Free triiodothyronine is associated with the occurrence and remission of nonalcoholic fatty liver disease in euthyroid women

Thyroid hormone action and liver disease, a complex interplay

Thyroid hormone action is involved in virtually all physiological processes. It is well known that the liver and thyroid are intimately linked, with thyroid hormone playing important roles in de novo lipogenesis, beta-oxidation (fatty acid oxidation), cholesterol metabolism, and carbohydrate metabolism. Clinical and mechanistic research studies have shown that thyroid hormone can be involved in chronic liver diseases, including alcohol-associated or NAFLD and HCC. Thyroid hormone action and synthetic thyroid hormone analogs can exert beneficial actions in terms of lowering lipids, preventing chronic liver disease and as liver anticancer agents. More recently, preclinical and clinical studies have indicated that some analogs of thyroid hormone could also play a role in the treatment of liver disease. These synthetic molecules, thyromimetics, can modulate lipid metabolism, particularly in NAFLD/NASH. In this review, we first summarize the thyroid hormone signaling axis in the context of liver biology, then we describe the changes in thyroid hormone signaling in liver disease and how liver diseases affect the thyroid hormone homeostasis, and finally we discuss the use of thyroid hormone-analog for the treatment of liver disease.

Associations of sex-related and thyroid-related hormones with risk of metabolic dysfunction-associated fatty liver disease in T2DM patients

BACKGROUND

We aimed to examine sex-specific associations between sex- and thyroid-related hormones and the risk of metabolic dysfunction-associated fatty liver disease (MAFLD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

Cross-sectional analyses of baseline information from an ongoing cohort of 432 T2DM patients (185 women and 247 men) in Xiamen, China were conducted. Plasma sex-related hormones, including estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), progesterone, and total testosterone (TT), and thyroid-related hormones, including free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and parathyroid hormone (PTH), were measured using chemiluminescent immunoassays. MAFLD was defined as the presence of hepatic steatosis (diagnosed by either hepatic ultrasonography scanning or fatty liver index (FLI) score > 60) since all subjects had T2DM in the present study.

RESULTS

Prevalence of MAFLD was 65.6% in men and 61.1% in women with T2DM (P = 0.335). For men, those with MAFLD showed significantly decreased levels of FSH (median (interquartile range (IQR)):7.2 (4.9-11.1) vs. 9.8 (7.1-12.4) mIU/ml) and TT (13.2 (10.4-16.5) vs. 16.7 (12.8-21.6) nmol/L) as well as increased level of FT3 (mean ± standard deviation (SD):4.63 ± 0.68 vs. 4.39 ± 0.85 pmol/L) than those without MAFLD (all p-values < 0.05). After adjusting for potential confounding factors, FSH and LH were negative, while progesterone was positively associated with the risk of MAFLD in men, and the adjusted odds ratios (ORs) (95% confidence intervals (CIs)) were 0.919 (0.856-0.986), 0.888 (0.802-0.983), and 8.069 (2.019-32.258) (all p-values < 0.05), respectively. In women, there was no statistically significant association between sex- or thyroid-related hormones and the risk of MAFLD.

CONCLUSION

FSH and LH levels were negative, whereas progesterone was positively associated with the risk of MAFLD in men with T2DM. Screening for MAFLD and monitoring sex-related hormones are important for T2DM patients, especially in men.

Sex-specific associations between the developmental alterations in the pituitary-thyroid hormone axis and thyroid nodules in Chinese euthyroid adults: a community-based cross-sectional study

Background

Previous studies have revealed the sex-specific features of pituitary-thyroid hormone (TH) actions and the prevalence of thyroid nodules (TNs) in children and adolescents. However, it was unclear in adults. We aimed to investigate the features of pituitary-TH actions in women and men at different ages, and the associations of thyrotropin (TSH), THs, and central sensitivity to THs indices including the thyroid feedback quantile-based index by FT4 (TFQIFT4) and the thyroid feedback quantile-based index by FT3(TFQIFT3) with of TNs in Chinese euthyroid adults.

Methods

8771 euthyroid adults from the communities in China were involved. Demographic, behavioral, and anthropometric data were gathered through the questionnaires. Ultrasound was performed to evaluate the TNs. TSH and THs levels were measured. The multivariable logistic regression and multivariable ordinal logistic regression were conducted.

Results

TFQIFT3 among both genders, except women aged 43 to 59 years, where it increased slightly. Additionally, there was an age-related decline in TFQIFT4 levels in both women and men at ages < 50 and < 53, respectively, but a marked increase after that. Lower TSH levels were significantly associated with a higher prevalence and lower odds of having fewer TNs using multiple nodules as the base category in both men and women (both P for trend < 0.05). Additionally, lower TFQIFT3 and TFQIFT4 levels were significantly associated with a higher prevalence of TNs in women (both P for trend < 0.05), and lower TFQIFT3 levels were significantly associated with a higher prevalence of TNs in men. Both higher TFQIFT3 and TFQIFT4 levels were significantly associated with higher odds of having fewer TNs using multiple nodules as the base category in women. However, the relationships between TFQIFT4 and the prevalence or number of TNs in men were not found.

