Increased Serum Thyroid-stimulating Hormone Research Articles

Assessment of left ventricle myocardial performance index (Tei index) by myocardial tissue Doppler imaging and its correlation with serum thyroid-stimulating hormone levels and atherogenic index of plasma in patients of subclinical hypothyroidism

ABSTRACT Background: Subclinical hypothyroidism (SCH) is defined as a state of increased serum thyroid-stimulating hormone (TSH) level with circulating thyroxine (T4) and triiodothyronine (T3) in the population reference range. Patients with SCH have an increased risk of subclinical cardiac dysfunction and dyslipidemia. Objective: The primary objective was to assess the left ventricular myocardial performance index (MPI), i.e., the Tei index which is a marker of global MPI in subclinical hypothyroid patients. There were two secondary objectives. The first was to assess the correlation between Left ventricle (LV) Tei index and serum TSH level in patients with SCH. The second was to measure the atherogenic index of plasma (AIP) in patients with SCH and it is correlation with the Tei index. Materials and Methods: This was a cross-sectional, observational study including 100 subclinical hypothyroid patients. All subclinical hypothyroid patients attending outpatient department underwent screening, detailed history taking, and clinical examination. Patients were analyzed for eligibility of the study. After taking consent, all eligible patients underwent tests for routine blood sampling, lipid profile, thyroid profile, antithyroid peroxidase antibodies, electrocardiography, and echocardiography including tissue Doppler imaging. MPI was calculated for each patient. MPI was correlated with serum TSH levels and also with atherogenic plasma index (AIP) using an appropriate statistical analysis tool. Results: Fifty-three percent of subclinical hypothyroid patients had abnormal lateral and medial Tei index. Fifty-one percent of subclinical patients had abnormal mean Tei index despite normal left ventricle ejection fraction. However, there was no correlation between the Tei index and TSH level. In this study, 48% and 29% of patients had high and intermediate cardiovascular risk, respectively, according to AIP. No statistically significant correlation was observed between the Tei index and atherogenic index of plasma. Conclusion: Subclinical hypothyroid patients have significant subclinical cardiac dysfunction (as determined by the Tei index) and dyslipidemia. AIP may serve as an effective screening method to identify subclinical hypothyroid individuals who are at higher risk of cardiovascular events. Large prospective studies are needed to validate the AIP-TSH-MPI relationship.

Subclinical hypothyroidism predicts outcome in heart failure: insights from the T.O.S.CA. registry.

Subclinical hypothyroidism (SH), defined as increased serum thyroid-stimulating hormone (TSH) with normal free T4 (fT4) levels, is frequently observed in the general population. Prevalence ranges from 0.6% to 1.8% in the adult population, depending on age, sex, and iodine intake. Several studies reported a worse prognosis in patients with heart failure with reduced ejection fraction (HFrEF) and SH, but they considered heterogeneous populations suffering mainly from severe SH. Aim of this study was to evaluate if SH was independently associated with the occurrence of cardiovascular death considering 30months of follow-up. 277 HFrEF patients enrolled in the prospective, multicenter, observational T.O.S.CA. (Terapia Ormonale Scompenso CArdiaco) registry, were included in this analysis. Patients were divided into two groups according to the presence of SH (serum TSH levels > 4.5mIU/L with normal fT4 levels). Data regarding clinical status, echocardiography, and survival were analyzed. Twenty-three patients displayed SH (87% mild vs 13% severe), while 254 were euthyroid. No differences were found in terms of age, sex, HF etiology, and left ventricular ejection fraction. When compared with the euthyroid group, SH patients showed higher TSH levels (7.7 ± 4.1 vs 1.6 ± 0.9, p < 0.001), as expected, with comparable levels of fT4 (1.3 ± 0.3 vs 1.3 ± 0.3, p = NS). When corrected for established predictors of poor outcome in HF, the presence of SH resulted to be an independent predictor of cardiovascular mortality (HR: 2.96; 5-95% CI:1.13-7.74; p = 0.03). Since thyroid tests are widely available and inexpensive, they should be performed in HF patients to detect subclinical disorders, evaluate replacement therapy, and improve prognosis.

Thyroid Nodule Correlation with Serum Prolactin and TPO Antibody Levels: A Case-Control Study

