Impaired Sensitivity to Thyroid Hormones Is Associated With Diabetes and Metabolic Syndrome

Associations between preoperative thyroid parameters, aggressive clinicopathological features and risk of recurrence in differentiated thyroid cancer

OBJECTIVE

The study aimed (1) to investigate the association between aggressive clinicopathological characteristics and the American Thyroid Association (ATA) recurrence risk classification in differentiated thyroid cancer (DTC) patients, and (2) to investigate the prognostic value of preoperative thyroid parameters.

METHODS

A total of 3833 patients histologically confirmed DTC were recruited. Preoperative clinical and postoperative pathologic data were retrospectively collected. Participants were stratified into low recurrence risk and intermediate-to-high recurrence risk groups based on the ATA risk stratification system.

RESULTS

The study cohort had a mean age of 48.87 ± 8.08 years, and 1,465 (76.82%) were female. Male (OR = 1.37, p = .024), aged 52 years and older (OR = 2.01, p < .001), larger tumor size (OR = 3.71, p = 0.011), nerve invasion (OR = 6.69, p = .004), margin involvement (OR = 5.46, p < .001), multifocality (OR = 3.71, p < .001), and bilaterality (OR = 3.95, p < .001) were identified as risk factors for a higher ATA recurrence risk classification, in addition to established factors such as lymph node metastasis and angioinvasion, after adjusting for potential confounding variables. Higher preoperative levels of free triiodothyronine (FT3), FT3 to free thyroxine (FT3/FT4), and lower thyroid feedback quantile-based index (TFQI) levels were associated with a higher ATA recurrence risk classification. The comprehensive predictive model incorporating these variables demonstrated excellent discrimination (AUC = 0.836). Furthermore, higher FT3/FT4 levels and lower TFQI levels were associated with higher risk of lymph node metastases and angioinvasion.

CONCLUSIONS

Factors such as male sex, older age, multifocality, bilaterality, margin involvement, nerve invasion, larger tumor size, and preoperative thyroid parameters serve as complementary predictors for higher ATA recurrence risk in DTC, in addition to conventional risk factors. These insights contribute to a more nuanced understanding and optimization of current risk stratification methodologies.

Impact of polycyclic aromatic hydrocarbon exposure on thyroid hormone sensitivity: a cross-sectional study of urinary metabolites in 2356 adults from NHANES

OBJECTIVE

The current study aimed to compare the relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and thyroid hormone (TH) sensitivity markers in individuals with normal thyroid function in the USA population during 2007-2008 and 2009-2012.

DESIGN

Observational cross-sectional study.

SETTING

US population data from 2007 to 2008 and 2009 to 2012.

MAIN OUTCOME MEASURES

Associations between PAH exposure and TH sensitivity were examined, stratified by sex and age, along with dose-response relationships between PAH metabolites and TH sensitivity indices.

RESULTS

In women, after adjusting for confounding variables, 1-hydroxynaphthalene was positively associated with thyroid feedback quantile index of FT4 (TFQIFT4) (β=0.0072, 95% CI 0.0018 to 0.0127, p=0.022), thyrotropin thyroxine resistance index (TT4RI) (β=0.0099, 95% CI 0.0024 to 0.0173, p=0.021) and thyroid-stimulating hormone index (TSHI) (β=0.0107, 95% CI 0.0038 to 0.0176, p=0.012). Among individuals aged 60 years and older, 1-hydroxyphenanthrene was negatively associated with free triiodothyronine/free thyroxine (FT3/FT4) (β = -0.9328, 95% CI -1.5055 to -0.3602, p=0.014). Dose-response analysis revealed no nonlinear relationships between PAH metabolites and TH sensitivity indices in women or individuals aged 60 years and older. Weighted quantile regression analysis demonstrated that OH-PAHs exerted a statistically significant effect (p<0.05) on TH sensitivity indices, including TFQIFT4, thyroid feedback quantile index of FT3, TT4RI, hyrotropin triiodothyronine resistance index and TSHI.

CONCLUSIONS

In the US population with normal thyroid function, PAH exposure may interfere with TH sensitivity, with effects varying by population characteristics.

Alterations in Thyroid Hormones in Obese Patients Are Associated With Body Composition Changes After Bariatric Surgery

CONTEXT

This article mainly explored the relationship between body composition and thyroid function in euthyroid obesity through correlation analysis, which showed the significant changes of thyroid function after bariatric surgery notably correlated with changes in body composition.

OBJECTIVE

This study investigates how metabolic/bariatric surgery (MBS) affects thyroid hormone (TH) levels and TH resistance in obese euthyroid individuals, focusing on their correlation with changes in body composition.

METHODS

We included 470 obese individuals and 118 controls for baseline assessment, and 125 obese patients receiving MBS for longitudinal study. Data on body composition and thyroid function were collected. Correlations between baseline and changes in thyroid function and body composition were assessed.

RESULTS

In the obese group, thyrotropin (TSH), free triiodothyronine (fT3) levels, and thyroid feedback quantile-based index (TFQI) were elevated and significantly decreased post MBS, along with visceral fat area (VFA) and body fat percentages, whereas skeletal muscle mass (SMM) percentage increased. Preoperative partial correlation analysis adjusted for age and sex revealed that TSH positively correlated with VFA (r = 0.109; P = .019), body fat percentage (r = 0.114; P = .013), and negatively correlated with SMM percentage (r = -0.104; P = .024). Similar correlations were observed between central TH resistance indices and body composition, but no statistically significant correlations were found in the control group. Post MBS, decreased TSH positively correlated with decreased VFA (r = 0.251; P = .006) and increased SMM percentage (r = 0.233; P = .011). While reductions in VFA and body fat percentage were linked to improved central TH resistance, a decrease in peripheral TH conversion was noted.

CONCLUSION

MBS significantly affects thyroid function and TH resistance, with notable correlations to changes in body composition.

Impaired sensitivity to thyroid hormones is positively associated to metabolic syndrome severity in euthyroid Chinese adults as revealed by a cross-sectional study

Objective

Thyroid hormones (THs) play a pivotal role in regulating metabolism, and their sensitivity may influence the risk of metabolic syndrome (MetS). This study aimed to investigate the association of impaired sensitivity to THs with MetS and MetS severity score (MetSSS) in Chinese euthyroid adults.

Methods

A cross-sectional analysis was conducted involving 17,272 health check-up participants. THs sensitivity indices, including Thyroid Feedback Quantile-Based Index (TFQI), Parametric Thyroid Feedback Quantile-Based Index (PTFQI), TSH Index (TSHI), Thyrotropin Thyroxine Resistance Index (TT4RI), and free triiodothyronine/free thyroxine (FT3/FT4) ratio were assessed. Multivariable regression and restricted spline cubic analyses were conducted to explore the association between THs sensitivity indices and MetS and MetSSS. Subgroup analysis was also performed to examine this association stratified by sex and age.

Results

Multivariable logistic regression analysis indicated that MetS risk was positively associated with all impaired THs sensitivity indices (per SD increase) (TFQI: OR=1.20, 95%CI: 1.15-1.25); PTFQI: OR=1.28, 95%CI: 1.23-1.33; TSHI: OR=1.35, 95%CI: 1.29-1.42; TT4RI: OR=1.57, 95%CI: 1.47-1.67; FT3/FT4: OR=1.17, 95%CI: 1.12-1.23)(all P-value<0.001). After adjusting for confounders, compared with the lowest group of MetSSS, individuals in the highest group of MetSSS were positively associated with all impaired THs sensitivity indices (per SD increase) (TFQI: OR=1.16, 95%CI: 1.07-1.21 PTFQI: OR=1.12, 95%CI: 1.06-1.17; TSHI: OR=1.13, 95%CI: 1.06-1.19; TT4RI: OR=1.25, 95%CI: 1.15-1.35; FT3/FT4: OR=1.82, 95%CI: 1.72-1.93). Nonlinear associations were found between THs sensitivity indicators and MetS (P for non-linear<0.001). Subgroup analysis indicated that all thyroid hormones sensitivity indices were positively associated with MetS by gender (male/female) and age (<60 years/≥60 years).

Conclusion

Impaired sensitivity to THs is associated with an increased risk of MetS and MetSSS in Chinese euthyroid adults. Future research should consider thyroid hormones sensitivity indices in the assessment of MetS risk.

Age-specific relationships between free triiodothyronine and biological aging

OBJECTIVE

Our study aims to examine the associations of thyroid function parameters with phenotypic age acceleration (PhenoAgeAccel) in different age groups.

METHOD

The analysis included 7,564 participants from the NHANES 1999-2018. PhenoAgeAccel was defined as calculated phenotypic age (PhenoAge) exceeding chronological age. Weighted multivariable logistic regression models were used to analyze the relationship between free triiodothyronine (FT3) and PhenoAgeAccel. The restricted cubic spline method was used to assess nonlinear associations of FT3 level with PhenoAgeAccel. Nomogram and the receiver operating characteristic (ROC) curve were constructed to evaluate the diagnostic performance of the predictive model.

RESULTS

Higher FT3 levels were associated with increased risk of PhenoAgeAccel in participants under 60 years old (OR: 1.316, 95% CI: (1.010, 1.715), p = 0.042). For those aged 60 years and above, higher FT3 levels were linked with decreased risk of PhenoAgeAccel (OR: 0.485, 95% CI: (0.309, 0.761), p = 0.002). These associations were more pronounced in males than in females. Restricted cubic spline curves showed similar trends between FT3 levels and PhenoAgeAccel in both age subgroups. The ROC curves including FT3 indicated that both models had fair prediction performance (age >  = 60 years, AUC = 0.722 (0.700-0.743); age < 60 years, AUC = 0.765 (0.751- 0.780)).

