Association between thyroid hormone and components of metabolic syndrome in euthyroid Korean adults: A population-based study

Investigating the connection among thyroid function, sensitivity to thyroid hormones, and metabolic syndrome in euthyroid children and adolescents affected by type 1 diabetes

OBJECTIVES

A connection between thyroid hormones (THs) and diverse metabolic pathways has been reported. We evaluated thyroid function and tissue sensitivity to THs in children and adolescents with T1D in comparison to euthyroid controls. Additionally, we investigate whether a relationship exists between sensitivity indices and metabolic parameters.

METHODS

A retrospective analysis was conducted on 80 pediatric patients diagnosed with T1D. Clinical parameters, TSH, FT3, FT4, and the presence of MS were documented. Additionally, indices of peripheral sensitivity (FT3/FT4 ratio) and central sensitivity (TSH index, TSHI; TSH T4 resistance index, TT4RI; TSH T3 resistance index, TT3RI) were assessed. Thirty healthy subjects were considered as controls.

RESULTS

The overall prevalence of MS was 7.27 %, with MS identified in 8 out of 80 (10 %) T1D subjects; none of the controls manifested MS (p<0.01). No significant differences were observed in indexes of tissue sensitivity to THs between subjects with or without MS (all p>0.05). Correlations between THs and indexes of THs tissue sensitivity and metabolic parameters in controls and T1D patients were noted.

CONCLUSIONS

This study affirms a heightened prevalence of MS in children with T1D compared to controls and underscores the potential role of THs in maintaining metabolic equilibrium.

Association of Thyroid Function With Lipid Profile in Patients With Metabolic Syndrome: A Prospective Cross-Sectional Study in the Indian Population

Introduction Metabolic syndrome is a group of aberrant metabolic indicators including hypertension, dyslipidemia, impaired fasting blood glucose, and obesity. It has been reported that thyroid hormones have a strong influence on the cardiovascular system, and hypothyroidism has been linked to metabolic syndrome components. The objective of the study was to find out the association of thyroid function with lipid profile in patients with metabolic syndrome. Methods A prospective cross-sectional study was conducted in an apparently healthy adult population visiting the outpatient Department of Indira Gandhi Institute of Medical Sciences (IGIMS), Patna, Bihar, India. Metabolic syndrome was diagnosed according to the International Diabetes Federation (IDF) criteria. Fasting blood glucose, triglyceride, and HDL levels were tested using the enzymatic photometric method. Thyroid-stimulating hormone (TSH), free T4, free T3, and insulin assays were performed using chemiluminescence immunoassay (CLIA). Results Out of 197 subjects recruited, 86 (51 males and 35 females) were diagnosed with metabolic syndrome according to the IDF criteria, and the rest 111 without metabolic syndrome were considered to be the controls. The mean age of subjects with and without metabolic syndrome was 45.8±8.5 and 46.4±9.6 years, respectively. The prevalence of thyroid dysfunction in the present study was 22%. In subjects with metabolic syndrome, most of the clinical and hormonal parameters (waist circumference, waist-height ratio, fasting blood sugar, fasting insulin, triglycerides, T3, and TSH) were significantly higher (p<0.001) as compared to those without metabolic syndrome. In case of lipid profile, the triglycerides in those with metabolic syndrome (262.8±112.3 mg/dL) were significantly higher (p<0.001) than those without metabolic syndrome (137.9±19.01 mg/dL), while the serum levels of HDL were significantly higher (p<0.001) in group without metabolic syndrome (50.5±3.9 mg/dL) as compared to those with metabolic syndrome (43.4±5.2 mg/dL). Also, the TSH levels were significantly higher (p<0.001) in subjects with metabolic syndrome (5.3±3.4 μl/mL) as compared to those without metabolic syndrome (2.6±1.4 μl/mL). Among all the components of metabolic syndrome, waist circumference and HDL showed a significant strong positive correlation (r=0.51) with TSH, and systolic blood pressure (r=0.39), diastolic blood pressure (r=0.39), and fasting blood sugar levels (r=0.44) showed significantly moderate positive correlation with TSH levels. T4 (OR=8.82; 95% CI: 1.56-49.8) and TSH (OR=1.61; 95% CI: 1.19-2.18) levels were observed to have significantly higher odds as risk factors for metabolic syndrome. Conclusion There is a significant association of thyroid function with lipid profile in metabolic syndrome. It was observed that along with metabolic alterations, cardiovascular symptoms of hypothyroidism and subclinical hypothyroidism are possible. Therefore, while evaluating people with metabolic syndrome, it may be appropriate to look into how well their thyroid glands are functioning.

