Impaired sensitivity to thyroid hormone correlates to osteoporosis and fractures in euthyroid individuals

Pituitary-Thyroid Hormones and Related Indices in Euthyroid Type 2 Diabetes: Association With Thyroid Nodules

Aim

Diabetes is an independent risk factor for thyroid nodules (TNs), however, the influencing factors of TNs have not been fully clarified under the condition of diabetes. Previous studies have shown a connection between pituitary-thyroid hormone (TH) functions and TNs in different populations. However, the potential link in euthyroid patients with diabetes is unclear. We aimed to explore the correlates of TNs in euthyroid type 2 diabetes (T2D) patients.

Methods

This cross-sectional study included 1965 euthyroid adults with T2D. Clinical and biochemical data, including TH and relevant covariates were collected. TNs were evaluated using ultrasound. Univariate and multivariate logistic regression analyses were performed to identify factors associated with TNs, with analyses stratified by sex.

Results

The overall prevalence of TNs was 51.9%. The prevalence of TNs was higher in females. Stratified by sex, the results from univariate and further logistic regression analyses showed that free triiodothyronine (FT3) (OR: 1.381; 95% CI: 1.066-1.790) and thyroid-stimulating hormone index (TSHI) (OR: 0.740; 95% CI: 0.584-0.937) were independently correlated with TNs only in females, while no TH-related indicators entered the regression model in males.

Conclusion

The relationship between TH and related indices with TNs exhibited sex differences. Specifically, FT3 and TSHI were independently associated with TNs in females. These findings underscore the importance of evaluating TH and related indices for early monitoring and management of TNs, particularly in euthyroid female T2D patients.

Impaired sensitivity to thyroid hormones is associated with lower heart rate in the euthyroid population

BACKGROUND

The association of thyroid hormone sensitivity with heart rate remains unclear.

OBJECTIVE

This study aims to elucidate the relationship between impaired thyroid hormone sensitivity and lower heart rate in the euthyroid population.

METHODS

A total of 550 participants were included. Heart rate and serum biochemicals were measured. Thyroid hormone sensitivity indices were calculated using the thyrotropin index (TSHI), thyrotropin thyroxine resistance index (TT4RI), thyroid feedback quantile-based index (TFQI), Chinese-referenced parametric TFQI (PTFQI), and the ratio of free triiodothyronine to free thyroxine (FT3/FT4 ratio). Logistic regression analyses were applied to explore the relationship between thyroid hormone sensitivity indices and heart rate.

RESULTS

TSHI, TT4RI, TFQI, and PTFQI were higher, and FT3/FT4 ratio was lower in participants with heart rate ≤ 60 beats/min (P < .001 for all). Participants with increased TSHI, TT4RI, TFQI, and PTFQI and reduced FT3/FT4 ratio had lower heart rate (≤60 beats/min) (P for trend < .001 for all). Odds ratios (95% confidence intervals) for TSHI, TT4RI, TFQI, PTFQI, and FT3/FT4 ratio in the highest quartile were 2.090 (1.092-4.000), 2.240 (1.151-4.361), 2.014 (1.043-3.887), 2.163 (1.123-4.166), and 0.498, (0.249-0.996), respectively, as compared with the lowest quartile after adjusting for sex, age, body mass index, smoking, drinking, hypertension, diabetes, coronary artery disease, glycated hemoglobin, total cholesterol, low-density lipoprotein cholesterol, and triglycerides.

CONCLUSION

Impaired sensitivity to thyroid hormones was associated with lower heart rate in euthyroid participants. Future large-scale studies are needed to confirm our findings.

Association between sensitivity to thyroid hormones and trabecular bone score in euthyroid individuals: a population-based cross-sectional study

BACKGROUND

Thyroid hormone is a known pivotal factor that affects bone metabolism; however, whether bone microarchitecture is associated with thyroid hormone sensitivity is poorly understood. The trabecular bone score (TBS) serves as an essential indicator for assessing bone microarchitecture. This study aimed to investigate the relationship between sensitivity to thyroid hormones and TBS in euthyroid individuals.

METHODS

This cross-sectional study involved 3320 euthyroid participants from the National Health and Nutrition Examination Survey (NHANES) 2007-2008. Data, including thyroid function, TBS and other related parameters, were extracted and analyzed. The indices of thyroid hormone sensitivity, including the thyrotropin thyroxine resistance index (TT4RI), thyroid-stimulating hormone index (TSHI), thyroid feedback quantile-based index (TFQI) and parametric thyroid feedback quantile-based index (PTFQI), were calculated. Greater values of these indicators indicated a greater degree of impaired thyroid hormone sensitivity.