CONCLUSION

This study revealed a novel age-dependent association between FT3 levels and biological aging acceleration, with lower FT3 potentially serving as a biomarker for accelerated aging in elderly individuals, while an inverse relationship was observed in younger adults. The study provides novel insights into the intricate relationship between thyroid function and systemic health across the lifespan.

Role of subclinical hypothyroidism on kidney damage in children with obesity

BACKGROUND/OBJECTIVES

The interplay of subclinical hypothyroidism (SH) with obesity has been well-documented, while an intriguing but still controversial association with kidney damage (KD) has recently emerged. Given the heightened cardiometabolic risk inherent to pediatric obesity, this might further impact on the overall health of children with obesity. Therefore, we aimed at evaluating the impact of SH on KD in children with obesity.

SUBJECTS/METHODS

We retrospectively examined 355 children with obesity stratified according to presence or absence of SH. KD was defined as reduced estimated glomerular filtration rate (eGFR<90 mL/min/1.73 m2) and/or hypertension, and/or albuminuria (≥30 mg/g urinary creatinine), while SH was defined by thyroid stimulating hormone (TSH) > 4.5μ UI/ml with normal free triiodothyronine and free thyroxine levels.

RESULTS

Children with SH showed a higher KD prevalence than those without SH (p = 0.004). They also had lower eGFR levels than their counterparts without SH (p = 0.001) and showed an adjusted OR to have KD of 2.04 (95% CI: 1.15-3.61; p = 0.015). A general linear model for eGFR variance showed an inverse association of eGFR with TSH levels (p < 0.0001).

CONCLUSIONS

Although preliminary, our data suggested an increased risk of KD in children with obesity and SH.

Association of the thyroid hormone sensitivity index with triglycerides in adolescents: a cross-sectional study

BACKGROUND

Inconsistent findings have emerged from studies examining the relationship between thyroid hormone sensitivity indices and triglycerides (TGs), especially in pediatric and adolescent cohorts. The present study investigates this relationship within adolescent populations in the United States.

METHODS

Data spanning three periods from 2007 to 2012 were analyzed, including 1813 participants. The thyroid hormone sensitivity index was calculated and weighted multiple linear regression was used to assess the relationships between TG levels and individual thyroid hormone sensitivity indices. Subgroup analyses were conducted as needed and smooth curve fitting plots visualized the linear relationships.

RESULTS

The FT3/FT4 ratio was positively correlated with TG (β = 0.649, 95% CI: 0.360-0.938, P < 0.001). This correlation persisted after adjusting for all variables (β = 0.439, 95% CI: 0.154-0.725, P < 0.01). The relationship between the TFQI score and TG concentration demonstrated a significant negative correlation, which remained after controlling for all covariates (β = -0.153, 95% CI: -0.239-0.067, P < 0.01). When stratified into quartiles, the FT3/FT4 ratio and TG exhibited a positive correlation only in the Q3 and Q4 groups. Conversely, the TFQI was significantly correlated with TG exclusively in the Q4 group's positive values. Stratified analyses by sex and age showed clearer associations in female adolescents.

CONCLUSIONS

The study confirmed the relationship between thyroid hormone sensitivity indices and TGs. Maintaining the FT3/FT4 ratio within a specific range may reduce TG levels. The TFQI may predict TG levels when actual TSH values exceed expected values based on FT4. These findings were most pronounced in female adolescents, highlighting the importance of early monitoring of thyroid health in this group. These results point to the need for improved thyroid function testing in predicting TG levels and preventing hypertriglyceridemia.

The research progress and future directions in the pathophysiological mechanisms of type 2 diabetes mellitus from the perspective of precision medicine

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by pathophysiological mechanisms such as insulin resistance and β-cell dysfunction. Recent advancements in T2DM research have unveiled intricate multi-level regulatory networks and contributing factors underlying this disease. The emergence of precision medicine has introduced new perspectives and methodologies for understanding T2DM pathophysiology. A recent study found that personalized treatment based on genetic, metabolic, and microbiome data can improve the management of T2DM by more than 30%. This perspective aims to summarize the progress in T2DM pathophysiological research from the past 5 years and to outline potential directions for future studies within the framework of precision medicine. T2DM develops through the interplay of factors such as gut microbiota, genetic and epigenetic modifications, metabolic processes, mitophagy, NK cell activity, and environmental influences. Future research should focus on understanding insulin resistance, β-cell dysfunction, interactions between gut microbiota and their metabolites, and the regulatory roles of miRNA and genes. By leveraging artificial intelligence and integrating data from genomics, epigenomics, metabolomics, and microbiomics, researchers can gain deeper insights into the pathophysiological mechanisms and heterogeneity of T2DM. Additionally, exploring the combined effects and interactions of these factors may pave the way for more effective prevention strategies and personalized treatments for T2DM.

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.

Sensitivity to thyroid hormones in children developing acute kidney injury at the onset of type 1 diabetes mellitus

BACKGROUND

Thyroid hormone (TH) sensitivity at type 1 diabetes mellitus (T1DM) onset and its connection with acute kidney injury (AKI) has not been investigated. We aimed to evaluate changes in TH sensitivity in children with and without AKI at T1DM onset and to assess the role of euthyroid sick syndrome (ESS) in this relationship.

METHODS

We included 161 children with new-onset T1DM and followed them until renal function normalized. The free triiodothyronine (FT3)/free thyroxine (FT4) ratio was used to assess peripheral TH sensitivity, while the TSH index (TSHI), thyrotroph T4 resistance index (TT4RI), thyrotroph T3 resistance index (TT3RI), Thyroid Feedback Quantile-based Index (TFQI), and parametric TFQI (PTFQI) were used for central sensitivity.

RESULTS

Patients with AKI exhibited greater weight loss, higher serum ketones, creatinine, corrected sodium, and glycated hemoglobin, but lower bicarbonate and estimated glomerular filtration rate compared to those without AKI. Logistic regression showed that the odds of AKI increased by 11.5-fold for each unit decrease in TFQI, 4.0-fold per unit decrease in PTFQI, and 1.7-fold per unit decrease in TSHI, adjusting for age and gender. After adjusting for age, gender, and ESS, the odds for AKI significantly increased (4.8-fold for each 1-unit decrease) only for TFQI.

CONCLUSIONS

AKI at the onset of T1DM has a dual effect on TH. It reduces peripheral sensitivity while increasing central sensitivity. This effect appears to be largely driven by ESS, with the exception of the association between AKI and TFQI, which remains independent of ESS.

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.

The Impact of Physical Activity on Thyroid Health: Insights From Representative Data in Korea

CONTEXT

Thyroid hormones are essential for energy metabolism related to thermogenesis and oxygen consumption.

OBJECTIVE

This study evaluated the potential association of thyroid function including thyroid peroxidase antibodies (TPOAb) with physical activity in nationally representative data.

DESIGN/SETTING/PARTICIPANTS

This retrospective cohort study used data from the Korean National Health and Nutrition Examination Survey between 2013 and 2015. Physical activity (PA) was assessed using metabolic equivalents based on the validated Korean version of the International Physical Activity Questionnaire Short Form. PA level was categorized into 3 groups of high, moderate, and low. Participants with abnormal thyroid function test, restricted activity, or previous history of thyroid disease were excluded in the study.

RESULTS

A total of 5372 participants was finally selected. The free T4 level was lowest in the low PA group, while TSH was not significantly different among the groups. TPOAb titers increased in the following order: moderate PA, low PA, and high PA. After adjustment for confounding factors, moderate PA was associated with a high T4 level and a decrease in TSH and TPOAb with significance. However, there were no significant changes in free T4, TSH, or TPOAb titer in the high PA group. In a subanalysis, females with moderate PA showed a significant decrease in TSH and TPOAb. In both males and females, insulin sensitivity was increased with moderate PA. In obese participants, TSH negatively correlated with PA, and free T4 levels decreased in the low PA. The sensitivity to thyroid hormone did not differ in our study.

CONCLUSION

The present study found an association between thyroid function and moderate PA. Therefore, moderate-intensity PA should be recommended to improve thyroid function.

Association of Sensitivity to Thyroid Hormones and Non-Alcoholic Fatty Liver Disease and the Severity of Liver Fibrosis in Euthyroid Adults: A Retrospective Study

Purpose

The relationship between non-alcoholic fatty liver disease (NAFLD) and thyroid function is controversial. A mild acquired thyroid hormone resistance may exist and explain these contradictions. This study aims to investigate the associations of thyroid hormone sensitivity with NAFLD and the severity of liver fibrosis in euthyroid populations.

Patients and Methods

Twenty-nine thousand three hundred and eighty-six adult subjects were recruited from the medical examination center of the Beijing Chao-Yang Hospital. Free triiodothyronine (FT3)/free thyroxine (FT4), thyroid feedback quartile-based index for FT4 (TFQIFT4) and for FT3 (TFQIFT3), thyroid stimulating hormone index (TSHI), thyrotropin thyroxine resistance index (TT4RI), and thyrotropin triiodothyronine resistance index (TT3RI) were calculated. Logistic regression analysis was used to analyze the associations of thyroid hormone sensitivity indices with the risks of NAFLD and related metabolic disorders. The correlation between thyroid hormone sensitivity and the severity of liver fibrosis evaluated by noninvasive fibrosis indices was analyzed through ordinal logistic regression.

