Evaluation of the therapeutic efficacy of different doses of LT4 in pregnant women with high-normal TSH levels and TPOAb positivity in the first half of pregnancy

BACKGROUND

The objective was to investigate the efficacy of different doses of levothyroxine therapy among pregnant women exhibiting high-normal thyroid stimulating hormone levels and positive thyroid peroxidase antibodies throughout the first half of pregnancy.

METHODS

Pregnant women exhibiting high-normal thyroid stimulating hormone levels and thyroid peroxidase antibodies positivity throughout the initial half of pregnancy were selected from January 2021 to September 2023. Based on the different doses of levothyroxine, the pregnant women were categorized into the nonintervention group (G0, 122 women), 25 µg levothyroxine intervention group (G25, 69 women), and 50 µg levothyroxine intervention group (G50, 58 women). Serum parameters, gastrointestinal symptoms, small intestinal bacterial overgrowth (SIBO), maternal and neonatal outcomes were compared after the intervention among the three groups.

RESULTS

After the intervention, in the G25 and G50 groups, the thyroid stimulating hormone, triglyceride and low-density lipoprotein levels were notably less in contrast to those in the G0 group (P < 0.05). The rates of abdominal distension and SIBO in the G25 and G50 groups were notably lower in contrast to the G0 group (P = 0.043 and 0.040, respectively). The G50 group had a lower rate of spontaneous abortion and premature membrane rupture than the G0 group (P = 0.01 and 0.015, respectively). Before 11+ 2 weeks of gestation and at thyroid peroxidase antibodies levels ≥ 117 IU/mL, in contrast to the G0 group, the G50 group experienced a decreased rate of spontaneous abortion (P = 0.008). The G50 group had significantly higher newborn weight than the G0 group (P = 0.014), as well as a notably longer newborn length than the G0 and G25 groups (P = 0.005).

CONCLUSIONS

For pregnant women with high-normal thyroid stimulating hormone levels and thyroid peroxidase antibodies positive during the first half of pregnancy, supplementation with 50 µg levothyroxine was more effective in improving their blood lipid status and gastrointestinal symptoms, reducing the incidence of SIBO and premature rupture of membranes, and before 11+2 weeks, TPOAb ≥ 117 IU/mL proved more beneficial in mitigating the risk of spontaneous abortion.

Thyrotropin induces atherosclerosis by upregulating large conductance Ca2+-activated K+ channel subunits

Hypothyroidism is associated with elevated levels of serum thyrotropin (TSH), which have been shown to promote abnormal proliferation of vascular smooth muscle cells and contribute to the development of atherosclerosis. However, the specific mechanisms underlying the TSH-induced abnormal proliferation of vascular smooth muscle cells remain unclear. The objective of this study was to investigate the role of TSH in the progression of atherosclerosis. Our research findings revealed that hypothyroidism can trigger early atherosclerotic changes in the aorta of Wistar rats. In alignment with our in vitro experiments, we observed that TSH induces abnormal proliferation of aortic smooth muscle cells by modulating the expression of α and β1 subunits of large conductance Ca2+-activated K+ (BKCa) channels within these cells via the cAMP/PKA signaling pathway. These results collectively indicate that TSH acts through the cAMP/PKA signaling pathway to upregulate the expression of α and β1 subunits of BKCa channels, thereby promoting abnormal proliferation of arterial smooth muscle cells. These findings may provide a basis for the clinical prevention and treatment of atherosclerosis caused by elevated TSH levels.

Comparison between transient and permanent congenital hypothyroidism on a thyroid function test after re-evaluation

PURPOSE

Congenital hypothyroidism (CH) is diagnosed with neonatal screening and is treated early in the neonatal period. Among these patients, transient CH (TCH) is included and requires re-evaluation. The purpose of this study was to find the best way to discontinue levothyroxine and to find trends in thyroid function tests (TFTs) after re-evaluation.

METHODS

We retrospectively reviewed 388 patients diagnosed with CH. They were classified as permanent CH (PCH) and TCH. The total number of the PCH and TCH groups was 83 (51 boys and 32 girls). We compared clinical parameters to predict TCH and to identify the trends of TFT.

RESULTS

The first thyroid-stimulating hormone (TSH) value after discontinuation and the average TSH value for 1, 2, and 3 years were all significantly higher in the PCH group (P<0.01). The first fT4 value after discontinuation and the average fT4 value for 1, 2, and 3 years were all significantly higher in the TCH group (P<0.01). The optimal cutoff value on the receiver operating characteristic curve for PCH prediction with an average of 3 years of TSH was greater than 9.05 μIU/mL, which was predicted with a sensitivity of 100% and a specificity of 100%.

CONCLUSION

When the TSH value ranges from 10 μIU/mL to 20 μIU/mL, clinicians can discontinue levothyroxine if the next result is around 10 μIU/mL or shows a decreasing trend.

Assessing the cardiovascular effects of levothyroxine use in an ageing United Kingdom population (ACEL-UK) protocol: a cohort and target trial emulation study

BACKGROUND

Subclinical hypothyroidism is diagnosed when serum thyroid stimulating hormone levels are higher whilst free thyroxine levels remain within their respective reference ranges. These reference ranges are uniformly applied in all adults, despite serum thyroid stimulating hormone levels naturally increasing with age. Research has found that mildly elevated thyroid stimulating hormone levels may be associated with some benefits in ageing patients, including reduced mortality and better cardiorespiratory fitness. Levothyroxine is typically prescribed to patients with hypothyroidism, but no conclusive evidence exists on whether levothyroxine therapy is beneficial or detrimental in older subclinical hypothyroid patients. Despite this, prescriptions for levothyroxine are increasing year-on-year. This study aims to determine if receiving levothyroxine affects the cardiovascular and bone health outcomes of subclinical patients in primary care aged 50 years and over.

METHODS

This project includes a retrospective cohort analysis and a target trial emulation study using electronic patient records collected between 2006 and 2021 and recorded in The Health Improvement Network database. The primary outcome of this study is to compare the cardiovascular outcomes of subclinical hypothyroid patients aged over 50 years treated with levothyroxine compared to those untreated. Secondary outcomes are bone health and all-cause mortality outcomes. Descriptive and inferential statistics will both be employed to analyse the data. Secondary analysis will explore confounding factors, including age, sex, smoking status, body mass index, co-morbidities, and levothyroxine dosage.

DISCUSSION

There needs to be a greater understanding of the potential risks of the current treatment for older patients with subclinical hypothyroidism in a primary care setting. We will investigate the clinical importance of this issue and whether older subclinical hypothyroid patients have poorer outcomes when treated. Clarifying this concern may help address the healthcare resource implications of ageing patients being misclassified as having mild hypothyroidism, as these patients are more likely to repeat their blood tests. This could reduce prescription wastage and improve patient outcomes and quality of life in the ageing population.

TRIAL REGISTRATION

Not applicable.

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.

Normal thyroid stimulating hormone is associated with all-cause mortality in patients with acute myocardial infarction after percutaneous coronary intervention

BACKGROUND

Circulating thyroid-stimulating hormone (TSH) levels within the normal reference range can affect the cardiovascular system. The present study investigated the prognostic value of normal TSH levels in patients presenting with acute myocardial infarction (AMI) following percutaneous coronary intervention (PCI).

METHODS

Between January 2013 and July 2019, 1240 patients with AMI and normal thyroid function were enrolled and classified according to TSH tertile. The trial endpoint was all-cause mortality. The integrated discrimination index (IDI) and the net reclassification index (NRI) were used to assess the combined predictive values of the TSH levels and the Global Registry of Acute Coronary Events (GRACE) scores.

RESULTS

After a median 44.25-month follow-up, 195 individuals died. Even after covariate adjustment by multivariate Cox regression (HR: 1.56; 95% CI 1.08-2.25; P = 0.017), the patients in the third TSH tertile were at the highest risk of all-cause mortality. A subgroup analysis revealed significant interactions between the TSH levels and the GRACE scores (high risk vs. low/medium risk) (P = 0.019). The addition of the TSH levels to the GRACE scores substantially improved the prediction of all-cause mortality, especially for high-risk patients (NRI = 0.239; IDI = 0.044; C-statistic value range 0.649-0.691; all significant).

CONCLUSIONS

The third TSH tertile is associated with a higher incidence of all-cause mortality than the first TSH tertile in high-risk patients presenting with AMI after PCI.

Neonatal reference intervals for thyroid stimulating hormone and free thyroxine assayed on a Siemens Atellica® IM analyzer: a cross sectional study

BACKGROUND

Deriving population specific reference intervals (RIs) or at the very least verifying any RI before adoption is good laboratory practice. Siemens has provided RIs for thyroid stimulating hormone (TSH) and free thyroxine (FT4) determined on their Atellica® IM analyzer for all age groups except the neonatal age group which provides a challenge for laboratories that intend to use it to screen for congenital hypothyroidism (CH) and other thyroid disorders in neonates. We set out to determine RIs for TSH and FT4 using data obtained from neonates undergoing routine screening for CH at the Aga Khan University Hospital, Nairobi, Kenya.

METHODOLOGY

TSH and FT4 data for neonates aged 30 days and below were extracted from the hospital management information system for the period March 2020 to June 2021. A single episode of testing for the same neonate was included provided both TSH and FT4 were done on the same sample. RI determination was performed using a non-parametric approach.

