Impaired Sensitivity to Thyroid Hormones Is Associated With Elevated Homocysteine Levels in the Euthyroid Population

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.

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.

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.

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.

Associations between sensitivity to thyroid hormones and insulin resistance in euthyroid adults with obesity

Background

Impaired sensitivity to thyroid hormones (TH) was associated with metabolic syndrome. The study aimed to explore the association between central TH sensitivity indices and insulin resistance (IR) in euthyroid adults with obesity.

Methods

This cross-sectional study enrolled 293 euthyroid outpatients with obesity in Beijing Chao-Yang Hospital. We used the thyroid feedback quantile-based index (TFQI), thyroid stimulating hormone index (TSHI), and thyrotrophic T4 resistance index (TT4RI) to indicate central TH sensitivity. IR was assessed by homeostasis model assessment of insulin resistance (HOMA-IR), hepatic insulin resistance index (hepatic-IR), the Matsuda index, and the adipose tissue insulin resistance index (Adipo-IR). Participants were categorized according to tertiles of TH sensitivity indices. We used multiple linear regressions to explore the associations.

Results

There was a significant stepwise increase in HOMA-IR and Adipo-IR from the lowest to the highest tertiles of TH sensitivity indices (all P<0.05). After adjustment for age, sex, body mass index, hypertension, hyperlipidemia, and diabetes, only Adipo-IR was significantly associated with TH sensitivity indices. On average, each unit increased in TFQI, TSHI, and TT4RI was associated with 1.19 (P=0.053), 1.16 (P=0.04), and 1.01 (P=0.03) units increased in Adipo-IR, respectively. There was no significant association between TH sensitivity indices and HOMA-IR, hepatic-IR, and the Matsuda index after adjustment for other risk factors.

Conclusions

Reduced central TH sensitivity was associated with increased adipose tissue insulin resistance in euthyroid adults with obesity. The results further confirmed the importance of TH sensitivity on metabolic diseases.

Association between thyroid hormone resistance and obesity: a cross-sectional study and mouse stimulation test

OBJECTIVE

Thyroid hormone influences key metabolic pathways, and reduced sensitivity to thyroid hormone is considered a new risk factor for adverse metabolic outcomes. However, the association between thyroid hormone resistance and obesity in euthyroid individuals is still unknown.

METHODS

We enrolled 8021 euthyroid individuals, calculated thyroid hormone resistance indices, and analyzed the association between thyroid hormone resistance and obesity by regression analysis. Furthermore, we conducted the thyrotropin-releasing hormone stimulation test in both control and obese mice (n = 5) to demonstrate the association.

RESULTS

The euthyroid adults with overweight and obesity had increased thyroid hormone resistance indices (all p < 0.05). BMI and prevalence of overweight and obesity increased (odds ratio of thyroid feedback quantile-based index [ORTFQI] = 1.164, p = 0.036; OR of free triiodothyronine/free thyroxine [ORFT3/FT4] = 1.508, p < 0.001) following the elevation of thyroid hormone resistance indices. Mediation analysis indicated a complete mediation effect (beta coefficient of indirect effect [βInd]= 6.838, p < 0.001) of metabolic disorders in the relationship. Furthermore, in the mice with obesity, the thyrotropin response to thyrotropin-releasing hormone stimulation (68.33-90.89 pg/mL) was comparatively blunted (p = 0.029).

CONCLUSIONS

Euthyroid individuals with obesity exhibit both central and peripheral thyroid hormone resistance, a phenomenon that is more pronounced in individuals with metabolic abnormalities. Thyroid hormone resistance is associated with an increased prevalence of overweight and obesity mediated by metabolic disorders.

Association of circulating vitamin levels with thyroid diseases: a Mendelian randomization study

Background

Previous observational studies have shown conflicting results of vitamins supplementation for thyroid diseases. The causal relationships between vitamins and thyroid diseases are unclear. Therefore, we conducted a two-sample bidirectional Mendelian randomization (MR) study to explore association of circulating vitamin levels with thyroid diseases.

