Causal relationship between thyroid dysfunction and gastric cancer: a two-sample Mendelian randomization study.

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.

Prevalence of hyperthyroidism and hypothyroidism in liver transplant recipients and associated risk factors.

The prevalence of hyperthyroidism and hypothyroidism and associated risk factors are unknown in liver transplant recipients. We aimed to determine the prevalence of hyperthyroidism and hypothyroidism and associated risk factors in liver transplant recipients and to compare it with controls from the general population. As part of the Danish Comorbidity in Liver Transplant Recipients (DACOLT) Study, all Danish liver transplant recipients over the age of 20 were invited for measurements of concentrations of thyrotropin and thyroid hormones. The prevalence of hyperthyroidism and hypothyroidism was compared to age- and sex-matched controls from the Copenhagen General Population Study. Using logistic regression adjusted for age, sex, smoking, and body-mass index, we investigated potential risk factors. We recruited 489 liver transplant recipients and 1808 controls. Among liver transplant recipients, 14 (2.9%) had hyperthyroidism compared with 21 (1.2%) of controls (adjusted odds ratio [aOR] 2.24, 95% confidence interval [CI] 1.05-4.75, P = 0.04), while 42 (5.7%) had hypothyroidism compared with 139 (7.7%) of controls (aOR 0.68, 95% CI 0.43-1.08, P = 0.10). Female sex, and autoimmune hepatitis and primary sclerosing cholangitis as causes of transplantation were associated with hyperthyroidism after adjustments. Age, female sex, and autoimmune liver diseases as cause of transplantation were associated with hypothyroidism after adjustments. DACOLT is registered in ClinicalTrials.gov (NCT04777032).

Prevalence of thyroid dysfunction and associated factors among adult type 2 diabetes mellitus patients, 2000-2022: a systematic review and meta-analysis.

BACKGROUND: Thyroid dysfunction (TD) and type 2 diabetes mellitus (T2DM) frequently co-occur and have overlapping pathologies, and their risk increases with age. Thyroid dysfunction along with T2DM will worsen macro- and microvascular complications, morbidity, and mortality. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guideline was followed. The databases used were Embase, ScienceDirect, PubMed, and Google Scholar. The Joana Briggs Institute (JBI) scale was used to assess the quality of the included studies. The data was extracted by Microsoft Excel and analyzed through STATA version 14 software. The overall pooled prevalence of TD and its main components were estimated using the random-effects model. The consistency of studies was assessed by I2 test statistics. Pooled meta-logistic regression was used to present the pooled prevalence with a 95% confidence interval (CI). Besides, subgroup and sensitivity analyses were employed. RESULT: Thirty-eight studies were included. The pooled prevalence of TD was 20.24% (95% CI: 17.85, 22.64). The pooled prevalence of subclinical hypothyroidism, hypothyroidism, subclinical hyperthyroidism, and hyperthyroidism was found to be 11.87% (95% CI: 6.90, 16.84), 7.75% (95% CI: 5.71, 9.79), 2.49% (95% CI: 0.73, 4.25), and 2.51% (95% CI: 1.89, 3.13), respectively. Subgroup analysis based on continent revealed a higher prevalence of TD in Asia and Africa. Factors like being female, HbA1c ≥ 7%, DM duration > 5 years, family history of TD, central obesity, smoking, the presence of retinopathy, and neuropathy were found associated with TD. CONCLUSION: The current systematic review and meta-analysis showed that the TD's pooled prevalence was relatively higher than the general population. Therefore, regular screening of TD should be done for T2DM patients.

Thyroid dysfunction after immune checkpoint inhibitors in a single-centre UK pan-cancer cohort: A retrospective study.