Results

Euthyroid adults with NAFLD had elevated levels of serum FT3 and FT4, reduced TSH, and impaired sensitivity to thyroid hormones. Compared with participants in the first quartile group, the risk of NAFLD was higher in the fourth quartile of TFQIFT3 (OR 1.25, 95% CI 1.13-1.39, P < 0.001) and FT3/FT4 (OR 1.45, 95% CI 1.32-1.60, P < 0.001) after adjusting for metabolic confounders. Among NAFLD patients, higher FT3/FT4 positively correlated with increased severity of liver fibrosis, with ORs per SD of 10.80 (95% CI 4.12-28.53, P < 0.001) for aminotransferase-to-platelet ratio index, 4.74 (95% CI 1.56-14.38, P = 0.006) for NAFLD fibrosis score and 3.21 (95% CI 1.02-10.08, P = 0.046) for fibrosis-4 index.

Conclusion

Impaired central sensitivity to FT3 and higher FT3/FT4 were associated with increased risks of NAFLD and related metabolic disorders. In patients with NAFLD, higher FT3/FT4 correlated with its progression to liver fibrosis. These findings might provide novel insight into the monitoring and evaluation of the risk of NAFLD and the severity of liver fibrosis.

Correlation between diabetic peripheral neuropathy and thyroid hormone sensitivity in elderly patients with type 2 diabetes mellitus

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a common complication of type 2 diabetes mellitus (T2DM), significantly affecting patients' quality of life and imposing a substantial economic burden. Recent studies have highlighted the role of thyroid hormones in diabetes complications, particularly in elderly patients with T2DM. However, the relationship between thyroid hormone sensitivity and DPN remains unclear.

AIM

To investigate the correlation between thyroid hormone sensitivity and DPN in elderly patients with T2DM.

METHODS

In a cohort of 256 elderly patients with T2DM, propensity score matching was used to balance age, sex, and diabetes duration. Clinical data were collected to calculate thyroid hormone sensitivity and analyze its correlation with DPN. A random forest model was used to evaluate the diagnostic value of free triiodothyronine/free thyroxine (FT3/FT4) for DPN.

RESULTS

Patients with DPN had a lower FT3/FT4 ratio [ (0.302 ± 0.053) vs (0.316 ± 0.049), P = 0.040]. Quartile stratification showed decreasing DPN prevalence with higher FT3/FT4 ratios. Spearman's correlation analysis showed that a lower FT3/FT4 ratio was associated with higher glycated hemoglobin, fasting blood glucose, reduced nerve conduction velocity, and electrical skin conductance. Logistic regression indicated a positive relationship between the median FT3/FT4 ratio and bilateral foot electrochemical skin conductance [odds ratio (OR): 1.019; 95%CI: 1.005-1.034; P = 0.007] and sural nerve sensory amplitude (OR: 1.310; 95%CI: 1.008-1.703; P = 0.043). Receiver operating characteristic analysis using a random forest model showed that incorporating FT3/FT4 improved predictive performance for DPN, with an area under the curve of 0.74, sensitivity of 0.79, specificity of 0.64, and accuracy of 0.77.

CONCLUSION

In elderly patients with T2DM with euthyroidism, a lower FT3/FT4 ratio is correlated with increased DPN incidence, affecting both large and small nerve fibers. FT3/FT4 is an effective predictor of DPN.

Effects of acarbose and metformin on thyroid function and thyroid hormone sensitivity in type 2 diabetes patients: a post-hoc analysis of the MARCH study

PURPOSE

While metformin is known to regulate thyroid stimulating hormone (TSH) levels, the effects of acarbose on thyroid function remain unreported. Our study was designed to evaluate the impact of acarbose and metformin on thyroid function and thyroid hormone sensitivity in type 2 diabetic patients.

METHODS

In the MARCH study, 788 patients with type 2 diabetes were randomly assigned to treat with acarbose (300 mg) or metformin (1,500 mg) for 48 weeks. Thyroid function was assessed at baseline, 24 weeks, and 48 weeks, and the thyroid feedback quantile index (TFQI) and parameterized thyroid feedback quantile index (PTFQI) were calculated. Generalized estimating equations adjusted for confounders were used to analyze changes over time.

RESULTS

Eighty-four patients with subclinical hypothyroidism (SCH) exhibited a decrease in TSH levels (p = 0.001) with no significant differences between the two treatment groups (p = 0.460). Both TFQI (p = 0.029) and PTFQI (p < 0.001) also decreased over time. Mediation analysis revealed that these change over time were not mediated by BMI (all p < 0.05). Among the 489 euthyroid subjects, no significant changes in TSH levels were observed (p > 0.05). Stratification by baseline TSH levels revealed significant increases in TSH, TFQI, and PTFQI (all p < 0.05) in the normal-low TSH group and significant decreases in PTFQI (all p < 0.05) in the normal-high TSH group after treatment with acarbose and metformin.

CONCLUSIONS

Acarbose and metformin have similar buffering effects on TSH levels, the TFQI and the PTFQI. In patients with lower TSH levels, acarbose and metformin do not further decrease TSH levels.

CLINICAL TRIAL REGISTRY NUMBER

ChiCTR-TRC-08000231.

Exposure to perchlorate and cardiovascular disease in China: A community-based cross-sectional study and benchmark dose estimation

The association between exposure to perchlorate, which inhibits thyroidal iodine uptake, and cardiovascular disease (CVD) is unclear in China. Moreover, the point of departure (POD) for perchlorate based on observed adverse health effect in Chinese populations remains absent. A total of 2355 adults (mean age 50.4 years and 39.2% male) from four communities in Shenzhen were included in analyses. Spot urine specimens were collected to measure urinary perchlorate concentrations, which were applied to estimate daily intakes of perchlorate. Multivariable logistic regression model was applied to examine the association between perchlorate and CVD. The roles of cardiometabolic risk factors, including obesity, abdominal obesity, hypertension, diabetes, and hyperlipidemia, were evaluated with mediation analyses. We further employed Bayesian benchmark dose (BMD) modeling to derive the POD for risk assessment. Comparing extreme tertiles, subjects in the highest perchlorate tertile had a significantly elevated risk of prevalent CVD (OR: 2.16; 95% CI: 1.28, 3.65). Multivariable-adjusted ORs for hypertension, diabetes, and hyperlipidemia associated with per doubling in urinary perchlorate concentration were 1.11 (95% CI: 1.01, 1.21), 1.15 (95% CI: 1.02, 1.28), and 1.11 (95% CI: 1.01, 1.20), respectively. Hypertension, diabetes, and hyperlipidemia partially mediated the perchlorate-CVD association (mediated proportion ranged from 7.75% to 11.30%). Given a benchmark response of 5% and 10%, the model-averaged BMD lower bounds (BMDLs) of perchlorate exposure on CVD were 0.15 and 0.40 μg/kg-bw day, respectively. Our estimated POD for perchlorate was lower than those recommended by other groups. These findings call for stricter regulations on perchlorate contamination to promote cardiovascular health in China.

When Should the Treatment of Obesity in Thyroid Disease Begin?

Obesity often coexists with thyroid diseases, and the prevalence of these disorders has been on the rise for years. While hypothyroidism can contribute to excess fat tissue, the relationship between Body Mass Index (BMI) and thyroid function hormones is bidirectional. Research confirms that fat tissue reduction can positively impact thyroid function. Thus, delaying the initiation of therapies beyond substitution treatment to achieve optimal weight reduction in individuals with thyroid dysfunction seems unwarranted. The authors summarize current knowledge on this topic in the article.

Actions of thyroid hormones and thyromimetics on the liver

Thyroid hormones (triiodothyronine and thyroxine) are pivotal for metabolic balance in the liver and entire body. Dysregulation of the hypothalamus-pituitary-thyroid axis can contribute to hepatic metabolic disturbances, affecting lipid metabolism, glucose regulation and protein synthesis. In addition, reductions in circulating and intrahepatic thyroid hormone concentrations increase the risk of metabolic dysfunction-associated steatotic liver disease by inducing lipotoxicity, inflammation and fibrosis. Amelioration of hepatic metabolic disease by thyroid hormones in preclinical and clinical studies has spurred the development of thyromimetics that target THRB (the predominant thyroid hormone receptor isoform in the liver) and/or the liver itself to provide more selective activation of hepatic thyroid hormone-regulated metabolic pathways while reducing thyrotoxic side effects in tissues that predominantly express THRA such as the heart and bone. Resmetirom, a liver and THRB-selective thyromimetic, recently became the first FDA-approved drug for metabolic dysfunction-associated steatohepatitis (MASH). Thus, a better understanding of the metabolic actions of thyroid hormones and thyromimetics in the liver is timely and clinically relevant. Here, we describe the roles of thyroid hormones in normal liver function and pathogenesis of MASH, as well as some potential clinical issues that might arise when treating patients with MASH with thyroid hormone supplementation or thyromimetics.

Adherence to adult clinical practice guidelines for Down syndrome

Adults with Down syndrome (DS) have unique health care needs with evidence-based care guidelines to address these. Yet, the 2020 adult guidelines were unstudied; we aimed to assess adherence to these guidelines. We reviewed clinical and demographic data from medical charts of 327 adults with DS who were seen in the MGH DSP. We calculated adherence to care guidelines and analyzed correlations between both demographic traits and clinical results. Mean adherence rate to each of the nine adult guidelines was 67.3%. Adherence rates that were below our mean adherence rate included colonoscopy (42.9%), iron (41.9%), audiology specialist (35.8%), and audiogram (35.2%). We found four significant correlations: assigned females at birth had a significantly higher body mass index (BMI) than assigned males at birth (p < 0.001), Hispanic patients had a significantly higher BMI than other patients (p = 0.015), Hispanic patients had a significantly higher rate of diabetes than other patients (p = 0.036), and Black patients had a significantly lower rate of hypothyroidism than other patients (p = 0.004). We assessed the adherence rates to adult DS guidelines and highlighted disparities in healthcare for patients with DS to inform clinicians on how to improve care for patients with DS.