RESULTS

A total of 1243 testing episodes from 1218 neonates had both TSH and FT4 results. A single set of test results from each neonate was used to derive RIs. Both TSH and FT4 declined with increase in age with a more marked decline seen in the first 7 days of life. There was a positive correlation between logFT4 and logTSH (r_s (1216) = 0.189, p = < 0.001). We derived TSH RIs for the age groups 2-4 days (0.403-7.942 µIU/mL) and 5-7 days (0.418-6.319 µIU/mL), and sex specific RIs for males (0.609-7.557 µIU/mL) and females (0.420-6.189 µIU/mL) aged 8-30 days. For FT4, separate RIs were derived for the age groups 2-4 days (1.19-2.59 ng/dL), 5-7 days (1.21-2.29 ng/dL) and 8-30 days (1.02-2.01 ng/dL).

CONCLUSION

Our neonatal RIs for TSH and FT4 are different from those published or recommended by Siemens. The RIs will serve as a guide for the interpretation of thyroid function tests in neonates from sub-Saharan Africa where routine screening for congenital hypothyroidism using serum samples is done on the Siemens Atellica® IM analyzer.

Association between gestational blood lipids and TSH levels and pregnancy outcome of patients with subclinical hypothyroidism

Objective

To investigate the association between gestational blood lipids and thyroid stimulating hormone (TSH) levels and pregnancy outcomes of patients with subclinical hypothyroidism (SCH).

Methods

In this retrospective observational study, we analyzed the clinical data of 82 patients (case group) with gestational SCH treated in our hospital from January 2021 to January 2022 at gestational weeks 25-33 and grouped them according to whether SCH was well controlled by treatment (case Group-A: well controlled, n=55; case Group-B: poorly controlled, n=27), and the clinical data of 41 pregnant women (control group) undergoing physical examination during the same period. After comparing the blood lipids and TSH levels of the three groups, we compared their adverse pregnancy outcomes to assess the possible correlations between blood lipids and TSH levels and pregnancy outcomes.

Results

The levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and TSH in the case Group-B were significantly higher than those in the case Group-A and the control group (P<0.05). Compared with case Group-B and the control group, the incidence of premature delivery, abortion and neonatal growth restriction was higher in case Group-A (P<0.05). Among 82 patients in the case group 42 presented adverse pregnancy outcomes. The levels of TC, TG, LDL-C and TSH in mothers and infants in the adverse outcome group were significantly higher than those in the favorable outcome group (P<0.05). Our Pearson analysis results showed that the levels of TC, TG and LDL-C were positively correlated with the TSH levels and the pregnancy outcomes, and that TSH was positively correlated with pregnancy outcomes (P<0.05).

Conclusion

The levels of TC, TG, LDL-C and TSH in patients with poorly controlled SCH were increased during pregnancy, and were associated with the pregnancy outcomes and positively correlated with each other.

Metabolic and biochemical profile in women with polycystic ovarian syndrome attending tertiary care centre of central NEPAL

BACKGROUND

Polycystic Ovarian Syndrome (PCOS) is a common endocrinopathy in women of reproductive age group and is highly associated with an increased risk of diabetes, hypertension, cardiovascular disease, and hyper estrogen-related malignancies in women with PCOS. This study was intended to assess the metabolic and hormonal profile of the patients with polycystic ovarian syndrome attending a tertiary care hospital.

METHODOLOGY

A descriptive cross-sectional study was conducted among 107 women diagnosed with polycystic ovarian syndrome from the Department of Clinical Biochemistry of Tribhuvan University and Teaching Hospital. Descriptive analysis was performed to determine the socio-demographic characteristics of the participants. Bivariate analysis was conducted to determine using a t-test for comparing means between two groups and ANOVA for comparing the hormonal and metabolic parameters.

RESULTS

The mean age of the participants was 27 ± 4 years. This study showed that blood pressure was significantly higher in overweight and obese women (p = 0.001). The obese group had significantly higher serum TSH than the normal group (10.04 vs. 2.73, p = 0.001). Abnormal glucose and hyperinsulinemia were present in 4% of the patients, while 40% had Vitamin D deficiency. Hypothyroidism (TSH ≥ 4.5 mIU/ml) was found in 11% of the PCOS participants with a mean value of 6.65 ± 21.17 mIU/ml. Hyperprolactinemia ≥ 26.8 ng/ml was depicted in 21% of the study population with a mean value of 37.25 ± 21.86 ng/ml.

CONCLUSION

Our study demonstrated that PCOS is most commonly prevalent in young women of the reproductive age group which can lead to reproductive, metabolic, and oncological complications in the long term. LH/ FSH ratio was found to be significantly deranged indicating that PCOS should be diagnosed and treated early in the adolescent age group.

The Correlation between the First Trimester Combined Test Results and Thyroid Stimulating Hormone Levels as Well as Its Effect on Pregnancy Outcomes

Background

Determining the pregnancy outcomes with independent prognostic factors in the first trimester combined screening test and thyroid stimulating hormone (TSH) is a concern for practitioners. We aimed to evaluate the correlation between TSH and first trimester combined screening test levels and examine their effects on pregnancy outcomes in healthy pregnant women.

Methods

A total of 349 pregnant women in Izmir Ataturk Training and Research Hospital, Turkey with normal TSH values in the first trimester between 2015 and 2020 were enrolled. Patients were divided into two groups as 274 and 75 patients according to TSH values with 2,5 as cut-off value; their birth weights and weeks were compared. Patients were also divided into three groups according to gestational weeks; their TSH values and combined tests were compared.

Results

When grouped based on the TSH threshold value (2.5uIU/ml), no significant relationship was found between the combined test parameters and TSH levels. In the combined test, after grouping according to the week of gestation, a negative correlation was observed between free beta-human chorionic gonadotropin (β-hCG) and TSH measured at 11 weeks (P=0.040, r=-0.189). A significant negative correlation was found between free β-hCG and newborn birth weight (P=0.032, r=-0.199), TSH and delivery time (P=0.011, r=-0.235).

Conclusion

Free β-hCG and TSH levels could guide practitioners for birth weight and early delivery, respectively. Postponing the combined test for patients with elevated serum TSH levels to between the 12th and 13th weeks of gestation may reduce false positives.

The prognostic utility of serum thyrotropin in hospitalized Covid-19 patients: statistical and machine learning approaches

PURPOSE

To assess the prognostic value of serum TSH in Greek patients with COVID-19 and compare it with that of commonly used prognostic biomarkers.

METHODS

Retrospective study of 128 COVID-19 in patients with no history of thyroid disease. Serum TSH, albumin, CRP, ferritin, and D-dimers were measured at admission. Outcomes were classified as "favorable" (discharge from hospital) and "adverse" (intubation or in-hospital death of any cause). The prognostic performance of TSH and other indices was assessed using binary logistic regression, machine learning classifiers, and ROC curve analysis.

RESULTS

Patients with adverse outcomes had significantly lower TSH compared to those with favorable outcomes (0.61 versus 1.09 mIU/L, p < 0.001). Binary logistic regression with sex, age, TSH, albumin, CRP, ferritin, and D-dimers as covariates showed that only albumin (p < 0.001) and TSH (p = 0.006) were significantly predictive of the outcome. Serum TSH below the optimal cut-off value of 0.5 mIU/L was associated with an odds ratio of 4.13 (95% C.I.: 1.41-12.05) for adverse outcome. Artificial neural network analysis showed that the prognostic importance of TSH was second only to that of albumin. However, the prognostic accuracy of low TSH was limited, with an AUC of 69.5%, compared to albumin's 86.9%. A Naïve Bayes classifier based on the combination of serum albumin and TSH levels achieved high prognostic accuracy (AUC 99.2%).

CONCLUSION

Low serum TSH is independently associated with adverse outcome in hospitalized Greek patients with COVID-19 but its prognostic utility is limited. The integration of serum TSH into machine learning classifiers in combination with other biomarkers enables outcome prediction with high accuracy.

Clinical observation of menopause hormone therapy in postmenopausal women with euthyroid and mild subclinical hypothyroidism

BACKGROUND

To evaluate the endocrine hormone and metabolic indices in postmenopausal women with euthyroid and mild subclinical hypothyroidism after menopause hormone therapy (MHT).

METHODS

A retrospective study of 587 postmenopausal women receiving MHT was conducted. Median (25-75th percentile) age was 52 (49-54) years. According to thyroid stimulating hormone (TSH) levels at initial diagnosis, the patients were divided into three groups: I (euthyroid with low normal TSH range, n = 460), II (euthyroid with upper normal TSH range, n = 106) and III (mild subclinical hypothyroidism, n = 21). After a continuous oral MHT regimen using the same estradiol potency for 6-18 month cycles, serum endocrine hormone and metabolic indices were reassessed.

RESULTS

Compared with baseline, serum TSH levels in groups I and II significantly changed but all values were within the normal range. No significant difference was observed in serum TSH levels in group III. After treatment, all serum free tri-iodothyronine and free thyroxine levels were within the normal range. Serum total cholesterol, triglyceride, fasting plasma glucose, fasting insulin levels and homeostasis model assessment of insulin resistance index had significantly decreased in group I. There were no significant differences in all observed lipid and glucose parameters in group III, before and after treatment.

CONCLUSION

MHT did not affect thyroid function in postmenopausal women with euthyroid and mild subclinical hypothyroidism. MHT led to an improvement in lipid and glucose indicators in euthyroid women with low normal TSH range.

