Search

Feline hyperthyroidism (FHT) is a debilitating disease affecting > 10% of elderly cats. It is generally characterised by chronic elevation of thyroid hormone in the absence of circulating TSH. Understanding of the molecular pathogenesis of FHT is currently limited. However, FHT shares clinical and histopathological similarities with human toxic multinodular goitre, which has been associated with activating mutations in TSH receptor (TSHR) and G s α encoding genes. Using RNA-seq transcriptomic analysis of thyroid tissue from hyperthyroid and euthyroid cats, we identified differentially expressed genes and dysregulated pathways in FHT, many of which are downstream of TSHR. In addition, we detected missense variants in thyroid RNA-seq reads that alter the structure of both TSHR and G s α. All FHT-associated mutations were absent in germline sequence from paired blood samples. Only a small number of hyperthyroid cats demonstrated TSHR variation, however all thyroids from advanced cases of FHT carried at least one missense variant affecting G s α. The activating nature of the acquired G s α mutations was demonstrated by increased cAMP production in vitro. These data indicate that constitutive activation of signalling downstream of TSHR is central to the TSH-independent production of thyroid hormone in FHT, offering a novel therapeutic target pathway in this common disease., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Previous researches have revealed some links between thyroid function and sleep characteristics, however it remains unclear which one causes the other. The purpose of this study was to investigate the potential causal relationship between hyperthyroidism, hypothyroidism, and sleep characteristics., Methods: We utilized aggregated data from published genome-wide association studies (GWAS) to select genetic instruments for sleep variables. The 5 sleep-related traits (chronotype, short sleep duration, long sleep duration, daytime sleepiness, and insomnia) were associated with distinct genetic variants chosen as instrumental factors. Employing MR Egger's analysis of Mendelian randomization (MR), weighted median, weighted mode, and inverse variance weighted (IVW) methods to assess the 5 sleep traits in relation to hyperthyroidism and hypothyroidism, we subsequently conducted inverse MR analysis to examine the causal relationship between thyroid function and the 5 sleep characteristics., Results: The IVW technique did not reveal a causal association between chronotype, short sleep duration, long sleep duration, daytime sleepiness, or insomnia and the risk of abnormal thyroid function in the study investigating the influence of sleep characteristics on this risk. The outcomes of the IVW approach were consistent with the remaining 3 methods. The IVW, weighted median, MR Egger, and weighted mode methods in the reverse magnetic resonance imaging investigation did not yield evidence of a causative association between the risk of time type, long sleep duration, and insomnia and abnormal thyroid function. In contrast, the weighted median and weighted mode methods showed a possible causal relationship between hypothyroidism and short sleep duration and daytime sleepiness. Sensitivity analyses showed that the results were robust and no pleiotropy or heterogeneity was detected., Conclusion: More precisely, our analysis did not uncover any indication of a reciprocal causal link between thyroid function and genetically predicted sleep characteristics., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Previous Mendelian randomization (MR) studies showed an association between hypothyroidism and cataract and between high-normal free thyroxine (FT4) and late age-related macular degeneration (AMD), but not between FT4, thyroid stimulating hormone (TSH), or hyperthyroidism and diabetic retinopathy or cataract. These studies included a limited number of genetic variants for thyroid function and did not investigate autoimmune thyroid disease (AITD) or glaucoma, include bidirectional and multivariable MR (MVMR), and examine sex differences or potential mediation effects of diabetes. We aimed to address this knowledge gap. Methods: We examined the causality and directionality of the associations of AITD, and FT4 and TSH within the reference range with common age-related eye diseases (diabetic retinopathy, cataract, early and late AMD, and primary open-angle glaucoma). We conducted a bidirectional two-sample MR study utilizing publicly available genome-wide association study (GWAS) summary statistics from international consortia (ThyroidOmics, International AMD Genetics Consortium, deCODE, UK Biobank, FinnGen, and DIAGRAM). Bidirectional MR tested directionality, whereas MVMR estimated independent causal effects. Furthermore, we investigated type 1 diabetes (T1D) and type 2 diabetes (T2D) as potential mediators. Results: Genetic predisposition to AITD was associated with increased risk of diabetic retinopathy ( p = 3 × 10 -4 ), cataract ( p = 3 × 10 -3 ), and T1D ( p = 1 × 10 -3 ), but less likely T2D ( p = 0.01). MVMR showed attenuated estimates for diabetic retinopathy and cataract when adjusting for T1D, but not T2D. We found pairwise bidirectional associations between AITD, T1D, and diabetic retinopathy. Genetic predisposition to both T1D and T2D increased the risk of diabetic retinopathy and cataract ( p < 4 × 10 -4 ). Moreover, genetically predicted higher FT4 within the reference range was associated with an increased risk of late AMD ( p = 0.01), particularly in women ( p = 7 × 10 -3 ). However, we neither found any association between FT4 and early AMD nor between TSH and early and late AMD. No other associations were observed. Conclusions: Genetic predisposition to AITD is associated with risk of diabetic retinopathy and cataract, mostly mediated through increased T1D risk. Reciprocal associations between AITD, diabetic retinopathy, and T1D imply a shared autoimmune origin. The role of FT4 in AMD and potential sex discrepancies needs further investigation.

Background: Thyroid hormones play a crucial role in cardiovascular physiology. Subclinical thyroid dysfunction has been associated with adverse cardiovascular outcomes, but evidence is mixed regarding causality., Objective: The purpose of this study was to investigate the potential causal relationships of thyroid-stimulating hormone (TSH), free thyroxine, hypothyroidism, and hyperthyroidism with cardiovascular outcomes, including atrial fibrillation (AF), coronary artery disease, myocardial infarction, heart failure, and ischemic stroke, as well as their effect on cardiac structure and function assessed by cardiac magnetic resonance imaging., Methods: A comprehensive 2-sample Mendelian randomization analysis was performed using summary data from large-scale meta-analyses of European ancestry individuals., Results: Genetically determined lower TSH levels (odds ratio 0.928; 95% confidence interval 0.884-0.974; P = .003) and genetic risk of hyperthyroidism (odds ratio 1.049; 95% confidence interval 1.016-1.083; P = .003) were associated with increased AF risk. These associations remained significant even after adjusting for cardiovascular risk factors. Colocalization and multivariable Mendelian randomization revealed height as a key mediator between TSH/hyperthyroidism and AF. These findings were further corroborated in the independent FinnGen cohort. However, no clear evidence was found for relationships between thyroid function and other cardiovascular outcomes and cardiac structure and function., Conclusion: Our study shows that reduced TSH levels and hyperthyroidism heighten AF risk, with height serving as an important mediator in these associations. The primary focus of thyroid management in cardiovascular health should be on preventing and treating arrhythmias, particularly AF. Our research highlights the importance of routine screening and timely treatment of thyroid dysfunction to optimize the prevention and management of arrhythmias., Competing Interests: Disclosures The authors declare that the study was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Clinical studies and meta-analyses have suggested a link between thyroid dysfunction and lens opacification. The objective of this study is to investigate the causal relationship between hyperthyroidism and the development of cataracts using the Mendelian randomization approach, with the aim of filling the gap in knowledge about the systemic effects of hyperthyroidism on ocular health. Leveraging genetic variants as instrumental variables, the analysis used extensive datasets from the UK Biobank and the FinnGen Database and employed three common approaches for causal inference (the Inverse Variance Weighted method, a regression based method the Weighted Median estimator, and MR-Egger regression) and accompanying sensitivity analyses to ensure robustness. The results demonstrate that there is a strong likely causal relationship, with hyperthyroidism increasing the risk of developing senile cataracts (OR = 361.09, 95%CI 5.024 to 2.60 × 10 4 , P = 0.007). A sensitivity analysis provided no evidence of horizontal pleiotropy and no significant outliers, suggesting the results are robust. In conclusion, our study established a significant causal relationship between hyperthyroidism and increased risk of cataract development, underscoring the importance of considering the systemic effects of hyperthyroidism in clinical and public health interventions and policies. Future research should focus on elucidating the molecular mechanisms underlying this association, exploring the potential benefits of early intervention in hyperthyroidism to prevent cataract development, and investigating whether these findings translate across different ethnic populations. Additionally, further GWAS studies aimed at identifying genetic variants associated with both hyperthyroidism and cataracts are warranted to confirm and expand upon our results., (© 2024. The Author(s).)

Objectives: Thyroid dysfunction is commonly associated with the risk of infertility in both females and males. However, recent randomized controlled trials have demonstrated that thyroid function levels in females are not significantly related to infertility, and evidence on the association between male thyroid function and infertility is limited. We aim to investigate the association between thyroid function levels and infertility in both females and males., Method: A two-sample Mendelian randomization study was conducted using four methods, with the inverse variance weighted method (IVW) as the primary approach. Data on thyroid function as the exposure were obtained from the ThyroidOmics Consortium and UK Biobank, including over 700,000 individuals from a large meta-analysis of genome-wide association studies for thyroid function and dysfunction. The outcome data for infertility in both sex encompassed more than 70,000 individuals from the FinnGen Consortium. All participants were adults of European ancestry. The MR Egger regression intercept and Cochran's Q test were employed to evaluate directional pleiotropy and heterogeneity., Results: The results indicated no causal effect of thyroid-stimulating hormone (TSH) and free tetraiodothyronine (fT4) on female and male infertility. Furthermore, no causal association between hypo- and hyperthyroidism and infertility were identified. Notably, we observed a causal relationship between high TSH and endometriosis-related infertility (OR=0.82, 95% CI: 0.74-0.91, P = 1.49E-04)., Conclusions: This study did not find evidence for casual relationship between thyroid function levels and risk of infertility. The findings suggest that overall thyroid function levels may not be a significant predictor of infertility risk., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Qiu, Jiang, Long, Zhu, Chen and Wen.)