Association between sensitivity to thyroid hormone indices and type 2 diabetic microvascular complications in euthyroid patients

The correlation between thyroid hormone (TH) sensitivity and microvascular complications of type 2 diabetes mellitus (T2DM) remains uncertain. This study aimed to explore the association between TH sensitivity and the risk of diabetic kidney disease (DKD), diabetic retinopathy (DR), and diabetic neuropathy (DNP) in euthyroid T2DM patients. This study included a total of 946 hospitalized T2DM patients and calculated their sensitivity to the TH index, and each patient completed screenings for DKD, DR, and DNP. Multivariate logistic regression, generalized additive modeling, and subgroup analysis were used to assess the association between TH index sensitivity and the risks of DKD, DR, and DNP. After adjusting for confounding factors, a significant linear correlation was observed between the sensitivity of the thyroid feedback quartile index 3 (TFQI3) and DKD risk. However, the sensitivities of thyroid-stimulating hormone index (TSHI), thyrotropin thyroxine resistance index (TT4RI) and partial thyroid feedback quartile index (PTFQI) exhibited nonlinear correlations with the risk of developing DKD. The effect sizes to the left of the inflection point for TSHI, TT4RI and PTFQI were (odd ratio [OR] = 0.53, 95% confidence interval [CI]: 0.288-0.977), (OR = 0.863, 95%Cl: 0.751-0.992) and (OR = 0.007, 95%Cl: 0-0.724), respectively. However, there was no significant correlation between TH index sensitivity and DR/DNP risk. This study provides valuable insights into the relationship between TH sensitivity and the risks of DKD, DR, and DNP, with substantial clinical implications for individual prediction among T2DM patients.

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 thyroid hormone sensitivity and carotid plaque risk: a health examination cohort-based study

Introduction

The involvement of thyroid hormone in cardiovascular disease remains debated. The aim of our research was to ascertain whether thyroid hormone sensitivity indices are related to carotid plaque (CAP) risk in the general population.

Methods

We recruited 5,360 participants for health examinations to explore the correlation between thyroid hormone sensitivity indices and CAP risk. We then compared baseline characteristics of participants with CAP to those without CAP based on multivariate logistic regression analysis. Additionally, we conducted subgroup analyses stratified by gender and age to further elucidate this relationship.

Results

Among the 5,360 participants, 1,055 (19.7%) were diagnosed with CAP. After adjusting for various confounding factors, our results showed a positive association between CAP risk and the indices (TFQI, PTFQI, TSHI, and TT4RI). Conversely, the FT3/FT4 ratio showed a negative correlation with CAP risk. Sex-based subgroup analysis revealed a stronger correlation between thyroid hormone sensitivity and CAP in females compared to males. In the age subgroup, the significant association was observed in older individuals (age >60) compared to middle-aged participants (age ≤60).

Conclusion

Our study suggests a significant correlation between thyroid hormone sensitivity and CAP, particularly in females and participants over the age of 60.

Interleukin-6 and thyroid-stimulating hormone index predict plaque stability in carotid artery stenosis: analyses by lasso-logistic regression

Objective

To develop and validate a new prediction model based on the Lass-logistic regression with inflammatory serologic markers for the assessment of carotid plaque stability, providing clinicians with a reliable tool for risk stratification and decision-making in the management of carotid artery disease.

Methods

In this study, we retrospectively collected the data of the patients who underwent carotid endarterectomy (CEA) from 2019 to 2023 in Nanjing Drum Tower Hospital. Demographic characteristics, vascular risk factors, and the results of preoperative serum biochemistry were measured and collected. The risk factors for vulnerable carotid plaque were analyzed. A Lasso-logistic regression prediction model was developed and compared with traditional logistic regression models. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used to evaluate the performance of three models.

Results

A total of 131 patients were collected in this study, including 66 (50.4%) in the vulnerable plaque group and 65 (49.6%) in the stable plaque group. The final Lasso-logistic regression model included 4 features:IL-6, TSH, TSHI, and TT4RI; AIC = 161.6376, BIC = 176.0136, both lower than the all-variable logistic regression model (AIC = 181.0881, BIC = 261.5936), and the BIC was smaller than the stepwise logistic regression model (AIC = 154.024, BIC = 179.9007). Finally, the prediction model was constructed based on the variables screened by the Lasso regression, and the model had favorable discrimination and calibration.

Conclusions

The noninvasive prediction model based on IL-6 and TSHI is a quantitative tool for predicting vulnerable carotid plaques. It has high diagnostic efficacy and is worth popularizing and applying.

Impaired sensitivity to thyroid hormones is associated with all-cause and cause-specific mortality among chronic kidney disease patients: results from National Health and Nutrition Examination Survey (NHANES) 2007-2012

BACKGROUND

Resistance to thyroid hormone shows underlying mechanical link with chronic kidney disease (CKD) and is prevalent in CKD population. However, whether it attributes to mortality risk among CKD population is unknown. This study aimed to examine the association of thyroid hormone resistance (THR) with all-cause and cause-specific mortality among CKD individuals.

METHODS

This study extracted CKD population from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. Death outcomes were ascertained by linkage to National Death Index records through 31 December 2019. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence interval (CI) for mortality from all causes, cardiovascular disease (CVD).

RESULTS

A total of 1,634 adults with CKD were included in the cohort, in which 663 deaths were recorded during an average follow-up of 8.72 years. After multivariate adjustment, resistance to thyroid hormone was significantly associated with higher all-cause and CVD mortality. There was an 18% and 31% increase in risks of all-cause and CVD mortality per-standard deviation (SD) increment in Parametric Thyroid Feedback Quantile-based Index (PTFQI) respectively. When PTFQI was analyzed as categorical variable (classified according to PTFQI percentiles), after adjusted for potential confounders and taking PTFQI ≤ P5 as reference, the HRs and 95% CIs in category with PTFQI > P95 for all-cause mortality and CVD mortality were 2.12 [1.10, 4.09] (p for trend 0.026) and 5.14 [1.81, 14.60] for (p for trend 0.018), respectively.

CONCLUSIONS

Resistance to thyroid hormone, centered on variations in the typical pituitary response to thyroid hormones, may independently correlate with all-cause and CVD mortality in CKD patients.

Thyroid FT4-to-TSH ratio in the first trimester is associated with gestational diabetes mellitus in women carrying male fetus: a prospective bi-center cohort study

Background

Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy, which increases the risk of other pregnant complications and adverse perinatal outcomes. Thyroid dysfunction is closely with the risk of diabetes mellitus. However, the relationship between euthyroid function in early pregnancy and GDM is still controversial.

Aims

This study was to find the relationship between thyroid function within normal range during early pregnancy as well as glucose and lipids metabolisms as well as the risk of subsequent GDM.

Methods

A total of 1486 pregnant women were included in this prospective double-center cohort study. Free thyroxine (FT4), thyroid stimulating hormone (TSH) and antithyroid peroxidase antibodies (TPOAb) were tested during 6-12 weeks of gestation and oral glucose tolerance test (OGTT) was conducted during 24-28 weeks to screen GDM. Relative risks (RR) with 95% confidence intervals (CI) for subsequent risk of GDM by thyroid function quartiles were assessed adjusting for major risk factors.

Results

The incidence of GDM was 23.0% (342/1486). TSH, FT4 and the percentage of positive TPOAb were no significant difference between women with and without GDM, but FT4/TSH ratio was significantly higher in GDM group compared with NGT group [6.97(0.84,10.61) vs. 4.88(0.66,12.44), P=0.025)]. The linear trends of TC, TG, HDL-C, LDL-C, fasting glucose in the first trimester, insulin, C-peptide, HOMA-IR, fasting glucose during OGTT and incidence of GDM according to FT4/TSH ratio were all statistically significant. Further analysis based on fetal sex presented only the third quartile of FT4/TSH ratio in women carrying male fetus was associated with higher incidence of GDM statistically significant [RR (95% CI), 1.917 (1.143,3.216)], rather than in women carrying female fetus.

Conclusions

Thyroid function even in normal range is closely related to glucose and lipids metabolisms during the first trimester. Unappropriated FT4/TSH ratio in the first trimester is an independent risk factor of GDM in women carrying male fetus.

Higher Parametric Thyroid Feedback Quantile-based Index Is a Predictor of Type 2 Diabetes in a German Population Sample

CONTEXT

Type 2 diabetes has been described to be associated with hypothyroidism but we recently found that a decrease in pituitary sensitivity to thyroid hormone is associated with diabetes, obesity, and metabolic syndrome.

OBJECTIVE

We aimed to assess the longitudinal nature of this association in the population-based Study of Health in Pomerania (SHIP) in Germany.

METHODS

Among a population-based sample of 4308 participants aged 20 to 79 years, 77% were followed for a period of 5 years. We studied 2542 participants without diabetes or thyroid medication at baseline and complete data in the variables of interest. Data of baseline free thyroxine (fT4) and thyrotropin (TSH) were used to calculate the Parametric Thyroid Feedback Quantile-based Index (PTFQI), which measures whether TSH remains elevated despite fT4 being high. It uses the average population response as reference. PTFQI association with incidence of type 2 diabetes over 5 years was estimated with Poisson regression models adjusted for age, sex, and body mass index (BMI).

RESULTS

Compared with the first PTFQI quartile, incidence rate ratios for diabetes were 1.54 (95% CI, 0.97-2.46), 1.55 (0.94-2.57), and 1.97 (1.27-3.10) for the upper quartiles (P trend = .004) after adjusting for age and sex. The association remained statistically significant after additionally adjusting for BMI: 1.64 (1.05-2.59) for the fourth vs the first quartile (P trend = .043).

CONCLUSION

An elevation of the pituitary TSH-inhibition threshold is associated with incident type 2 diabetes independently of BMI. The PTFQI might have clinical potential for prognosis and metabolic status monitoring.