Methods

We performed a bidirectional MR analysis using genome-wide association study (GWAS) data. Genetic tool variables for circulating vitamin levels include vitamins A, B9, B12, C, D, and E, Genetic tool variables of thyroid diseases include autoimmune hyperthyroidism, autoimmune hypothyroidism, thyroid nodules (TNs), and Thyroid cancer (TC). Inverse-variance weighted multiplicative random effects (IVW-RE) was mainly used for MR Analysis, weighted median (WM) and MR Egger were used as supplementary methods to evaluate the relationships between circulating vitamin levels and thyroid diseases. Sensitivity and pluripotency were evaluated by Cochran's Q test, MR-PRESSO, Radial MR, MR-Egger regression and leave-one-out analysis.

Results

Positive MR evidence suggested that circulating vitamin C level is a protective factor in autoimmune hypothyroidism (ORIVW-RE=0.69, 95%CI: 0.58-0.83, p = 1.05E-04). Reverse MR Evidence showed that genetic susceptibility to autoimmune hyperthyroidism is associated with reduced level of circulating vitamin A(ORIVW-RE = 0.97, 95% CI: 0.95-1.00, p = 4.38E-02), genetic susceptibility of TNs was associated with an increased level of circulating vitamin D (ORIVW-RE = 1.02, 95% CI: 1.00-1.03, p = 6.86E-03). No causal and reverse causal relationship was detected between other circulating vitamin levels and thyroid diseases.

Conclusion

Our findings provide genetic evidence supporting a bi-directional causal relationship between circulating vitamin levels and thyroid diseases. These findings provide information for the clinical application of vitamins prevention and treatment of thyroid diseases.

Impaired sensitivity to thyroid hormones is associated with albuminuria in the euthyroid population: results from NHANES

PURPOSE

The relationship between thyroid hormone sensitivity and albuminuria remains unclear. We aimed to investigate the association between thyroid hormone sensitivity and the risk of albuminuria in a euthyroid population.

METHODS

This cross-sectional study included 7634 euthyroid adults collected from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2012. Central sensitivity to thyroid hormones was evaluated using the thyroid-stimulating hormone index (TSHI), the thyrotrophic thyroxine resistance index (TT4RI), and the thyroid feedback quantile-based index (TFQI). Peripheral sensitivity to thyroid hormones was measured using the free triiodothyronine/free thyroxine (FT3/FT4) ratio. Furthermore, the independent relationship between sensitivity to thyroid hormones and albuminuria was assessed.

RESULTS

The proportion of albuminuria increased with a higher interquartile range of TFQI levels (7.31% vs. 7.89% vs. 7.95% vs. 9.89%, P = 0.024). Furthermore, TFQI was found to be independently associated with the risk of albuminuria after adjusting for confounding factors (OR = 1.28, 95% CI 1.01-1.60, P = 0.037). Subgroup analysis revealed a significant relationship between TFQI and albuminuria, especially among individuals over 60.

CONCLUSIONS

In euthyroid subjects, impaired central sensitivity to thyroid hormones is associated with albuminuria. TFQI holds significant potential as an epidemiological tool for quantifying the impact of impaired central sensitivity on the risk of albuminuria.

Impaired Thyroid Hormone Sensitivity Increases Risk of Cardiovascular Events in Patients Undergoing Coronary Angiography

CONTEXT

Previous studies found inconsistent results on the relationship between thyroid function and cardiovascular risks.

OBJECTIVE

This study aimed to investigate the association of thyroid hormone sensitivity with the risk of major adverse cardiovascular events (MACE) and cardiovascular death in a euthyroid population undergoing coronary angiography.

METHODS

This prospective cohort study enrolled 1470 euthyroid participants who underwent coronary angiography between March and November of 2013. The participants were followed up from July to November in 2022. Thyrotroph thyroxine resistance index (TT4RI), TSH index (TSHI), and feedback quantile-based index (TFQI) were calculated to evaluate the sensitivity to thyroid hormone. Kaplan-Meier curve and multivariable Cox proportional hazard model were performed to analyze the association between thyroid hormone sensitivity and risk of MACE and cardiovascular death.