Analytical Variation Between Two Different TSH Reagents from the Same Manufacturer

Thyroid stimulating hormone (TSH) immunoassays are known for giving varying results based on the platform of testing and the generation of kit used. It is generally expected that the results should not vary to affect clinical diagnosis and management. We aimed to perform method comparison study between two TSH assays by the same manufacturer Siemens Healthineers. Results show that there is a large proportional error between the assays with a bias of -3.71mIu/L indicating that TSH assay gives higher values for TSH for the same patient as measured against the TSH3-Ultra kit. This can affect interpretation of results leading to false increase in patients categorized under hypothyroidism and subclinical hypothyroidism. We strongly suggest, to prevent errors in clinical evaluation of a patient with thyroid dysfunction, validation of the performance of the assay and method comparison should be performed in-house.

Serum TSH, 25(OH) D and phosphorus levels predict weight loss in individuals with diabetes/prediabetes and morbid obesity: a single-center retrospective cohort analysis

BACKGROUND

To evaluate the association of vitamin D and thyroid-stimulating hormone (TSH) with weight loss (WL) percentage (%) in patients with diabetes/prediabetes and Class II/III obesity.

METHODS

A retrospective cohort study was designed. Data were collected from a database of a referral endocrinology clinic that is prospectively and systematically generated. After exclusion of unavailable cases, the study enrolled 285 patients (51 ± 11 years old, female/male = 208/77; diabetes/prediabetes = 159/126; no/on levothyroxine replacement = 176/109; Class II/III obesity = 184/101, respectively) who maintained euthyroidism and were followed up for ≥6 months. The data were analyzed to determine the predictors of WL%.

RESULTS

Compared with baseline, in the median 22 months of follow-up, the whole study group lost 5.1% of their baseline body weight. As most obesity management trials define success as 'at least 10% of WL compared to baseline', we stratified the patients based on WL% extents. The distribution was as follow: Group 1 (n = 61) lost ≥10% body weight, Group 2 (n = 162) lost < 10% body weight, while Group 3 (n = 62) gained weight by the final visit. In groups 1 and 2 (weight losers), the serum thyroid stimulatig hormone (TSH) and parathyroid hormone (PTH) levels decreased and the free thyroxine (fT4), calcium, phosphorus, and 25-hydroxyvitamin D (25(OH)D) levels increased. In Group 3 (weight gainers), these changes were not observed (except for an increase in calcium levels). Regression analysis revealed that the final visit TSH (β = - 0.14, p < 0.05), 25(OH) D (β = 0.15, p < 0.05), and phosphorus (β = 0.20, p < 0.05) levels predicted WL%. However, if patients with autoimmune thyroiditis were excluded from the analysis, the decrease in TSH levels was not statistically significant.

CONCLUSIONS

Serum TSH, phosphorus, and 25(OH) D levels predict WL% in euthyroid patients with diabetes/prediabetes and morbid obesity. TSH predictivity seems to be a function of thyroid autoimmunity present with increased frequency in this cohort. Greater levels of phosphorus within the reference range and a sufficient vitamin D status are associated with a greater WL%.

Thyroid stimulating hormone suppresses the expression and activity of cytosolic sulfotransferase 1a1 in thyrocytes

Sulfonation is an important step in the metabolism of dopamine, estrogens, dehydroepiandrosterone, as well as thyroid hormones. However, the regulation of cytosolic sulfotransferases in the thyroid is not well understood. In a DNA microarray analysis of rat thyroid FRTL-5 cells, we found that the mRNA expression of 10 of 48 sulfotransferases was significantly altered by thyroid stimulating hormone (TSH), with that of sulfotransferase family 1A member 1 (SULT1A1) being the most significantly affected. Real-time PCR and Western blot analyses revealed that TSH, forskolin and dibutyryl cyclic AMP significantly suppressed SULT1A1 mRNA and protein levels in a time- and concentration-dependent manner. Moreover, immunofluorescence staining of FRTL-5 cells showed that SULT1A1 is localized in the perinuclear area in the absence of TSH but is spread throughout the cytoplasm with reduced fluorescence intensity in the presence of TSH. Sulfotransferase activity in FRTL-5 cells, measured using 3'-phosphoadenosine-5'-phosphosulfate as a donner and p-nitrophenol as an acceptor substrate, was significantly reduced by TSH. These findings suggest that the expression and activity of SULT1A1 are modulated by TSH in thyrocytes.

Investigating Investigation (Ab)Use: Thyroid Function Test Audit in a Tertiary Care Teaching Institute in Eastern India

An essential component of contemporary health care is laboratory testing. As the utilization of diagnostic tests grow, there is also an increase in the scrutiny of such tests for its effectiveness, balance of cost and over- utilization. Thyroid dysfunction is common across all age groups and is associated with a number of comorbid states. The thyroid function tests (TFTs) are very important for the diagnosis and monitoring of such patients. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism, except in few cases. This study was conducted to study the investigation requesting pattern of TFTs. Our results showed that TFT panel was ordered in almost equal numbers (35.58%) as single test of TSH (41.27%). Subclinical thyroid disease was diagnosed in 22.1% of cases and the rest were excluded as having any thyroid dysfunction. Over 2/3rd of all requests were for women. An important conclusion from our study was that, the essentiality of lab tests is a decision entirely in the hands of the treating physician keeping in mind the cost and best outcome for patients. Hospitals can develop strategic protocols for ordering laboratory tests keeping resources, need and patient satisfaction and outcomes optimal.

The prevalence and clinical correlates of suicide attempts in comorbid subclinical hypothyroidism in patients with never-treated major depressive disorder in China

BACKGROUND

Previous studies have emphasized the possible association between subclinical hypothyroidism (SCH) and major depressive disorder (MDD). This study aimed to further investigate suicide attempts and their clinical correlates in MDD patients with comorbid SCH.

METHODS

This cross-sectional study recruited 1706 eligible MDD outpatients. The Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression of Severity Scale (CGI-S) were applied to evaluate mental status. Fasting blood samples were collected to examine thyroid function. SCH was defined as thyroid stimulating hormone (TSH) > 8 mIU/L with normal free thyroxine levels.

RESULTS

The prevalence of suicide attempts in the SCH group (51.7 %) was significantly higher than that in the non-SCH group (15.4 %; p < 0.001). Logistic regression showed that patients with comorbid SCH were 1.81 times more likely to have attempted suicide as compared with those without (p = 0.001). Among those with TSH > 8 mIU/L, patients with severe anxiety were 3.57 times more likely to attempt suicide compared with those without (p < 0.01). Logistic regression also showed that the CGI-S score (p < 0.001) was independently associated with suicide attempts, while TSH level was not.

CONCLUSIONS

SCH comorbidity may pose a specific hazard in MDD patients due to increased suicide attempts. Exhibiting severe anxiety, overall severity of depressive and psychotic symptoms, but not TSH levels, may be independently correlated with suicide attempts in MDD patients with TSH > 8 mIU/L.

Levothyroxine treatment for congenital hypothyroidism based on thyroid function: a 10-year clinical retrospective study

OBJECTIVE

To explore the appropriate dosage of levothyroxine treatment for congenital hypothyroidism patients with different thyroid stimulating hormone (TSH) levels.

METHODS

A total of 116 patients, who were regularly followed-up in our endocrine clinic from January 2010 to December 2020, were divided into four groups based on their thyroid function (group A: TSH ≥ 100 mIU/L, group B: TSH ≥ 20, and < 100, group C: TSH > 4.6 mIU/L and < 20 mIU/L with free thyroxine (FT4) < 6.6 pmol/L, and group D: TSH > 4.6 mIU/L and < 20 mIU/L with FT4 > 6.6 pmol/L). The initial dosage of levothyroxine was individualized for each patient based on their TSH level and then adjusted according to their thyroid function at every follow-up time point. The levothyroxine dosage at each time point was compared between the groups, and thyroid function and physical and neurological development after treatment were also compared.

RESULTS

After individualized dosage adjustment, all patients achieved normal thyroid function. Although there were statistical differences in neurological development between the four groups (p < 0.05), development was within the normal range for all groups.

CONCLUSION

An individualized levothyroxine dosage can provide the same therapeutic effect compared to the recommended dosage. This strategy may also reduce the risk of a drug overdose.

Adherence to treatment for hypothyroidism in pregnancy and relationship with thyrotropin control: a retrospective observational cohort study

Background

Hypothyroidism is the second most common endocrinological disease during pregnancy, with percentages that can range between 3.2 and 5.5%. A good maternal and foetal health outcome depends on thyroid hormone replacement therapy. The goal of such therapy is to maintain thyrotropin (TSH) in a range that is specific for pregnant women and varies between the trimesters of pregnancy. In our study, we wanted to analyse the adherence to hypothyroidism treatment among pregnant women and to evaluate the degree of control of the disease.

Methods

We performed a retrospective observational cohort study in pregnant women between 2012 and 2018 in the Lleida health region. Therapeutic adherence was analysed by the proportion of days covered (PDC). The relationship with other variables was assessed using the regression coefficients and their 95% confidence interval (CI).

Results

We examined a sample of 17,281 women, representing more than 92% of the pregnant women in the Lleida health region in the period analysed. Among this sample, the mean prevalence of hypothyroidism was 6.52% (0.07% clinical and 6.45% subclinical). 3.3% of the 17,281 pregnant women were treated. Among them, the mean adherence score was 79.6 ± 22.2. Of these, 54% presented high adherence. The latter had a higher mean age and better TSH control, in comparison to the ones showing low adherence.

Conclusions

Half of the treated patients had good adherence to treatment and a better TSH control, in comparison to the others. Most of them achieved a good control at the third trimester of pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04483-8.