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.

Increased FT3/FT4 ratio in a certain range is associated with decreased glycemic variability in patients with type 2 diabetes

Thyroid hormone (TH) plays a crucial role in regulating glucose metabolism. However, the potential impact of the FT3/FT4 ratio, which reflects peripheral sensitivity to thyroid hormones, on glycemic variability in patients with type 2 diabetes (T2DM), has not been previously reported. To investigate the correlation between the FT3/FT4 ratio and glycemic variability in individuals with T2DM. In this retrospective analysis, a total of 468 inpatients with T2DM underwent continuous glucose monitoring (CGM) systems for a period of 6-14 days. Baseline clinical characteristics, laboratory tests, and CGM parameters were documented to investigate the correlation between FT3/FT4 ratio and CGM parameters. The levels of HBA, MG, SD, CV, LAGE, MODD and TAR2Scale were all higher in FT3/FT4Q1 compared with FT3/FT4Q2, FT3/FT4Q3 and FT3/FT4Q4 (all P < 0.01). Additionally, TIR was lower in FT3/FT4Q1 compared with the other quartiles (P < 0.01). Smooth curve fitting and saturation effect analysis revealed that there are curve-like relationships between the FT3/FT4 ratio and SD, MAGE, MODD and TAR2Scale. The inflection points of the fitted curves were found to be at FT3/FT4 = 0.279, 0.237, 0.253 and 0.282 respectively (all P < 0.05). Prior to the inflection point, the FT3/FT4 ratio was negatively related to SD, MAGE, MODD and TAR2Scale (all P < 0.05). Furthermore, The FT3/FT4 ratio exhibits a negative linear correlation with HBA and MG, while demonstrating a positive linear relationship with TIR (all P < 0.05). Binary logistic regression demonstrated that the FT3/FT4 ratio was independently related to HBA (P = 0.001), MG (P = 0.01), TAR2Scale (P = 0.003), LAGE (P = 0.014) and MAGE (P < 0.001). The increased FT3/FT4 ratio within a certain range (FT3/FT4 ≤ 0.282) is associated with decreased blood glucose variability and increased TIR. The FT3/FT4 ratio may act as a potential independent protective factor for glycemic fluctuation and glycemic control in patients with T2DM when it increases within a specific range.

Correlation of thyroid function and sensitivity to thyroid hormone with spinal bone mineral content, bone mineral density, and osteoporotic vertebral fracture: A cross-sectional study based on NHANES

Previous studies have demonstrated that thyroid hormone plays an important role in normal bone development, bone metabolism, and establishment of peak bone mass. However, the correlation of thyroid status with bone mineral content (BMC), bone mineral density (BMD), and osteoporotic vertebral fracture (OVF) is rarely discussed. The current study probes into the potential association between thyroid status and spinal BMC, BMD, and OVF from a novel perspective of thyroid function (TF) and sensitivity to thyroid hormone based on the National Health and Nutrition Examination Survey database. A total of 1844 participants were included in this study. The association of thyroid status with outcome variables, like spinal BMC, BMD, and OVF, was analyzed using thyroid function indices and sensitivity to thyroid hormone indices as influence factors. The correlation of them were assessed using univariate and multivariable weighted linear regression, weighted logistic regression models, restricted cubic spline model, and subgroup analyses. The results of this study showed that the association of free triiodothyronine (FT3)/free thyroxine (FT4) with BMC remained negatively associated after adjustment for all covariates. Higher thyroid peroxidase antibody (TPOAb) was significantly associated with an increased risk of developing OVF in both unadjusted and adjusted models. In addition, the results of the restricted cubic spline model were consistent with the weighted multivariate regression analysis after adjustment. The results of this cross-sectional study showed that higher FT3/FT4 and TPOAb were associated with decreased spinal BMC and the increased risk of OVF, indicating a complex link between thyroid status and bone health. Therefore, patients with hyperthyroidism, hypothyroidism, autoimmune thyroid disease, or abnormal peripheral thyroid sensitivity, especially who with elevated TPOAb or FT3/FT4, should focus on the prevention of vertebral osteopenia, osteoporosis, and OVF.

The mediating role of serum 25-hydroxyvitamin D on the association between reduced sensitivity to thyroid hormones and periodontitis in Chinese euthyroid adults

Aim

Thyroid dysfunction is closely associated with periodontitis. We aim to explore the association between sensitivity to thyroid hormones (THs) and periodontitis and to investigate the mediating role of serum 25-hydroxyvitamin D[25(OH)D] in this relationship in Chinese euthyroid populations.

Methods

This population-based retrospective study included 2,530 euthyroid participants. Central sensitivity to THs was assessed by the thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI), thyrotrophic thyroxine resistance index (TT4RI) and thyroid-stimulating hormone index (TSHI), while FT3/FT4 was evaluated to assess peripheral sensitivity. Multivariable regression analysis and restricted cubic spline were performed to explore the association between sensitivity to THs and periodontitis. Threshold effect and subgroup analysis were also conducted. Mediation analysis was performed to estimate direct and indirect effects through 25(OH)D.

Results

Multivariable regression analysis indicated that central sensitivity to THs indices(per SD increase) were positively associated with periodontitis risk [TFQI: OR=1.19,95% CI (1.09, 1.31); PTFQI: OR=1.22, 95% CI(1.12,1.34); TSHI: OR=1.36, 95% CI (1.21,1.52); TT4RI: OR=1.43, 95% CI (1.25,1.63)](all P value<0.001). TT4RI only had a non-linear relationship with periodontitis in euthyroid participants. Subgroup analysis showed that no significant correlations were founded among those aged over 65 years or with hypertension/diabetes. Mediation analysis revealed that the proportions mediated by 25(OH)D on the association of TFQI, PTFQI,TSHI, TT4RI and periodontitis risk were 16.37%, 16.43%, 9.93% and 10.21%, respectively.

Conclusions

Impaired central sensitivity to THs is positively associated with periodontitis in euthyroid and serum 25(OH)D might be one of its biological mechanisms.

Physical activity affects dysthyreosis by thyroid hormones sensitivity: a population-based study

Objective

Physical activity (PA) plays an important role in human health. However, the relationship between the PA and dysthyreosis was not clear. This study aimed to explore this question.

Methods

We performed a population-based study on the basis of the participant's information that was collected from the National Health and Nutrition Examination Survey (NHANES) database. The association of the thyroid hormone and total PA metabolic equivalent task (MET) were assessed via linear regression analysis with adjusting for different covariates. Moreover, we also used path analysis to explore the causality between PA, thyroid hormone index, and dysthyreosis. The restricted cubic spline analysis was used to explore the non-linear relationship between the thyroid hormone index and the PA total MET.

Results

A total of 2118 participants aged≥20, including 969 females and 1149 males, were collected from NHANES. The linear regression with multivariate adjustment suggested a linear relationship between the PA total MET and Thyroid-Stimulating Hormone Index (TSHI), and Thyroid Feedback Quantile-Based Index (TFQI), respectively. And TFQI and dysthyresis occurrence were significantly correlated (P<0.05). The path analysis showed that the PA total MET affected dysthyreosis occurrence by TFQI. In addition, we found a non-linear relationship between the total PA met and dysthyreosis via restricted cubic spline analysis.

Conclusions

PA was significantly correlated with dysthyreosis via thyroid hormone sensitivity. Therefore, it can be considered to prevent the occurrence of dysthyreosis by regulating thyroid hormone sensitivity through PA in daily life.

Relationship of thyroid parameters with chronic inflammation in patients with euthyroid type 2 diabetes

Aims

We evaluated the association of multiple thyroid parameters with the levels interleukin 6 (IL6) and interleukin 8 (IL8) in patients with euthyroid type 2 diabetes (T2D).

Methods

A total of 166 adults with euthyroid T2D were examined. Serum IL6, IL8, triiodothyronine (FT3), free thyroxin (FT4), thyroid-stimulating hormone (TSH), five thyroid sensitivity indexes (FT3/FT4, TSH index [TSHI], thyrotroph T4 resistance index [TT4RI], thyroid feedback quantile-based index by FT3 [TFQIFT3], and TFQIFT4), and biochemical parameters were determined.

Results

The median age was 64 years (IQR: 54.75,70) and the median duration of diabetes was 10 years (IQR: 3,18). Patients with high levels of IL6 (≥2.38 pg/mL) had lower levels of FT3 and TFQIFT3 (P<0.05). Patients with high levels of IL8 (≥18.1 pg/mL) had lower levels of TSH and higher levels of FT4 (P<0.05). IL6 was negatively correlated with FT3 (r=-0.359, P<0.001), TFQIFT3 (r=-0.273, P=0.009), and FT3/FT4 (r=-0.22, P=0.037). IL8 was negatively correlated with TSH (r=-0.256, P=0.01), TSHI (r=-0.226, P=0.033), and TT4RI (r=-0.244, P=0.021). Binary logistic regression analysis with multiple adjusted models showed that a high level of IL6 was negatively associated with FT3 (aOR: 0.529; 95%CI: 0.302, 0.926, P=0.026), and that a high level of IL8 was negatively associated with TSH (aOR: 0.343; 95%CI: 0.155, 0.759; P=0.008) and TT4RI (aOR: 0.398;95%CI: 0.191, 0.831; P=0.014).

Conclusion

Patients with euthyroid T2D who had lower levels of FT3 had significantly higher levels of IL6, and those with lower levels of TSH and TT4RI had significantly higher levels of IL8.