RESULTS

Among 1089 participants who completed the follow-up, 342 cases of MACE and 77 cardiovascular deaths were identified during a medium follow-up duration of 111 months. In the multivariable Cox proportional hazard model, the higher levels of TFQI (hazard ratio [HR] = 1.41; 95% CI, 1.08-1.84; P for trend = .01), TT4RI (HR = 1.40; 95% CI, 1.06-1.84; P for trend = .02) and TSHI (HR = 1.61; 95% CI, 1.22-2.13; P for trend = .001) were associated with increased risk of MACE. The higher levels of TFQI (HR = 2.21; 95% CI, 1.17-4.17; P for trend = .02) and TSHI (HR = 2.05; 95% CI; 1.08-3.91; P for trend = .03) were also associated with increased risk of cardiovascular death.

CONCLUSION

Impaired sensitivity to thyroid hormone is associated with higher risks of MACE and cardiovascular death in a euthyroid population undergoing coronary angiography.

l-thyroxine attenuates extracellular Hsp90α-induced vascular endothelial calcification in diabetes mellitus, as revealed by parallel metabolic profiles

BACKGROUND AND AIMS

Diabetic atherosclerotic vascular disease is characterized by extensive vascular calcification. However, an elevated blood glucose level alone does not explain this pathogenesis. We investigated the metabolic markers underlying diabetic atherosclerosis and whether extracellular Hsp90α (eHsp90α) triggers vascular endothelial calcification in this particular metabolic environment.

METHODS

A parallel human/animal model metabolomics approach was used. We analyzed 40 serum samples collected from 24 patients with atherosclerosis and from the STZ-induced ApoE-/- mouse model. A multivariate statistical analysis of the data was performed, and mouse aortic tissue was collected for the assessment of plaque formation. In vitro, the effects of eHsp90α on endothelial cell calcification were assessed by serum analysis, Western blotting and immunoelectron microscopy.

RESULTS

Diabetic ApoE-/- mice showed more severe plaque lesions and calcification damage. Stearamide, oleamide, l-thyroxine, l-homocitrulline and l-citrulline are biomarkers of diabetic ASVD; l-thyroxine was downregulated in both groups, and the thyroid sensitivity index was correlated with serum Hsp90α concentration. In vitro studies showed that eHsp90α increased Runx2 expression in endothelial cells through the LRP1 receptor. l-thyroxine reduced the increase in Runx2 levels caused by eHsp90α and affected the distribution and expression of LRP1 through hydrogen bonding with glutamine at position 1054 in the extracellular segment of LRP1.

CONCLUSIONS

This study provides a mechanistic link between characteristic serum metabolites and diabetic atherosclerosis and thus offers new insight into the role of extracellular Hsp90α in promoting vascular calcification.

Impaired thyroid hormone sensitivity increases the risk of papillary thyroid cancer and cervical lymph node metastasis

BACKGROUND

The association of thyroid hormone sensitivity with papillary thyroid carcinoma (PTC) is unclear. This study investigated the relationship between the thyroid hormone sensitivity indices and the risk of PTC and the influence of thyroid hormone sensitivity on the aggressive clinicopathologic features of PTC.

METHODS

This retrospective study recruited 1225 PTC patients and 369 patients with benign nodules undergoing surgery in Zhongshan Hospital in 2020. The thyroid hormone sensitivity indices were thyroid feedback quantile-based index (TFQI), TSH index (TSHI) and thyrotropin thyroxine resistance index (TT4RI). We employed logistic regression models to explore the correlation between the thyroid hormone sensitivity indices and the risk of PTC and its cervical lymph node metastasis (LNM).