Objective: The association between thyroid function, coagulation and venous thromboembolism (VTE) has been reported in observational studies with conflicting findings. This study aimed to elucidate the causal effects of thyroid function on coagulation and VTE from a genetic perspective., Methods: Two sample Mendelian randomization analysis was conducted using summary statistics from genome-wide association studies in a European population. Coagulation status was associated with nine coagulation-related factors (F VIII, F IX, F XI, Fibrinogen, Antithrombin-III, Thrombomodulin, Plasminogen activator inhibitor-1, Protein C and Protein S). Inverse variance weighting with random effect method was used as the main analytic approach with MR-Egger, weighted median, simple mode and weighted mode methods serving as complements. Sensitivity analyses including heterogeneity test, horizontal pleiotropy test and leave-one-out analysis were conducted to further assess the reliability of results., Results: No genetic causal effects of thyroid function on VTE (including pulmonary embolism and deep venous thrombosis) were found. Genetically, hyperthyroidism was suggestively related to decreased Antithrombin-III (β: -0.04 [95% CI: -0.06 to - 0.01], p = 0.010) and Protein C (β: -0.03 [95% CI: -0.06 to 0.00], p = 0.045). No notable associations were observed between other thyroid function parameters and coagulation-related factors., Conclusion: We provide suggestive genetic evidence supporting the causal effect of hyperthyroidism on decreased level of anticoagulant factors including Antithrombin-III and Protein C. However, whether this genetic causality could lead to clinically significant hypercoagulable state and increased risk of VTE in hyperthyroid population needs to be further addressed., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Familial hypokalemic periodic paralysis (HypoPP) is an uncommon genetic disorder characterized by recurrent episodes of muscle weakness and hypokalemia, typically starting in early adulthood. The existence of hyperthyroidism in the presence of HypoPP is more strongly associated with a diagnosis of thyrotoxic periodic paralysis (TPP), with most cases occurring in Asian males with pathogenic KCNJ2 or KCNJ18 variants and without a family history of the condition. This case is novel due to the combination of familial HypoPP and hyperthyroidism induced by Graves' disease, a rare occurrence especially in non-Asian populations., Case Presentation: A 40-year-old African American man presented with profound muscle weakness after consuming a high-salt meal. He had a significant family history of hyperthyroidism and hypokalemia. On examination, he showed profound weakness in all extremities. Laboratory tests confirmed hypokalemia and hyperthyroidism, and genetic testing identified a pathogenic variant in the CACNA1S gene (c.1583 G > A, p. R528H), with normal SCN4A, KCNJ2 and KCNJ18 sequencing. He was diagnosed with familial HypoPP and hyperthyroidism due to Graves' disease. He was started on PO methimazole 10 mg three times a day and PO acetazolamide 250 mg twice a day. He was advised to follow a low carbohydrate and low salt diet., Conclusions: This case highlights the importance of considering a genetic basis for HypoPP in patients with a family history of the condition, even when hyperthyroidism is present. The combination of familial HypoPP and Graves' disease is rare and emphasizes the need for careful genetic and clinical evaluation in similar cases. Management should focus on correcting hypokalemia, treating hyperthyroidism, and lifestyle modifications to prevent recurrence., (© 2024. The Author(s).)

Background: The interinfluence of thyroid function and daily physical activity (PA) remains unclear. We examined the causal relationship between genetically proxied thyroid-related traits; hypothyroidism, hyperthyroidism, thyroid stimulating hormone (TSH) and free thyroxine (FT4), and daily PA measures; leisure screen time (LST) and moderate-to-vigorous physical activity (MVPA), using Mendelian randomisation (MR) analysis., Methods: We used genome-wide association study (GWAS) data from the ThyroidOmics Consortium and the most comprehensive meta-analysis on PA, comprising data on hypothyroidism (n = 53 423), hyperthyroidism (n = 51 823), TSH within the reference range (n = 54 288), fT4 within the reference range (n = 49 269), LST (n = 526 725), and MVPA (n = 608 595) to conduct a bidirectional two-sample MR analysis. The inverse variance weighted (IVW) method was employed as the primary result. Sensitivity analyses included MR-Egger, weighted median, and MR pleiotropy residual sum and outlier (MR-PRESSO) regression. Similar investigations were conducted in the reverse direction. Finally, we analysed a multivariable MR using body mass index (BMI)-related traits GWAS data., Results: In the primary IVW analysis, an increase in genetically proxied TSH levels significantly increased LST (correlation coefficient (β) = 0.040; 95% confidence interval (CI) = 0.020-0.061, P = 9.776 × 10 -5 ). The multivariable MR analysis indicated that the positive causal effect still existed when considering the influence of BMI (MVMR-IVW: β = 0.042; 95% CI = 0.011-0.073, P = 0.007). Conversely, there was no evidence to suggest that PA impacts thyroid function., Conclusions: The results of this MR analysis suggest that thyroid function influences daily PA. The positive association between TSH and LST is not confounded or mediated by BMI., Competing Interests: Disclosure of interests: The authors completed the ICMJE Disclosure of Interest Form (available upon request from the corresponding author) and disclose no relevant interests., (Copyright © 2024 by the Journal of Global Health. All rights reserved.)

Background: Emerging observational studies indicated an association between hyperthyroidism and gastrointestinal disorders. However, it remains unclear whether this association is causal, particularly in the case of gastroesophageal reflux (GERD) and esophageal cancer., Methods: To assess the potential causal relationship between hyperthyroidism and GERD or esophageal cancer, we conducted a bidirectional 2-sample Mendelian randomization study. Independent genetic instruments for hyperthyroidism from the UK Biobank (N case=3,545 and N control=459,388) and public genome-wide association study (GWAS) dataset (N case=3,731 and N control=480,867) were used to investigate the association with esophageal cancer in the UK Biobank study (N case=740 and N control=372,016) and GERD in the public GWAS database (N case=20,381 and N control=464,217). Four different approaches (inverse variance weighted (IVW), weighted mode, MR-Egger, and weighted median regression) were used to ensure that our results more reliable. Additional sensitivity analyses were also performed to validate our results., Results: When hyperthyroidism was considered as the exposure factor, it appeared to act as a protective factor for GERD (OR IVW = 0.88, 95% CI, 0.79-0.99, P = 0.039), while as a risk factor for esophageal cancer (OR IVW = 1.03, 95% CI, 1.01-1.06, P = 0.003). However, there is no evidence supporting a reverse causal relationship between genetic susceptibility to hyperthyroidism and GERD or esophageal cancer., Conclusion: Our findings provided genetic evidence supporting bidirectional causal relationships between hyperthyroidism and GERD or esophageal cancer. These results substantiate certain discoveries from previous observational studies on a causal level and provide insight into relevant genetic susceptibility factors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhu, Li, Gan and Guo.)

An association between thyroid function and multiple sclerosis (MS) has been reported in several observational studies, but the causal relationship between them is still unclear. Thus, this study used a bidirectional Mendelian randomization (MR) to investigate the associations between thyroid function and MS. Bidirectional MR was used to explore the causal relationship between thyroid function (thyroid-stimulating hormone [TSH], free thyroxine [FT4], hyperthyroidism, and hypothyroidism) and MS. Genome-wide association study (GWAS) data of thyroid function and MS were obtained from the ThyroidOmics Consortium and the FinnGen Consortium, respectively. Inverse-variance weighted method (IVW) was the primary analysis method to assess causality with Weighted median, MR-Egger regression, weighted mode, and simple mode as auxiliary methods. Sensitivity analyses were performed using heterogeneity tests, horizontal pleiotropy tests and leave-one-out method. There was a positive causal relationship between TSH and MS (IVW: OR = 1.202, 95% CI: 1.040-1.389, P = .013), and no strong evidence was found for an effect of FT4 (IVW: OR = 1.286, 95% CI: 0.990-1.671, P = .059), hypothyroidism (IVW: OR = 1.247, 95% CI: 0.961-1.617, P = .096), and hyperthyroidism (IVW: OR = 0.966, 95% CI: 0.907-1.030, P = .291) on the risk of MS. In the reverse MR results, there was no causal relationship between MS and TSH (IVW: β = -0.009, P = .184), FT4 (IVW: β = -0.011, P = .286), hypothyroidism (IVW: OR = 0.992, 95% CI: 0.944-1.042, P = .745), and hyperthyroidism (IVW: OR = 1.026, 95% CI: 0.943-1.117, P = .549). Cochran's Q test, MR-Egger intercept test, MR-PRESSO global test, and Leave-one-out did not observe horizontal pleiotropy and heterogeneity. In conclusion, MR analysis supported a positive causal relationship between TSH and MS., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Observational studies have shown positive associations between thyroid dysfunction and risk of sarcopenia. However, the causality of this association remains unknown. This study aimed to evaluate the potential causal relationship between thyroid dysfunction and sarcopenia using Mendelian randomization (MR)., Methods: This study collected pooled data from genome-wide association studies focusing on thyroid dysfunction and three sarcopenia-related features: low hand grip strength, appendicular lean mass (ALM), and walking pace, all in individuals of European ancestry. The primary analytical method used was inverse-variance weighted, with weighted median and MR-Egger serving as complementary methods to assess causal effects. Heterogeneity and pleiotropy tests were also performed, and the stability of the results was evaluated using the Leave-one-out., Results: The MR analysis indicated that hyperthyroidism could lead to a significant decrease in ALM in the extremities (OR = 1.03; 95% CI = 1.02 to 1.05; P < 0.001). The analysis also found that hypothyroidism could cause a notable reduction in grip strength (OR = 2.03; 95% CI = 1.37 to 3.01; P < 0.001) and walking pace (OR = 0.83; 95% CI = 0.77 to 0.90; P < 0.001). There was a significant association between subclinical hyperthyroidism and a reduced walking pace (OR = 1.00; 95% CI = 0.99 to 1.00; P = 0.041)., Conclusion: This study provides evidence that hyperthyroidism, hypothyroidism, and subclinical hyperthyroidism can all increase the risk of sarcopenia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wei, Hou, Hei and Wang.)

