Associations between the levels of thyroid hormones and lipid/lipoprotein levels: Data from National Health and Nutrition Examination Survey 2007-2012

Association between multipollutant exposure and thyroid hormones in elderly people: A cross-sectional study in China

Environmental chemicals have been indicated to cause disruption of thyroid homeostasis in human populations. However, previous studies mostly focused on single group of chemicals. Herein, we investigate the independent and combined effects of multiple pollutants on thyroid homeostasis, including thyroid-stimulating hormone (TSH), total and free thyroxine (tT4 and fT4) and total and free triiodothyronine (tT3 and fT3) in elderly people. These environmental pollutants (n = 144) are from ten categories, including phenols, parabens, perfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), synthetic pyrethroids (SPs), herbicides, and metals. Few studies have evaluated the health risks of these 144 chemicals, especially their joint effects. In single-pollutant evaluations, multiple linear regression (MLR) models were used to estimate the independent associations between multiple exposures and thyroid biomarkers. In multi-pollutant evaluations, elastic net regression and Bayesian kernel machine regression (BKMR) models were used to estimate the combined associations. The MLR models showed that 41 chemicals were significantly related to THs levels. BKMR models revealed the most important chemical groups: metals for TSH, PAHs, SPs and PCBs for tT4, herbicides and SPs for tT3. This study will contribute to the understanding of multipollutant exposure and help prioritize specific chemical groups related to thyroid hormone disruption.

Low thyroid function is associated with metabolic dysfunction-associated steatotic liver disease

Background and Aim

Metabolic dysfunction-associated steatotic liver disease (MASLD) is recently introduced to better highlight the pathogenic significance of cardiometabolic dysfunction, as compared with non-alcoholic fatty liver disease. This study aimed to investigate the association between low thyroid function and MASLD in the new context.

Methods

We recruited 2901 participants for our retrospective cohort study from 2016 to 2021. Participants were divided into strict-normal thyroid function and low thyroid function groups (low-normal thyroid function, subclinical hypothyroidism) based on initial thyroid stimulating hormone (TSH) levels, respectively. Cox regression models were used to estimate the hazard ratios (HRs) and 95% CI.

Results

During a median follow-up of 15.6 months, 165 (8.9%) strict-normal thyroid function subjects and 141 (13.4%) low thyroid function subjects developed MASLD; this result was statistically relevant (P < 0.05). Univariate regression analysis showed that low thyroid function and subclinical hypothyroidism were statistically significantly associated with MASLD (low thyroid function: HR1.53; 95% CI 1.22-1.92; subclinical hypothyroidism: HR1.95; 95% CI 1.47-2.60).

Conclusions

MASLD is associated with low thyroid function and the relationship between MASLD and low thyroid function is independent.

Effect of coffee consumption on thyroid function: NHANES 2007-2012 and Mendelian randomization

Background

Coffee is one of the most consumed beverages worldwide, but the effects on the thyroid are unknown. This study aims to examine the association between coffee and thyroid function.

Methods

Participant data (≥ 20 years, n = 6578) for the observational study were obtained from NHANES 2007-2012. Analysis was performed using weighted linear regression models and multiple logistic regression models. Genetic datasets for Hyperthyroidism and Hypothyroidism were obtained from the IEU database and contained 462,933 European samples. Mendelian randomization (MR) was used for the analysis, inverse variance weighting (IVW) was the main method of analysis.

Results

In the model adjusted for other covariates, participants who drank 2-4 cups of coffee per day had significantly lower TSH concentrations compared to non-coffee drinkers (b=-0.23, 95% CI: -0.30, -0.16), but no statistically significant changes in TT4, FT4, TT3 and FT3. In addition, participants who drank <2 cups of coffee per day showed a low risk of developing subclinical hypothyroidism. (OR=0.60, 95% CI: 0.41, 0.88) Observational studies and MR studies have demonstrated both that coffee consumption has no effect on the risk of hyperthyroidism and hypothyroidism.

Conclusions

Our study showed that drinking <2 cups of coffee per day reduced the risk of subclinical hypothyroidism and drinking 2-4 cups of coffee reduced serum TSH concentrations. In addition, coffee consumption was not associated with the risk of hyperthyroidism and hypothyroidism.