PURPOSE: This study investigated thyroid dysfunction with immune checkpoint inhibitors (ICIs) in terms of proportions affected, risk factors, thyroid sequelae, and overall survival (OS). METHODS: Among patients with normal baseline free T4 (fT4) and thyroid stimulating hormone (TSH) receiving ICIs at a large cancer centre, proportions of hyperthyroidism/hypothyroidism were determined (any, subclinical [normal fT4, abnormal TSH], overt [abnormal fT4, abnormal TSH], isolated hyperthyroxinaemia/hypothyroxinaemia and secondary) with onset times and subsequent thyroid statuses. Associations of overt dysfunction with OS were estimated using Cox regression and methods robust to immortal time bias (time-dependent Cox regression and 3- and 6-month landmark analyses). Associations of baseline variables with overt hyperthyroidism and hypothyroidism were estimated using Fine and Gray regression. RESULTS: Of 1349 patients, 34.2% developed hyperthyroidism (10.3% overt), including 54.9% receiving combination ICIs, while 28.2% developed hypothyroidism (overt 9.3%, secondary 0.5%). A third of overt hypothyroidism cases occurred without preceding hyperthyroidism. Subclinical thyroid dysfunction returned directly to normal in up to half. Overt hyperthyroidism progressed to overt hypothyroidism in 55.4% (median 1.6 months). Melanoma treatment in the adjuvant vs. advanced setting caused more overt hyperthyroidism (12.1% vs. 7.5%) and overt hypothyroidism (14.5% vs. 9.7%). Baseline eGFR < 60 mL/min/1.73 m2 (HR=1.68, 1.07-2.63) was associated with overt hyperthyroidism and sex (HR=0.60, 0.42-0.87) and TSH (4th vs. 1st quartile HR=1.87, 1.10-3.19) with overt hypothyroidism. Overt dysfunction was associated with OS in the Cox analysis (HR=0.65, 0.50-0.85, median follow-up 22.2 months) but not in the time-dependent Cox (HR=0.79, 0.60-1.03) or landmark analyses (3-month HR=0.74, 0.51-1.07; 6-month HR=0.91, 0.66-1.24). CONCLUSION: Thyroid dysfunction affects up to half of patients receiving ICIs. The association with OS is unclear after considering immortal time bias. The clinical courses include recovery, thyrotoxicosis and de novo overt hypothyroidism. Adjuvant treatment for melanoma, where longer-term harms are of concern, causes more frequent/aggressive dysfunction.

Melissa officinalis extract palliates redox imbalance and inflammation associated with hyperthyroidism-induced liver damage by regulating Nrf-2/ Keap-1 gene expression in γ-irradiated rats.

BACKGROUND: Melissa officinalis (MO) is a well-known medicinal plant species used in the treatment of several diseases; it is widely used as a vegetable, adding flavour to dishes. This study was designed to evaluate the therapeutic effect of MO Extract against hyperthyroidism induced by Eltroxin and γ-radiation. METHODS: Hyperthyroidism was induced by injecting rats with Eltroxin (100 µg/kg/ day) for 14 days and exposure to γ-radiation (IR) (5 Gy single dose). The hyperthyroid rats were orally treated with MO extract (75 mg/kg/day) at the beginning of the second week of the Eltroxin injection and continued for another week. The levels of thyroid hormones, liver enzymes and proteins besides the impaired hepatic redox status and antioxidant parameters were measured using commercial kits. The hepatic gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its inhibitor Kelch-like ECH-associated protein-1(Keap-1) in addition to hepatic inflammatory mediators including tumor necrosis factor-α (TNF- α), Monocyte chemoattractant protein-1 (MCP-1) and fibrogenic markers such as transforming growth factor-beta1 (TGF-ß1) were determined. RESULTS: MO Extract reversed the effect of Eltroxin + IR on rats and attenuated the thyroid hormones. Moreover, it alleviated hyperthyroidism-induced hepatic damage by inhibiting the hepatic enzymes' activities as well as enhancing the production of proteins concomitant with improving cellular redox homeostasis by attenuating the deranged redox balance and modulating the Nrf2/Keap-1 pathway. Additionally, MO Extract alleviated the inflammatory response by suppressing the TNF- α and MCP-1 and prevented hepatic fibrosis via Nrf2-mediated inhibition of the TGF-ß1/Smad pathway. CONCLUSION: Accordingly, these results might strengthen the hepatoprotective effect of MO Extract in a rat model of hyperthyroidism by regulating the Nrf-2/ Keap-1 pathway.

Paraneoplastic Hyperthyroidism Secondary to a Chemotherapy-Induced Surge in ß-hCG in a Patient with Non-Seminomatous Germ Cell Tumor.