Objective: Some correlations between thyroid disorders and insomnia have been found in previous studies; however, the causal relationship between them is unclear. The aim of this study was to investigate the causal relationship between insomnia and five thyroid disorders (hyperthyroidism, hypothyroidism, thyroiditis, thyroid nodules, and thyroid cancer)., Methods: We assessed the causal relationship between insomnia and thyroid disorders using inverse variance weighted, weighted median, and Mendelian randomization (MR)-Egger analyses in MR analyses and then used inverse MR analyses to assess the causal relationship between thyroid disorders and insomnia., Results: MR analysis showed that insomnia did not increase the risk of hyperthyroidism, hypothyroidism, thyroiditis, thyroid nodules, and thyroid cancer. However, reverse MR analysis showed that thyroid cancer increased the risk of insomnia (OR = 1.01, 95%CI: 1.00-1.02, p = .01), and the other four thyroid disorders had no direct causal relationship with insomnia. Sensitivity analyses indicated that the results were robust and no pleiotropy or heterogeneity was detected., Conclusion: This study did not find evidence of a bidirectional causal relationship between genetically predicted insomnia and hyperthyroidism, hypothyroidism, thyroiditis, and thyroid nodules. However, we found that although insomnia does not increase the risk of thyroid cancer, thyroid cancer does increase the risk of insomnia., (© 2024 The Author(s). Brain and Behavior published by Wiley Periodicals LLC.)

Background: Previous observational studies have suggested that thyroid function may be associated with functional outcome after ischemic stroke (IS). Nevertheless, the causal relationship remains unclear. This study aimed to explore the causal effect of thyroid function [thyroid-stimulating hormone (TSH), free thyroxine (FT4), hyperthyroidism, and hypothyroidism] on functional outcome (based on the modified Rankin scale) after IS by two-sample Mendelian randomization (MR) analysis., Methods: Inverse variance weighted (IVW) was the primary method for evaluating causal associations. In addition, six additional MR methods (MR-Egger regression, weighted median, maximum likelihood, simple mode, weighted mode, and MR-PRESSO) were employed to supplement IVW. Furthermore, various sensitivity tests were conducted to assess the reliability: (i) Cochrane's Q test for assessing heterogeneity; (ii) MR-Egger intercept test and MR-PRESSO global test for evaluating horizontal pleiotropy; (iii) leave-one-out sensitivity test for determining stability., Results: The results of IVW indicated that elevated TSH levels significantly improved functional outcome after IS (OR = 0.74, 95 % CI: 0.57-0.97, P = 0.028). In addition, six additional MR methods suggested parallel results. However, no causal effect of FT4, hyperthyroidism, and hypothyroidism on functional outcome after IS was identified. In addition, sensitivity tests demonstrated the reliability of the MR analyses, suggesting that the MR analysis was not influenced by significant heterogeneity and horizontal pleiotropy., Conclusions: Our MR study supported that elevated TSH levels might improve functional outcome after IS. Therefore, regular monitoring and maintenance of stable TSH levels may benefit patients recovering from IS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Thyroid dysfunction has been associated with preeclampsia (PE) during pregnancy, but the observational results are conflicting. Our study aims to investigate the causal association and direction between genetically predicted effects of thyroid function on PE and vice versa via two large summary genetic data., Methods: We conducted a two-sample bidirectional Mendelian randomization (MR) study using genome-wide association studies (GWAS) summary data from two primarily European cohorts: the ThyroidOmics Consortium and the FinnGen Biobank. We applied the random effects inverse variance weighted (IVW) as our main analysis. MR-Egger and weighted median were used for sensitivity analysis. Statistical analysis was performed using the R program (version 4.3.0) with the two-sample package (version 0.5.6)., Results: The results suggest that genetically predicted hyperthyroidism is causally associated with PE during pregnancy [ β  = 0.06, 95% confidence interval (CI): 1.01-1.12; P  = 0.02], and genetically predicted hypothyroidism is also causally associated with PE during pregnancy ( β  = 0.11, 95% CI: 1.03-1.21; P  = 0.01). These effects were further confirmed with sensitivity analysis. Conversely, preeclampsia is not associated with the risk of thyroid dysfunction in the reverse MR results: thyroid-stimulating hormone ( β  = 0.00, P  = 0.92), free thyroxine (FT4) ( β  = -0.01, P  = 0.56), triiodothyronine (FT3) ( β  = -0.00, P  = 0.72), FT3/FT4 ( β  = -0.01, P  = 0.38), thyroid peroxidase antibodies ( β  = -0.01, P  = 0.64), hyperthyroidism ( β  = -0.11, P  = 0.29) and hypothyroidism ( β  = 0.04, P  = 0.12)., Conclusion: Our study suggests that hyper-/hypo-thyroidism causally affected preeclampsia, while PE is not causally associated with thyroid dysfunctions., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Studies have been conducted on the relationship between depression and thyroid diseases and function, its causal relationship remains unclear., Methods: Using summary statistics of genome-wide association studies of European and East Asian ancestry, we conducted 2-sample bidirectional Mendelian randomization to estimate the association between MDD and thyroid function (European: normal range TSH, T4, T3, fT4, TPOAb levels and TPOAb-positives; East Asian: T4) and thyroid diseases (hypothyroidism, hyperthyroidism, and Hashimoto's thyroiditis), and used Mediation analysis to evaluate potential mediators (alcohol intake, antidepressant) of the association and calculate the mediated proportions., Results: It was observed a significant causal association between MDD on hypothyroidism (P = 8.94 × 10 -5 ), hyperthyroidism (P = 8.68 × 10 -3 ), and hashimoto's thyroiditis (P = 3.97 × 10 -5 ) among European ancestry, which was mediated by Alcohol intake (alcohol intake versus 10 years previously for hypothyroidism (P = 0.026), hashimoto's thyroiditis (P = 0.042), and alcohol intake frequency for hypothyroidism (P = 0.015)) and antidepressant (for hypothyroidism (P = 0.008), hashimoto's thyroiditis (P = 0.010)), but not among East Asian ancestry (P MDD-hypothyroidism  = 0.016, but β direction was different; P MDD-hyperthyroidism  = 0.438; P MDD-hashimoto ' s thyroiditis  = 0.496). There was no evidence for bidirectional causal association between thyroid function mentioned above and MDD among both ancestry (all P > 0.05)., Conclusion: We importantly observed a significant causal association between MDD on risk of hypothyroidism, hyperthyroidism, and hashimoto's thyroiditis among European ancestry, and Alcohol intake and antidepressant as mediators for prevention of hypothyroidism, hashimoto's thyroiditis attributable to MDD., Competing Interests: Declaration of competing interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Hyperthyroidism is an endocrine disorder with a relatively low global prevalence but significantly higher incidence among females compared to males. The onset age primarily ranges from 30 to 50, although it is not limited to this age group. Challenges in the treatment of hyperthyroidism include individualized treatment plan formulation, management of side effects, and prediction of disease progression, necessitating comprehensive consideration to achieve more effective therapy and management. Mendelian randomization studies can reveal more precise therapeutic targets between blood and urine biomarkers and hyperthyroidism, providing more decadent treatment options for the condition., Methods: The study will build upon the omics Mendelian randomization (MR) framework by conducting MR analysis using 35 blood and urine biomarkers separately for two distinct databases of hyperthyroidism. Subsequently, the results will undergo meta-analysis and multiple corrections to ensure accuracy and reliability. Finally, positive findings will undergo reverse MR validation to verify causal relationships with hyperthyroidism., Results: In the British database, the MR analysis of Total bilirubin levels about hyperthyroidism yielded an odds ratio ( OR ) of 1.097 (95% CI : 0.951-1.265, P = 0.205). Conversely, in the Thyroid Omics Association database, the MR analysis revealed an OR of 1.283 (95% CI : 1.122-1.467, P = 0.0002) for the same relationship. Meta-analysis of the MR analysis results from both databases, following multiple corrections, resulted in an OR of 1.192 (95% CI : 1.081-1.314, P = 0.015). Additionally, the direction of beta values in the MR analysis results from both databases was consistent., Conclusion: The urine biomarker total bilirubin levels may contribute to an increased risk of hyperthyroidism and accelerate its progression, thus representing a risk factor for the condition., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xu, Wu, Chen, Zhang and Yang.)

Objective: The aim of the study is to map the shared genetic component and relationships between thyroid and reproductive health traits to improve the understanding of the interplay between those domains., Design: A large-scale genetic analysis of thyroid traits (hyper- and hypothyroidism, and thyroid-stimulating hormone levels) was conducted in up to 743 088 individuals of European ancestry from various cohorts., Methods: We evaluated genetic associations using genome-wide association study (GWAS) meta-analysis, GWAS Catalog lookup, gene prioritization, mouse phenotype lookup, and genetic correlation analysis., Results: GWAS meta-analysis results for thyroid phenotypes showed that 50 lead variants out of 253 (including 5/52 of the novel hits) were linked to reproductive health in previous literature. Genetic correlation analyses revealed significant correlations between hypothyroidism and reproductive phenotypes. The results showed that 31.9% of thyroid-associated genes also had an impact on reproductive phenotypes, with the most affected functions being related to genitourinary tract issues., Conclusions: The study discovers novel genetic loci linked to thyroid phenotypes and highlights the shared genetic determinants between thyroid function and reproductive health, providing evidence for the genetic pleiotropy and shared biological mechanisms between these traits in both sexes., Competing Interests: Conflict of interest: the authors declare no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Previous observational studies found associations between Helicobacter pylori infection and autoimmune thyroid diseases (AITDs), but the causal nature of this association is still uncertain. We investigated the causal effect of six crucial antibodies against H. pylori on AITDs using a bidirectional Mendelian randomization (MR). We found that anti- H. pylori outer membrane protein (OMP) significantly increased the risk of hyperthyroidism and Graves' disease (GD). In addition, our reverse MR analysis indicated that hyperthyroidism could increase the levels of cytotoxin-associated gene A and OMP antibodies. We also observed causal roles of GD on anti- H. pylori OMP. Our analyses indicate the mutual effects of H. pylori infection and AITDs, suggesting the existence of a gut-thyroid axis. These results also provide evidence of the bidirectional causal association between anti- H. pylori OMP with hyperthyroidism and GD, resulting in a vicious circle.