Low thyroid function is associated with an increased risk of advanced fibrosis in patients with metabolic dysfunction-associated fatty liver disease

AIMS

Observational studies showed that low thyroid function may perturb liver function. We aimed to evaluate the association of low thyroid function with both metabolic dysfunction-associated fatty liver disease (MAFLD) and advanced hepatic fibrosis.

METHODS

Participants who underwent abdominal ultrasonography and thyroid function test in a Chinese hospital from 2015 to 2021were enrolled. Fibrosis-4 index (FIB-4) > 2.67 and/or non-alcoholic fatty liver disease fibrosis score (NFS) > 0.676 were used to define advanced fibrosis. Descriptive analyses were performed to characterize the epidemiology of MAFLD according to levels of thyroid-stimulating hormone (TSH). The logistic regression model was applied to estimate the association of low thyroid function with MAFLD and advanced fibrosis.

RESULTS

A total of 19,946 participants (52.78% males, mean age: 47.31 years, 27.55% MAFLD) were included, among which 14,789 were strict-normal thyroid function, 4,328 were low-normal thyroid function, 829 were subclinical hypothyroidism. TSH levels were significantly higher in MAFLD patients with a FIB-4 > 2.67 and /or NFS > 0.676 than their counterparts. The logistic regression model adjusted for age and sex showed that low-normal thyroid function increased the risk of MAFLD (odds ratio [OR] = 1.09; 95% confidence interval [CI] 1.01-1.18). Multivariable regression model adjusted for age, sex, body mass index, type 2 diabetes, and hypertension showed low-normal thyroid function increased the risk of advanced fibrosis in patients with MAFLD (FIB-4 > 2.67: OR = 1.41, 95% CI 1.02-1.93; NFS > 0.676: OR = 1.72, 95% CI 1.08-2.72).

CONCLUSION

Elevated TSH concentrations are associated with advanced hepatic fibrosis, even in the euthyroid state.

The relationships between thyroid functions of short-term rapid hypothyroidism and blood lipid levels in post-thyroidectomy patients of differentiated thyroid cancer

Objective

To explore the relationship between short-term rapid hypothyroidism and blood lipid levels in patients with differentiated thyroid cancer (DTC).

Methods

Seventy-five DTC patients scheduled to receive radioactive iodine ablation were enrolled. Levels of thyroid hormone and serum lipids were tested at two time points: the euthyroid before thyroidectomy, and the hypothyroid (off thyroxine). Then the collected data were analyzed.

Results

Totally 75 DTC patients enrolled, among them, 5o were female (66.67%) and 25 were male (33. 33%), with an average age of 52.24 ± 1.24 years old. The short-term rapid severe hypothyroidism induced by thyroid hormone withdrawal significantly aggravated dyslipidemia, particularly in patients with dyslipidemia before thyroidectomy (All P < 0.01). However, there was no significant differences between blood lipid levels with different thyroid stimulating hormone (TSH) levels. And our study showed significant negative correlations between free triiodothyronine levels and the changes from euthyjroidism to hypothyroidism in total cholesterol (r=-0.31, P=0.03), triglycerides (r=-0.39, P=0.006), high density lipoprotein-cholesterol (HDL-C) (r=-0.29, P=0.042), and significant positive correlations between free thyroxine and the changes of HDL-C (r=-0.32, P=0.027) were identified in females, however, which were not observed in males.

Conclusion

Short-term rapids severe hypothyroidism caused by thyroid hormone withdrawal can lead to rapid significant changes in blood lipid levels. It is necessary to pay attention to dyslipidemia and its long-term effects after thyroid hormone withdrawal, especially in patients with dyslipidemia before thyroidectomy.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03006289?term=NCT03006289&draw=2&rank=1, identifier NCT03006289.

Association of thyroid function with abnormal lipid metabolism in young patients with first-episode and drug naïve major depressive disorder

INTRODUCTION

Abnormal lipid metabolism in patients with major depressive disorder (MDD) has received increasing attention. The coexistence of MDD and abnormal thyroid function has been intensively studied. Moreover, thyroid function is closely related to lipid metabolism. The aim of this study was to investigate the relationship between thyroid function and abnormal lipid metabolism in young patients with first-episode and drug naïve (FEDN) MDD.

METHODS

A total of 1,251 outpatients aged 18-44 years with FEDN MDD were enrolled. Demographic data were collected, and lipid and thyroid function levels were measured, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free tetraiodothyronine (FT4), anti-thyroglobulin antibody (TG-Ab), and anti-thyroid peroxidase antibody (TPO-Ab). The Hamilton Rating Scale for Depression (HAMD), Hamilton Anxiety Rating Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) positive subscale were also assessed for each patient.