Perfluoroalkyl substances and thyroid stimulating hormone levels in a highly exposed population in the Veneto Region

BACKGROUND

Per- and poly-fluoroalkyl substances (PFAS) are persistent and widespread environmental pollutants. People living in Veneto Region (Italy) have been exposed from the late 1970s to 2013 to elevated concentrations of PFAS through drinking water. The effect of PFAS on thyroid function is still controversial and studies focusing on thyroid stimulating hormone (TSH) have shown inconsistent results. The aim of this study was to evaluate the association between serum PFAS and TSH levels and its dose-response relationship in a large population of highly exposed individuals.

METHODS

A cross-sectional study was conducted on 21,424 individuals aged 14-39 living in the contaminated area. In the main analysis, participants with prevalent thyroid disease and pregnant women were excluded. Serum levels of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) were measured. Generalized Additive Models were used to evaluate the association between TSH levels and serum PFAS, using thin plate spline smooth terms to model the potential non-linear relationship. Models were stratified by sex and age group and adjusted for potential confounders. A secondary analysis was conducted to evaluate the association between PFAS with prevalent self-reported thyroid disorders.

RESULTS

We found no association between TSH and any type of PFAS among adolescents or women. A decrease in TSH concentration was observed in association with an IQR increase in PFHxS and a mild decrease in TSH at low levels of PFOA, PFOS and PFHxS among male adults. Self-reported thyroid disease was more common among women with higher levels of PFNA concentrations, whereas all other PFAS were not associated with thyroid diseases regardless of sex or age.

CONCLUSIONS

Overall there is no evidence of an association between TSH and PFAS. However, some results are suggestive of a possible inverse association of TSH with PFOA, PFOS and PFHxS among adult males.

Characterization of ambient carbon monoxide and PM 2.5 effects on fetus development, liver enzymes and TSH in Isfahan City, central Iran

Ambient carbon monoxide (CO) and particulate matters (PMs) are two important air pollutants in urban areas with known impacts on fetuses. Hence, this study measured some biochemistry factors of 200 neonates with birth dates from January 19 to October 12, 2020, including the birth weight and height and the serum levels of ALT, AST, ALP, GGT, and TSH. The Support Vector Machine-fitted land-use regression approach was used to predict the spatio-temporal variability of intra-urban PM 2.5 and CO concentrations by month during the pregnancy period of the cases employing 5 variables of Digital Elevation Model (DEM), slope, and distance from Compressed Natural Gas (CNG) stations, Bus Rapid Transit (BRT) stations, and mines and industries. Spearman correlation analysis (p < 0.05) was performed between the neonate indices and mean monthly PM 2.5 and CO concentrations at the exact residential address of maternal cases and their nearby areas in 250, 500, 1000, 1500, and 2000 m-radius buffer rings. All modeling efforts succeeded in predicting CO and PM 2.5 levels with acceptable adjusted r² values. Northern Isfahan had relatively higher CO and PM 2.5 concentrations due to its adjacency to low-vegetated open lands and its high traffic load as compared to southern areas. The correlation results between the neonate biochemistry indices and mean PM 2.5 and CO concentrations were mostly positive in most buffer rings, especially in the >500 m-radius buffer rings for PM 2.5 and in the 2000 m-radius rings for CO. Although the correlation results of PM 2.5 followed a detectable trend in the buffer rings, the associations between CO and the neonate biochemistry indices differed significantly between the buffer rings. Results showed that increasing mean monthly concentration of CO and PM 2.5 may stimulate further production of liver enzymes while decreasing the birth weight and height.

Thyroid hormones in relation to toxic metal exposure in pregnancy, and potential interactions with iodine and selenium

BACKGROUND

Several endocrine-disrupting metals may affect thyroid function, but the few available studies of exposure during pregnancy and thyroid hormones are inconclusive.

OBJECTIVE

To explore if environmental exposure to cadmium (Cd), lead (Pb), and methylmercury (MeHg) impacts thyroid function in pregnancy, and interacts with iodine and selenium status.

METHODS

Women in a Swedish birth cohort provided blood and urine samples in early third trimester. Concentrations of erythrocyte Cd, Pb, and Hg (n = 544), urinary Cd and iodine (n = 542) and plasma selenium (n = 548) were measured using inductively coupled plasma-mass spectrometry.Free and total thyroxine (fT4, tT4) and triiodothyronine (fT3, tT3), and thyroid stimulating hormone (TSH), were measured in plasma (n = 548) with electrochemiluminescence immunoassays. Metal-hormone associations were assessed in regression models, and metal mixture effects and metal-nutrient interactions were explored in Bayesian kernel machine regression (BKMR).

RESULTS

In multivariable-adjusted regression models, a doubling of urinary Cd was associated with a mean increase in tT4 of 2.7 nmol/L (95% CI: 0.78, 4.6), and in fT3 and tT3 of 0.06 pmol/L (0.02, 0.10) and 0.09 nmol/L (0.05, 0.13), respectively. A doubling of urinary Cd was associated with a -0.002 (-0.003, -0.001) and -0.03 (-0.05, -0.02) decrease in the fT4:tT4 and fT3:tT3 ratio, respectively. A doubling of erythrocyte Hg (>1 µg/kg) was associated with a decrease in fT3 and tT3 by -0.11 pmol/L (-0.16, -0.05) and -0.11 nmol/L (-0.16, -0.06), respectively, and a -0.013 (-0.02, -0.01) decrease in the fT3:fT4 ratio. BKMR did not indicate any mixture effect of toxic metals or interactions between metals and iodine or selenium in relation to the hormones.

CONCLUSION

Our findings suggest that exposure to Cd and Hg, at levels globally prevalent through the diet, may affect thyroid function during pregnancy, independently of iodine and selenium levels. Further studies on potential implications for maternal and child health are warranted.

Thyroid stimulating hormone levels and geriatric syndromes: secondary nested case-control study of the Mexican Health and Aging Study

PURPOSE

To determine the incidence of geriatric syndromes (GS) in community dwelling older adults with subclinical hypothyroidism.

METHODS

This is an analysis from the Mexican Health and Aging Study, of a subsample of 2089 subjects with TSH determination. From this last subsample, we included 1628 individuals with TSH levels in the subclinical range (4.5-10 µU/ml).

RESULTS

The multivariate analysis showed that when comparing data obtained from the 2012 wave with the 2015 wave results, there was a significant incidence of some GS such as falls (OR 1.79, CI 1.16-2.77, p = 0.0116), fatigue (OR 2.17, CI 1.40-3.38, p = 0.0348) and depression (OR 1.70, CI 1.06-2.71, p = 0.0246) among the subclinical hypothyroidism group.

CONCLUSION

This study showed a greater incidence of GS in subjects 50 years and older with sub-clinical hypothyroidism, when compared to those with normal thyroid function.

Assessment of thyroid function in the preterm and/or very low birth weight newborn

The screening program or early detection of congenital hypothyroidism is one of the greatest advances achieved in Pediatrics. Thyroid hormones are essential for brain development and maturation, which continue into the neonatal stage. Alterations in thyroid function in premature and underweight children in the first months of life causes irreversible damage to the central nervous system and is one of the most frequent and avoidable causes of mental retardation. Diagnosis in the neonatal period is difficult, so it requires an analytical study to be able to carry out the appropriate treatment. The relevance of this problem justifies its communication to all areas of pediatrics. The main objective is to avoid brain damage in these patients. Other aspects to optimize the adequate development of these children with all the necessary periodic controls and to achieve the inclusion of the diagnosis of thyroid alterations during the stay in neonatal units and in the first months of life, need to implement the resources of the health centers and continue advancing according to current knowledge. In this document, we will focus on the screening of preterm newborns VLBW (<32 weeks of gestation) and/or very low weight for gestational age (1500-1000 g VLBW or <1000 g) and the function evaluation protocol thyroid in premature babies. We update the diagnostic procedures, the essential and complementary tests required, the etiology and the differential diagnoses in this pathology.

Interpretative commenting in clinical chemistry with worked examples for thyroid function test reports

Correct interpretation of pathology results is a requirement for accurate diagnosis and appropriate patient management. Clinical Pathologists and Scientists are increasingly focusing on providing quality interpretative comments on their reports and these comments are appreciated by clinicians who receive them. Interpretative comments may improve patient outcomes by helping reduce errors in application of the results in patient management. Thyroid function test (TFT) results are one of the areas in clinical chemistry where interpretative commenting is practised by clinical laboratories. We have provided a series of TFT reports together with possible interpretative comments and a brief explanation of the comments. It is felt that this would be of help in setting up an interpretative service for TFTs and also assist in training and continuing education in their provision.

Establishing reference interval for thyroid-stimulating hormone in children below two-year ages in Pakistani population

Introduction

Reference intervals (RIs) of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) are age, assay and population specific. Currently, the age and assay-specific RIs for TSH are not available for children under two years of age. This study aimed to establish reference intervals for serum concentrations of TSH and FT4 in healthy children aged 1–24 months as per CLSI C28-A3 guidelines.

Methods

This prospective cross-sectional study was conducted in children from 1 to 24 months visiting the clinical laboratory for serum vitamin D testing but without any recent illness, hospitalization, medication and history of maternal thyroid diseases from August 2018 to March 2019 were invited to participate in the study.

Serum TSH and FT4 were measured on ADVIA Centaur (Siemens Diagnostics, US), using chemiluminescence immunoassay. Kolmogorov–Smirnov test assessed normality of the data and RIs based on central 95% of the population were established using the non-parametric approach.