Background: The relationship between thyroid hormone (TH) levels in vivo and osteoarthritis (OA) remains inconclusive. This study aims to investigate the association between TH levels and OA, analyze the effect of triiodothyronine on hypertrophic chondrocyte differentiation and OA progression, and identify potential target genes of triiodothyronine in OA to evaluate its diagnostic value., Methods: Two-sample mendelian randomization method was used to probe the causal links between hyperthyroidism and OA. Differentially expressed genes (DEGs) from two RNA-sequencing data in Gene Expression Omnibus (GSE199847 and GSE114007) and enrichment analysis of DEGs (166 commonly upregulated genes and 71 commonly downregulated genes of GSE199847 and GSE114007) was performed to analyze the effect of triiodothyronine (T3) on hypertrophic chondrocyte differentiation and OA. C28/I2 cells treated with T3 and reverse transcription and quantitative real-time polymerase chain reaction were used to validate T3 targeted genes. The diagnostic performance of target genes was assessed by the receiver operating characteristic (ROC) curve and area under the curve (AUC)., Results: There was a positive causal association between hyperthyroidism and OA (IVW result, OR = 1.330, 95% CI 1.136-1.557, P = 0.0004). Weighted median and Weighted mode analysis also demonstrated that hyperthyroidism had a positive causal association with OA (p < 0.05, OR > 1). Bioinformatics analysis indicated T3 can partially induce the emergence of late hypertrophic chondrocyte and promote OA through extracellular matrix organization, blood vessel development, skeletal system development and ossification. Post-T3 treatment, MAFB, C1QTNF1, COL3A1 and ANGPTL2 were significantly elevated in C28/I2 cells. ROC curves in GSE114007 showed that AUC of all above genes were ≥ 0.7., Conclusions: This study identified that hyperthyroidism has a positive causal association with OA by MR analysis. T3 induced hypertrophic chondrocytes promote OA progression by upregulating genes such as MAFB, C1QTNF1, COL3A1 and ANGPTL2, which can also serve as OA diagnosis., (© 2024. The Author(s).)

Objective: To explore the causal relationship between thyroid dysfunction and sepsis based on the bidirectional two-sample Mendelian randomization (MR) method., Methods: The genome-wide association study (GWAS) dataset were selected to screen single nucleotide polymorphisms (SNP) associated with thyroid dysfunction as instrumental variable (IV) for genetic variation, using hypothyroidism and hyperthyroidism as exposure factor and sepsis as outcome factor. Potential causal relationship between thyroid dysfunction and sepsis was analyzed using a bidirectional two-sample MR method primary analysis method of inverse-variance weighted (IVW). Potential pleiotropic analysis of SNP was performed using the MR Egger regression intercept test. Sensitivity analysis was performed using the "leave one out" test. Reverse MR method was used to prove the causal relationship., Results: The GWAS data were screened based on the three main assumptions of MR, resulting in 101 SNP strongly associated with hypothyroidism and 10 SNP strongly associated with hyperthyroidism entering the MR analysis. The results of the MR using the IVW method showed that the risk of sepsis in individuals with hypothyroidism was 2.293 times higher than those without hypothyroidism [odds ratio (OR) = 2.293, 95% confidence interval (95%CI) was 1.199-4.382, P = 0.012]. There was no significant difference in the risk of sepsis between hyperthyroid and non-hyperthyroid populations (OR = 1.049, 95%CI was 0.999-1.100, P = 0.560). MR Egger regression intercept test showed that the included SNP did not have pleiotropy, and the MR-PRESSO test did not find outliers. Sensitivity analysis suggested that the results of MR were stable. The results of the reverse MR analysis showed that the reverse causal relationship between hyperthyroidism and sepsis was not proved (OR = 0.996, 95%CI was 0.988-1.004, P = 0.338), which further confirmed the robust MR analysis result., Conclusions: The results of the bidirectional two-sample MR analysis show that hypothyroidism can increase the risk of sepsis onset, while there is no causal relationship between hyperthyroidism and sepsis.

Objective: Some observational studies have suggested the association between thyroid function and polycystic ovary syndrome (PCOS). However, it remains to be determined whether these associations are causal or not. The aim of this study was to investigate the underlying causal association between different thyroid function status and PCOS., Methods: Bidirectional Mendelian randomization (MR) analysis was conducted to explore the impact of different thyroid function statuses on PCOS. The study included 10,074 individuals with PCOS and 103,164 controls for the primary analysis, with validation analysis repeated in the FinnGen R9 and EstBB PCOS cohorts. Female-specific thyroid function GWAS data were obtained from European population, including Hyperthyroidism (22,383 cases and 54,288 controls) and Hypothyroidism (27,383 cases and 54,288 controls) from the UK Biobank, and TSH (54,288 cases and 72,167 controls) and FT4 (49,269 cases and 72,167 controls) within the reference range from the ThyroidOmics Consortium. Inverse variance weighting (IVW) was chosen as the principal method, and sensitivity analysis was conducted to test for the presence of horizontal pleiotropy or heterogeneity., Results: The IVW analysis indicated nominal significance between normal TSH levels and PCOS after adjusted for age and BMI [OR (95% CI) = 0.78(0.62,0.97), P = 0.029], suggesting that maintaining normal TSH levels might act as a protective factor against the pathogenesis of PCOS. Besides, in order to increase the statistical power, we pooled PCOS GWAS above together by meta-analysis and found PCOS contributed to the occurrence of hyperthyroidism [OR(95%CI) = 1.37(0.73,2.57), P = 0.012]. However, no causal relationship was found after Bonferroni correction (P-value < 0.0031)., Conclusion: Although the MR analysis didn't indicate genetic causal association between thyroid function and PCOS after Bonferroni correction. Further efforts are needed to interpret the potential causal relationship between thyroid function and PCOS in different age and BMI subgroup., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Numerous organs, including the thyroid gland, depend on vitamin D to function normally. Insufficient levels of serum 25-hydroxyvitamin D [25(OH)D] are seen as a potential factor contributing to the emergence of several thyroid disorders, however, the causal relationship remains unclear. Here we use a Mendelian randomization (MR) approach to investigate the causal effect of serum 25(OH)D concentration on the indicators of thyroid function., Methods: We conducted a two-sample MR analysis utilizing summary data from the most extensive genome-wide association studies (GWAS) of serum 25(OH)D concentration (n = 443,734 and 417,580), thyroid-stimulating hormone (TSH, n = 271,040), free thyroxine (fT4, n = 119,120), free triiodothyronine (fT3, n = 59,061), total triiodothyronine (TT3, n = 15,829), as well as thyroid peroxidase antibody levels and positivity (TPOAb, n = 12,353 and n = 18,297), low TSH (n = 153,241), high TSH (n = 141,549), autoimmune hypothyroidism (n = 287,247) and autoimmune hyperthyroidism (n = 257,552). The primary analysis was conducted using the multiplicative random-effects inverse variance weighted (IVW) method. The weighted mode, weighted median, MR-Egger, MR-PRESSO, and Causal Analysis Using Summary Effect estimates (CAUSE) were used in the sensitivity analysis., Results: The IVW, as well as MR Egger and CAUSE analysis, showed a suggestive causal effect of 25(OH)D concentration on high TSH. Each 1 SD increase in serum 25(OH)D concentration was associated with a 12% decrease in the risk of high TSH (p = 0.02). Additionally, in the MR Egger and CAUSE analysis, we found a suggestive causal effect of 25(OH)D concentration on autoimmune hypothyroidism. Specifically, each 1 SD increase in serum 25(OH)D concentration was associated with a 16.34% decrease in the risk of autoimmune hypothyroidism (p = 0.02)., Conclusions: Our results support a suggestive causal effect which was negative in direction across all methods used, meaning that higher genetically predicted vitamin D concentration possibly lowers the odds of having high TSH or autoimmune hypothyroidism. Other thyroid parameters were not causally influenced by vitamin D serum concentration., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Pleić et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Some previous observational studies have linked deep venous thrombosis (DVT) to thyroid diseases; however, the findings were contradictory. This study aimed to investigate whether some common thyroid diseases can cause DVT using a two-sample Mendelian randomization (MR) approach., Methods: This two-sample MR study used single nucleotide polymorphisms (SNPs) identified by the FinnGen genome-wide association studies (GWAS) to be highly associated with some common thyroid diseases, including autoimmune hyperthyroidism (962 cases and 172,976 controls), subacute thyroiditis (418 cases and 187,684 controls), hypothyroidism (26,342 cases and 59,827 controls), and malignant neoplasm of the thyroid gland (989 cases and 217,803 controls. These SNPs were used as instruments. Outcome datasets for the GWAS on DVT (6,767 cases and 330,392 controls) were selected from the UK Biobank data, which was obtained from the Integrative Epidemiology Unit (IEU) open GWAS project. The inverse variance weighted (IVW), MR-Egger and weighted median methods were used to estimate the causal association between DVT and thyroid diseases. The Cochran's Q test was used to quantify the heterogeneity of the instrumental variables (IVs). MR Pleiotropy RESidual Sum and Outlier test (MR-PRESSO) was used to detect horizontal pleiotropy. When the causal relationship was significant, bidirectional MR analysis was performed to determine any reverse causal relationships between exposures and outcomes., Results: This MR study illustrated that autoimmune hyperthyroidism slightly increased the risk of DVT according to the IVW [odds ratio (OR) = 1.0009; p = 0.024] and weighted median methods [OR = 1.001; p = 0.028]. According to Cochran's Q test, there was no evidence of heterogeneity in IVs. Additionally, MR-PRESSO did not detect horizontal pleiotropy (p = 0.972). However, no association was observed between other thyroid diseases and DVT using the IVW, weighted median, and MR-Egger regression methods., Conclusions: This study revealed that autoimmune hyperthyroidism may cause DVT; however, more evidence and larger sample sizes are required to draw more precise conclusions., (© 2024. The Author(s).)