Conclusions

The trends of THs, TSH, TFQIFT4, and TFQIFT3 at different ages were sex-dependent. Both TFQIFT4 and TFQIFT3 levels were negatively associated with the prevalence and number of TNs in women. The present results may lead to a better understanding of the sex-specific relationships between the development of the pituitary-TH axis and the formation of TNs.

Central Sensitivity to Free Triiodothyronine With MAFLD and Its Progression to Liver Fibrosis in Euthyroid Adults

CONTEXT

Impaired sensitivity to thyroid hormones has been demonstrated to be positively associated with the prevalence of metabolic disorders. However, the relationship between sensitivity to thyroid hormones and metabolic dysfunction-associated fatty liver disease (MAFLD) and liver fibrosis remained unclear.

OBJECTIVE

We aimed to determine the associations of thyroid hormone sensitivity indices with MAFLD and its progression to liver fibrosis in Chinese euthyroid adults.

METHODS

This community-based study included 7906 euthyroid adults. We calculated the thyroid sensitivity indices, including free triiodothyronine to free thyroxine (FT3/FT4) ratio, Thyroid Feedback Quantile-based Index by FT4 (TFQIFT4), and Thyroid Feedback Quantile-based Index by FT3 (TFQIFT3), indicating peripheral and central thyroid hormone sensitivity respectively. Liver steatosis and fibrosis were diagnosed by vibration-controlled transient elastography (VCTE). Multivariable logistic/linear regression and restricted cubic spline (RCS) analysis were conducted.

RESULTS

Compared with participants in the first quartile (Q1), the prevalence of MAFLD was increased by 62% in the fourth quartile (Q4) of FT3/FT4 ratio (OR 1.62; 95% CI [1.38, 1.91]) and by 40% in Q4 of TFQIFT3 (OR 1.40; 95% CI [1.18, 1.65]) (both P < .05). No associations between TFQIFT4 and the prevalence of MAFLD were found. In addition, compared with participants in Q1, the prevalence of liver fibrosis was increased by 45% in Q4 of TFQIFT3 (OR 1.45; 95% CI [1.03, 2.06]) (P < .05) in participants with MAFLD.

CONCLUSION

Impaired central sensitivity to FT3 was associated with MAFLD and its progression to liver fibrosis. More prospective and mechanism studies are warranted to confirm these conclusions.

Sensitivity to thyroid hormones is associated with advanced fibrosis in euthyroid patients with non-alcoholic fatty liver disease: A cross-sectional study

BACKGROUND AND AIMS

The relationship between thyroid hormone sensitivity and the occurrence of advanced hepatic fibrosis in non-alcoholic fatty liver disease (NAFLD) remains unclear. We aimed to explore the association between sensitivity to thyroid hormones and advanced fibrosis (F3-F4) of NAFLD in patients with biopsy-proven euthyroid NAFLD.

METHODS

In this study, 129 participants with biopsy-proven euthyroid NAFLD were enrolled, all of whom underwent thyroid function tests and liver biopsy. Indicators reflecting the sensitivity to thyroid hormones were also calculated. A logistic regression model was used to evaluate the association between thyroid hormone sensitivity and risk of advanced liver fibrosis.

RESULTS

Among the 129 participants, 40 (31.0%) had advanced fibrosis. Advanced fibrosis was independently associated with TSH, FT3, FT3/FT4, thyrotroph T4 resistance index (TT4RI), TSH index (TSHI), and thyroid feedback quantile-based index (TFQI) (P<0.05), even after adjusting for sex, age, and metabolic factors. The combination of TFQI with age, waist circumference (WC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C) performed best for advanced fibrosis diagnosis.

CONCLUSION

In euthyroid NAFLD patients, higher FT3/FT4, TFQI, TT4RI, and TSHI values were strongly associated with an increased incidence of advanced liver fibrosis. The combination of TFQI with age, WC, TGs, and LDL-C can be used as a predictor for advanced fibrosis in patients with NAFLD.

The nonlinear relationship between thyroid function parameters and metabolic dysfunction-associated fatty liver disease

BACKGROUND

The relationship between thyroid function parameters and metabolic dysfunction-associated fatty liver disease (MAFLD) remains controversial. Additionally, little is known about the relationship between thyroid function parameters and MAFLD in the Chinese population.