Results

After excluding one subject with confirmed congenital hypothyroidism, a total of 131 children were included in the study. The median (IQR) age of the study subjects was 12 months (11), and majority 78 (59.5%) were boys. The RIs were established using non-parametric approach as the data was not normally distributed. Reference interval for TSH was 0.73–4.94 μIU/mL and for FT4 was 0.81–1.51 ng/dl.

Conclusion

We established assay-specific RIs for serum TSH and FT4 in children aged 1–24 months in our population. The RIs were slightly lower from RIs developed on other platforms in different population.

•

Reference intervals (RIs) of TSH and FT4 are age, assay and population specific.

•

RIs of TSH & FT4 for <2 yrs Pakistani children on Advia Centaur analyzer not available.

•

The RIs for TSH (0.73–4.94μIU/mL) and FT4 (0.81–1.51 ng/dl) for < 2 yrs old children.

The Joint Role of Iodine Status and Thyroid Function on Risk for Preeclampsia in Finnish Women: a Population-Based Nested Case-Control Study

Preeclampsia, a pregnancy disorder that includes hypertension and proteinuria, is a major cause of maternal and fetal morbidity and mortality. Some studies, but not all, have found that women with preeclampsia have significantly lower iodine levels than healthy pregnant women. Resolving this issue is important because iodine deficiency in pregnancy is common in the USA and parts of Europe including Finland. We conducted a nested case-control study to determine whether the risk for preeclampsia is associated with iodine status. We measured serum iodine, thyroglobulin (Tg), and thyroid stimulating hormone (TSH) at 10-14 weeks gestational age in 204 women with preeclampsia and 246 unaffected controls selected from all births in Finland. We found no significant difference in iodine (case mean = 26.04 ng/mL, control mean = 27.88 ng/mL, p = 0.995), Tg (case mean = 31.11 ng/mL, control mean = 29.61 ng/mL, p = 0.996), and TSH (case mean = 1.30 mIU/L, control mean = 1.24 mIU/L, p = 0.896) levels between cases and controls. There was no significant relationship between preeclampsia risk and iodine, Tg, or TSH after adjustment for known risk factors. These results are reassuring given the high prevalence of iodine deficiency in pregnancy.

[Assessment of thyroid function in the preterm and/or very low birth weight newborn]

The screening program or early detection of congenital hypothyroidism is one of the greatest advances achieved in Pediatrics. Thyroid hormones are essential for brain development and maturation, which continue into the neonatal stage. Alterations in thyroid function in premature and underweight children in the first months of life causes irreversible damage to the central nervous system and is one of the most frequent and avoidable causes of mental retardation. Diagnosis in the neonatal period is difficult, so it requires an analytical study to be able to carry out the appropriate treatment. The relevance of this problem justifies its communication to all areas of pediatrics. The main objective is to avoid brain damage in these patients. Other aspects to optimize the adequate development of these children with all the necessary periodic controls and to achieve the inclusion of the diagnosis of thyroid alterations during the stay in neonatal units and in the first months of life, need to implement the resources of the health centers and continue advancing according to current knowledge. In this document, we will focus on the screening of preterm newborns VLBW (<32 weeks of gestation) and/or very low weight for gestational age (1500-1000g VLBW or <1000g) and the function evaluation protocol thyroid in premature babies. We update the diagnostic procedures, the essential and complementary tests required, the etiology and the differential diagnoses in this pathology.

Prevalence and risk factors of overweight and obesity in Chinese patients with first-episode drug-naïve major depressive disorder

BACKGROUNDS

Obesity and overweight are common in patients with major depressive disorder (MDD); the results are inconsistent due to confounding variables involved in studies. Furthermore, no well-designed study has been published to investigate the prevalence, risk factors and underlying mechanisms of obesity/overweight in Chinese MDD patients. This study aimed to investigate the prevalence of obesity/overweight and related risk factors in first-episode, drug-naïve (FEDN) patients with MDD in China.

METHODS

A total of 1718 patients were recruited. Their clinical and anthropometric data, thyroid function and biochemical parameters were collected. All patients were evaluated on the 17-item Hamilton Rating Scale for Depression, 14-item Hamilton Anxiety Rating Scale and the Positive and Negative Syndrome Scale.

RESULTS

The prevalence of obesity and overweight was 3.73% and 56.00%, respectively. Multivariable logistic regression analysis showed that TSH was the only independent risk factor for weight gain in MDD patents. The fitting curve of the relationship between TSH and BMI formed an inverted U-shaped parabola. The ordinal logit mode showed that when TSH<=2.68 was set as a reference, the odd rates of weight increased with the increase of TSH, and the highest rate was 3.929 (95%CI: 2.879-5.361, P<0.0001).

LIMITATION

Causality cannot be drawn due to cross-sectional design.

CONCLUSION

Our results suggest that overweight is very common among patients with FEDN MDD rather than obesity. TSH is a promising predictor and potential biomarker of high weight in MDD patients, and there is an inverted U-shaped parabolic relationship between TSH and BMI.

Implementing reference systems for thyroid function tests - A collaborative effort

Measurements of thyroid stimulating hormone (TSH) and free thyroxine (fT4) are critical for the early detection of thyroid diseases and for monitoring treatment. The IFCC Committee for Standardization of Thyroid Function Tests (C-STFT) established reference systems for TSH harmonization and FT4 standardization, and is now working national partners on implementing these reference systems. These implementation activities include the maintenance of the reference systems, their use to standardize and harmonize assays, and educational activities to inform stakeholders about anticipated changes in measurement values as a result of standardization and harmonization. The IFCC C-STFT formed a network of reference laboratories for FT4 and is creating a new harmonization panel for TSH. The U.S. Centers for Disease Control and Prevention is a member of the reference laboratory network and is launching a formal standardization program for FT4. In Japan, national organizations successfully implemented TSH harmonization and established harmonized reference intervals for TSH. The C-STFT made available on its website research findings about potential concerns, communication needs and benefits of FT4 standardization and is assisting local organizations with communicating changes related to these standardization and harmonization efforts. Implementation of fT4 standardization and TSH harmonization is a complex, continuous task that requires collaboration with IVD manufacturers, laboratories, physicians and health care providers. C-STFT is working successfully with national organizations and local groups on improving FT4 and TSH measurements.

Primary thyroid dysfunction after single intravenous iodinated contrast exposure in young children: a propensity score matched analysis

BACKGROUND

Data suggest an increased risk of thyroid dysfunction following iodine-based contrast material (IBCM) in children.

OBJECTIVE

To estimate the prevalence of thyroid stimulating hormone (TSH) abnormalities following exposure to a single dose of intravenous IBCM during computed tomography (CT) in young children.

MATERIALS AND METHODS

Inpatients ≤24 months of age who underwent a single CT with intravenous IBCM (exposed cohort) or abdominal ultrasound (US) (unexposed cohort) examination and had a TSH value obtained within 90 days after imaging between January 2009 to November 2018 were identified. Propensity score matching with 20 variables was performed. Primary thyroid dysfunction was defined by abnormally high or low TSH value. Multivariable logistic regression identified risk factors, including intravenous IBCM, for thyroid dysfunction.

RESULTS

From the eligible 4,215 imaging examinations, 114 unique patients were included in the propensity matched population (n=57 per group). Thyroid dysfunction was identified in 14% (8/57) and 7% (4/57) of the IBCM-exposed and IBCM-unexposed cohorts, respectively. No patient in either cohort was started on thyroid hormone supplementation within the 3 months after imaging. Intravenous IBCM exposure was not a significant predictor of thyroid dysfunction on univariable (odds ratio [OR]=2.16, 95% confidence interval [CI]=0.61-7.64, P=0.23) or multivariable (OR=2.61, 95% CI=0.65-10.55, P=0.18) analyses. Significant independent predictors of post-imaging thyroid dysfunction included height (OR=1.25, P=0.0095) and trisomy 21 (OR=4.04, P=0.019).

CONCLUSION

Hospitalized children ≤24 months of age who received a single dose of intravenous IBCM for CT examination had a similar prevalence of TSH abnormalities compared to a propensity score matched group who underwent abdominal US. One dose of intravenous IBCM likely does not cause prolonged TSH abnormalities; however, larger studies are needed.

Thyroid Hormones within the Normal Range and Cardiac Function in the General Population: The EPIPorto Study

BACKGROUND

Hypothyroidism and hyperthyroidism are associated with marked changes in cardiac structure and function. However, the association of thyroid function within the normal range with cardiac structure and function in the general population remains uncertain.

METHODS

Eight hundred thirty-five subjects aged ≥45 years from the EPIPorto cohort (evaluation between 2006 and 2008) were cross-sectionally analyzed. We excluded participants with TSH, free T4 (FT4), or free T3 (FT3) outside of the reference range or with self-reported cardiovascular or thyroid disease. Cardiac structure and function were evaluated by echocardiography. We used linear regression models unadjusted and adjusted for sex and age (model 1), and sex, age, BMI, diabetes, hypertension, and smoking (model 2). Nonlinear associations were assessed using restricted cubic splines.

RESULTS

The mean age was 61.5 years (SD 10.5); 61.1% of the patients were women. In the adjusted model 2, heart rate was positively associated with FT3; diastolic blood pressure was positively associated with TSH; LV end-diastolic and end-systolic volumes were inversely associated with TSH, and ejection fraction was nonlinearly associated with FT3, with higher ejection fractions near the limits of the reference range. Left ventricle (LV) posterior wall thickness was nonlinearly associated with FT4 in the adjusted model 1, with a greater thickness near the limits of the reference range. Regarding diastolic function, no significant associations were observed in adjusted models.