The prevalence of thyroid dysfunction diseases (TDFDs) and osteoporosis (OP) is high. Previous studies have indicated a potential association between TDFDs and OP, yet the causal direction remains unclear. This study aimed to investigate the potential causal relationship between TDFDs and the risk of developing OP and related fractures. We obtained pooled data from genome-wide association studies (GWASs) conducted on TDFDs and OP in European populations and identified single-nucleotide polymorphisms (SNPs) with genome-wide significance levels associated with exposure to TDFDs as instrumental variables. Inverse variance weighted (IVW) was employed as the primary method for Mendelian randomization (MR) analysis, supplemented by MR‒Egger, weighted median, simple mode and weighted mode methods. Sensitivity analyses were conducted to evaluate the robustness of the findings. The IVW method demonstrated an increased risk of OP in patients with TDFDs, including hyperthyroidism and hypothyroidism (TDFDs: OR = 1.11; 95% CI 1.09, 1.13; hypothyroidism: OR = 1.14; 95% CI 1.10, 1.17; hyperthyroidism: OR = 1.09; 95% CI 1.06, 1.12). These findings were supported by supplementary analysis, which revealed a positive correlation between TDFDs and the risk of OP. Multiple sensitivity analyses confirmed the absence of horizontal pleiotropy in the study, thus indicating the robustness of our results. The causal relationship between TDFDs and increased risk of OP implies the need for early bone mineral density (BMD) screening and proactive prevention and treatment strategies for individuals with TDFDs., (© 2024. The Author(s).)

Introduction: The established association between thyroid disorders (TD) and its two main subtypes-hyperthyroidism and hypothyroidism-and the incidence of oral and oropharyngeal cancer (OCPC) has been substantiated. However, the direct causal relationship and potential intermediary mechanisms linking these conditions have not been clearly defined in prior studies., Material & Methods: This study employed univariate Mendelian randomization (MR) analysis to explore those relationship. Instrumental variables from genome-wide association study (GWAS) datasets for TD (n = 218,792), hyperthyroidism (n = 460,499), hypothyroidism (n = 213,990), and OCPC (n = 12,619), along with 41 intermediary inflammatory cytokines (n = 8293), were analyzed. Inverse variance weighting (IVW) method assessed the causal relationships, while summary MR analysis with pQTL datasets from decode and 91 inflammatory cytokines explored the cytokines' roles as biomarkers and therapeutic targets for OCPC. Multivariable MR (MVMR) analysis quantified the mediation effect of these cytokines in the TD-OCPC relationship., Results: UVMR analysis provided strong evidence for a causal relationship between TD (OR = 1.376, 95 % CI = 1.142-1.656, p = 0.001), hyperthyroidism (OR = 1.319, 95 % CI=1.129-1.541, p = 0.001), hypothyroidism (OR = 1.224, 95 % CI = 1.071-1.400, p = 0.003), and the risk of OCPC. CXCL9 was identified as a significant intermediary in mediating the risk of OCPC from TD and its two subtypes (OR = 1.218, 95 % CI = 1.016-1.461, P = 0.033), suggesting its potential as a predictive biomarker for OCPC. MVMR analysis further revealed that CXCL9 mediated 7.94 %, 14.4 %, and 18 % of the effects of TD, hyperthyroidism, and hypothyroidism on OCPC risk, respectively., Discussion: This study not only elucidated the potential causal relationships between TD including its two subtypes and OCPC risk, but also highlighted CXCL9 as a pivotal mediator in this association., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Numerous studies establish a significant correlation between autoimmune disorders (AIDs) and prostate cancer (PCa). Our Mendelian randomization (MR) analysis investigates the potential connection between rheumatoid arthritis (RA) and PCa, aiming to confirm causal links between systemic lupus erythematosus (SLE), hyperthyroidism, and PCa. Summary statistics from genome-wide association studies provided data on PCa and three AIDs. MR analysis, using IVW as the main approach, assessed causal relationships, validated by sensitivity analysis. IVW revealed a correlation between genetically anticipated RA and PCa, notably in Europeans (OR = 1.03; 95% CI 1.01-1.04, p = 2*10-5). Evidence supported a lower PCa risk in individuals with SLE (OR = 0.94; 95% CI 0.91-0.97, p = 2*10-4) and hyperthyroidism (OR = 0.02; 95% CI 0.001-0.2, p = 2*10-3). Weighted mode and median confirmed these findings. No pleiotropic effects were observed, and MR heterogeneity tests indicated dataset homogeneity. Our study establishes a causal link between RA, SLE, hyperthyroidism, and PCa., (© 2024. The Author(s).)

Purpose: Observational studies and clinical validation have suggested a link between thyroid dysfunction and an elevated ovarian cancer (OC) risk. However, whether this association indicates a cause-and-effect relationship remains uncertain. We aimed to investigate the plausible causal impact of thyroid dysfunction on OC through a Mendelian randomization (MR) study., Methods: Genome-wide association study (GWAS) data for thyrotropin (TSH), free thyroxine (FT4), hypothyroidism, and hyperthyroidism were obtained as exposures and those for OC (N = 199,741) were selected as outcomes. Inverse variance-weighted method was used as the main estimation method. A series of sensitivity analyses, including Cochran's Q test, MR-Egger intercept analysis, forest plot scatter plot, and leave-one-out test, was conducted to assess the robustness of the estimates., Results: Genetic prediction of hyperthyroidism was associated with a potential increase in OC risk (odds ratio = 1.094, 95% confidence interval: 1.029-1.164, p = 0.004). However, no evidence of causal effects of hypothyroidism, TSH, and FT4 on OC or reverse causality was detected. Sensitivity analyses demonstrated consistent and reliable results, with no significant estimates of heterogeneity or pleiotropy., Conclusions: This study employed MR to establish a correlation between hyperthyroidism and OC risk. By genetically predicting OC risk in patients with hyperthyroidism, our research suggests new insights for early prevention and intervention of OC., (© 2024. The Author(s).)

Hyperthyroidism is a well-known trigger of high bone turnover that can lead to the development of secondary osteoporosis. Previously, we have shown that blocking bone morphogenetic protein (BMP) signaling systemically with BMPR1A-Fc can prevent bone loss in hyperthyroid mice. To distinguish between bone cell type-specific effects, conditional knockout mice lacking Bmpr1a in either osteoclast precursors (LysM-Cre) or osteoprogenitors (Osx-Cre) were rendered hyperthyroid and their bone microarchitecture, strength and turnover were analyzed. While hyperthyroidism in osteoclast precursor-specific Bmpr1a knockout mice accelerated bone resorption leading to bone loss just as in wildtype mice, osteoprogenitor-specific Bmpr1a deletion prevented an increase of bone resorption and thus osteoporosis with hyperthyroidism. In vitro, wildtype but not Bmpr1a-deficient osteoblasts responded to thyroid hormone (TH) treatment with increased differentiation and activity. Furthermore, we found an elevated Rankl/Opg ratio with TH excess in osteoblasts and bone tissue from wildtype mice, but not in Bmpr1a knockouts. In line, expression of osteoclast marker genes increased when osteoclasts were treated with supernatants from TH-stimulated wildtype osteoblasts, in contrast to Bmpr1a-deficient cells. In conclusion, we identified the osteoblastic BMP receptor BMPR1A as a main driver of osteoporosis in hyperthyroid mice promoting TH-induced osteoblast activity and potentially its coupling to high osteoclastic resorption., (© 2024. The Author(s).)

Backgroud: Gastric cancer is one of the most common cancers worldwide, and its development is associated with a variety of factors. Previous observational studies have reported that thyroid dysfunction is associated with the development of gastric cancer. However, the exact relationship between the two is currently unclear. We used a two-sample Mendelian randomization (MR) study to reveal the causal relationship between thyroid dysfunction and gastric cancer for future clinical work., Materials and Methods: This study is based on a two-sample Mendelian randomization design, and all data are from public GWAS databases. We selected hyperthyroidism, hypothyroidism, free thyroxine (FT4), and thyroid-stimulating hormone (TSH) as exposures, with gastric cancer as the outcome. We used three statistical methods, namely Inverse-variance weighted (IVW), MR-Egger, and weighted median, to assess the causal relationship between thyroid dysfunction and gastric cancer. The Cochran's Q test was used to assess the heterogeneity among SNPs in the IVW analysis results, and MR-PRESSO was employed to identify and remove IVs with heterogeneity from the analysis results. MR-Egger is a weighted linear regression model, and the magnitude of its intercept can be used to assess the horizontal pleiotropy among IVs. Finally, the data were visualized through the leave-one-out sensitivity test to evaluate the influence of individual SNPs on the overall causal effect. Funnel plots were used to assess the symmetry of the selected SNPs, forest plots were used to evaluate the confidence and heterogeneity of the incidental estimates, and scatter plots were used to assess the exposure-outcome relationship. All results were expressed as odds ratios (OR) and 95% confidence intervals (95% CI). P<0.05 represents statistical significance., Results: According to IVW analysis, there was a causal relationship between hypothyroidism and gastric cancer, and hypothyroidism could reduce the risk of gastric cancer (OR=0.936 (95% CI:0.893-0.980), P=0.006).This means that having hypothyroidism is a protective factor against stomach cancer. This finding suggests that hypothyroidism may be associated with a reduced risk of gastric cancer.Meanwhile, there was no causal relationship between hyperthyroidism, FT4, and TSH and gastric cancer., Conclusions: In this study, we found a causal relationship between hypothyroidism and gastric cancer with the help of a two-sample Mendelian randomisation study, and hypothyroidism may be associated with a reduced risk of gastric cancer, however, the exact mechanism is still unclear. This finding provides a new idea for the study of the etiology and pathogenesis of gastric cancer, and our results need to be further confirmed by more basic experiments in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Mu, Jiang, Zhao, Wang and Shen.)