RESULTS

Compared with young MDD patients without comorbid lipid metabolism abnormalities, patients with comorbid lipid metabolism abnormalities had higher body mass index (BMI) values, HAMD score, HAMA score, PANSS positive subscale score, TSH levels, TG-Ab levels, and TPO-Ab levels. Binary logistic regression analysis showed that TSH level, HAMD score and BMI were risk factors for abnormal lipid metabolism. TSH levels were an independent risk factor for abnormal lipid metabolism in young MDD patients. Stepwise multiple linear regression showed that both TC and LDL-C levels were positively correlated with TSH levels, HAMD and PANSS positive subscale scores, respectively. HDL-C levels were negatively correlated with TSH levels. TG levels were positively correlated with TSH and TG-Ab levels and HAMD score.

DISCUSSION

Our results show that thyroid function parameters, especially TSH levels, are implicated in abnormal lipid metabolism in young patients with FEDN MDD.

Age-specific serum thyrotropin reference range for the diagnosis of subclinical hypothyroidism and its association with lipid profiles in the elderly population

The overdiagnosis of subclinical hypothyroidism (SCH) in the elderly has driven researchers to establish age-specific thyroid stimulating hormone (TSH) intervals to precisely evaluate the prevalence of SCH. Moreover, abnormal lipid profiles, an insidious manifestation of SCH, show various impacts on different age groups. This study aimed to establish an age-specific TSH reference range to clarify the spectrum of SCH in the elderly. The prevalence of dyslipidemia and the age-specific association between TSH and lipid profiles were analyzed to elucidate the relationship between SCH and dyslipidemia. This cross-sectional study enrolled 2460 participants aged ≥ 65 years via cluster sampling. All participants received physical, laboratory tests and thyroid ultrasound examination and completed the questionnaire. The chi-square test was used to analyze variations of dyslipidemia prevalence among different groups. The Cochran-Armitage trend test was applied for testing the linear trends of age-specific prevalence of dyslipidemia among different TSH intervals in each age group. After adjusting for confounding factors, the age-specific association between TSH and lipid profiles was identified using multi-variate linear regression analysis. The TSH reference ranges in the 65-70 age group, 71-80 age group and > 80 age group were 0.65-5.51 mIU/L, 0.85-5.89 mIU/L and 0.78-6.70 mIU/L, respectively. Using these age-specific reference ranges, the prevalence of SCH in the whole population was 3.74%, which was significantly lower than the prevalence based on the laboratory reference range (10.28%). In the 65-70 age group, only the prevalence of high total cholesterol (TC) increased significantly with the age-specific TSH intervals, and TSH was positively associated with TC and low-density lipoprotein cholesterol (LDL-C). In the 71-80 and > 80 age groups, the prevalence of high TC, high triglycerides (TGs), and high LDL-C increased significantly with elevated TSH reference ranges. The levels of TC, TGs, and LDL-C were also positively associated with TSH level in 71-80 age group. However, such an association disappeared in > 80 age group. An age-specific reference range for TSH can effectively prevent the overdiagnosis of SCH in the elderly. Aging could somewhat attenuate the impact of TSH on lipid profiles.

Update on dyslipidemia in hypothyroidism: the mechanism of dyslipidemia in hypothyroidism

Hypothyroidism is often associated with elevated serum levels of total cholesterol, LDL-C and triglycerides. Thyroid hormone (TH) affects the production, clearance and transformation of cholesterol, but current research shows that thyroid-stimulating hormone (TSH) also participates in lipid metabolism independently of TH. Therefore, the mechanism of hypothyroidism-related dyslipidemia is associated with the decrease of TH and the increase of TSH levels. Some newly identified regulatory factors, such as proprotein convertase subtilisin/kexin type 9, angiogenin-like proteins and fibroblast growth factors are the underlying causes of dyslipidemia in hypothyroidism. HDL serum concentration changes were not consistent, and its function was reportedly impaired. The current review focuses on the updated understanding of the mechanism of hypothyroidism-related dyslipidemia.