METHODS

We conducted a retrospective cross-sectional study involving 177,540 individuals with thyroid function tests and MAFLD diagnosis from 2010-2018. The association between thyroid function parameters and MAFLD was evaluated on a continuous scale with restricted cubic spline (RCS) models and by the prior-defined centile categories with multivariable-adjusted logistic regression models. Thyroid function parameters included free triiodothyronine (FT3), free tetra-iodothyronine (FT4), and thyroid stimulating hormone (TSH). Additionally, fully adjusted RCS models stratified by sex, age, and location were studied.

RESULTS

In the RCS models, the risk of MAFLD increased with higher levels of FT3 when FT3 <5.58pmol/L, while the risk of MAFLD decreased with higher levels of FT3 when FT3 ≥5.58pmol/L (P nonlinearity <0.05). While RCS analysis suggested that the FT4 levels had a negative association with MAFLD (P nonlinearity <0.05), indicating an increase in FT4 levels was associated with a decreased risk of MAFLD. RCS analysis suggested an overall positive association between the concentration of TSH and MAFLD risk (P nonlinearity <0.05). The rising slope was sharper when the TSH concentration was less than 1.79uIU/mL, which indicated the association between TSH and MAFLD risk was tightly interrelated within this range. The multivariable logistic regression showed that populations in the 81st-95th centile had the highest risk of MAFLD among all centiles of FT3/TSH, with the 1st-5th centile as the reference category.

CONCLUSIONS

Our study suggested nonlinear relationships between thyroid function parameters and MAFLD. Thyroid function parameters could be additional modifiable risk factors apart from the proven risk factors to steer new avenues regarding MAFLD prevention and treatment.

Independent associations of thyroid-related hormones with hepatic steatosis and insulin resistance in euthyroid overweight/obese Chinese adults

PURPOSE

The aim of the study is to explore the independent association of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) with hepatic steatosis and insulin resistance.

METHODS

A cross-sectional study of 88 overweight/obese adults who underwent anthropometric measurements [BMI, waist circumference (WC) and waist-to-height ratio (WHtR)], hepatic steatosis assessment (FibroScan) and thyroid-related hormones tests was conducted from 2018 to 2020 in Xiamen, China.

RESULTS

Subjects with increasing tertiles of FT3 showed significantly higher levels of controlled attenuation parameter (CAP) ((295.4 ± 44.1, 290.1 ± 68.2 and 331.7 ± 43.6 (dB/m) for tertile 1-3, respectively, p = 0.007) and fatty liver index (FLI) score (47.7 (33.9-60.8), 61.5 (45.1-88.9) and 90.5 (84.5-94.8), respectively, p < 0.001). FT3 significantly and positively correlated with obesity index (BMI, WC, and WHtR), homeostatic model assessment of insulin resistance (HOMA-IR) and hepatic steatosis (CAP and FLI). Multivariable linear regression analyses with adjustment for potential confounding factors showed FT3 was independently associated with BMI (regression coefficient (β (95%CI): 0.024 (0.004-0.043), p = 0.020), HOMA-IR (β (95%CI): 0.091 (0.007-0.174), p = 0.034), CAP (β (95%CI): 25.45 (2.59-48.31), p = 0.030) and FLI (β (95%CI): 0.121 (0.049-0.194), p = 0.001). Neither FT4 nor TSH was significantly associated with any indicators of obesity, insulin resistance or hepatic steatosis.

CONCLUSIONS

Increased FT3, but not FT4 or TSH, was independently associated with higher risks of hepatic steatosis and insulin resistance in euthyroid overweight/obese Chinese adults. Trial registration Registration is not applicable for our study.

Free Triiodothyronine Is Associated With Hepatic Steatosis and Liver Stiffness in Euthyroid Chinese Adults With Non-Alcoholic Fatty Liver Disease

OBJECTIVE

The association between non-alcoholic fatty liver disease (NAFLD) and thyroid hormones in euthyroid subjects is unclear. We investigated the relationship between thyroid function and the severity of hepatic steatosis and liver fibrosis in a large cohort of euthyroid Chinese adults.

METHODS

A total of 3496 participants were enrolled. Liver ultrasonography was used to define the presence of NAFLD (n=2172) or the absence of NAFLD (n=1324). Anthropometric and biochemical measurements were made and thyroid function parameters including free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH) were measured. The severity of hepatic steatosis and liver stiffness was assessed by transient elastography.

RESULTS

Levels of FT3 were significantly higher in the severe NAFLD group and moderate NAFLD group than in the mild NAFLD group (5.18 ± 0.58 vs 5.11 ± 0.57 vs 4.98 ± 0.60 pmol/L, P<0.001). Participants with F4 and F3 liver fibrosis had higher FT3 levels than those with F2 fibrosis (6.33 ± 0.39 vs 5.29 ± 0.48 vs 5.20 ± 0.50 pmol/L, P<0.001). However, FT4 and TSH levels did not correlate with hepatic steatosis or liver fibrosis severity. In addition, the proportions of participants with NAFLD (46.0% vs 63.1% vs 73.3%, P<0.001) and liver fibrosis (11.5% vs 18.6% vs 20.8%, P<0.001) increased as FT3 levels increased. Logistic regression analysis showed that FT3 levels were positively associated with the severity of hepatic steatosis and liver fibrosis presence, even after adjustment for metabolic risk factors including BMI. In non-obese participants, the FT3 level was an independently risk factor for the severity of hepatic steatosis.