Thyrotoxicosis as the presenting syndrome of an underlying ß-hCG-secreting malignancy is well described. It has been previously theorized, but not reported, that the surge of ß-hCG secondary to chemotherapy induction may inadvertently trigger thyrotoxicosis. After thorough review, this is the first documented case of such event in peer-reviewed medical literature published in the English language. This is a case of a 21-year-old male with stage IIIc non-seminomatous germ cell tumor who developed paraneoplastic hyperthyroidism within 4 days of the first cycle of chemotherapy. Management considerations are suggested based on this case and review of the literature.

Hyperthyroidism and the risk of non-thyroid cancer: a Danish register-based long-term follow-up study.

Objective: Cancer is the second most common cause of death worldwide. It is currently debated whether thyroid dysfunction is a modifiable cancer risk factor. Our aim was to evaluate the risk of cancer in patients with hyperthyroidism. Methods: This is a register-based nationwide cohort study of individuals with a diagnosis of hyperthyroidism. Each hyperthyroid case was matched with four reference individuals according to age and sex. Using Fine and Gray competing risk regression models, we studied the association of hyperthyroidism and subsequent all-cause cancer diagnoses, adjusted for preexisting morbidity. Sub-analyses were stratified for cause of hyperthyroidism (Graves' disease and toxic nodular goiter, age when diagnosed with hyperthyroidism, sex, and cancer localization (lung, prostate, breast, and colorectal cancer)). Results: The cohort consisted of 95,469 patients with hyperthyroidism (followed for a median of 10.9 years (range: 5.2-17.2)), and 364,494 reference individuals (followed for a median of 11.2 years (range: 5.4-17.4)). Hyperthyroidism was associated with increased all-cause cancer risk (sub-distribution hazard ratio (SHR): 1.12; 95% CI: 1.10-1.14), as well as an increased risk of breast (SHR: 1.07; 95% CI: 1.02-1.13), lung (SHR: 1.20; 95% CI: 1.16-1.26), and prostate cancer (SHR: 1.10; 95% CI: 1.02-1.19), but not colorectal cancer (SHR: 1.04; 95% CI: 0.99-1.09). Sub-analyses stratified for age when diagnosed with hyperthyroidism and cause of hyperthyroidism yielded similar results. Conclusion: In this register-based study, patients with hyperthyroidism had an increased risk of cancer, in particular lung, prostate, and breast cancer. Whether a causal link exists remains to be proven.

Thyroid hormone resistance and large goiter mimicking infiltrative carcinoma in a pediatric patient.

OBJECTIVES: Resistance to thyroid hormone (RTH) is a genetic condition, caused by mutations in the thyroid hormone receptor gene and characterized by impaired end organ responsiveness to thyroid hormone. Here we describe a novel case of THR associated with large goiter mimicking infiltrative c. CASE PRESENTATION: A 13-year-old male with a hyperthyroid phenotype of RTH diagnosed as a toddler, on methimazole and nadolol therapies presented with an increase in goiter size and possible nodule. Thyroid ultrasound was concerning for a diffuse infiltrative process or malignancy. Methimazole was discontinued and he underwent further imaging, fine needle aspiration and core biopsies. Biopsy results were reassuring and imaging findings were subsequently attributed to RTH rather than malignancy. He started every other day liothyronine therapy, which led to a decrease in goiter size, thyroglobulin level, and improvement of hyperthyroid symptoms. CONCLUSIONS: This is the first case to our knowledge describing the above thyroid imaging findings in association with RTH. It also adds important information to the pediatric literature regarding management of the hyperthyroid phenotype of RTH, including the role of liothyronine therapy.

Hypothyroidism and hyperthyroidism related to gynecologic cancers: a nationwide population-based cohort study.