Low Urinary Iodine Concentration Is Associated with Increased Risk for Elevated Plasma Glucose in Females: An Analysis of NHANES 2011-12

Iodine intake in the US has declined in recent years. Iodine insufficiency increases the risk for inadequate thyroid hormone production and there is growing evidence that sub-clinical hypothyroidism may be disruptive to metabolic health, including insulin resistance (IR). We investigated the association between urinary iodine concentrations (UIC), a measurement of iodine status, and IR in adults. Data from 1286 US adults (≥20 years) in the NHANES 2011-2012 were analyzed. Two subgroups (low = UIC < 100 µg/L and normal = UIC ≥ 100 µg/L) were compared for markers of IR, including fasting plasma glucose (FPG) and insulin, homeostatic model assessment of insulin resistance (HOMA-IR), and glycated hemoglobin (HbA1C). Chi-square test, both linear and logistic regression models were used. In males, there were no significant associations between UIC and markers of IR; however, females with normal UIC had greater risks for elevated HOMA-IR (AOR = 0.56, 95% CI= 0.32-0.99) and HbA1C (AOR = 0.56, 95% CI = 0.34-0.90), while females with low UIC had a greater risk for FPG ≥ 5.6 mmol/L (AOR = 1.73, 95% CI = 1.09-2.72). Results only partially support our hypothesis that UIC is associated with the odds of IR in adults. The finding of an increased risk for elevated FPG, a marker of prediabetes, in female adults with low iodine status requires further investigation.

Unfavorable Triglyceride-rich Particle Profile in Subclinical Thyroid Disease: A Cross-sectional Analysis of ELSA-Brasil

Subclinical thyroid disorders have been associated with atherosclerosis and increased cardiovascular risk. As triglyceride-rich lipoprotein particles (TRLPs) have recently emerged as a casual factor for atherogenesis, the aim of this study was to evaluate the relationship between subclinical hypo- and hyperthyroidism and TRLP subfractions. We selected 5066 participants from the ELSA-Brasil cohort with available data of thyroid function and lipid profile measured by nuclear magnetic resonance (NMR) spectroscopy. Individuals were divided into 3 groups by baseline thyroid function (subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism). Triglyceride-rich lipoprotein particle subfractions were analyzed through NMR spectroscopy. To examine the association between TRLP subfractions and thyroid function, we conducted univariate and multivariate linear regression models adjusted for demographic characteristics, body mass index, diabetes, smoking status, and alcohol use. Of 3304 individuals, 54% were women, with a mean age of 50.6 ± 8.7 years, 51% white, and 53% with at least a college education. Of these individuals, 92% were euthyroid, whereas 6.8% had subclinical hypothyroidism and 1.2% had subclinical hyperthyroidism. The univariate linear regression showed that very small TRLPs (P = 0.026) and very large TRLPs (P = 0.008) were statistically increased in subclinical hypothyroidism when compared with euthyroidism. In subclinical hyperthyroidism, there was a reduction in total TRLPs (P = 0.003), seemingly driven by reduced very small TRLPs (P = 0.067). The findings were confirmed when adjusted for demographic characteristics, as well as comorbidities. This study suggests that subclinical hypothyroidism is associated with very small and very large TRLPs, which are related to an unfavorable atherogenic profile. Subclinical hyperthyroidism is associated to lower very small TRLPs.

Reference values and the effect of clinical parameters on thyroid hormone levels during early pregnancy

OBJECTIVE

Thyroid dysfunction is a common endocrine problem during pregnancy; correct diagnosis and appropriate treatments are essential to avoid adverse pregnancy outcomes. Besides, it is vital to identify and quantify the major risk factors for gestational thyroid dysfunction, including thyroid autoimmunity, human chorionic gonadotropin (HCG) concentration, body mass index (BMI) and parity. The study objective was to establish reference ranges during early pregnancy and to explore the relationship between risk factors and thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyroxine (FT3).

DESIGN, PATIENTS AND MEASUREMENTS

To establish the reference ranges of thyroid hormone during early pregnancy in China and to identify the risk factors for thyroid dysfunction, woman in the first trimester of pregnancy (4-12 weeks gestation) were recruited. After excluding thyroid peroxidase antibody (TPO-Ab) positive and/or thyroglobulin antibody (TG-Ab) positive women, previous thyroid disease, a lack of iodine intake, reference values were calculated by 2.5th to 97.5th percentiles.