RESULTS

PTC patients had significantly higher levels of TSH, TFQI, TSHI and TT4RI compared to the patients with benign nodules, but thyroid hormone levels did not differ significantly between the two groups. Logistic regression analysis revealed that the higher levels of TFQI, TSHI, and TT4RI were associated with an increased risk of PTC after adjustment for multiple risk factors (TFQI: OR = 1.92, 95% CI: 1.39-2.65, P < 0.001; TSHI: OR = 2.33, 95% CI:1.67-3.26, P < 0.001; TT4RI: OR = 2.41, 95% CI:1.73-3.36, P < 0.001). In addition, patients with decreased thyroid hormone sensitivity had a higher risk of cervical LNM in multiple logistic regression analysis (TFQI: OR = 1.38, 95% CI:1.03-1.86, P = 0.03; TSHI: OR = 1.37, 95% CI:1.02-1.84, P = 0.04; TT4RI: OR = 1.41, 95% CI:1.05-1.89, P = 0.02).

CONCLUSION

Impaired sensitivity to thyroid hormone was associated with an increased risk of PTC, and it is also associated with a higher risk of cervical LNM in PTC patients.

Impaired Sensitivity to Thyroid Hormones Is Associated With Decreased Vitamin D Levels in the Euthyroid Population

CONTEXT

The relationship between vitamin D and thyroid profiles lacks consensus despite extensive investigations. Whether vitamin D levels correlate with thyroid hormone sensitivity remains largely unexplored.

OBJECTIVE

To explore the relationship between vitamin D levels and thyroid hormone sensitivity among euthyroid individuals.

METHODS

This study involved 6452 euthyroid participants. Clinical parameters, including TSH, free thyroxine, 25-hydroxyvitamin D [25(OH)D], and other relevant indicators were extracted from the National Health and Nutrition Examination Survey 2007-2012. To quantify thyroid hormone sensitivity, we calculated the Thyroid Feedback Quantile-based Index (TFQI), the TSH index (TSHI), and the thyrotropin thyroxine resistance index (TT4RI).

RESULTS

Subjects with impaired thyroid hormone sensitivity have decreased 25(OH)D levels (TFQI, TT4RI: P < 0.05; TSHI: P = .05574) following adjustment of confounding variables. Age-specific analysis found negative correlations between thyroid hormone sensitivity indices and 25(OH)D within the 20 to 60 years subgroup, turning positive in the 60 to 80 years subgroup. In females, thyroid hormone sensitivity indices and vitamin D levels were negatively linked, while in males, vitamin D's relationships with TFQI, TT4RI, and TSHI shifted from negative to positive when 25(OH)D levels exceeded 63.5 nmol/L, 56.7 nmol/L, and 56.7 nmol/L, respectively. Stratification by race revealed U-shaped curvilinear patterns resembling those found in the males. In body mass index (BMI) subanalysis, vitamin D had differing associations with thyroid hormone sensitivity indices: negative in the <25 kg/m2 and ≥30 kg/m2 subgroups and U-shaped in the 25-30 kg/m2 subgroup.

CONCLUSION

Impaired thyroid hormone sensitivity correlates with decreased vitamin D levels among euthyroid subjects, with associations varying by age, sex, race, and BMI.

Association Between Serum Thyroid Measurements and Hyperhomocysteinemia in Euthyroid Subjects: A Retrospective Cross-Sectional Study

Objective

The objective of this study was to investigate the association between serum thyroid measurements and homocysteine (HCy) in euthyroid participants.

Methods

This retrospective study was based on Hospital Information Systems. After excluding participants with thyroid dysfunction and those who had recently taken medications that affected serum HCy, 775 participants were enrolled. We compared the serum thyroid function measurements of patients with or without hyperhomocysteinemia (HHCy) and analyzed the effect of thyroid indicators on HHCy prevalence and HCy levels. Multivariate regression analysis was utilized to analyze the association of thyroid-stimulating hormone (TSH) and thyroid peroxidase (TPOAb) with HCy.