The purpose of this study was to assess the risks of hyperthyroidism and hypothyroidism related to gynecological cancers. Population-based retrospective cohort study. We conducted a cohort study using the Taiwan National Health Insurance Research Database to explore hyperthyroidism and hypothyroidism associated with site-specific gynecologic cancers in women from January 1, 2000 to December 31, 2018. The examined gynecologic cancers included endometrial (EC), uterine corpus cancer (UC), and ovarian cancer (OC). The incidence and hazard ratios were quantified using Cox proportional hazards models. The incidence of developing gynecological (Gyn) cancers in the hyperthyroid and hypothyroid women was 0.29 and 0.44 per 1000 person-years, which was 0.86 fold lower and 1.13 fold higher than that in the comparison cohort (p < 0.001). Compared with patients aged 20-40 years, patients in older age groups had a lower and higher risk of developing Gyn cancers (for hyperthyroid, 40-65 years: adjusted hazard ratio (aHR) = 0.82; > 65 years: aHR = 0.94; for hypothyroid, adjusted hazard ratio (aHR) = 1.26; > 65 years: aHR = 1.38). Compared with the non-hypothyroid women and non-hyperthyroid women beyond 6 years of follow-up, hypothyroid and hyperthyroid women showed decreased risk of Gyn cancers. Medication treatment for hyperthyroid and hypothyroid disease did not showed significant association in subgroup analyses (aHR = 0.99 and 0.80, respectively). Our results show that women with hyperthyroidism have a significantly reduced risk of gynecological cancers, whereas women with hypothyroidism have a slightly increased risk of gynecological cancers suggesting an association between thyroid function level and risk of gynecological cancers.

Comparison of pathophysiology in subclinical hyperthyroidism with different etiologies.

Subclinical hyperthyroidism (SHyper) is defined as normal levels of free thyroxine (fT4) and free triiodothyronine (fT3) with suppressed levels of TSH. Previous studies have reported the individual pathophysiology of endogenous SHyper patients and athyreotic patients receiving TSH suppression therapy with levothyroxine; however, apparently no studies have compared the two conditions. Five-hundred-forty untreated endogenous SHyper patients and 1,024 patients receiving TSH suppression therapy who underwent total thyroidectomy for papillary thyroid carcinoma were sampled. Thyroid hormone profiles and peripheral indices related to thyrotoxicosis were investigated in endogenous SHyper patients, athyreotic patients receiving TSH suppression therapy, and healthy participants. Endogenous SHyper patients showed significantly higher thyroid hormone levels (fT4 [p < 0.001] and fT3 [p < 0.001]), and peripheral indices showed a significant tendency towards thyrotoxicosis (strong TSH suppression: alkaline phosphatase [ALP, p < 0.001], creatinine [Cre, p < 0.001], pulse rate [p < 0.05]; and mild TSH suppression: Cre [p < 0.05]) than healthy participants. In contrast, athyreotic patients receiving TSH suppression therapy showed a significant tendency towards thyrotoxicosis than healthy participants only when TSH was strongly suppressed (fT3 [p < 0.001] and Cre [p < 0.001]). Endogenous SHyper patients showed significantly higher fT3 levels (p < 0.001) than athyreotic patients receiving TSH suppression therapy; however, there was a significant tendency towards thyrotoxicosis only when TSH was strongly suppressed (ALP [p < 0.05] and pulse rate [p < 0.05]). The effects of endogenous SHyper and TSH suppression therapy on target organ function are different. Although the serum thyroid hormone profile is similar to that of the thyrotoxic state, athyreotic patients receiving TSH suppression therapy with mildly suppressed serum TSH levels are not thyrotoxic.

Diagnosis of Resistance to Thyroid Hormone due to a Rare Mutation in the Thyroid Hormone Receptor Beta Gene in a Patient Previously Presumed to Have Graves' Disease.

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.

Hyperthyroidism and cardiovascular disease: an association study using big data analytics.