CONCLUSIONS

Thyroid function within the reference range was associated with heart rate, blood pressure, cardiac structure, and function. Increasing thyroid function (lower TSH, higher FT4, or higher FT3) was associated with a higher heart rate, a lower diastolic blood pressure, and larger LV volumes. LV wall thickness and ejection fraction had a U-shaped association with thyroid hormones.

Thyroid hormone status in patients with impaired kidney function

PURPOSE

We aimed to investigate the prevalence of thyroid hormone abnormalities and the relationship between free triiodothyronine (fT3), thyroid stimulating hormone (TSH) and free thyroxine (fT4) serum levels with kidney function and proteinuria in 4108 subsequent patients admitted to a Nephrology Clinic at a tertiary Medical Centre.

METHODS

All patients were categorized based on their estimated glomerular filtration rate (eGFR) as follows: normal-eGFR ≥ 60 ml/min, mild kidney impairment-30 ≤ eGFR < 60 ml/min, and severe kidney impairment-eGFR < 30 ml/min.

RESULTS

Subjects with normal eGFR presented a laboratory constellation of hypothyroidism in 3.38% and "low-T3 syndrome" in 8.28%, while subjects with severe kidney impairment were diagnosed with hypothyroidism in 2.82% and "low-T3 syndrome" in 22.9%. Multivariate regression analysis showed that eGFR was a strong independent predictor of serum fT3 levels in patients with eGFR < 60 ml/min. Impaired kidney function was associated with low fT4 and fT3 but not TSH. Our findings showed an inverse correlation of fT3 and fT4 levels and proteinuria range. FT4 inversely correlated with the extent of proteinuria in all subgroups of patients. In contrast, the inverse correlation of fT3 serum levels and proteinuria disappeared in patients with eGFR < 60 ml/min.

CONCLUSION

In a large cohort of inpatients, the prevalence of low-T3 syndrome was 2.5 times higher in patients with advanced kidney disease, compared to those with normal kidney function. In advanced CKD, both eGFR and proteinuria were strongly correlated with thyroid hormones. Therefore, close screening of the "thyroid profile" in patients with any stage of CKD, especially to those with proteinuria, might be warranted.

Lower normal free thyroxine is associated with a higher risk of metabolic syndrome: a retrospective cohort on Chinese population

BACKGROUND

Recently, the relationship between thyroid hormones (THs) across the euthyroid ranges and metabolic syndrome (MetS) has been widely discussed. This study aimed to present specific cutoff values of THs to assess the association between THs and MetS in a euthyroid cohort.

METHODS

Data of 2694 subjects, aged 18-80 years, who attended health examination in Xi'an Electric Power Central Hospital from April 2011 to December 2015 were collected and analyzed. The first cohort enrolled 929 participants (followed up by 2221 person-years totally) to assess correlations between serum thyrotropin (TSH), triiodothyronine (T3), thyroxine (T4) levels and MetS. The second cohort included 698 participants (followed up by 1709 person-years totally) to evaluate relationships between serum free triiodothyronine (FT3), free thyroxine (FT4) levels and MetS. MetS was defined according to the criteria of the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) scientific statements of 2009. Euthyroidism was defined as serum TSH, FT3 and FT4 levels within the reference ranges without taking any thyroid medication.

RESULTS

The cutoff values for TSH, T3, T4, FT3 and FT4 were 2.0mIU/L, 1.9 nmol/L, 117 nmol/L, 4.3 pmol/L and 16 pmol/L, respectively. Participants were categorized into two groups according to cutoff values: the lower-THs group and the higher-THs group. There was no significant difference in the risk of MetS between two groups in TSH, T3, T4 and FT3. The incidence of MetS was significantly higher in lower-FT4 group than higher-FT4 group (1.00 vs 0.622 (0.458, 0.846), P = 0.002). The lower-FT4/higher-TSH group had the highest hazard ratios of MetS. (2.131vs 1.0 (1.380,3.291), P = 0.006).

CONCLUSIONS

Lower normal FT4 (FT4 ≤ 16.0 pmol/L) is an independent risk factor for MetS, and lower normal thyroid function (TSH > 2.0 mIU/L and FT4 ≤ 16.0 pmol/L) is associated with a higher risk of developing MetS.

Serum thyroid stimulating hormone level for predicting utility of thyroid uptake and scan

BACKGROUND

Thyroid uptake and scan (TUS) is a clinical tool used for differentiation of thyrotoxicosis etiologies. Although guidelines recommend ordering a TUS for evaluation of low TSH levels, no specific value is defined. This study aimed to determine a TSH cutoff at which TUSs yield a greater likelihood of successful determination of etiology to avoid unnecessary testing.

METHODS

This was a retrospective study on 137 patients seen by an endocrinologist who underwent TUS for evaluation of low TSH (<0.4 μU/mL). A receiver operating curve analysis was performed to determine the TSH cutoff with maximal sensitivity and specificity for prediction of diagnostic utility.

RESULTS

Ninety percent of TUSs (n = 123) led to a diagnosis, while 10% (n = 14) were inconclusive or normal. Diagnoses included Graves' diseases (52%), toxic multinodular goiter (19%), thyroiditis (12%), and solitary toxic adenoma (7%). The median TSH value was 0.008 μU/mL (IQR 0.005, 0.011), and the median free T4 value was 1.7 μU/mL (IQR 1.3, 2.8). The ROC analysis produced an area under the curve of 0.86. The optimal TSH cutoff value was 0.02 μU/mL (sensitivity 80%, specificity 93%) for prediction of diagnostic yield.

CONCLUSION

This study demonstrates that TSH is a useful predictor of the utility of TUS in yielding an etiology of thyrotoxicosis. Our analysis showed that TUS had a greater likelihood of determining an etiology when TSH was ≤0.02 μU/mL. This information can help clinicians avoid unnecessary cost and patient time burden when TUS is unlikely to aid in determining the etiology of thyrotoxicosis.

Photoperiodic regulation of pituitary thyroid-stimulating hormone and brain deiodinase in Atlantic salmon

Seasonal timing is important for many critical life history events of vertebrates, and photoperiod is often used as a reliable seasonal cue. In mammals and birds, it has been established that a photoperiod-driven seasonal clock resides in the brain and pituitary, and is driven by increased levels of pituitary thyroid stimulating hormone (TSH) and brain type 2 iodothyronine deiodinase (DIO2), which leads to local increases in triiodothyronine (T₃). In order to determine if a similar mechanism occurs in fish, we conducted photoperiod manipulations in anadromous (migratory) Atlantic salmon (Salmo salar) that use photoperiod to time the preparatory development of salinity tolerance which accompanies downstream migration in spring. Changing daylength from short days (light:dark (LD) 10:14) to long days (LD 16:8) for 20 days increased gill Na⁺/K⁺-ATPase (NKA) activity, gill NKAα1b abundance and plasma growth hormone (GH) levels that normally accompany increased salinity tolerance of salmon in spring. Long-day exposure resulted in five-fold increases in pituitary tshβb mRNA levels after 10 days and were sustained for at least 20 days. tshβb mRNA levels in the saccus vasculosus were low and not influenced by photoperiod. Increased daylength resulted in significant increases in dio2b mRNA levels in the hypothalamus and midbrain/optic tectum regions of the brain. The results are consistent with the presence of a photoperiod-driven seasonal clock in fish which involves pituitary TSH, brain DIO2 and the subsequent production of T₃, supporting the hypothesis that this is a common feature of photoperiodic regulation of seasonality in vertebrates.

Prenatal Maternal Low Selenium, High Thyrotropin, and Low Birth Weights

In consideration of the potential roles of selenoproteins in thyroid function, we aimed to evaluate the association of low selenium status with hypothyroidism during pregnancy and the association of maternal low thyroid function with infant birth size. We conducted a prospective birth cohort study in Shanghai in 2010 and investigated 1931 pregnant mothers of gestational weeks 28-36. Maternal serum selenium and thyrotropin (TSH) levels were determined and birth weights and lengths of newborns were measured. Other covariates were obtained through maternal interviews and medical records. A non-linear association was observed between maternal selenium and TSH levels. Two-piecewise multivariable linear regression models were therefore applied to assess the association of serum selenium with TSH levels, and multivariable linear regression models were applied to assess the association of TSH levels with birth weight/length. Adjusting for potential confounders, when maternal serum selenium levels < 103.7 μg/L (P25th), each unit increase in selenium levels (μg/L) was significantly associated with a decrease of 0.014 μIU/mL in TSH levels (β = - 0.014, 95%CI - 0.025, - 0.002, P = 0.023). However, when selenium levels ≥ 103.7 μg/L, there were no significant relationships between selenium and TSH (β = 0.000, 95%CI - 0.001, 0.002, P = 0.859). Maternal TSH levels were significantly inversely associated with infant birth weight (β = - 0.060, 95%CI - 0.100, - 0.010, P = 0.010). We observed a non-linear association between maternal selenium status and TSH levels. Low selenium status during pregnancy may associate with low thyroid function that was related with low birth weights. Graphical abstract .

Heterophilic antibody interference with TSH measurement on different immunoassay platforms

INTRODUCTION

Interference due to the presence of heterophilic antibodies may lead to falsely low or high analyte concentrations, but falsely elevated values are more common in most immunoassay platforms. We report a case of a 53-y old female patient underwent radical thyroidectomy for thyroid papillary carcinoma and the results of TSH in the Siemens Advia Centaur XP after surgery were not suppressed, ranging from 5.73 and 6.61 μIU/ml.