Results

The serum TSH level (2.10 ± 1.06 mIU/L) of HHCy patients (n = 98) was significantly higher than controls (n = 677) (1.65 ± 0.90 mIU/L) (p < 0.05), as was the positive rate of TPOAb (19.4% vs 10.0%, p < 0.05). The serum HCy levels in subjects with TSH within the highest quartile were significantly higher than those in the lowest quartile (13.49 ± 7.78 vs 9.81 ± 3.59 μmol/L, p < 0.05). HCy was also significantly higher in TPOAb-positive patients than in negative subjects (14.06 ± 8.89 vs 11.48 ± 5.47 μmol/L, p < 0.05). Among the TSH quartiles, the prevalence of HHCy showed a similar significant upward trend to that described above. The prevalence of HHCy was also significantly higher in TPOAb-positive patients. The results of multivariate regression analysis suggested that both TSH elevation and TPOAb positivity were independent risk factors for HCy elevation and HHCy prevalence. However, we found no definitive association between linear increases in TPOAb titers and HCy concentrations or HHCy prevalence.

Conclusion

Patients with HHCy had significantly higher TSH levels and positive rates of TPOAb. Elevated TSH and positive TPOAb levels were independent risk factors for elevated HCy concentrations and HHCy risk.

Maternal pre-pregnancy obesity modifies the association between first-trimester thyroid hormone sensitivity and gestational Diabetes Mellitus: a retrospective study from Northern China

BACKGROUND

Contradictory relationships have been observed between thyroid function and gestational diabetes mellitus (GDM). Previous studies have indicated that pre-pregnancy BMI (pBMI) could modify their relationships. Few studies have illustrated the role of thyroid hormone sensitivity on GDM. We aimed to explore the effect of pre-pregnancy obesity on the association between early pregnancy thyroid hormone sensitivity and GDM in euthyroid pregnant women.

METHODS

This study included 1310 women with singleton gestation. Subjects were classified into pre-pregnancy obese and non-obese subgroups by pBMI levels with a cutoff of 25 kg/m2. Sensitivity to thyroid hormone was evaluated by Thyroid Feedback Quartile-Based Index (TFQI), Chinese-referenced parametric TFQI (PTFQI), TSH Index (TSHI) and Thyrotrophic T4 Resistance Index (TT4RI). The associations between these composite indices and GDM were analyzed using multivariate regression models in the two subgroups, respectively.

RESULTS

In pre-pregnancy non-obese group, early pregnancy TFQI, PTFQI, TSHI and TT4RI levels were higher in subjects with incident GDM compared to those without GDM (all P < 0.05). By contrast, obese women with GDM exhibited lower levels of those indices (all P < 0.05). The occurrence of GDM were increased with rising TFQI, PTFQI, TSHI and TT4RI quartiles in non-obese women ( all P for trend < 0.05), while exhibited decreased trend across quartiles of those indices in obese women (all P for trend < 0.05). Further logistic analysis indicated contrary relationships between thyroid hormone sensitivity and the occurrence of GDM in the two groups, respectively. The OR of the fourth versus the first quartile of TFQI for GDM was 1.981 (95% CI 1.224, 3.207) in pre-pregnancy non-obese group, while was 0.131 (95% CI 0.036, 0.472) in pre-pregnancy obese group. PTFQI and TSHI yielded similar results.

CONCLUSIONS

The association between maternal sensitivity to thyroid hormones during early gestation and the occurrence of GDM was modified by pre-pregnancy obesity.

Thyroid hormone sensitivity and diabetes onset: a longitudinal cross-lagged cohort

Purpose

Thyroid hormones sensitivity is a newly proposed clinical entity closely related with metabolic health. Prior studies have reported the cross-sectional relationship between thyroid hormones sensitivity and diabetes; however, the longitudinal association is unclear to date. We aimed to explore the relationship between impaired thyroid hormone sensitivity at baseline and diabetes onset using a cohort design.

Methods

This study enrolled 7283 euthyroid participants at the first visit between 2008 and 2009, and then annually followed until diabetes onset or 2019. Thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) were measured to calculate thyroid hormone sensitivity by thyroid feedback quantile-based index (TFQI), Chinese-referenced parametric thyroid feedback quantile-based index (PTFQI), thyrotropin index (TSHI), thyrotroph thyroxine resistance index (TT4RI) and FT3/FT4 ratio. Cox proportional hazard model and cross-lagged panel analysis were used.