Chronic thyrotoxic myopathy development is associated with thyroid hormone sensitivity index, predicted by lower-limb fatigue and the squat-up test

Thyroid hormones (THs) may affect chronic thyrotoxic myopathy (CTM). The relationship between TH sensitivity and CTM is inconsistent. We aimed to investigate the associations between TH sensitivity and the risk of CTM and to screen potential CTMs with strength and function tests. A total of 162 Chinese patients (36.58% men) with Graves' disease were enrolled and divided into CTM and non-CTM groups. TH and sensitivity indices were measured. Muscle power and function were assessed by grip, upper-limb fatigue (ULFT), lower-limb fatigue (LLFT), and squat-up (SUT) tests, and walking pace. Association between sensitivity to TH indices and the risk of developing CTM was assessed via multivariate logistic regression. The diagnostic effectiveness of muscle power and function for predicting CTM was evaluated via receiver operating characteristic (ROC) curves. Thyroid feedback quantile-based index FT3 (TFQIFT3) and the parametric TFQIFT3 (PTFQIFT3), TFQIFT4, and PTFQIFT4 were positively associated with CTM risk by using inverse probability of treatment weighting multivariate logistic regression. For each 1-SD increase in TFQIFT3 and PTFQIFT3, TFQIFT4 and PTFQIFT4, the odds ratios for CTM were 1.67 (95% CI = 1.17-2.48) ,1.64 (95% CI = 1.51-2.93), 1.60 (95%CI = 1.12-2.32), 1.58 (95%CI = 1.11-2.30), respectively. LLFT and SUT best predicted male/female CTM, respectively (AUC = 0.89/0.85). In Graves' disease patients, TH sensitivity is associated with CTM development, which can be predicted by SUT and LLFT results.

Increased thyroid hormone sensitivity is correlated with visceral obesity in patients with type 2 diabetes

OBJECTIVE

The study aimed to assess whether thyroid hormone (TH) sensitivity is related to visceral fat area (VFA) and visceral obesity in euthyroid subjects with type 2 diabetes (T2D).

METHODS

750 euthyroid patients with T2D were enrolled. A VFA of 80 cm2 or more was considered visceral obesity. Central TH sensitivity was conducted using thyrotrophic thyroxine resistance index (TT4RI), thyrotropin index (TSHI), and thyroid feedback quantile-based index (TFQI). Free triiodothyronine to free thyroxine (FT3/FT4) was utilized for assessing peripheral TH sensitivity.

RESULTS

The subjects had a mean age of 51.5 ± 11.1 years, and 540 (72.0%) of them were men. In multivariable regression analyses, there was a positive correlation of FT3/FT4 tertile with visceral obesity, after full adjustment for confounding variables (P < 0.05). The middle and highest FT3/FT4 tertiles were correlated with a 134% [95% CI (1.24, 4.44)] and 98% [95% CI (1.04, 3.78)] higher prevalence of visceral obesity than the lowest tertile, respectively. Conversely, elevated TFQI levels were linked to a decreased prevalence of visceral obesity. Stratified analysis revealed that these associations were particularly pronounced in participants who are neither overweight nor obese and those aged less than 60 years (all P < 0.05).

CONCLUSIONS

Higher TH sensitivity is correlated with visceral obesity and elevated VFA in euthyroid patients with T2D, particularly among those younger than 60 years and individuals who are neither overweight nor obese.

Association between sensitivity to thyroid hormones and non-high-density lipoprotein cholesterol levels in patients with type 2 diabetes mellitus

BACKGROUND

Dyslipidemia and type 2 diabetes mellitus (T2DM) are chronic conditions with substantial public health implications. Effective management of lipid metabolism in patients with T2DM is critical. However, there has been insufficient attention given to the relationship between thyroid hormone sensitivity and dyslipidemia in the T2DM population, particularly concerning non-high-density lipoprotein cholesterol (non-HDL-C).

AIM

To clarify the association between thyroid hormone sensitivity and dyslipidemia in patients with T2DM.

METHODS

In this cross-sectional study, thyroid hormone sensitivity indices, the thyroid feedback quantile-based index (TFQI), the thyroid-stimulating hormone index (TSHI), the thyrotrophic T4 resistance index (TT4RI), and the free triiodothyronine (FT3)/free thyroxine (FT4) ratio were calculated. Logistic regression analysis was performed to determine the associations between those composite indices and non-HDL-C levels. Random forest variable importance and Shapley Additive Explanations (SHAP) summary plots were used to identify the strength and direction of the association between hyper-non-HDL-C and its major predictor.

RESULTS

Among the 994 participants, 389 (39.13%) had high non-HDL-C levels. Logistic regression analysis revealed that the risk of hyper-non-HDL-C was positively correlated with the TFQI (OR: 1.584; 95%CI: 1.088-2.304; P = 0.016), TSHI (OR: 1.238; 95%CI: 1.034-1.482; P = 0.02), and TT4RI (OR: 1.075; 95%CI: 1.006-1.149; P = 0.032) but was not significantly correlated with the FT3/FT4 ratio. The relationships between composite indices of the thyroid system and non-HDL-C levels differed according to sex. An increased risk of hyper-non-HDL-C was associated with elevated TSHI levels in men (OR: 1.331; 95%CI: 1.003-1.766; P = 0.048) but elevated TFQI levels in women (OR: 2.337; 95%CI: 1.4-3.901; P = 0.001). Among the analyzed variables, the average SHAP values were highest for TSHI, followed by TT4RI.

CONCLUSION

Impaired sensitivity to thyroid hormones was associated with high non-HDL-C levels in patients with T2DM.

Association between the triglyceride-glucose index and thyroid disorders: a cross-sectional survey and Mendelian randomization analysis

BACKGROUND

Metabolic diseases are associated with thyroid disorders. Insulin resistance is the common pathological basis of metabolic diseases. We explored the relationship between the triglyceride-glucose (TyG) index, a simple insulin-resistance marker, and thyroid disorders.

METHODS

Eligible TIDE (Thyroid Diseases, Iodine Status and Diabetes Epidemiology) subjects (n = 47,710) were screened with inclusion/exclusion criteria. Thyroid disorder prevalence among different TyG index groups was stratified by sex. Logistic regression evaluated the correlation between the TyG index and thyroid disorders. Multiple linear regression evaluated the association between the TyG index and TSH. Additionally, two-sample Mendelian randomization (MR) using published genome-wide association study data evaluated causality in the association between the TyG index and TSH.

RESULTS

Men and women with greater TyG indices had a significantly greater prevalence of thyroid disorders than individuals with the lowest quartile (Q1) of TyG index (p < 0.05). Following adjustment for confounding factors, we observed that a greater TyG index significantly increased the risk of subclinical hypothyroidism in men and women (men: Q2: odds ratio (OR) [95% confidence interval (CI)] = 1.22 [1.07-1.38], p = 0.002; Q3: OR [95% CI] = 1.28 [1.12-1.45], p < 0.001; Q4: OR [95% CI] = 1.29 [1.12-1.50], p = 0.001; women: Q2: OR [95% CI] = 1.25 [1.12-1.39], p < 0.001; Q3: OR [95% CI] = 1.47 [1.31-1.64], p < 0.001; Q4: OR [95% CI] = 1.61 [1.43-1.82], p < 0.001). Only among women was the highest TyG index quartile associated with hypothyroidism (OR [95% CI] = 1.70 [1.15-2.50], p = 0.007). Additionally, in men, the association exists only in the more than adequate iodine intake population. In women, the relationship between the TyG index and thyroid disorders disappears after menopause. Furthermore, the TyG index exhibited a linear positive correlation with TSH levels. The MR analysis results revealed a causal relationship between a genetically determined greater TyG index and increased TSH (inverse-variance weighting (IVW): OR [95% CI] = 1.14 [1.02-1.28], p = 0.020); however, this causal relationship disappeared after adjusting for BMI in multivariable MR (MVMR) analysis (MVMR-IVW: OR 1.03, 95% CI 0.87-1.22, p = 0.739).

CONCLUSIONS

A greater TyG index is associated with hypothyroidism and subclinical hypothyroidism and varies by sex and menopausal status. MR analysis demonstrated that the causal relationship between a genetically determined greater TyG index and elevated TSH levels is confounded or mediated by BMI.

Impaired thyroid hormone sensitivity exacerbates the effect of PM2.5 and its components on dyslipidemia in schizophrenia

BACKGROUND

Dyslipidemia in schizophrenia causes a serious loss of healthy life expectancy, making it imperative to explore key environmental risk factors. We aimed to assess the effect of PM2.5 and its constituents on dyslipidemia in schizophrenia, identify the critical hazardous components, and investigate the role of impaired thyroid hormones (THs) sensitivity in this association.

METHODS

We collected disease data on schizophrenia from the Anhui Mental Health Center from 2019 to 2022. Logistic regression was constructed to explore the effect of average annual exposure to PM2.5 and its components [black carbon (BC), organic matter (OM), sulfate (SO42-), ammonium (NH4+), and nitrate (NO3-)] on dyslipidemia, with subgroup analyses for age and gender. The degree of impaired THs sensitivity in participants was reflected by the Thyroid Feedback Quantile-based Index (TFQI), and its role in the association of PM2.5 components with dyslipidemia was explored.

RESULTS

A total of 5125 patients with schizophrenia were included in this study. Exposure to PM2.5 and its components (BC, OM, SO42-, NH4+, and NO3-) were associated with dyslipidemia with the odds ratios and 95 % confidence interval of 1.13 (1.04, 1.23), 1.16 (1.07, 1.26), 1.15 (1.06, 1.25), 1.11 (1.03, 1.20), 1.09 (1.00, 1.18), 1.12 (1.04, 1.20), respectively. Mixed exposure modeling indicated that BC played a major role in the effects of the mixture. More significant associations were observed in males and groups <45 years. In addition, we found that the effect of PM2.5 and its components on dyslipidemia was exacerbated as impaired THs sensitivity in the patients.