Introduction: The prevalence of thyroid nodules poses a grave clinical concern as they may lead to malignancy. Prolactin has been found to have anti-cell death properties and stimulates the growth of breast and prostate cells, as has been discovered in exploratory examinations. In light of this, the current research was designed to investigate whether a possible relationship exists between thyroid nodules and serum prolactin levels. Material and Methods: Ninety participants were enrolled in this study, of which 60 presented with thyroid nodules (30 antithyroid peroxidase antibody (TPO-Ab) positive and 30 TPO-Ab negative) and 30 without thyroid nodules (control group). Patients' serum prolactin, TPO-Ab, thyroid-stimulating hormone (TSH), T4 values, and thyroid ultrasound reports were scrutinized. Statistically significant outcomes were determined by a P-value less than 0.05. Results: Serum TSH, prolactin, and TPO-Ab levels were significantly higher in the case group than in the control group (P=0.041, 0.050, and 0.000, respectively). The case group had more instances of hyperprolactinemia than the control group (35% vs. 13.3%) (OR=3.5, CI 95%=1.08-11.38, P=0.031). Furthermore, the TPO-Ab positive group demonstrated greater solidity than the TPO-Ab negative group (93.3% vs. 73.3%, P=0.038). Conclusion: The present study confirmed the presence of a positive correlation between thyroid nodules and increased serum TSH, prolactin, and TPO-Ab levels. Furthermore, TPO-Ab positive nodules exhibited greater solidity and elevated TSH levels.

Effect of levothyroxine administration on oxidative stress and cytokine levels in rats with experimental hypothyroidism

In this study, it was aimed to determine the effects of levothyroxine (L-T4) administration on serum free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH) and serum total antioxidant capacity (TAC), serum total oxidant capacity (TOC), oxidative stress index (OSI) and superoxide dismutase (SOD) activity, liver malondialdehyde (MDA) and the effects of cytokines on tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels in rats with experimental hypothyroidism. In the study, 48, 39-day-old, male Wistar albino rats were randomly divided into 3 groups containing 16 rats in each as control, hypothyroid and levothyroxine (L-T4) treated hypothyroid group. The rats in the control group were injected with 1 mL of saline and the rats in the hypothyroid group were injected via intraperitoneal (i.p.) route with 6-n-propyl thiouracil (PTU) at a dose of 10 mg/kg/day for 28 days. In the levothyroxine treated group, after induction of hypothyroidism 5 µg of levothyroxine diluted in 1 mL of sodium chloride (NaCl) administered via i.p. route for 15 days. At the end of the study, serum and liver samples were taken from the rats. In hypothyroidism group, serum fT3, fT4 and TAK levels as well as SOD (P&lt;0.001) activity decreased statistically compared to the control group while serum TSH, TOC, OSI (P&lt;0.001), liver MDA (P&lt;0.01), TNF-α and IL-6 (P&lt;0.001) levels increased significantly. The decreased serum fT3, fT4, TAC levels and SOD (P&lt;0.001) activity in the hypothyroidism group increased with levothyroxine administration whereas the increased serum TSH, TOC, OSI and tissue MDA (P&lt;0.01), TNF-α and IL-6 (P&lt;0.001) levels were found to be decreased and approached to control levels. In conclusion, it has been shown that levothyroxine administration is effective against PTU-induced hypothyroidism in rats, inhibits lipid peroxidation and increases antioxidant status, minimizes the levels of inflammatory markers and protects against PTU-induced liver damage in rats. Because, the potential therapeutic use of levothyroxine in the treatment of hypothyroidism is thought to be appropriate.

A synergistic analgesic effect of morphine in combination with the CB1 receptor agonist, ACPA, in normal, hypothyroid, and hyperthyroid male rats.

Both cannabinoid and opioid receptors are involved in pain behavior. The administration of morphine and cannabis in rats has been shown to decrease thyroid weight and thyroid‑stimulating hormone (TSH) levels. We hypothesized that the third ventricle, due to its adjacency to the hypothalamus, is involved in the modulation of hypothalamic‑pituitary‑thyroid axis activity and descending pain pathways. The present study examined the effect of intra‑third ventricle administration of morphine and cannabis agents on the modulation of pain behavior in normal, hypothyroid (increased serum TSH), and hyperthyroid (decreased serum TSH) rats using the tail‑flick test. The results indicated that intra‑third ventricle injection of AM251 (CB1 receptor antagonist) caused hyperalgesia, while intra‑third ventricle administration of ACPA (CB1 receptor agonist) and morphine produced analgesia in normal, hypothyroid, and hyperthyroid rats. A non‑effective dose of morphine (0.5 μg/rat) did not attenuate hyperalgesia induced by an effective dose of AM251. Co‑injection of ACPA and morphine into the third ventricle induced anti‑nociceptive effect in normal, hypothyroid, and hyperthyroid rats. An isobolographic analysis demonstrated a synergistic effect between ACPA and morphine in the production of the anti‑nociceptive effect. Consequently, the third ventricle may modulate pain behavior induced by cannabinoid and opioid receptors via descending pain pathways in normal, hypothyroid, and hyperthyroid rats.