Results

The mean baseline age was 44.2 ± 11.9 years, including 4170 (57.3%) male. During a median follow-up of 5.2 years, 359 cases developed diabetes. There was no significant association between thyroid hormones sensitivity indices and diabetes onset, and adjusted hazard ratios per unit (95% CIs) were 0.89 (0.65-1.23) for TFQI, 0.91 (0.57-1.45) for PTFQI, 0.95 (0.70-1.29) for TSHI, 0.98 (0.70-1.01) for TT4RI and 2.12 (0.17-5.78) for FT3/FT4 ratio. Cross-lagged analysis supported the temporal association from fasting glucose to impaired thyroid hormones sensitivity indices.

Conclusions

Our findings could not demonstrate that thyroid hormones sensitivity status is a predictor of diabetes onset in the euthyroid population. Elevated fasting glucose (above 7.0 mmol/L) appeared to precede impaired sensitivity indices of thyroid hormones.

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

BACKGROUND

There is growing evidence that thyroid function affects bone metabolism and even fractures risk. However, little is known about the relationship between thyroid sensitivity and osteoporosis and fractures. Therefore, we explored the relationship between thyroid sensitivity-related indices and bone mineral density (BMD) and fractures in euthyroid US adults.

METHODS

In this cross-sectional study, 20,686 subjects from National Health and Nutrition Examination Survey (NHANES) data were extracted and analyzed during 2007 to 2010. A total of 3403 men and postmenopausal women aged 50 years or older with available data on diagnosis of osteoporosis and/or fragility fractures, bone mineral density (BMD) and thyroid function, were eligible. TSH index (TSHI), thyrotrophin T4/T3 resistance index (TT4RI/TT3RI), Thyroid feedback quantile-based index (TFQI), Parametric TFQI (PTFQI), free triiodothyronine to free thyroxine ratio (FT3/FT4), the secretory capacity of the thyroid gland (SPINA-GT) and the sum activity of peripheral deiodinases (SPINA-GD) were calculated.

RESULTS

FT3/FT4, SPINA-GD, FT4, TSHI, TT4RI, TFQI and PTFQIFT4 were significantly correlated with BMD (P < 0.001). Multiple linear regression analysis showed that FT3/FT4 and SPINA-GD was significantly positively associated with BMD, while FT4, TSHI, TT4RI, TFQI and PTFQIFT4 were negatively associated with BMD (P < 0.05 or P < 0.001). In logistic regression analysis, the odds ratio (OR) for osteoporosis of TSHI, TFQI and PTFQIFT4 were 1.314(1.076, 1.605), 1.743(1.327, 2.288) and 1.827(1.359, 2.455) respectively, and were 0.746(0.620, 0.898) for FT3/FT4 (P < 0.05).

CONCLUSIONS

In elderly euthyroid individuals, impaired sensitivity to thyroid hormones correlates to osteoporosis and fractures, independent of other conventional risk factors.

Vitamin D Deficiency Is Associated with Impaired Sensitivity to Thyroid Hormones in Euthyroid Adults

The relationship between vitamin D deficiency and sensitivity to thyroid hormones was unclear. We aimed to explore the association of 25-hydroxyvitamin D (25(OH)D) levels with thyroid hormone sensitivity in euthyroid adults. A total of 3143 subjects were included. The serum 25(OH)D, free thyroxine (FT3), free thyrotropin (FT4), thyroid-stimulating hormone (TSH), and other clinical variables were measured. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. Thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI), thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI), and FT3/FT4 were calculated to assess thyroid hormone sensitivity. Results showed that 58.8% of the participants had vitamin D deficiency. They had significantly higher levels of triglyceride, insulin, FT3, FT4, TSH, TFQI, PTFQI, TSHI, and TT4RI and lower levels of high-density lipoprotein cholesterol than those with sufficient vitamin D (all p < 0.05). Logistic regression analysis showed that the risk of impaired sensitivity to thyroid hormones evaluated by TFIQ, PTFQI, TSHI, and TT4RI increased by 68% (OR: 1.68; 95%CI: 1.45-1.95; and p < 0.001), 70% (OR: 1.70; 95%CI: 1.46-1.97; and p < 0.001), 66% (OR: 1.66; 95%CI: 1.43-1.92; and p < 0.001), and 50% (OR: 1.50; 95%CI: 1.30-1.74; and p < 0.001), respectively, in participants with vitamin D deficiency compared with those with sufficient vitamin D after adjusting for multiple confounders. In conclusion, in euthyroid populations, vitamin D deficiency was associated with impaired sensitivity to thyroid hormones.