Background: 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., Methods: 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., Results: 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)., Conclusion: 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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Dong, Qu, Ma and Lu.)

Background and Aims: Hyperthyroidism is an endocrine disease with multiple etiologies and manifestations. Heart failure (HF) is a common, costly, and deadly medical condition in clinical practice. Numerous studies have suggested that abnormal thyroid function can induce or aggravate the development of heart disease. However, no study has demonstrated a causal relationship between hyperthyroidism and heart failure. Therefore, the purpose of this study was to explore the causal link between hyperthyroidism and HF., Methods: Summary data for genetically predicted hyperthyroidism were obtained from a genetic association study. The data examined for genetically determined all-cause heart failure came from 218,208 individuals from the FinnGen Consortium. Two-sample Mendelian randomization (MR) analysis was used to estimate the causal link between hyperthyroidism and heart failure. Statistical analyses were conducted using the inverse variance-weighted, weighted median, simple median, weighted mode, MR-PRESSO (number of distribution = 5000), MR-Egger, and leave-one-out., Results: The results of the inverse-variance weighted analysis indicated a causal association between hyperthyroidism and an increased risk of all-cause heart failure (IVW: β=0.048, OR=1.049, 95%CI: [1.013 to 1.087], P=0.007). Similarly, the weighted median approach demonstrated a positive correlation between hyperthyroidism and all-cause heart failure (OR=1.049, [95% CI, 1.001-1.100]; P=0.044). Additionally, no horizontal pleiotropy or heterogeneity was observed. The leave-one-out analysis revealed that the majority of the SNP-driven associations were not influenced by a single genetic marker., Conclusion: Our study observed a causal relationship between hyperthyroidism and all-cause heart failure. Hyperthyroidism may associate with heart failure genetically., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Wu, Li, Cheng and Ye.)

Background: Parkinson's disease (PD) is the second most prevalent degenerative disease globally. While observational studies have demonstrated a correlation between thyroid function and PD, the causal relationship between these two factors remains uncertain., Methods: A bidirectional Mendelian randomization (MR) analysis was performed to explore the causal relationship between thyroid function (free thyroxine [FT4], thyroid-stimulating hormone [TSH], hyperthyroidism, and hypothyroidism) and PD. GWAS summary-level statistics of thyroid function and PD were obtained from publicly available GWAS databases. The inverse variance weighted method was the main MR approach to assess causal associations. In addition, two additional MR methods (MR-Egger regression and weighted median) were performed to supplement the IVW. Furthermore, various sensitivity tests were performed to verify the reliability of the MR findings: (i) Heterogeneity was examined by Cochrane's Q test. (ii) Horizontal pleiotropy was assessed by the MR-Egger intercept test and MR-PRESSO global test. (iii) The robustness of MR results was estimated using the leave-one-out method., Results: Various MR results showed that FT4, TSH, hyperthyroidism, and hypothyroidism did not causally affect PD (P > 0.05). Likewise, PD did not causally affect FT4, TSH, hyperthyroidism, and hypothyroidism (P > 0.05). Cochrane's Q test indicated that MR analysis was not affected by significant heterogeneity (P > 0.05). MR-Egger intercept test and MR-PRESSO global test indicated that MR analysis was not affected by a remarkable horizontal pleiotropy (P > 0.05). The leave-one-out method demonstrated the stability of MR results., Conclusion: MR analysis did not support a causal relationship between thyroid function and PD., (© 2023. Fondazione Società Italiana di Neurologia.)

Background: Multiple evidence suggests that thyroid function is associated with polycystic ovary syndrome (PCOS), but whether thyroid function is causally related to PCOS is unclear. To investigate whether the association reflect causality, a Mendelian randomization (MR) analysis was conducted., Methods: Single nucleotide polymorphisms (SNPs) involved in this study were acquired from The ThyroidOmics Consortium and the IEU Open Genome-wide association study (GWAS) database, respectively. In forward MR analysis, we included normal free thyroxine (FT4, n=49,269), normal thyroid-stimulating hormone (TSH, n=54,288), hypothyroidism (n=53,423) and hyperthyroidism (n=51,823) as exposure. The outcome was defined as PCOS in a sample size of 16,380,318 individuals. The exposure in the reverse MR analyses was chosen as PCOS, while the outcome consisted of the four phenotypes of thyroid function. The inverse-variance weighted (IVW) method was performed as the major analysis, supplemented by sensitivity analyses., Results: The occurrence of PCOS was associated with increased risk of hyperthyroidism (IVW, OR=1.08, 95%CI=1.02-1.13, P=0.004). No evidence suggested that other phenotypes of thyroid function were related to PCOS., Conclusions: Our findings demonstrate a cause-and-effect connection between PCOS and hyperthyroidism. The study established foundation for further investigation for interaction between thyroid function and PCOS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhao, Gao, Pei, Wang, Wang and Zhang.)

Background: The role of thyroid health in temporomandibular disorders (TMDs) has been emphasized in observational studies. However, whether the causation exists is unclear, and controversy remains about which specific disorder, such as hypothyroidism or hyperthyroidism, is destructive in TMDs. This study aims to investigate the overall and specific causal effects of various thyroid conditions on TMDs., Methods: Mendelian randomization (MR) studies were performed using genetic instruments for thyrotropin (TSH, N = 119,715), free thyroxine (fT4, N = 49,269), hypothyroidism (N = 410,141), hyperthyroidism (N = 460,499), and TMDs (N = 211,023). We assessed the overall effect of each thyroid factor via inverse-variance weighted (IVW), weighted median, and MR-Egger methods, and performed extensive sensitivity analyses. Additionally, multivariable MR was conducted to evaluate the direct or indirect effects of hypothyroidism on TMDs whilst accounting for TSH, fT4 and hyperthyroidism, and vice versa., Results: Univariable MR analyses revealed a causal effect of hypothyroidism on an increased risk of TMDs (IVW OR: 1.12, 95% CI: 1.05-1.20, p = 0.001). No significant association between genetically predicted hyperthyroidism, TSH, or fT4 and TMDs. In the multivariable MR analyses, the effects of hypothyroidism on TMDs occurrence remained significant even after adjSusting for TSH, fT4 and hyperthyroidism (multivariable IVW OR: 1.10, 95% CI: 1.03-1.17, p = 0.006). No pleiotropy and heterogeneity were detected in the analyses (p > 0.05)., Conclusions: Hypothyroidism might causally increase the risk of TMDs through a direct pathway, highlighting the critical role of managing thyroid health in the prevention of TMDs. Clinicians should give heightened attention to patients with hypothyroidism when seeking medical advice for temporomandibular discomfort. However, caution is warranted due to the potential confounders, pleiotropy, and selection bias in the MR study., (© 2024. The Author(s).)

Objective: To determine whether there is a causal relationship between thyroid dysfunction and the risk of age-related cataract (ARC) in the European population., Design: A two-sample Mendelian randomization (MR) study., Methods: Hypothyroidism, hyperthyroidism, free thyroxine (fT4), and thyrotropin (TSH) were selected as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were obtained from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for fT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. ARC was used as the outcome. The SNPs associated with ARC were selected from a GWAS of 216,362 individuals in the FinnGen database. The main method used was the inverse variance-weighted method, together with four complementary methods. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO, MR-Egger regression and leave-one-out test. MR pleiotropy was used to test for pleiotropy. MR Steiger test was used to test for the directionality., Results: Two-sample MR analysis revealed a positive association between genetically predicted hypothyroidism and risk of ARC (OR = 2.501, 95% CI: 1.325-4.720; P = 0.004). Hyperthyroidism, circulating fT4 and TSH levels did not have a significant causal effect on ARC ( P > 0.05). The results were robust and reliable, and no horizontal pleiotropy was found after sensitivity analyses. In the MR Steiger test, we found no reverse causal effects of hypothyroidism on the ARC ( P < 0.001)., Conclusions: Our study provides strong evidence that hypothyroidism is a causal determinant of ARC risk., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Sun, Gu, Bao, Wang, Qin and Yuan.)