High free triiodothyronine, and free-triiodothyronine-to-free-thyroxine ratio are associated with metabolic syndrome in a euthyroid employee population: the Zhejiang Zhenhai study

Objective

The aim of this study was to elaborate the link of thyroid hormones (THs) and metabolic syndrome (MetS) in a Chinese euthyroid employee population with MetS component(s).

Methods

An annual health checkup was performed on employees in 2019. Anthropometric parameters, metabolic parameters, and thyroid function were measured. A questionnaire was used in conjunction with Zhenhai Lianhua Hospital database to receive employees' medication records and thyroid surgical history records.

Results

A total of 5486 eligible employees were included; the prevalence of MetS was generally higher in males than in females (38.9 vs. 30.4%, P < 0.001). Among employees with central obesity, hypertriglyceridemia, hyperglycemia, hypertension, and low high-density lipoprotein cholesterol (HDL-C), the prevalence of MetS was 68.8, 63.6, 68.2, 48.8, and 60.0% in males and 72.6, 63.3, 61.3, 42.3, and 42.3% in females, respectively. Logistic regression analysis showed that thyroid-stimulating hormone and free thyroxine (FT4) quartiles had no significant impact on MetS. Free triiodothyronine/free thyroxine (FT3/FT4) and free triiodothyronine (FT3)) quartiles were positively associated with the increased odds ratio (OR) for MetS and dyslipidemia (hypertriglyceridemia and low HDL-C), regardless of gender. In males, FT3 and FT3/FT4 quartiles were positively associated with the OR for central obesity, whereas FT4 quartiles were negatively associated; both FT3 and FT4 quartiles were positively associated with increased OR of hyperglycemia, while similar results were not observed in females. Interaction analysis indicated no significant effect of gender and TH interactions on risk of MetS.

Conclusion

High FT3 and FT3/FT4 were strongly linked with MetS and dyslipidemia in our study, even in the euthyroid individuals. Tighter control of thyroid function was necessary for those with preexisting MetS component(s).

Thyroid Function and Metabolic Syndrome in Children and Adolescents with Neuromotor Disability

Thyroid function plays a crucial role in nervous system integrity and metabolic homeostasis. We evaluated the pattern of TSH, FT4 and FT3 release in children with neuromotor impairment (NI) in relationship with metabolic syndrome (MS). We enrolled 55 patients with NI and 30 controls. Clinical parameters, thyroid function and MS presence were recorded. Principal component analysis (PCA), cluster analysis, and logistic regression models were performed. MS was detected in 54.5% of patients. Four clusters were identified: the first one included only controls and, contrasting with cluster 4, was exclusively characterized by children with disability and MS. This latter showed increased FT4 and FT3 and decreased TSH levels. Cluster 2, characterized by disability without MS showed high FT4 and FT3, whereas cluster 3 with low FT4 and FT3 mainly included disability (90%) and showed prevalent MS (57%). The association between TSH and NI is represented by a U-shape structure. The TSH, FT3 and FT4 release patterns may reflect thyrotropic adaptation, allostatic response and compensatory mechanisms. These mechanisms, found in both MS and disability, show that the odds of having a condition of NI with or without MS increase as the TSH values deviate, in both directions, from a value of 2.5 mLU/mL.