Folate deficiency may increase the risk for elevated TSH in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) and thyroid dysfunction (TD) are two common chronic endocrine disorders that often coexist. Folate deficiency has been reported to be related with the onset and development of T2DM. However, the relationship between folate deficiency and TD remains unclear. This study aims to investigate the association of serum folate with TD in patients with T2DM.

METHODS

The study used data on 268 inpatients with T2DM in the Beijing Chao-yang Hospital, Capital Medical University from October 2020 to February 2021. Thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and serum folate were measured with chemiluminescence immunoassay (CLIA), and folate deficiency was defined as a serum folate concentration < 4.4 ng/mL. Ordinary least squares regression models were used to assess the association of serum folate with TSH concentration. Multivariable logistic regression models were performed to explore the correlation of folate deficiency and the risk for elevated TSH.

RESULTS

15.3% of T2DM patients had TD. Among those patients with TD, 80.5% had elevated TSH. Compared with the normal-TSH and low-TSH groups, the prevalence of folate deficiency was significantly higher in the elevated-TSH group (P < 0.001). Serum folate level was negatively associated with TSH (β=-0.062, 95%CI: -0.112, -0.012). Folate deficiency was associated with the higher risk for elevated TSH in patients with T2DM (OR = 8.562, 95%CI: 3.108, 23.588).

CONCLUSIONS

A low serum folate concentration was significantly associated with a higher risk for elevated TSH among T2DM patients.

Impaired Sensitivity to Thyroid Hormones is Associated with Mild Cognitive Impairment in Euthyroid Patients with Type 2 Diabetes

Purpose

The prevalence of mild cognitive impairment (MCI) in patients with type 2 diabetes (T2D) is rapidly increasing. Thyroid hormones are key regulators of cognitive function in adults. The purpose of this study was to investigate the relationship between thyroid hormone sensitivity and MCI in euthyroid T2D patients.

Patients and Methods

A total of 400 euthyroid T2D patients were enrolled in this cross-sectional study, including 218 patients with normal cognition and 182 MCI patients. The Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive function. The free triiodothyronine to free thyroxine (FT3/FT4) ratio was calculated as a measure of peripheral sensitivity to thyroid hormones; the thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI) and thyroid feedback quantile-based index (TFQI) were calculated as measures of central sensitivity to thyroid hormones. Linear regression analysis and logistic regression analysis were performed to explore the relationships between these indices of thyroid hormone sensitivity and the MoCA score and MCI, respectively.

Results

Compared with the normal cognitive function group, patients in the MCI group had higher TSHI, TT4RI and TFQI but a lower FT3/FT4 ratio (P<0.05). The MoCA score was positively correlated with the FT3/FT4 ratio but negatively correlated with TSHI, TT4RI and TFQI (P< 0.05). Multivariate logistic regression analysis showed that a low FT3/FT4 ratio and high TSHI, TT4RI and TFQI were independently associated with MCI (P<0.05). After adjustment for confounding factors, the odds ratio (OR) for the association between MCI and the highest tertile of the FT3/FT4 was 0.455 (95% CI: 0.264-0.785), for the highest tertile of TSHI, the OR was 2.380 (95% CI: 1.376-4.119), for the highest tertile of TT4RI, the OR was 2.342 (95% CI:1.353-4.054), and for the highest tertile of TFQI, the OR was 2.536 (95% CI: 1.466-4.387) (P< 0.05).