BACKGROUND: The cardiovascular (CV) system is profoundly affected by thyroid hormones. Both hypo- and hyperthyroidism can increase the risk of severe CV complications. OBJECTIVE: To assess the association of hyperthyroidism with major CV risk factors (CVRFs) and CV diseases (CVDs) using a big data methodology with the Savana Manager platform. MATERIAL AND METHODS: This was an observational and retrospective study. The data were obtained from the electronic medical records of the University Hospital Puerta de Hierro Majadahonda (Spain). Artificial intelligence techniques were used to extract the information from the electronic health records and Savana Manager 3.0 software was used for analysis. RESULTS: Of a total of 540,939 patients studied (53.62% females; mean age 42.2 ± 8.7 years), 5504 patients (1.02%; 69.9% women) had a diagnosis of hyperthyroidism. Patients with this diagnosis had a significantly (p < 0.0001) higher frequency of CVRFs than that found in non-hyperthyroid subjects. The higher frequency of CVRFs in patients with hyperthyroidism was observed in both women and men and in patients younger and older than 65 years of age. The total frequency of CVDs was also significantly (p < 0.0001) higher in patients diagnosed with hyperthyroidism than that found in patients without this diagnosis. The highest odds ratio values obtained were 6.40 (4.27-9.61) for embolic stroke followed by 5.99 (5.62-6.38) for atrial fibrillation. The frequency of all CVDs evaluated in patients with a diagnosis of hyperthyroidism was significantly higher in both women and men, as well as in those younger and older than 65 years, compared to subjects without this diagnosis. A multivariate regression analysis showed that hyperthyroidism was significantly and independently associated with all the CVDs evaluated except for embolic stroke. CONCLUSION: The data from this hospital cohort suggest that there is a significant association between the diagnosis of hyperthyroidism and the main CVRFs and CVDs in our population, regardless of the age and gender of the patients. Our study, in addition to confirming this association, provides useful information for understanding the applicability of artificial intelligence techniques to "real-world data and information".

Adequacy of thyroid hormone replacement for people with hypothyroidism in real-world settings: A systematic review and meta-analysis of observational studies.

OBJECTIVE: Thyroid hormone under-replacement and over-replacement are associated with adverse health outcomes. This systematic review aimed to evaluate the extent of thyroid hormone replacement adequacy for patients with known hypothyroidism in real-word settings, excluding those receiving thyroid hormone suppressive therapy as thyroid cancer treatment. DESIGN: Four electronic databases (Embase [Ovid], Medline [Ovid], PubMed and SCOPUS) were searched for published and unpublished observational studies until 12 December 2022. The results of the studies were meta-analysed to calculate pooled prevalence estimates for thyroid hormone supplementation adequacy, over-replacement and under-replacement. Quality assessment of studies was performed using the Joanna-Briggs appraisal tool for prevalence studies. RESULTS: Seven studies with a total of 4230 patients were eligible for quantitative synthesis. The pooled prevalence estimates of adequate thyroid replacement, over-replacement and under-replacement were 0.55 (95% confidence interval [CI]: 0.49-0.60, p = .001), 0.20 (95% CI: 0.14-0.27, p = .001) and 0.24 (95% CI: 0.13-0.36, p = .001), respectively. Four studies subclassified hypothyroidism and hyperthyroidism into overt and subclinical. The pooled prevalence of overt and subclinical hyperthyroidism was 0.04 (95% CI: 0.00-0.11, p = .01) and 0.17 (95% CI: 0.09-0.27 p = .001), respectively. For overt and subclinical hypothyroidism, the pooled prevalence was 0.02 (95% CI: 0.01-0.03, p = .001) and 0.20 (95% CI: 0.12-0.29, p = .001), respectively. CONCLUSIONS: On average, approximately half of patients with hypothyroidism are only treated to target euthyroidism. In real-world practice, a significant number of patients are over-treated or under-treated, leading to adverse healthcare outcomes. It is imperative that more effective thyroid monitoring strategies be implemented, with an emphasis on primary care thyroid function monitoring, to minimise inappropriate thyroid replacement treatments and optimise healthcare outcomes at a population level.

Causal relationship between rheumatoid arthritis and hypothyroidism or hyperthyroidism: a bidirectional two-sample univariable and multivariable Mendelian randomization study.

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.

Genetic link between primary sclerosing cholangitis and thyroid dysfunction: a bidirectional two-sample Mendelian randomization study.

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.

Is Thyroid Dysfunction Associated with Unruptured Intracranial Aneurysms? A Population-Based, Nested Case-Control Study from Korea.