METHODS

The status of the thyroid was then assessed using 4 assay platforms from Siemens, Abbott, Roche and Beckman.

RESULTS

The results of TSH were 5.52, 0.54, 0.12, and <0.015 μIU/ml, respectively. After the samples were pretreated with the heterophilic antibody blocker, results given by Siemens, Abbott, and Roche showed significant decreases of 0.003, 0.001, and 0.005 μIU/ml, respectively. Therefore, it was confirmed that the presence of heterophilic antibodies in the patient samples interfered with the TSH measurements in multiple assay systems.

CONCLUSIONS

Clinicians must be aware of the possible assay interference, including the measurements of FT4, FT3 and TSH, results may be misleading in the presence of heterophilic antibodies, in particular when the results of thyroid function tests do not fit the patient clinical presentation.

Epidemiology of metabolic syndrome and its components in Chinese patients with a range of thyroid-stimulating hormone concentrations

Objective

To investigate the relationship between thyroid stimulating hormone (TSH) concentration and the risks of developing metabolic syndrome and its components.

Methods

A total of 10,140 residents of the Yunyan district of Guiyang (Guizhou, China) who were ≥40 years old were selected by cluster random sampling between May and August 2011, of whom 5692 were eligible. TSH concentration and indices of metabolic syndrome were documented at baseline and 3 years later. Participants were allocated to a euthyroid (TSH 0.55–4.78 mIU/L) or high TSH concentration (TSH >4.78 mIU/L) group. Patients with overt hypothyroidism or were undergoing treatment for hypothyroidism were excluded.

Results

The crude and adjusted prevalences of metabolic syndrome were 39.9% and 33.9% in the euthyroid group and 44.3% and 37.5% in the high TSH group, respectively. Binary logistic regression analysis revealed a positive correlation between a high TSH concentration at baseline and the cumulative incidence of metabolic syndrome during follow up.

Conclusions

High TSH is associated with a higher risk of developing metabolic syndrome or one of its components; therefore, people with a high TSH concentration should be screened regularly to permit the early identification of metabolic syndrome and followed up thoroughly.

Body mass index (BMI) is associated with serum thyroid-stimulating hormone (TSH) level in infertile women: a cross-sectional study

Studies suggest that there is a relationship between body mass index (BMI) and thyroid-stimulating hormone (TSH) levels. But conflicting evidence exists regarding the relationship between the two variables. Moreover, thyroid function is closely related to female fertility and has certain effects on infertility. Therefore, the present study will explore the relationship between BMI and TSH levels in patients with infertility in our center. We retrospectively analyzed relevant indicators of 2,789 in Tubal Factor Infertility patients undergoing assisted reproduction technology from January 2016 to December 2018 in our center in order to analyze the relationship between BMI and serum TSH level. The medical histories of patients were reviewed. The relationship between BMI and TSH was assessed using smooth curve fitting and multivariate regression model. The smoothing curve fitting between BMI and TSH exhibited a non-linear relationship, and the resulting curve exhibited a two-stage change and a breakpoint. By multivariate piecewise linear regression, we found that the TSH level was increased with the increase of BMI when the BMI was greater than 25.3 kg/m² (β 0.06, 95% CI 0.02, 0.01; p = 0.0028). In contrast, the TSH level was decreased with the increase of BMI when the BMI was less than 25.3 kg/m² (β -0.02, 95% CI -0.05, 0.00; p = 0.0573). Collectively, our study described a non-linear relationship between BMI and TSH level in infertile patients after adjustment of potential confounders. However, such causal relationship between BMI and TSH in infertile women still needs to be further clarified in future investigations.

Study on the changes in TSH, TPO-Ab and other indicators due to Vitamin D deficiency in Pregnant Women with subclinical hypothyroidism in the first trimester

Objective:

To investigate the effect of vitamin D deficiency on the levels of thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPO-Ab), interleukin-1 (IL-1) and high-sensitivity C-reactive protein (hs-CRP) in pregnant women with early pregnancy complicated by subclinical hypothyroidism.

Methods:

A total of 172 pregnant women with subclinical hypothyroidism in the first trimester diagnosed and treated in a given hospital from August 2014 to May 2018 were selected, and their levels of vitamin D were determined. Depending on the abnormality of their vitamin D levels, the study participants were divided into two groups: the study group (vitamin D≤20 ng/L) and the control group (vitamin D>20 ng/L). The levels of TSH, TPO-Ab, IL-1 and hsCRP in the two groups were measured.

Results:

The levels of TSH, hsCRP and TPO-Ab in the study group were significantly higher than those in the control group (P<0.05). The comparison between the two groups in terms of IL-1 showed no statistically significant difference.

Conclusion:

Vitamin D deficiency in the first trimester is associated with in an increased level of TSH in the first trimester, thereby aggravating subclinical hypothyroidism. The mechanism may be associated with the impact of vitamin D deficiency on hs-CRP and other body inflammation indicators, as well as on thyroid autoantibodies and other immune indicators, but has no effect on IL-1 levels.

Thyroid Hormone Tests Ordering Practice and Cost-Effectiveness in Samples Referred to International Clinical Laboratories from Addis Ababa Health Facilities

Background

Thyroid dysfunction accounts for majority of endocrine disorders. In sub-Saharan Africa Graves' disease and hypothyroidism have accounted for 13.1% and 8.8% while the burden of thyroid disorder has ranged from 6.18 to47.34% among countries in the Arab world. The cost for a primary thyroid test done to evaluate the gland function constituted a large proportion of the public health budget. For instance, 10 million thyroid functions have been done each year by laboratories which cost 30 million UK pounds, and they represent 8% of laboratory charge in the US. When a TSH-only protocol (guideline) was used, 95% of the requests were sufficient for diagnosis without requiring further tests, thereby resulting in 50% savings on FT4 reagent and reducing the annual TFT reagent cost by 25%. This is an original study, and its objective was to assess the ordering pattern of TSH tests and their cost-effectiveness in patients' samples referred to ICL from Addis Ababa health facilities between July2015 to June 2016.

Method

An institution-based cross-sectional study design was utilized to study the ordering pattern of thyroid function tests using one-year retrospective data from ICL.

Results

Thyroid profiles were ordered more frequently (49.5%) compared to TSH only (24.3%). An additional 2625.70 USD was paid by patients for individual components in the profile tests that turned out normal.

Conclusion

Guidelines advocate TSH as the initial test for thyroid dysfunction, but the use of a combination of tests is more common.

Identifying a critical window of maternal metal exposure for maternal and neonatal thyroid function in China: A cohort study

BACKGROUND

China, a developing country, has a particularly serious problem with metal pollution. We evaluated the association of metal exposure during pregnancy with maternal and neonatal thyroid function, and identified the critical window for maternal metal exposure effects on maternal and neonatal thyroid functions.

METHODS

The maternal urinary concentrations of mercury (Hg), cadmium (Cd), arsenic (As) and cesium (Cs) were determined in pregnant women during their first (n = 389) or third (n = 257) trimesters in a prospective cohort from 2014 to 2015 in Nanjing, China, using an inductively coupled plasma mass spectrometry (ICP-MS) instrument. Maternal serum-free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured by electrochemiluminescent microparticle immunoassays in the second and third trimesters. Neonatal TSH levels were detected 72 h after birth.

RESULTS

Hg (>0.162 µg/L), Cd (>0.084 µg/L), As (>0.348 µg/L) and Cs (>0.093 µg/L) were detectable in 76.9%, 90.1%, 100% and 100% of maternal urine samples from women in the first trimester of pregnancy. In the multiple adjusted linear regression models, maternal exposures to Hg and Cd in the first trimester were positively associated with maternal TSH levels in the second trimester (P < 0.01, P = 0.02). Moreover, maternal exposures to Cd and Cs in the first trimester were positively associated with neonatal TSH levels (P = 0.04, P = 0.02). In the Bayesian kernel machine regression (BKMR) model, the results were stable and consistent with the linear regression model.

CONCLUSIONS

Maternal exposure to Hg, Cd and Cs in the first trimester was related to TSH levels in mothers and newborns. Efforts to identify maternal and neonatal thyroid disruptors should carefully consider the effects of exposure to these metals.

Subclinical hypothyroidism is associated with albuminuria in Japanese nondiabetic subjects

PURPOSE

Thyroid dysfunction is a risk factor of cardiovascular disease (CVD), and albuminuria is a predictor of CVD. For preventing the CVD, it is essential to clarify from which stage of thyroid dysfunction the risk of CVD starts developing. We thus investigated the association between subclinical thyroid dysfunction and albuminuria, focusing on a nondiabetic general population.

METHODS

We analyzed the data of 17,221 nondiabetic subjects who underwent annual health checkups by multivariate logistic regression analyses.

RESULTS

Compared with the subjects with euthyroidism, those with subclinical hypothyroidism presented a higher prevalence of albuminuria. By a multivariate logistic regression analysis, subclinical hypothyroidism showed a significant and independent association with the high prevalence of albuminuria compared with euthyroidism (OR 1.64, 95% CI 1.21-2.21, p = 0.001). In accord with this result, the analysis in which the lowest quartile of thyroid stimulating hormone (TSH) concentration (<0.96 µIU/mL) was used as a reference revealed that the highest quartile (>2.07 µIU/mL) had a significant and independent association with the prevalence of albuminuria (OR 1.23, 95% CI 1.01-1.51, p = 0.04). One microliter unit per milliliter increase of the serum concentration of TSH also had a significant and independent association with the prevalence of albuminuria (OR 1.07, 95% CI 1.02-1.12, p = 0.006). The association between subclinical hyperthyroidism and the prevalence of albuminuria was not significant.