CONCLUSIONS

There are positive associations of FT3 levels with the severity of hepatic steatosis and the presence of liver fibrosis in NAFLD with euthyroidism.

Association Between Thyroid Hormone Levels and Advanced Liver Fibrosis in Patients with Type 2 Diabetes Mellitus and Non-Alcoholic Fatty Liver Disease

PURPOSE

To evaluate the effects of serum thyroid hormone levels on advanced liver fibrosis in cases with NAFLD (non-alcoholic fatty liver disease) and T2DM (type 2 diabetes mellitus).

PATIENTS AND METHODS

A total of 1422 cases with T2DM who were admitted to Peking University International Hospital between December 2014 and October 2019 were retrospectively analyzed. Standard anthropometry as well as clinical and laboratory evaluation were performed on all patients. Abdominal ultrasonography was performed to diagnose NAFLD. NFS (NAFLD fibrosis score) was used to identify advanced fibrosis in patients with T2DM and NAFLD.

RESULTS

In cases with T2DM and NAFLD, the serum FT3 level in cases with advanced fibrosis was lower than that in those without advanced fibrosis (4.79±0.89 vs 4.28±1.19, P < 0.05), and significant difference was not found in serum levels of FT4 and TSH between cases with advanced fibrosis and those without advanced fibrosis (P > 0.05). The incidence of advanced fibrosis declined as the rise of serum FT3 levels (P _trend < 0.05). Besides, FT3 (OR, 0.492; 95% CI, 0.384-0.631) was noted as a factor influencing advanced fibrosis in cases with T2DM and NAFLD (P< 0.05).

CONCLUSION

In cases with T2DM and NAFLD, the incidence of advanced fibrosis is negatively correlated with serum FT3 levels, and a low FT3 level is an independent risk factor of advanced fibrosis.

The Role of Thyroid Hormones and Autoantibodies in Metabolic Dysfunction Associated Fatty Liver Disease: TgAb May Be a Potential Protective Factor

BACKGROUND

Previous studies have shown that metabolic dysfunction associated fatty liver disease (MAFLD) is associated with thyroid hormones (THs), immunity, and inflammation status, but few studies involved thyroid autoimmunity. This study aimed to evaluate the role of THs, thyroid autoantibodies, inflammatory biomarkers in MAFLD, its cofactors, and other possible determinants.

MATERIALS AND METHODS

In the study, a total of 424 Chinese patients were selected and categorized as non-MAFLD and MAFLD. Serum thyroid hormone, thyroid autoantibody and high-sensitive C-reactive protein (hsCRP) levels were measured. The data of blood pressure, the serum lipid profile, glucose and liver enzymes were collected. The differences and association between research findings were examined and analyzed by Wilcoxon Signed Rank Test, One-Way ANOVA test and Multiple Logistic Regression models.

RESULTS

The study showed significant increase in the prevalence of MAFLD with high thyroid stimulating hormone (TSH) levels (P < 0.01) and abnormal high-sensitive C-reactive protein (hsCRP) levels (P < 0.01). The proportion of MAFLD patients decreased significantly with the rise of free thyroxine (FT4) (P = 0.04), thyrotropin receptor antibodies (TRAb) (P < 0.01), anti-thyroglobulin antibodies (TgAb) (P < 0.01), and thyroid peroxidase antibodies (TPOAb) levels (P < 0.01). Based on logistic regression analysis, MAFLD was significantly associated with lower levels of TgAb (P < 0.01), TPOAb (P < 0.01), and higher levels of hsCRP (P < 0.01) in male. In female, elevated TgAb (P < 0.01) may be a protective factor, while higher levels of hsCRP (P < 0.01) showed increased risk of MAFLD. Logistic models were adjusted for age, BMI, SBP, DBP, FBG, ALT, AST, TC, TG, LDL, HDL.

CONCLUSIONS

Taken together, TgAb may be a potential protective factor for MAFLD and elevated hsCRP level should be considered as an independent risk factor for MAFLD in both genders. TPOAb also demonstrated protective effect, but only in male. The prevalence of MAFLD increased with higher TSH levels and lower FT4, TRAb levels, but no significant association were found. However, Our findings provide a new insight into the pathogenesis of MAFLD by further investigating the impact of THs, thyroid autoimmunity, and inflammation on MAFLD patients.