Background: Few risk factors for the development of intracranial aneurysms (IAs) are known. We investigated the potential role of thyroid diseases in IA development using nationwide real-world data. Methods: A nested case-control study within the National Health Insurance Service-National Sample Cohort data from 2002 to 2019 was performed. A total of 5335 patients with unruptured IA were matched by age and sex with 80,025 controls at a ratio of 1:15. We estimated the odds ratios (ORs) and corresponding confidence intervals [CIs] between thyroid diseases and unruptured IA using a multivariable conditional logistic regression model. Results: Tobacco smoking, use of antihypertensive medication, and hypothyroidism were significantly associated with an elevated risk for unruptured IA in univariate analysis. In multivariable analysis, a history of hypothyroidism was associated with unruptured IA (adjusted OR: 1.46 [CI: 1.26-1.69]). Among patients with hypothyroidism, long-term use of thyroid hormone for >5 years was associated with a reduced risk for unruptured IA (adjusted OR: 0.69 [CI: 0.48-0.99]). A history of hyperthyroidism was associated with a reduced risk for unruptured IAs (adjusted OR: 0.71 [CI: 0.54-0.93]). In secondary analyses of the data according to sex, the respective observed associations between hypothyroidism and hyperthyroidism and the risk of IAs were found to be statistically significant in females but not in males. Conclusions: Hypothyroidism is associated with an increased risk of unruptured IAs, whereas hyperthyroidism is associated with a reduced risk. Overall, the findings suggest that thyroid hormones may play a protective role in the development of unruptured IAs. Further studies are needed to clarify potential direct causality and the biologic mechanisms relating thyroid dysfunction and unruptured IA.

The relationship of hip fracture and thyroid disorders: a systematic review.

Introduction: Bone density regulation is considered one of the systems affected by thyroid hormones, leading to low bone density that can result in pathologic fractures, including hip fractures. This review aimed to update clinicians and researchers about the current data regarding the relationship between hip fractures and thyroid disorders. Methods: English papers were thoroughly searched in four main online databases of Scopus, Web of Science, PubMed, and Embase. Data extraction was done following two steps of screening/selection using distinct inclusion/exclusion criteria. This study used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) checklist and the Newcastle-Ottawa Scale (NOS) as bias assessment. Results: In total, 19 articles were included in the research. The risk of hip fractures in women with differentiated thyroid cancer (DTC) is higher than hip fractures caused by osteoporosis. Men with hyperthyroidism and subclinical hyperthyroidism are at higher risk for hip fracture. Also, a decrease in serum thyroid stimulating hormone (TSH) may be associated with an increased risk of hip fracture. Conclusion: Reaching a consensus conclusion regarding the association between subclinical thyroid dysfunction and hip fracture is not feasible due to the heterogenicity of evidence; however, there may be a higher risk of fracture in individuals with subclinical hyperthyroidism.

The effect of hyperthyroidism on cognitive function, neuroinflammation, and necroptosis in APP/PS1 mice.

BACKGROUND: Increasing evidence has linked the thyroid dysfunction to the pathogenesis of dementia. Evidence from clinical studies has demonstrated that hypothyroidism is related to an increased risk of dementia. But the association of hyperthyroidism with dementia is largely unknown. METHODS: We used the adenovirus containing thyrotropin receptor (TSHR) amino acid residues 1-289 (Ad-TSHR289)-induced Graves' disease (GD) phenotype in Alzheimer's disease (AD) model mice (APP/PS1 mice) to evaluate the effect of hyperthyroidism on the cognitive function and ß-amyloid (Aß) accumulation. RESULTS: GD mice exhibited a stable long-term hyperthyroidism and cognitive deficits. Single Cell RNA-sequencing analysis indicated that microglia function played a critical role in the pathophysiological processes in GD mice. Neuroinflammation and polarization of microglia (M1/M2 phenotype) and activated receptor-interacting serine/threonine protein kinase 3 (RIPK3)/mixed lineage kinase domain-like pseudo-kinase (MLKL)-mediated necroptosis contributed to the pathological process, including Aß deposition and neuronal loss. RIPK3 inhibitor could inhibit GD-mediated Aß accumulation and neuronal loss. CONCLUSIONS: Our findings reveal that GD hyperthyroidism aggravates cognitive deficits in AD mice and induces Aß deposition and neuronal loss by inducing neuroinflammation and RIPK3/MLKL-mediated necroptosis.