RESULTS

After exclusion of TPO-Ab and/or TG-Ab positive women, reference values were as follows: TSH, 0.11-3.67 mIU/l; FT3, 3.19-5.91 pmol/l; FT4 10.95-16.79 pmol/l. Higher BMI was associated with lower FT4 concentrations (P=0.005). In multiple regression analysis, TSH was significantly and positively associated with TG (P=0.03). Maternal parity and maternal age may be risk factors for the abnormal thyroidal response to hCG concentrations.

CONCLUSIONS

Our study defined first trimester-specific reference ranges for serum TSH, FT4, FT3 in a Chinese population, and demonstrated that BMI ≥23kg/m2, maternal parity ≥3 and maternal age ≥30 years may increase the risk of thyroid dysfunction.

Clinical Parameters Are More Likely to Be Associated with Thyroid Hormone Levels than with Thyrotropin Levels: A Systematic Review and Meta-Analysis

Background: Though the functional states of other endocrine systems are not defined on the basis of levels of controlling hormones, the assessment of thyroid function is based on levels of the controlling hormone thyrotropin (TSH). We, therefore, addressed the question as to whether levels of thyroid hormones [free thyroxine (fT4), total triiodothyronine (TT3)/free triiodothyronine (fT3)], or TSH levels, within and beyond the reference ranges, provide the better guide to the range of clinical parameters associated with thyroid status. Methods: A PubMed/MEDLINE search of studies up to October 2019, examining associations of levels of thyroid hormones and TSH, taken simultaneously in the same individuals, with clinical parameters was performed. We analyzed atrial fibrillation, other cardiac parameters, osteoporosis and fracture, cancer, dementia, frailty, mortality, features of the metabolic syndrome, and pregnancy outcomes. Studies were assessed for quality by using a modified Newcastle-Ottawa score. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. A meta-analysis of the associations was performed to determine the relative likelihood of fT4, TT3/fT3, and TSH levels that are associated with the clinical parameters. Results: We identified 58 suitable articles and a total of 1880 associations. In general, clinical parameters were associated with thyroid hormone levels significantly more often than with TSH levels-the converse was not true for any of the clinical parameters. In the 1880 considered associations, fT4 levels were significantly associated with clinical parameters in 50% of analyses. The respective frequencies for TT3/fT3 and TSH levels were 53% and 23% (p < 0.0001 for both fT4 and TT3/fT3 vs. TSH). The fT4 and TT3/fT3 levels were comparably associated with clinical parameters (p = 0.71). More sophisticated statistical analyses, however, indicated that the associations with TT3/fT3 were not as robust as the associations with fT4. Conclusions: Thyroid hormones levels, and in particular fT4 levels, seem to have stronger associations with clinical parameters than do TSH levels. Associations of clinical parameters with TSH levels can be explained by the strong negative population correlation between thyroid hormones and TSH. Clinical and research components of thyroidology currently based on the measurement of the thyroid state by reference to TSH levels warrant reconsideration.

Hypothyroidism-Induced Nonalcoholic Fatty Liver Disease (HIN): Mechanisms and Emerging Therapeutic Options

Nonalcoholic fatty liver disease (NAFLD) is an emerging worldwide problem and its association with other metabolic pathologies has been one of the main research topics in the last decade. The aim of this review article is to provide an up-to-date correlation between hypothyroidism and NAFLD. We followed evidence regarding epidemiological impact, immunopathogenesis, thyroid hormone-liver axis, lipid and cholesterol metabolism, insulin resistance, oxidative stress, and inflammation. After evaluating the influence of thyroid hormone imbalance on liver structure and function, the latest studies have focused on developing new therapeutic strategies. Thyroid hormones (THs) along with their metabolites and thyroid hormone receptor β (THR-β) agonist are the main therapeutic targets. Other liver specific analogs and alternative treatments have been tested in the last few years as potential NAFLD therapy. Finally, we concluded that further research is necessary as well as the need for an extensive evaluation of thyroid function in NAFLD/NASH patients, aiming for better management and outcome.

