіпотиреозу. 108 пацієнтів з гіпотиреозом були включені в дослідження, підписавши інформаційну згоду. Пацієнти були розділені на дві групи відповідно до прихильності до лікування: хворі, які відповідали вимогам лікування, і хворі, які не дотримувались режиму лікування. Результати. Рівень тиреотропного гормона (ТТГ) перед включенням у дослідження у групі осіб, які відповідали вимогам лікування, був вірогідно нижчим, ніж у групі хворих, які не дотримувались режиму лікування (p<0,001). При цьому рівень вільного тироксину (вТ4) серед пацієнтів першої групи був вірогідно вищим, ніж в осіб другої групи (p=0,04). Медіана нерегулярного прийому левотироксину становила 35 (10–90) днів у групі осіб, які не відповідали вимогам лікування, і 0 (0–0) днів у групі осіб, які відповідали вимогам лікування (p<0,001). Кількість днів, коли левотироксин використовувався нерегулярно, вірогідно позитивно корелювала з останнім значенням ТТГ (r=0,564, p<0,001) та негативно— з останнім значенням вT4 (r=–0,492, p<0,001). Середній об’єм еритроцитів (MCV) у хворих першої та другої груп становив 85 (69,1–97,5) та 89 (66–96,6) фл відповідно (p=0,03). Ретроспективний характер та порівняно невелика кількість досліджуваних були двома основними обмеженнями проведеного дослідження. Висновки. Дотримання режиму лікування є дуже важливим для досягнення стану еутиреозу в пацієнтів з гіпотиреозом під час пандемії COVID-19. Підвищений рівень MCV може передбачати невідповідність лікування у хворих на гіпотиреоз.