Clinicians may confuse an impaired sensitivity to thyroid hormone with hyperthyroidism and offer an inappropriate treatment. We report a diagnosis of resistance to thyroid hormone (RTH) caused by a rare mutation in the thyroid hormone receptor beta gene in a patient previously presumed to have Graves' disease. We have found only one published case of a novel point mutation, c.749T>C (p.Ile250Thr variant) associated with 50% reduction in thyroid hormone receptor binding affinity for triiodothyronine in the I250T mutant; it was found in this patient. A 66-year-old male veteran, with a history of non-ischemic cardiomyopathy and arrhythmias, was referred by a cardiologist with concerns for a possible thyrotropin (TSH) adenoma on account of elevated TSH and free thyroxine (FT4) levels. Pituitary imaging was negative. He was previously treated with radioiodine for presumptive Graves' disease in the civilian sector. Examination revealed a goiter with no nodules. Repeat TSH and FT4 levels were elevated and also free triiodothyronine (FT3) and reverse triiodothyronine. These findings and other test results were consistent with RTH, which was confirmed by genetic testing. Mutation analysis showed the patient to be heterozygous for the p.Ile250Thr variant. He later developed hypothyroidism. Resistance to thyroid hormone can be misdiagnosed as hyperthyroidism with consequent inappropriate treatment. Treatment is not needed in most RTH-beta patients. Thyroid ablation should generally be avoided. Clinicians must be cautious whenever they encounter concurrent elevation of TSH, FT4, and FT3. This RTH-beta patient has a rare I250T mutant of the thyroid hormone receptor beta gene, the second reported case in the literature., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: We found the G132R heterozygous mutation of thyroid stimulating hormone receptor (TSHR) gene in a patient with recurrent hypokalemia. Because the patient had a medical history of hyperthyroidism, the mutation was suspected to be related to hyperthyroidism at first. Subsequently, the expression and function studies in vitro were conducted., Methods: Wide-type TSHR and mutant TSHR (mutTSHR) were constructed in the phage vector and pEGFP-C1 vector. After transfection, the samples were collected for detection of mRNA level, protein expression, cell activity and cAMP content., Results: Compared with the wild-type TSHR, the mRNA level of the mutTSHR was not significantly different. But the protein expression, cell activity and cAMP content of the mutTSHR were significantly lower. So this indicated that the G132R mutation is a loss-of-function mutation., Conclusion: We identified the G132R monoallelic heterozygous mutation of TSHR gene in a patient with hyperthyroidism. Based on disease history of the patient, we speculated that the heterozygous mutation did not cause thyroid dysplasia or hypothyroidism for her. Our study enriched experiment content in vitro studies and clinical phenotype about the G132R mutation in TSHR gene., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Previous studies have often observed a possible association between thyroid and fatty liver diseases. The pathogenesis of both diseases is complex, with many confounding factors and controversies. We used a two-sample Mendelian randomization (MR) analysis to test the causality between thyroid disease and the risk of developing fatty liver disease., Materials and Methods: All data were obtained from the genome-wide association studies (GWAS) Catalog database. Thyroid disorders include hypothyroidism, hyperthyroidism, autoimmune thyroiditis, and Hashimoto's thyroiditis. Fatty liver diseases include alcoholic fatty liver disease and non-alcoholic fatty liver disease (NAFLD). The inverse variance weighting (IVW) method was used for MR analysis, and sensitivity analysis was further performed to test its robustness., Results: We discovered no causal relationship between thyroid disease and alcoholic fatty liver disease after excluding weak instrumental variables (IVs). Hyperthyroidism and hypothyroidism had a significant causal relationship with NAFLD. Hypothyroidism increased the risk of NAFLD using the IVW method (OR=7.62, 95% CI: 2.61-22.25, p<0.001). MR-Egger regression did not suggest potential evidence of directional pleiotropy (intercept, p=0.698). Hyperthyroidism also significantly increased the risk of NAFLD (OR=11.83, 95% CI: 2.9-22.54, p=0.026). MR-Egger regression did not suggest any potential directional pleiotropy (intercept, p=0.295)., Conclusions: Hypothyroidism can significantly increase NAFLD incidence, and hyperthyroidism may be a risk factor for NAFLD.

Objective: The causal relationship between Rheumatoid arthritis (RA) and hypothyroidism/hyperthyroidism remains controversial due to the limitations of conventional observational research, such as confounding variables and reverse causality. We aimed to examine the potential causal relationship between RA and hypothyroidism/hyperthyroidism using Mendelian randomization (MR)., Method: We conducted a bidirectional two-sample univariable analysis to investigate the potential causal relationship between hypothyroidism/hyperthyroidism and RA. Furthermore, we performed a multivariate analysis to account for the impact of body mass index (BMI), smoking quantity, and alcohol intake frequency., Results: The univariable analysis indicated that RA has a causative influence on hypothyroidism (odds ratio [OR]=1.07, 95% confidence interval [CI]=1.01-1.14, P=0.02) and hyperthyroidism (OR=1.32, 95% CI=1.15-1.52, P<0.001). When hypothyroidism/hyperthyroidism was considered as an exposure variable, we only observed a causal relationship between hypothyroidism (OR=1.21, 95% CI=1.05-1.40, P=0.01) and RA, whereas no such connection was found between hyperthyroidism (OR=0.91, 95% CI=0.83-1.01, P=0.07) and RA. In the multivariate MR analyses, after separately and jointly adjusting for the effects of daily smoking quantity, alcohol intake frequency, and BMI, the causal impact of RA on hypothyroidism/hyperthyroidism and hypothyroidism on RA remained robust. However, there is no evidence to suggest a causal effect of hyperthyroidism on the risk of RA (P >0.05)., Conclusion: Univariate and multivariate MR analyses have validated the causal association between RA and hypothyroidism/hyperthyroidism. Hypothyroidism confirmed a causal relationship with RA when employed as an exposure variable, whereas no such relationship was found between hyperthyroidism and RA., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lai, Deng, Lv, Liu, Zhou and Peng.)

Context: Many observational studies have reported on the association between educational attainment (EA) and thyroid function, but the causal relationship remains unclear., Objective: We aimed to obtain causal effects of EA on thyroid function and to quantify the mediating effects of modifiable risk factors., Methods: Two-sample mendelian randomization (MR) was performed by using summary statistics from large genome-wide association studies (GWAS) to assess the effect of EA on thyroid function, including hypothyroidism, hyperthyroidism, thyrotropin (TSH), and free thyroxine (FT4). A multivariable analysis was conducted to assess the mediating role of smoking and help to explain the association between EA and thyroid function. Similar analysis was further performed using data from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2002., Results: In MR analysis, EA was causally associated with TSH (β = .046; 95% CI, 0.015-0.077; P = 4.00 × 10-3), rather than hypothyroidism, hyperthyroidism, and FT4. Importantly, smoking could serve as a mediator in the association between EA and TSH, in which the mediating proportion was estimated to be 10.38%. After adjusting for smoking in the multivariable MR analysis, the β value of EA on TSH was attenuated to 0.030 (95% CI, 0.016-0.045; P = 9.32 × 10-3). Multivariable logistic regression model in NHANES suggested a dose-response relationship between TSH (quartile [Q]4 vs Q1: odds ratio = 1.33; 95% CI, 1.05-1.68; P for trend = .023) and EA. Smoking, systolic blood pressure, and body mass index partially mediated the association between EA and TSH, with the proportion of the mediation effects being 43.82%, 12.28%, and 6.81%, respectively., Conclusion: There is a potentially causal association between EA and TSH, which could be mediated by several risk factors, such as smoking., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Oxidative stress plays an important role in the pathology of thyroid disorders. This study examined the effect of gallic acid (GA) on the oxidative status and expression of liver antioxidant genes including thioredoxin (TXN1 & TXN2) and thioredoxin reductase1 (TXNRd1) in hypo- and hyperthyroid rat models. Forty-nine male Wistar rats were randomly assigned into seven groups as follows: control group, hypothyroid and hyperthyroid groups respectively induced by propylthiouracil and levothyroxine, hypo- and hyper thyroid-treated groups (where the groups were separately treated with 50 and 100 mg/kg of GA daily, orally). The levels of thyroid hormones and serum oxidative stress markers were evaluated after 5 weeks. The relative expression of TXN1,2 and TXNRd1 genes was measured via real-time qRT-PCR. The mean level of total antioxidant capacity (TAC), malondialdehyde, and uric acid index diminished in the hypothyroid group. Increased TAC reached almost the level of control in hypothyroid groups treated with GA. Elevation of thiol index in the hypothyroid group was observed ( p  < 0.01), which diminished to the control level after GA treatment. The relative expression of TXN1, TXNRd1, and TXN2 genes in the hypothyroid and hyperthyroid groups significantly increased compared to the control group ( p  ≥ 0.05), but in the groups treated with GA, the expression of these genes declined significantly ( p  ≥ 0.05). Our results indicated GA can affect the expression of TXN system genes in the rat liver. Also, the results suggest GA has a more positive effect on modulating serum oxidative parameters in hypothyroid rat models than in hyperthyroid.

Thyroid hormones play a critical role in regulation of multiple physiological functions and thyroid dysfunction is associated with substantial morbidity. Here, we use electronic health records to undertake a genome-wide association study of thyroid-stimulating hormone (TSH) levels, with a total sample size of 247,107. We identify 158 novel genetic associations, more than doubling the number of known associations with TSH, and implicate 112 putative causal genes, of which 76 are not previously implicated. A polygenic score for TSH is associated with TSH levels in African, South Asian, East Asian, Middle Eastern and admixed American ancestries, and associated with hypothyroidism and other thyroid disease in South Asians. In Europeans, the TSH polygenic score is associated with thyroid disease, including thyroid cancer and age-of-onset of hypothyroidism and hyperthyroidism. We develop pathway-specific genetic risk scores for TSH levels and use these in phenome-wide association studies to identify potential consequences of pathway perturbation. Together, these findings demonstrate the potential utility of genetic associations to inform future therapeutics and risk prediction for thyroid diseases., (© 2023. Springer Nature Limited.)

Background: Observational studies have demonstrated an association between primary sclerosing cholangitis (PSC) and thyroid dysfunction (TD). However, the causal relationship between PSC and TD remains uncertain. The purpose of this study is to investigate the causal associations and specific direction between these two conditions. Gaining insight into the potential causal relationship between PSC and TD is valuable for elucidating the pathogenesis of PSC and for devising innovative approaches for the prevention and treatment of PSC and its associated complications., Methods: We conducted a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal association between PSC and TD, such as autoimmune thyroid disease (AITD), thyroid cancer (TC), thyroid stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), among others. PSC was the exposure variable, while TD was the outcome variable. To identify suitable instrumental variables (IVs), we utilized genome-wide association study (GWAS) datasets to select potential candidate single-nucleotide polymorphisms (SNPs). The primary statistical approach employed was the inverse-variance weighted (IVW) method, which was complemented by a series of sensitivity analyses to assess the robustness of the results by estimating heterogeneity and pleiotropy., Results: We found that the causal associations between genetically predicted PSC and Graves' disease (GD), hyperthyroidism (IVW OR=1.230, 95%CI: 1.089-1.389, P=0.001; IVW OR=1.001, 95%CI: 1.000-1.002, P=0.000) were statistically significant. The reverse MR analysis indicated that genetic susceptibility to hyperthyroidism (P=0.000) and hypothyroidism (p=0.028) might be the risk of PSC. There was no statistically significant causal association observed between PSC and other TD (IVW P>0.05), with the exception of GD, hyperthyroidism, and hypothyroidism as determined through bidirectional two-sample analysis. To ensure the reliability of our findings, additional sensitivity analyses were conducted, including the leave-one-out (LOO) test, heterogeneity test, and pleiotropic test., Conclusion: In this study, we conducted an investigation into the causal association between PSC and TD. Our findings indicate that PSC significantly elevates the susceptibility to GD and hyperthyroidism from a statistical perspective. These results shed light on the etiology of PSC and have implications for the management of patients with PSC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling editor JW declared a shared parent affiliation with the authors WZ, RL at the time of review., (Copyright © 2023 Zhang and Lang.)