RESULTS

Impaired sensitivity to thyroid hormones was associated with degraded bone microarchitecture following adjustments for confounding variables (TT4RI: P = 0.005, TSHI: P = 0.008, TFQI: P = 0.003 and PTFQI: P = 0.006). The restricted cubic spline model demonstrated a positive relationship between TT4RI, TSHI, TFQI, PTFQI and degraded bone microarchitecture. Similar findings were observed in the analysis of subgroups stratified by age, sex, race, diabetes status, hypertension status and hyperuricemia status.

CONCLUSIONS

In euthyroid individuals, impaired sensitivity to thyroid hormones is associated with degraded bone microarchitecture. However, further studies are required to confirm this relationship.

Association Between Indices of Thyroid Hormone Resistance and Constipation Prevalence in the US Population: NHANES 2007-2010

BACKGROUND

Chronic constipation is a common and complex condition that significantly impairs the quality of life and health care costs. Identifying the underlying cause is crucial for effective management, and hypothyroidism is frequently implicated. Nevertheless, extensive studies are scarce regarding this correlation. The research aims to examine the association between indices of thyroid hormone resistance, particularly the Thyroid Feedback Quantile-based Index of Free Thyroxine (TFQIFT4), and the occurrence of constipation among the population of the United States.

METHODS

The analysis examined data collected from 6354 participants in the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2010. Chronic constipation was determined as the Bristol Stool Form Scale (BSFS) types of 1 to 2 or <3 bowel movements weekly. Thyroid hormone resistance was assessed using various indices. The statistical analysis comprised weighted logistic regression, restricted cubic splines (RCS), subgroup analysis, and sensitivity analysis.

RESULTS

Chronic constipation was diagnosed in 10% of participants, displaying distinct characteristics. A nonlinear association between TFQIFT4 and constipation was observed, with inflection points at -0.25 and 0.376. Above a TFQIFT4 value of -0.25, a significantly negative association with constipation was found, primarily in females (OR=0.21; 95% CI: 0.10-0.44). No such association was found in males.

CONCLUSIONS

The study elucidates a complex correlation between thyroid hormone resistance, particularly TFQIFT4, and constipation. Gender-specific correlations were evident, with TFQIFT4 demonstrating a negative association with constipation, primarily in females. These findings underscore the need for further investigation into the underlying mechanisms involving central thyroid resistance and constipation across genders.

A Case of Thyroid Hormone Resistance Syndrome with a Novel Mutation (c.947G>a) in the THRB Gene: Experience in Diagnosis and Treatment

Background

Thyroid hormone resistance syndrome (RTH) is a rare hereditary endocrine disease that can manifest as hyperthyroidism, hypothyroidism, or remain asymptomatic. It can easily be confused with other types of thyroid diseases. The diagnosis of the disease depends on genetic testing.

Case Report

We report a 19-year-old male patient with elevation of thyroid hormones. Serological examination showed elevated thyroid hormone levels, and thyroid-stimulating hormone levels within the reference interval. The patient was finally diagnosed with RTH after genetic testing that identified a gene mutation inherited from his mother. Due to timely diagnosis, the patient's condition has been well controlled, and his prognosis is good.

Conclusion

The clinical manifestations of RTH lack specificity, and serological examination typically shows elevated thyroid hormone levels and unsuppressed thyrotropin levels. Differential diagnosis requires a combination of serological examination, imaging studies, and functional tests to distinguish RTH from other conditions. The purpose of this treatment is to improve symptoms and should not involve the blind administration of antithyroid drugs, thyroid surgery, or radiotherapy.

Investigating the causal relationship between thyroid dysfunction diseases and osteoporosis: a two-sample Mendelian randomization analysis

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.

Thyroid function and thyroid homeostasis parameters are associated with increased urinary albumin excretion in euthyroid individuals over 60 years old from NHANES

Introduction

The relationship between thyroid function/homeostasis parameters and renal function has been extensively studied. However, the relationship between thyroid function and thyroid homeostasis parameters with albuminuria among elderly individuals remains unclear.

Methods

The population was divided into an albuminuria group and a non-albuminuria group for baseline characteristic difference analysis. Multivariable logistic regression was used to test the association between thyroid function, and thyroid homeostasis parameters and albuminuria. The nonlinear relationship was explored with restricted cubic splines. Meanwhile, we investigated whether the relationship also existed in the diabetes and hypertension subgroups. Receiver operating characteristic (ROC) curves were used to assess the effectiveness of the indices.