Conclusion

Impaired sensitivity to thyroid hormones is associated with MCI in euthyroid T2D patients.

Association of impaired sensitivity to thyroid hormones with hyperuricemia through obesity in the euthyroid population

BACKGROUND

Impaired sensitivity to thyroid hormones is a newly proposed clinical entity associated with hyperuricemia in the subclinical hypothyroid population. However, it is unknown whether the association exists in the euthyroid population. This study aimed to explore the association of impaired sensitivity to thyroid hormones (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]) with hyperuricemia and quantify the mediating effect of body mass index BMI in the euthyroid population.

METHODS

This cross-sectional study enrolled Chinese adults aged ≥ 20 years who participated in the Beijing Health Management Cohort (2008-2019). Adjusted logistic regression models were used to explore the association between indices of sensitivity to thyroid hormones and hyperuricemia. Odds ratios [OR] and absolute risk differences [ARD] were calculated. Mediation analyses were performed to estimate direct and indirect effects through BMI.

RESULTS

Of 30,857 participants, 19,031 (61.7%) were male; the mean (SD) age was 47.3 (13.3) years; and 6,515 (21.1%) had hyperuricemia. After adjusting for confounders, individuals in the highest group of thyroid hormone sensitivity indices were associated with an increased prevalence of hyperuricemia compared with the lowest group (TFQI: OR = 1.18, 95% CI 1.04-1.35; PTFQI: OR = 1.20, 95% CI 1.05-1.36; TT4RI: OR = 1.17, 95% CI 1.08-1.27; TSHI: OR = 1.12, 95% CI 1.04-1.21). BMI significantly mediated 32.35%, 32.29%, 39.63%, and 37.68% of the associations of TFQI, PTFQI, TT4RI and TSHI with hyperuricemia, respectively.

CONCLUSIONS

Our research revealed that BMI mediated the association between impaired sensitivity to thyroid hormones and hyperuricemia in the euthyroid population. These findings could provide useful evidence for understanding the interaction between impaired sensitivity to thyroid hormone and hyperuricemia in euthyroid individuals and suggest the clinical implications of weight control in terms of impaired thyroid hormones sensitivity.

Sensitivity to thyroid hormone indices are associated with papillary thyroid carcinoma in Chinese patients with thyroid nodules

BACKGROUND

The association between thyroid hormone sensitivity and thyroid cancer is unknown, and we aimed to investigate the association between sensitivity to thyroid hormone indices and papillary thyroid carcinoma (PTC) in Chinese patients with thyroid nodules (TNs).

METHODS

A total of 1,998 patients undergoing thyroid surgery due to TNs from Nanjing Drum Tower Hospital were included in this study. We evaluated central sensitivity to thyroid hormones, such as thyroid stimulating hormone index (TSHI), TSH T4 resistance index (TT4RI), thyroid feedback quantile-based index (TFQI), and parametric thyroid feedback quantile-based Index (PTFQI). Peripheral sensitivity to thyroid hormone was evaluated by FT3 to FT4 ratio. Multivariate logistic regression analysis was performed to evaluate the association between sensitivity to thyroid hormone indices and PTC risk.

RESULTS

The results showed that central indices of thyroid hormone sensitivity, including TSHI, TT4RI, TFQI, and PTFQI, were positively associated with PTC risk. For each SD increase in TSHI, TT4RI, TFQI, and PTFQI, the odds ratios (OR, 95% CI) of PTC were 1.31 (1.18-1.46), 1.01 (1.01-1.02), 1.94 (1.45-2.60), and 1.82 (1.41-2.34), respectively. On the other hand, the association between peripheral sensitivity to thyroid hormone and PTC was significantly negative. For each SD increase in FT3/FT4 ratio, the OR (95% CI) of PTC was 0.18 (0.03-0.96), and a negative correlation was found between FT3/FT4 ratio and TNM staging of PTC.

CONCLUSIONS

Sensitivity to thyroid hormone indices could be used as new indicators for predicting PTC in Chinese patients with TNs. Future researches are still needed to confirm our findings.