CONCLUSIONS

Exposure to PM2.5 and its components is associated with an increased risk of dyslipidemia in schizophrenia, which may be exacerbated by impaired THs sensitivity. Our results suggest a new perspective for the management of ambient particulate pollution and the protection of thyroid function in schizophrenia.

The non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) is associated with thyroid hormones and thyroid hormone sensitivity indices: a cross-sectional study

BACKGROUND

Lipids and thyroid hormones (TH) are closely interrelated. However, previous studies have not mentioned the linkage encompassing the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) alongside TH level, as well as sensitivity indices.

METHODS

This cross-sectional study leverages expansive datasets from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2012. Weighted multivariate linear regression, smoothed curve fitting and sensitivity analyses were used to investigate the associations of the NHHR with the thyroid. Subgroup analyses and interaction tests were conducted to determine the robustness of the findings across diverse segments of the population, ensuring the consistency and generalizability of the observed associations.

RESULTS

The NHHR was significantly positively correlated with free triiodothyronine (FT3) levels, thyroid-stimulating hormone (TSH) levels, the FT3 to FT4 ratio (FT3/FT4), and the quantile-based thyroid feedback index for FT3 (TFQIFT3) and negatively correlated with free thyroxin (FT4) levels [0.17(0.07-0.27), P = 0.001; 0.60 (0.03-1.17), P = 0.040; 0.06 (0.04-0.08), P < 0.0001; 0.23 (0.16-0.30), P < 0.0001; and -0.65 (-1.05--0.24), P = 0.002]. Smoothed curve fitting revealed nonlinear correlations of the NHHR with thyroid function and thyroid hormone sensitivity indices. In subgroup analyses, interaction tests, and smoothed curve fitting analyses, different populations presented largely consistent statistical differences.

CONCLUSION

Among American adults, the NHHR was significantly positively correlated with FT3 levels, TSH levels, the FT3/FT4 and the TFQIFT3. Conversely, a negative association was noted between the NHHR and FT4 levels.

Changes in Central Sensitivity to Thyroid Hormones vs. Urine Iodine during Pregnancy

INTRODUCTION/AIM

Central sensitivity to thyroid hormones refers to the responsiveness of the hypothalamic-pituitary-thyroid (HPT) axis to changes in circulating free thyroxine (fT4). Although dose-response relationships between thyroid hormones per se and urinary iodine (UI) levels have been observed, central sensitivity to thyroid hormones in relation to UI remains unexplored. The aim of the present study was to evaluate central sensitivity to thyroid hormones (by means of the Thyroid Feedback Quantile-based Index [TFQI], which is a calculated measure, based on TSH and fT4, that estimates central sensitivity to thyroid hormones) in pregnancy and to assess whether it differs according to gestational age and/or iodine intake.

MATERIALS AND METHODS

One thousand, one hundred and two blood and urine samples were collected from pregnant women (with a mean age ± SD of 30.4 ± 4.6 years) during singleton pregnancies; women with known/diagnosed thyroid disease were excluded. Specifically, TSH and fT4, anti-thyroid peroxidase antibodies and UI were measured in each trimester and at two months postpartum, while the TFQI was calculated for all the study samples. After the elimination of outliers, statistical analysis was conducted with analysis of variance (ANOVA) for the variables versus time period, while Pearson's correlation was used to assess the TFQI versus UI.

RESULTS

The mean TFQI index ranged from -0.060 (second trimester) to -0.053 (two months postpartum), while the corresponding UI was 137 and 165 μg/L, respectively. The TFQI-UI correlation was marginally negative (Pearson r: -0.323, p: 0.04) and significantly positive (r: +0.368, p: 0.050) for UI values over 250 μg/L, in the first and the second trimesters of pregnancy, respectively.

DISCUSSION

The TFQI is a new index reflecting central sensitivity to thyroid hormones. A lower TFQI indicates higher sensitivity to thyroid hormones. In our sample, the TFQI was mainly positively related to iodine intake in the second trimester of pregnancy (following the critical period of organogenesis). Thus, the observed changes in the TFQI may reflect the different ways of the central action of thyroid hormones, according to the phase of pregnancy. These results have the potential to enhance our comprehension of the changes in the HPT axis' function via variations in central sensitivity to thyroid hormones and its interplay with nutritional iodine status during pregnancy.

Causal association between hyperthyroidism and risk of gastroesophageal reflux or esophageal cancer: a bidirectional Mendelian randomization investigation

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 (ORIVW = 0.88, 95% CI, 0.79-0.99, P = 0.039), while as a risk factor for esophageal cancer (ORIVW = 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.

Effects of thyroid hormones modify the association between pre-pregnancy obesity and GDM: evidence from a mediation analysis

Objective

Conflicting associations have been noted between thyroid function and gestational diabetes mellitus (GDM), with indications that pre-pregnancy BMI might influence these relationships. This study aims to examine the effect of thyroid hormone indices and their mediation role on the risk of GDM.

Methods

Pregnant women in our study were recruited from the Zhoushan Pregnant Women Cohort, Zhejiang Province, China. Participants who had their first prenatal follow-up and measured thyroid biomarkers in the first trimester, and oral glucose tolerance test (OGTT) records in the second trimester were eligible for inclusion in this study. The data were extracted from the Electronic Medical Record System database, at Zhoushan Maternal and Child Care Hospital. Maternal information about sociodemographic and health-related characteristics was extracted from the dataset. A unique personal identification number was provided to link both datasets. Multivariate logistic regression models were applied to investigate the correlations between thyroid hormone indices with GDM. The interaction effects of first-trimester thyroid hormone indices with pre-pregnancy BMI on GDM risk using a generalized linear regression model. Furthermore, the mediation analysis was used to explore the potential mediating effects of thyroid hormone indices on the relationship between pre-pregnancy BMI and GDM.

Results

Overall, 5895 pregnant women were included in this study. The first-trimester FT4, thyroid feedback quantile-based index (TFQI), thyrotropin index (TSHI) and thyrotroph thyroxine resistance index (TT4RI) levels were negatively associated with fasting blood glucose (FBG) and postprandial blood glucose (PBG2H) in the second trimester (all P<0.05); FT3 and the FT3-to-FT4 ratio levels were positively associated with PBG1H and PBG2H in the second trimester (all P<0.05). Moreover, there were significant correlations between the highest quartile FT4, FT3, FT3-to-FT4 ratio, TSHI, and TFQI with GDM (all P < 0.05). The mediating effect of thyroid hormone parameters was 24.9% on the association between pre-pregnancy BMI and GDM.

Conclusions

In conclusion, the low FT4, high FT3-to-FT4 ratio, and low TFQI in the first trimester significantly increase the risk of GDM and should be given more attention. Furthermore, increased pre-pregnancy BMI might partially increase the risk of GDM by influencing the body's thyroid function.

Association between total body muscle-fat ratio and risk of thyroid disorders: a cross-sectional study

BACKGROUND

Thyroid disorders(TD) poses a significant health threat to Americans due to its high incidence rate. Obesity, a common factor linked to thyroid disorders, has garnered increasing attention. While Body mass index (BMI) is a widely used obesity index, it fails to account for the distribution of muscle and fat in the body. Recently, tMFR has emerged as a crucial obesity index in clinical research, warranting further investigation into its association with TD.

OBJECTIVE

Exploring the association between tMFR and thyroid disorders.

METHOD

A comprehensive survey and data analysis were conducted using the NHANES database to investigate the relationship between tMFR and the risk of TD. This study utilized multiple logistic regression, smooth curve fitting, and subgroup analysis across four periods from 2011 to 2018.

RESULT

A total of 11,912 subjects were included in the study, showing a prevalence of 7.14% for TD. The research indicated that tMFR had an inverse correlation with the risk of TD in a comprehensive model (OR = 0.90, 95% CI 0.82 to 1.00). When tMFR was divided into quartiles (Q1-Q4), individuals in the highest quartile had a 28% lower risk of TD than those in Q1 (OR = 0.72, 95% CI 0.57 to 0.91). Analysis using smoothed curve fitting demonstrated a nonlinear relationship between tMFR and TD risk, with the inflection point for tMFR saturation effect identified as 1.5. Subgroup analysis further confirmed the strong association between tMFR and TD risk. Receiver operating characteristic (ROC) curve analysis indicated that tMFR exhibited superior predictive ability for TD relative to BMI.

CONCLUSION

The study found a negative association between tMFR and the risk of TD; however, additional prospective studies are required to validate these findings.

Associations between peripheral thyroid sensitivity and all-cause and cardiovascular mortality in the US adults with metabolic syndrome

Background

The relationship between peripheral sensitivity to thyroid hormones, as indicated by the ratio of free triiodothyronine (fT3) to free thyroxine (fT4) (fT3/fT4), and the prognosis of metabolic syndrome (MetS) remains unclear.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2007 and 2012. MetS was defined based on the criteria established by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III). Kaplan-Meier survival curves, restricted cubic spline (RCS) analysis, and Cox proportional hazards models were employed to investigate the association between peripheral thyroid sensitivity and mortality outcomes among adults with MetS.

Results

A total of 3,101 adult participants (1,594 males and 1,507 females; median age: 52.00 years) with MetS were included in the analysis. Multivariate Cox regression analysis revealed that elevated levels of fT4 were positively associated with increased risks of both all-cause and cardiovascular mortality in the MetS population [adjustedhazard ratio (aHR): 2.74, 95% confidence interval (CI): 1.94-3.87, p < 0.001 for all-cause mortality; aHR: 3.93, 95% CI: 2.07-7.45, p < 0.001 for cardiovascular mortality]. Conversely, higher levels of fT3 and the fT3/fT4 ratio were found to be protective factors, reducing the mortality risk in the MetS population (fT3: aHR: 0.76, 95% CI: 0.57-0.99, p = 0.046 for all-cause mortality; fT3/fT4 ratio: aHR: 0.75, 95% CI: 0.67-0.85, p < 0.001 for all-cause mortality; aHR: 0.66, 95% CI: 0.52-0.83, p < 0.001 for cardiovascular mortality). The fT3/fT4 ratio exhibited a nonlinear association with all-cause mortality, but a linear and inverse association with cardiovascular mortality.