Results

FT4 and TFQIFT4 were positively correlated with albuminuria (OR = 1.12; 95% CI = 1.02-1.23, p = 0.02; OR = 1.79; 95% CI = 1.08-2.99, p = 0.03), and FT3/FT4 was negatively correlated with albuminuria (OR = 0.03; 95% CI = 0.00-0.26, p = 0.003). Additionally, the nonlinear relationship between FT3/FT4 as well as TSHI and albuminuria was approximately U-shaped. Similar results were observed in the hypertension subgroup but not in the diabetes subgroup. There was a U-shaped nonlinear relationship between FT3 and albuminuria in the diabetes group. In addition, FT3/FT4 performed better than TFQI, TT4RI, and TSHI in ROC analyses for albuminuria prediction.

Conclusion

FT4, TFQIFT4, and a low FT3/FT4 ratio were risk factors for albuminuria in euthyroid individuals over 60 years old. However, FT3 was more associated with albuminuria in the diabetes subgroup. TSH was not associated with albuminuria in any analysis. In our study, we attempted to provide more reasonable thyroid parameters and basis for evaluating patients with underlying albuminuria. FT3/FT4 may be used as a helpful indicator to predict albuminuria and provide novel ideas for the evaluation and treatment of albuminuria.

Higher Peripheral Thyroid Sensitivity Is Linked to a Lower Risk of Heart Failure After Acute Myocardial Infarction

CONTEXT

It is still not clear how the free triiodothyronine (FT3) to free thyroxine (FT4) ratio affects the prognosis of acute myocardial infarction (AMI), especially the risk of heart failure (HF) subsequent to AMI.

OBJECTIVE

The purpose of this study was to see how peripheral sensitivity to thyroid hormones, as measured by the FT3/FT4 ratio, affected HF and mortality after AMI.

METHODS

Our study was a retrospective cohort study. The primary endpoint was HF after AMI during and after hospitalization. The secondary endpoints were all-cause death and cardiovascular death after hospitalization.

RESULTS

The main sample included 3648 inpatients with AMI with a median age of 61.0 years; 68.9% were male. In the fully adjusted model, compared with patients in the lowest Q1 of the FT3/FT4 ratio, the risk of in-hospital HF in the highest Q4 patients was reduced by 44% (OR 0.56, 95% CI 0.44-0.72, P trend < .001), the risk of out-of-hospital HF was reduced by 37% (HR 0.63, 95% CI 0.48-0.84, P trend < .001), and the risks of all-cause and cardiovascular death were also significantly reduced. The analysis of different subgroups is consistent with the overall results. Furthermore, the sensitivity analysis of the euthyroid sample of 2484 patients was consistent with the main sample. Mediation analysis showed that altered levels of amino-terminal pro-B-type natriuretic peptide were mediators between the FT3/FT4 ratio and all endpoints in our study.

CONCLUSION

The thyroid hormone peripheral sensitivity of the FT3/FT4 ratio is an independent predictor of HF and mortality after AMI.

Association between sensitivity to thyroid hormone indices and osteoporosis in euthyroid patients with type 2 diabetes mellitus

Background

Thyroid hormones are known to regulate bone metabolism and may influence bone mineral density (BMD), as well as the risk of osteoporosis (OP) and fractures in patients with type 2 diabetes mellitus (T2DM). Recently, sensitivity to thyroid hormone indices has been linked with T2DM and OP independently. However, the relationship between thyroid hormone sensitivity and OP in euthyroid T2DM patients has yet to be investigated.

Objectives

The aim of this study was to determine the association between sensitivity to thyroid hormone indices and the risk of OP in euthyroid patients with T2DM.

Design

This study employed a retrospective, cross-sectional design and utilized data acquired from the Cangzhou Central Hospital in China between 2019 and 2020.

Methods

We retrospectively analyzed the data of 433 patients with T2DM for anthropometric measurements, clinical laboratory test results, and BMD. The thyroid-stimulating hormone index, thyrotroph thyroxine resistance index, and thyroid feedback quantile-based index (TFQI) were calculated to determine thyroid hormone sensitivity. Finally, multivariable logistic regression, generalized additive models, and subgroup analysis were performed to detect the association between sensitivity to thyroid hormone indices and the risk of OP in these patients.

Results

We did not observe a statistically significant linear relationship between sensitivity to thyroid hormones indices and OP after covariate adjustment. However, a nonlinear relationship existed between TFQI and the prevalence of OP. The inflection point of the TFQI was at -0.29. The effect sizes (odds ratio) on the left and right of the inflection point were 0.07 [95% confidence interval (CI): 0.01-0.71; p = 0.024] and 2.78 (95% CI: 1.02-7.58; p = 0.046), respectively. This trend was consistent in older female patients with higher body mass index (BMI; 25-30 kg/m2).

Conclusion

An approximate U-shaped relationship was observed between sensitivity to thyroid hormone indices and OP risk in euthyroid patients with T2DM with variations in sex, age, and BMI. These findings provide a new perspective to elucidate the role of thyroid hormones in OP, specifically in patients with T2DM.