CONCLUSION

Our data indicated that subclinical hypothyroidism was significantly and independently associated with the high prevalence of albuminuria.

Relationship between Thyroid and Kidney Function: Analysis from the Korea National Health and Nutrition Examination Survey Between 2013 and 2015

INTRODUCTION

Thyroid function is evaluated by thyroid stimulating hormone (TSH) and free thyroxine (fT4). Although many studies have indicated an intimate relationship between thyroid hormones and kidney functions, reports about the simultaneous evaluation of TSH and fT4 are rare.

OBJECTIVE

We aimed to analyze the association between TSH and kidney function, with emphasis on a potential nonlinear relationship, and identify an independent relationship between fT4 and kidney function.

METHODS

We reviewed the data of 7,061 subjects in the Korea National Health and Nutrition Examination Surveys who were randomly subsampled for thyroid function evaluation between 2013 and 2015. A total of 5,578 subjects were included in the final analysis, after excluding people <18 years old, and those with a short fasting time, abnormal fT4 levels, and thyroid disease or related medications. Creatinine-based estimated glomerular filtration rate (eGFR) was used to define kidney function.

RESULTS

A 1 mmol/L increase of logarithmic TSH was associated with decreased eGFR (β: -1.8; 95% CI -2.3 to -1.2; p < 0.001), according to multivariate linear regression analysis. On the multivariate generalized additive model plot, TSH demonstrated an L-shaped relationship with eGFR, showing a steeper slope for 0-4 mIU/L of TSH. A 1 µg/dL increase of fT4 was also associated with decreased eGFR (β: -7.0; 95% CI -0.94 to -4.7; p < 0.001) on the multivariate linear regression analysis; this association was reversed after adjusting for age. On the mediation analysis, the indirect effect via age and direct effect per 1 µg/dL increase of fT4 on eGFR was 9.9 (8.1 to 11.7, p < 0.001) and -7.1 (-9.3 to -4.8, p < 0.001), respectively.

CONCLUSIONS

Increased TSH was associated with decreased eGFR, particularly in the reference range. The direct effect of increased fT4 was decreased eGFR, which may be affected indirectly by age.

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.

Same-sex twins have a high incidence of congenital hypothyroidism and a high probability to be missed at newborn screening

BACKGROUND

We estimated the incidence of CH in twins, analyse the clinical features of CH cases in twins and further evaluate the CH screening strategy and recall procedures for twins.

METHODS

A retrospective investigation of the screening results and confirmed cases in 724,791 newborns was conducted from 2015 to 2017 in Guangzhou. Clinical features were compared between twins with CH and singletons with CH. In addition, the twins were further divided into same-sex twins and different-sex twins to analyse the characteristics and incidence of CH and to compare differences in the confirmed cases in the 2 groups.

RESULTS

The incidence of CH in same-sex twins was 1/593, which was much higher than the incidence of CH in singletons (1/1323) and different-sex twins (1/3060). Of the 20 twins diagnosed with CH, 17 were same-sex twins and 3 were different-sex twins. Among the six pairs of same-sex twins with CH, four had TSH inconsistency, which reached 67%. Eight of the 17 cases of same-sex twins diagnosed with CH had negative results at the first screening.

CONCLUSIONS

Distinguishing same-sex twins from different-sex twins during newborn screening is more feasible. The incidence of CH in same-sex twins is much higher than that in the general population and the risk of transient CH is relatively high. In positive cases in same-sex twins, the simultaneous recall of the twin can effectively avoid a missed diagnosis. The screening center should properly evaluate the recall strategy and screening procedure for twins, especially twins of the same-sex.

Maternal and neonatal iodine status in Dakshina Kannada district of Karnataka, India

This study was designed to assess iodine status of mother-fetus dyad by estimation of spot urine iodine concentration (UIC) in the study district. It is a cross-sectional study of 250 pregnant women with euthyroid status and their term neonates residing in Dakshina Kannada district. Neonates with foetal growth restriction or requiring intensive care were excluded. Median UIC was quantified using modified Sandell-Kolthoff reaction by microplate method. World Health Organization (WHO) classification was used to categorise the iodine status of pregnant women. Among 250 pregnant women, the majority were primigravida (38%). Median maternal thyroid stimulating hormone (TSH) was 1.54 mIU/l, and median UIC was 352 mcg/l. Urine iodine levels were insufficient (<150 mcg/l) in 1.2% (n = 3), adequate (150-249 mcg/l) in 9.2% (n = 23) and above requirement (250-499 mcg/l) in 89.6% (n = 224); none had excess (> 500 mcg/l). Median birth weight was 3,000 g and head circumference was 34 cm. Median cord blood TSH was 8.1 mIU/l, and median UIC 344.5 mcg/l. All the newborns had adequate (> 100 mcg/l) iodine status, including those born to mothers with insufficient values. Maternal and newborn median UIC showed positive correlation (r = 0.139; p = 0.028). Iodine statuses were above requirement or adequate in pregnant women from the study district and their neonates, respectively, indicating successful salt iodisation.

Perfluoroalkyl acids and thyroid hormones across stages of kidney function

Data for US adults aged ≥20 years for 2007-2012 (N = 7020) were used to study concentrations of thyroid stimulating hormone (TSH), free (FT3) and total triiodothyronine (TT3), free (FT4) total thyroxine (TT4), and thyroglobulin (TGN) across stages of glomerular function (GF). Data for 2007-2008 and 2011-2012 (N = 2549) were used to study associations between thyroid hormone biomarkers and five serum perfluoroalkyl acids (PFAAs). We report how thyroid hormone biomarkers vary in human serum across stages of GF. Stages considered were: GF-1 (normal, eGFR >90 mL/min/1.73 m²), GF-2 (60 ≤ eGFR≤90 mL/min/1.73 m²), GF-3A (45 ≤eGFR<60 mL/min/1.73 m²), and GF-3B/4 (15 ≤ eGFR<45 mL/min/1.73 m²). Regression models stratified by GF stages were fitted to evaluate associations between the concentrations of selected PFAAs and thyroid hormones and to evaluate the variability in concentrations of thyroid hormones across the stages of GF. Adjusted geometric means (AGM) for TSH sharply increased from GF-1 (1.34 μIU/mL) to GF-2 (1.58 μIU/mL) and then remained relatively stable. AGMs of FT3 and TT3 decreased consistently from GF-1 to GF-3B/4; from 3.24 to 2.79 pg/mL for FT3 and from 115.7 to 96.4 ng/dL for TT3. AGMs for FT4 increased from GF-2 onward. TGN increased as glomerular filtration worsened from GF-1 through GF-3B/4. In contrast to strong relationships of thyroid hormone markers to stages of renal function, only scattered, inconsistent findings characterized relationship of PFAAs to thyroid markers across stages of kidney disease. For example, TSH was positively associated with PFOA at GF-2 (β = 0.08522, p < 0.01) but negatively associated at GF-3A (β = - 0.22926, p = 0.04). Thus, associations between kidney disease and thyroid hormone are clear, but the relationships between PFAAs and thyroid hormones vary inconsistently from stage to stage and reveal no trend. For thyroid hormone investigations, we conclude stratification by glomerular function stage is likely not needed.

Association between thyroid-stimulating hormone and maternal hemodynamics in hypertensive disorders of pregnancy: an observational study

Background

Hypertensive disorders of pregnancy (HDP) are characterized by hemodynamic disturbances. Altered thyroid function is a risk factor for poor outcomes of pregnancy. However, the associations between thyroid function biomarkers and maternal hemodynamics during pregnancy in HDP remain unclear.

Methods

From January 2016 to January 2018, pregnant women diagnosed with HDP admitted to the Nanjing Maternity and Child Health Care Hospital were prospectively enrolled in the third trimester. Normally distributed variables were expressed as mean ± standard deviation and skewed variables were expressed as median (25th percentile, 75th percentile). Correlations between thyroid-stimulating hormone (TSH) or free thyroxine (FT4) and maternal hemodynamic parameters were assessed by Pearson’s correlation coefficient and 95% confidence interval (95%CI). Bonferroni’s correction for multiple correlations was performed. Logistic regression models with odd ratio (OR) and 95%CI were applied to confirm the associations.

Results

A total of 163 third-trimester pregnant women with HDP with a mean gestational age of 35.62 ± 2.83 weeks were recruited. The infant birth weight of patients with elevated TSH levels was lower than that of patients with normal TSH levels (2635 ± 867 g vs. 3037 ± 673 g, p = 0.002). Reduced cardiac output (CO) was defined as CO < 3.5 L/min. The infant birth weight of patients with reduced CO was lower than that of patients with normal CO (2250 ± 510 g vs. 2890 ± 774 g, p = 0.002). TSH levels were significantly and negatively correlated with CO (r = − 0.260, 95%CI: − 0.392- -0.103, p < 0.001). FT4 levels were not significantly correlated with any of the maternal hemodynamic parameters (all p > 0.05). TSH level (OR = 1.371, 95%CI: 1.086–1.733, p = 0.008) was confirmed associated with reduced CO in the logistic regression analysis.

Conclusions

Elevated TSH levels are associated with reduced CO in HDP during the third trimester.