Conclusion

The findings of this study suggest that higher peripheral thyroid sensitivity, as indicated by the fT3/fT4 ratio, may be associated with reduced mortality risks among adults with MetS. Further research is warranted to validate these associations.

Impaired Sensitivity to Thyroid Hormones is Associated with Central Obesity in Euthyroid Type 2 Diabetes Mellitus Patients with Overweight and Obesity

Background

Thyroid hormone levels are associated with the distribution of body components in humans.

Objective

This study aimed to investigate the associations between thyroid hormone (TH) levels, central sensitivity to THs, and body composition in overweight and obese patients with euthyroid type 2 diabetes mellitus (T2DM).

Methods

This cross-sectional study included 1215 euthyroid T2DM patients (721 men and 494 women) aged 20-80 years. The thyroid hormone sensitivity indices included the thyroid feedback quartile-based index (TFQI), thyrotroph T3 resistance index (TT3RI), thyrotroph T4 resistance index (TT4RI), and thyroid-stimulating hormone index (TSHI). The appendicular fat ratio, trunk fat ratio, android fat ratio, gynoid fat ratio, and appendicular skeletal muscle mass (ASM) were measured via dual-energy X-ray absorptiometry.

Results

The data revealed a greater proportion of subjects with impaired central sensitivity to THs in the obese group. TFQIFT4 and TFQIFT3 levels were positively correlated with the upper limb fat ratio, lower limb fat ratio, gynoid fat ratio, and total fat ratio. TSHI was positively correlated with body mass index (BMI), upper limb fat ratio, lower limb fat ratio, trunk fat ratio, android fat ratio, gynoid fat ratio, total fat ratio, and appendicular skeletal muscle mass index (ASMI) in women. In men, TSHI was only positively correlated with upper limb fat ratio, lower limb fat ratio, and total fat ratio. Logistic regression analysis indicated that TT3RI and TFQIFT3 were independently and positively associated with central obesity and low muscle mass in overweight and obese men. No significant differences were found among the women.

Conclusion

THs central sensitivity is related to the body composition of euthyroid T2DM patients. Specifically, high levels of TT3RI and TFQIFT3 are associated with central obesity and low muscle mass in T2DM men with overweight and obesity.

Changes in thyroid hormones predict weight regain in patients with obesity who undergo metabolic surgery

AIM

To investigate the relationship between thyroid function and weight regain in patients with obesity after metabolic surgery.

METHODS

This retrospective study enrolled 162 patients who underwent metabolic surgery. Correlations between decreases in thyroid hormone levels and changes in weight, waist circumference (WC) and the Chinese visceral adiposity index (CVAI) were assessed. Binary logistic regression and receiver operating characteristic (ROC) curves were used to identify predictors and clinically useful cut-off values, respectively.

RESULTS

The levels of thyroid-stimulating hormone (TSH) and free triiodothyronine (FT3) decreased markedly at 1 year after surgery, as did weight, body mass index (BMI), triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, WC and CVAI. Decreases in TSH and FT3 after metabolic surgery were associated with changes in weight, BMI and CVAI. Binary logistic regression and ROC curve analyses confirmed that decreases in TSH can predict good weight loss after metabolic surgery to some extent. Finally, binary logistic regression and ROC curve analyses confirmed that changes in TSH can predict weight regain after metabolic surgery.

CONCLUSIONS

Changes in TSH and FT3 after metabolic surgery were correlated with changes in weight and CVAI. Changes in thyroid hormones can predict weight regain in patients with obesity who underwent metabolic surgery.

Extreme temperatures, PM2.5 and trajectories of impaired thyroid hormone sensitivity: A longitudinal study of patients with schizophrenia

BACKGROUND

The climate change scenario has witnessed an increase in extreme temperature events (ETEs), including heat waves and cold spells, and a heightened occurrence of compounding with fine particulate matter (PM2.5). However, the impact of this phenomenon on the sensitivity to thyroid hormones (THs) in humans is unclear, especially in a group as specific as schizophrenia.

METHODS

A longitudinal study was constructed using longitudinal measurements of thyroid function in schizophrenia in the Anhui Mental Health Center. The latent growth mixture model was applied to assess the optimal trajectory of change in impaired THs sensitivity. We then used logistic regression to explore associations between heat waves, cold spells, and PM2.5 with impaired THs sensitivity trajectories in the total population and different gender and age subgroups. Furthermore, the effect of the frequency, intensity, and duration of ETEs in the above associations was explored, as well as an assessment of the interaction between ETEs and PM2.5.

RESULTS

Among 931 participants, we identified two classifications of trajectories of impaired THs sensitivity: "Low-stable" (n = 836, 89.80 %) and "Rise-slight down" (n = 95, 10.20 %). Logistic regression showed significant associations between each additional day of heat waves (≥3 days with temperature thresholds above the 95th percentile) and cold spells (≥3 days with temperature thresholds below the 5th percentile) and "Rise-slight down" trajectory, with odds ratios (95 % confidence intervals) of 1.06 (1.02, 1.10) and 1.19 (1.14, 1.24), respectively, and the strength of this association increased with the intensity and duration of ETEs. Subgroup analyses indicated that the association was more pronounced in males and the age group above 40 years. Furthermore, PM2.5 was found to interact with heat waves, with high concentrations exacerbating the effects of heat waves.

CONCLUSIONS

Our findings suggest that mitigating both ETEs and PM2.5 exposures may bring health co-benefits in preventing thyroid impairment in schizophrenia.

Correlation between thyroid hormone sensitivity and diabetic peripheral neuropathy in euthyroid patients with type 2 diabetes mellitus

Previous studies have revealed that thyroid hormone (TH) levels are associated with the risk of diabetic peripheral neuropathy (DPN) in euthyroid patients with type 2 diabetes mellitus (T2DM). However, the relationship between TH sensitivity, a complementary method for assessing thyroid function, and DPN remains unclear. This study aimed to investigate the correlation between DPN and TH sensitivity in euthyroid patients with T2DM. Exactly 708 euthyroid adults with T2DM were retrospectively enrolled. The FT3/FT4 ratio was used to estimate peripheral TH sensitivity. Central TH sensitivity was assessed using the Thyrotroph T4 Resistance Index (TT4RI), Thyroid-Stimulating Hormone Index (TSHI), Thyroid Feedback Quantile-based Index (TFQI), and Parametric TFQI (PTFQI). DPN was assessed using neurologic symptoms, signs, and nerve conduction velocity tests. The relationship between DPN and TH sensitivity was examined using logistic regression analysis. We observed that an elevated FT3/FT4 ratio was associated with DPN (OR = 1.36, 95%CI: 1.13-1.63, p = 0.0012). For each standard deviation (SD) increase in the TT4RI, TSHI, TFQI, and PTFQI, the OR of DPN was 0.80 (95%CI: 0.68-0.94, p = 0.0078), 0.72 (95%CI: 0.60-0.86, p = 0.0002), 0.69 (95%CI: 0.58-0.83, p < 0.0001), and 0.69 (95%CI: 0.58-0.82, p < 0.0001), respectively. These results suggested that reduced central and peripheral TH sensitivity is associated with a decreased risk of developing DPN.

Associations of Perchlorate, Nitrate, and Thiocyanate with Bone Mineral Density in the US General Population: A Multi-Cycle Study of NHANES 2011-2018

BACKGROUND

Perchlorate, nitrate, and thiocyanate are widely recognized as endocrine disrupting chemicals, which are closely related to thyroid function. Animal and human studies show a correlation between thyroid hormone and bone mineral density (BMD). However, it remains unknown whether perchlorate, nitrate, and thiocyanate were associated with BMD. This study aimed to explore the association between perchlorate, nitrate, and thiocyanate exposure with BMD.

METHOD

A cross-sectional analysis among 5607 participants from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) was conducted in the present study. Perchlorate, nitrate, and thiocyanate were detected in urine by ion chromatography. Survey-weighted generalized linear regression, restricted cubic splines, and qgcomp models were used to assess the association of BMDs with single and mixed perchlorate, nitrate, and thiocyanate exposures. In addition, age, gender, and BMI stratified these associations.

RESULTS

Negative associations were found between perchlorate and nitrate with BMDs. Furthermore, based on the qgcomp model results, the combined association of perchlorate, nitrate, and thiocyanate exposure was negatively associated with BMDs (β = -0.017, 95% CI: -0.041, -0.024 for total BMD; β = -0.017, 95% CI: -0.029, -0.005 for lumbar BMD). Additionally, there was a significant effect after gender, age, and BMI stratification between perchlorate, nitrate, and thiocyanate with BMDs in the normal weight group (β = -0.015, 95% CI: -0.020, -0.011 for total BMD; β = -0.022, 95% CI: -0.028, -0.016 for lumbar BMD) and children and adolescents group (β = -0.025, 95% CI: -0.031, -0.019 for total BMD; β -0.017, 95% CI: -0.029, -0.005 for lumbar BMD).

CONCLUSIONS

The present study indicated a negative correlation between BMDs and urinary perchlorate, nitrate, and thiocyanate levels, with nitrate being the main contributor to the mixture effect. People with normal weight and children and adolescents were more likely to be affected.