Relationship between TSH Levels and the Advanced Lipoprotein Profile in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

The relationship between thyroid-stimulating hormone (TSH) and lipoprotein subfractions by Vertical Auto Profile (VAP) is unclear. We aimed to evaluate lipoprotein profiles according to TSH levels in euthyroid individuals.Material and Methods: Cross-sectional analysis of 3,525 participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) with no previous thyroid disease and who were not on lipid-lowering medication. Total-cholesterol and its fractions, lipoprotein subfractions, triglycerides, and triglyceride-rich lipoprotein cholesterol [TRL-C (VLDL₁₊₂-C, VLDL₃-C, IDL-C)] were determined by VAP. Associations between TSH quintiles and lipoprotein subfractions were evaluated by crude and adjusted linear regression models.Results: For the total sample, significant beta-coefficients in full adjusted models for the 5^th quintile of TSH (compared to 1^st) were found for the following VAP lipids and lipoproteins: IDL-C (β: 0.90; 0.11 to 1.69); VLDL-C (β: 2.80; 1.51 to 4.08), triglycerides (β: 18.66; 8.07 to 29.25), non-HDL-C (β: 4.63; 0.50 to 8.75 mg/dl), TRL-C (β:1.93;0.70 to 3.17), VLDL₃-C (β: 1.04; 0.50 to 1.57), as well as, TC/HDL-C (β: 0.15; 0.03 to 0.26) and TG/HDL-C ratio (β: 0.49;0.21 to 0.77). In women, similar results were found for VLDL-C, triglycerides, non-HDL-C, TRL-C, VLDL₃-C, TC/HDL-C and TG/HDL-C-ratios. In men, we also found positive associations between the highest quintile of TSH with VLDL-C, triglycerides, VLDL₃-C and TG/HDL-C.Conclusions: In the ELSA-Brasil, the highest TSH levels were mostly positively associated with lipoprotein levels, particularly TG, TRL and their remnants. Notwithstanding, our findings suggest that TSH levels within the normal range have little impact on the atherogenic profile.

Data mining: Seasonal fluctuations and associations between thyroid stimulating hormone and lipid profiles

OBJECTIVE

Thyroid stimulating hormone (TSH) is associated with lipid metabolism. In this study, we aimed to evaluate seasonal variations and the association between TSH and lipid profiles based on clinical big data.

METHOD

This observational, retrospective big data study enrolled a total of 20,192 individuals who visited Peking Union Medical College Hospital for routine health check-ups from 2014 to 2018. Demographic, medical history, common biochemical analytes, and thyroid related test data were obtained. A Kruskal-wallis analysis was used to compare the differences in total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) by TSH quartiles. Spearman correlation analysis was used to evaluate the association between TSH and lipid profiles as well as temperature.

RESULTS

TC and LDL did not vary significantly with TSH concentration; however, TG and HDL-C did. TSH concentration showed weak positive correlation with serum TC, TG, and HDL-C but not with LDL-C. Serum TC concentration was positively correlated with TG and LDL-C. TG was positively correlated with LDL-C but negatively correlated with HDL-C. HDL-C was negatively correlated with LDL-C. TSH and lipid profiles showed seasonal fluctuations. Monthly median TSH, TC, and LDL-C peaked in winter and dropped to a minimum in summer. The correlation coefficient (r) between the average monthly temperature and TSH, TC, TG, HDL-C, and LDL-C was -0.424 (p = 0.001), -0.539 (p < 0.001), -0.020 (p = 0.880), -0.199 (p = 0.127), and -0.442 (p < 0.001), respectively.

CONCLUSION

Seasonal variation was observed in both TSH and lipids. Apart from the seasonal variation of TC and LDL-C, our results also have clinical interpretation. It suggested that it may not reflect the real status of lipids during and immediately after the Spring festival. Thus, in order to diagnosis of hypercholesterolemia, re-testing was needed later to provide the precision diagnostic, monitoring and treatment.

Low-Normal Thyroid Function Is Associated With Advanced Fibrosis Among Adults in the United States

The pathogenetic pathways leading to increasing prevalence of advanced fibrosis in the setting of nonalcoholic fatty liver disease (NAFLD) and resulting in higher rates of liver-related and cardiovascular morbidity and mortality in the United States are multifactorial.¹ The negative health impact of "low-normal" thyroid function, which is defined as a higher level of thyroid-stimulating hormone (TSH) within the euthyroid reference range, may be comparable with overt and subclinical hypothyroidism.^2-4 We reported a strong association between biopsy-proven advanced fibrosis in NAFLD with increasing TSH levels in a dose-dependent manner even within the euthyroid reference range.⁵ To generalize our findings across all ethnicities, we examined the association of both low-normal thyroid function and subclinical hypothyroidism with advanced fibrosis in the US general population.