Objective: Hyperthyroidism in Chinese children is relatively high and has been increasing in recent years, which has a significant impact on their healthy development. Hyperthyroidism is a polygenic disorder that presents greater challenges in terms of prediction and treatment than monogenic diseases. This study aims to elucidate the associated functions and gene sets of mutated genes in children with hyperthyroidism in terms of the gene ontology through GO enrichment analysis and in terms of biological signaling pathways through KEGG enrichment analysis, thereby enhancing our understanding of the expected effects of multiple mutated genes on hyperthyroidism in children., Methods: Whole-exome sequencing was performed on the DNA samples of children with hyperthyroidism. Screening for pathogenic genes related to hyperthyroidism in affected children was performed using the publicly available disease databases Malacards, MutationView, and Clinvar, and the functions and influences of the identified pathogenic genes were analyzed using statistical analysis and the gene enrichment approach., Results: Through GO enrichment analysis, it was found that the most significant gene ontology enrichment was the function "hormone activity" in terms of gene ontology molecular function. The corresponding mutated genes set that has common effects on hyperthyroidism in children included TG, CALCA, POMC, CGA, PTH, GHRL, FBN1, TRH, PRL, LEP, ADIPOQ, INS, GH1. The second most significant gene ontology enrichment was the function "response to peptide hormone" in terms of biological process. The corresponding mutated genes set that has common effects on hyperthyroidism in children included LRP6, TSC2, KANK1, COL1A1, CDKN1B, POMC, STAT1, MEN1, APC, GHRL, TSHR, GJB2, FBN1, GPT, LEP, ADIPOQ, INS, GH1. Through KEGG enrichment analysis, it was found that the most significant biological signaling pathway enrichment was the pathway "Thyroid hormone signaling pathway" function. The corresponding mutated genes set that has common effects on hyperthyroidism in children included NOTCH3, MYH7, TSC2, STAT1, MED13L, MAP2K2, SLCO1C1, SLC16A2, and THRB. The second most significant biological signaling pathway enrichment was the pathway "Hypertrophic cardiomyopathy" in terms of biological process. The corresponding mutated genes set that has common effects on hyperthyroidism in children included IGF1, CACNA1S, MYH7, IL6, TTN, CACNB2, LAMA2, and DMD., Conclusion: The mutated genes in children with hyperthyroidism were closely linked to function involved in "hormone activity" and "response to peptide hormone" in terms of the biological signaling pathway, and to the functional pathways involved in "Thyroid hormone signaling pathway" and "Hypertrophic cardiomyopathy" in terms of the biological signaling pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Mao, Tang, Li, Zhang, Liu, Wang and Headar.)

Background: The role of thyroid hormones in cancers has been discussed in observational studies; however, the causal relationship between them remains controversial., Methods: The SNPs associated with hypothyroidism and hyperthyroidism were selected from a FinnGen biobank of 342,499 (190,879 females and 151,620 males) Finnish adult subjects. Data from the Thyroidomics Consortium on 72,167 individuals were used to assess genetically determined thyroid-stimulating hormone (TSH) and free thyroxine (FT4). Lung cancer, lung adenocarcinoma and squamous cell lung cancer GWAS data from the International Lung Cancer Consortium(ILCCO). Six different Mendelian randomization (MR) Methods, including Inverse variance weighted (IVW), MR-Egger, Simple mode, MR-Pleiotropy Residual Sum and Outlier methods (MR-PRESSO), Weighted mode and Weighted median were used to Two-Sample MR analysis. IVW was used as the primary estimate. Sensitivity analyses were examined via four aspects (Cochran's Q-test, MR Egger intercept analysis, Funnel plot and Leave-one-out sensitivity test)., Results: The OR of hypothyroidism on lung cancer was 0.918 (95% CI, 0.859-0.982; p = 0.013) in MR analysis with IVW method. No evidence for effects of hyperthyroidism, TSH and FT4 on lung cancer risk was found via six MR methods. Meanwhile, there was no evidence for effects of lung cancer on hypothyroidism through six MR methods. Lung adenocarcinoma and squamous cell lung carcinoma were further analyzed on the basis of lung cancer. The OR of hypothyroidism on lung adenocarcinoma was 0.893(95% CI, 0.813-0.981; p = 0.019), the OR of hypothyroidism on squamous cell lung cancer was 0.888(95%CI,0.797-0.990, p = 0.032) in MR analysis with IVW method., Conclusion: In summary, hypothyroidism genetically had a protective causal association with lung cancer. Furthermore, hypothyroidism had protective effects both on lung adenocarcinoma and squamous cell lung cancer. Further work is needed to elucidate the potential mechanisms., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Context: Observational studies have provided insufficient information on the association between thyroid function and the risk of cerebral small vessel disease (CSVD); moreover, the causality of this link is still unclear., Objective: This study aims to investigate whether genetically predicted variation within thyroid function is causally associated with the risk of CSVD using 2-sample Mendelian randomization (MR) analysis., Methods: In this 2-sample MR study with genome-wide association variants, we estimated the causal effects of genetically predicted thyrotropin (thyroid-stimulating hormone, TSH; n = 54 288), free thyroxine (FT4; n = 49 269), hypothyroidism (n = 51 823), and hyperthyroidism (n = 51 823) on 3 neuroimaging markers of CSVD, including white matter hyperintensity (WMH; n = 42 310), mean diffusivity (MD; n = 17 467), and fractional anisotropy (FA, n = 17 663). The primary analysis was conducted by the inverse variance-weighted MR method, followed by sensitivity analyses using MR-PRESSO, MR-Egger, weighted median, and weighted mode methods., Results: Genetically increased TSH was associated with increased MD (β = .311, 95% CI 0.0763, 0.548, P = .01). Genetically increased FT4 was associated with increased FA (β = .540, 95% CI 0.222, 0.858, P < .001). Sensitivity analyses using different MR methods showed similar directions but lower precision. No significant associations of hypothyroidism or hyperthyroidism with WMH, MD, or FA were found (all P > .05)., Conclusion: This study indicated that genetically predicted increased TSH was associated with increased MD, as well as increased FT4 with increased FA, implying the causal effect of thyroid dysfunction on white matter microstructural injury. There were no significant causal relationships of hypothyroidism or hyperthyroidism with CSVD. Further investigations should verify these findings and clarify the underlying pathophysiological mechanisms., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: To clarify the controversy between systemic lupus erythematosus (SLE) and thyroid disease, our study was designed to determine whether or not thyroid problems are associated with SLE., Methods: We obtained the IEU GWAS database for summary information on genome-wide association studies (GWAS) of SLE and thyroid disease (hypothyroidism and hyperthyroidism) in people with European ancestry. Three approaches were employed to assess the causal link between SLE and thyroid disease: MR-Egger, weighted median (WM), and inverse variance weighted (IVW). The pleiotropy and heterogeneity were examined using a variety of techniques, including the MR-Egger intercept, the MR-PRESSO approach, and the Cochran's Q test., Results: MR analysis revealed a relationship between SLE and an elevated incidence of hypothyroidism (IVW OR: 1.004, 95% CI: [1.003, 1.005], P = 8.45E-16) and hyperthyroidism (IVW OR: 1.0009, 95% CI: [1.0005, 1.0010], P = 1.30E-5). Neither horizontal pleiotropy nor heterogeneity was detected in the sensitivity analysis., Conclusion: Our MR study presents strong evidence demonstrating a link between SLE and an elevated risk of thyroid illness. This could help us learn more about what causes SLE and give people with SLE more thorough thyroid function tests and evaluations. Key points • We did not discover modest heterogeneity and pleiotropy in our study. •The findings of this study indicate that SLE is related to an elevated risk of hypothyroidism and hyperthyroidism., (© 2023. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Objective: Although previous studies have reported an association between thyroid function and anti-Müllerian hormone (AMH) levels, which is considered a reliable marker of ovarian reserve, the causal relationship between them remains uncertain. This study aims to investigate whether thyrotropin (TSH), free thyroxine (fT4), hypo- and hyperthyroidism are causally linked to AMH levels., Methods: We obtained summary statistics from three sources: the ThyroidOmics Consortium (N = 54,288), HUNT + MGI + ThyroidOmics meta-analysis (N = 119,715), and the most recent AMH genome-wide association meta-analysis (N = 7,049). Two-sample MR analyses were conducted using instrumental variables representing TSH and fT4 levels within the normal range. Additionally, we conducted secondary analyses to explore the effects of hypo- and hyperthyroidism. Subgroup analyses for TSH were also performed., Results: MR analyses did not show any causality relationship between thyroid function and AMH levels, using normal range TSH, normal range fT4, subclinical hypothyroidism, subclinical hyperthyroidism and overt hypothyroidism as exposure, respectively. In addition, neither full range TSH nor TSH with individuals <50 years old was causally associated with AMH levels. MR sensitivity analyses guaranteed the robustness of all MR results, except for the association between fT4 and AMH in the no- DIO1 + DIO2 group., Conclusion: Our findings suggest that there was no causal association between genetically predicted thyroid function and AMH levels in the European population., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Liang, Xu and Liu.)