Bisphenol analogues induce thyroid dysfunction via the disruption of the thyroid hormone synthesis pathway

Bisphenol analogues are widely used in industrial and daily-use consumer products having imperfect thyroid hormones (THs) structures. Widespread exposure interferes with thyroid-related health outcomes in human. The mechanisms of disruption on TH synthesis and subsequent thyroid dysfunction by different bisphenol analogues remain unclear. Here, we evaluated bisphenol-induced thyroid endocrine disruption in C57BL/6 mice at doses of 0.002, 0.02, 2, and 20 mg/kg body weight/day (BW/d) for five consecutive weeks. Administration of 20 mg/kg BW/d bisphenol S (BPS) and 2 mg/kg BW/d tetrabromobisphenol S (TBBPS) significantly increased serum thyrotropin (TSH) levels to 1.21-fold and 1.20-fold of control group, respectively, indicating that bisphenols induced thyroid dysfunction in mice. Height of the thyroid follicle epithelium significantly increased to 1.27-, 1.24-, 1.26-, and 1.36-fold compared to control group with BPA, BPS, TBBPA, and TBBPS at 20 mg/kg BW/d, respectively, indicating impairment of the thyroid gland structure, and TBBPS showed potent effect. Exposure to bisphenol analogues of 0.02 mg/kg BW/d downregulated the protein expression levels of thyrotropin receptor, the sodium/iodide symporter, thyroperoxidase. The TH-dependent effects were further determined using the T-Screen assay at 10−11 M to 10−5 M concentrations. Bisphenol analogues significantly decreased TH-dependent GH3 cell proliferation, indicating the antagonistic activity of bisphenol analogues. The gene responsible for THs synthesis of thyrotropin releasing hormone receptor and TSH were upregulated, but downregulation of thyroid receptor β was observed. Our results suggest that bisphenol analogues distinctly induce thyroid dysfunction via TH synthesis, implying adverse effect of bisphenol analogues on TH homeostasis and subsequent physiological processes.

Thyrotropin-releasing hormone stimulates NR4A3 expression in the pituitary thyrotrophs of proestrus rats.

The secretion of several hypothalamic peptide hormones is activated during the preovulatory period. Hypothalamic thyrotropin-releasing hormone (TRH) is one such hormone with reproductive and/or metabolic significance. However, it remains unclear whether thyroid-stimulating hormone (TSH)-producing thyrotrophs are produced during the preovulatory period. We previously found a transient increase in the expression of the nuclear receptor NR4A3, a well-known immediate early gene, in the proestrus afternoon in the anterior pituitary glands of rats. To investigate the relationship between TRH secretion and pituitary NR4A3 expression during proestrus, we used proestrus and thyroidectomized rats to identify NR4A3-expressing cells and examined the regulation of Nr4a3 gene expression via the hypothalamus-pituitary-thyroid (HPT) axis. The percentage of NR4A3-expressing cells increased in thyrotrophs at 14:00 h of proestrus. Incubation of rat primary pituitary cells with TRH transiently stimulated Nr4a3 expression. Thyroidectomy to attenuate the negative feedback effects led to increased serum TSH levels and Nr4a3 gene expression in the anterior pituitary, whereas thyroxine (T4) administration conversely suppressed Nr4a3 expression. Additionally, the administration of T4 or TRH antibodies significantly suppressed the increase in Nr4a3 expression at 14:00 h of proestrus. These results demonstrate that pituitary NR4A3 expression is regulated by the HPT axis, and that TRH stimulates thyrotrophs and induces NR4A3 expression during the proestrus afternoon. This suggests the potential involvement of NR4A3 in the regulation of the HPT axis during pre- and post-ovulatory periods.

High-throughput Screening in Combination With a Cohort Study for Iodothyronine Deiodinases.

Regulatory mechanisms of iodothyronine deiodinases (DIOs) require further elucidation, and conventional methods for evaluating DIOs are unsuitable for high-throughput screening (HTS). Here we explored factors of transcriptional regulation of 3 types of DIOs (DIO1, DIO2, and DIO3) from a chemical library using our designed HTS. We constructed HTS based on a promoter assay and performed a screen of 2480 bioactive compounds. For compounds that were clinically approved, we validated hit compounds through a retrospective cohort study in our department that evaluated changes in thyroid function in patients using the compounds as drug therapy. Furthermore, we verified the involvement of DIOs using mice treated with the compounds. Of the hit compounds, 6 and 7 compounds transcriptionally up- and downregulated DIO1, respectively; 34 transcriptionally upregulated DIO2; and 5 and 2 compounds transcriptionally up- and downregulated DIO3, respectively. The cohort study clarified the clinical effects of some hit compounds: ritodrine increased free triiodothyronine (fT3)/free thyroxine (fT4) ratio and decreased serum thyroid-stimulating hormone (TSH) levels, tadalafil increased serum fT3 levels, and tyrosine kinase inhibitors (TKIs) decreased serum fT3 and fT4 levels and increased serum TSH levels. Following in vivo experiments using treated mice, consistent results were observed in ritodrine, which upregulated DIO2 in the thyroid gland. In conclusion, we completed HTS for DIOs and obtained attractive hit compounds. Our cohort study revealed the clinical significance of ritodrine, sildenafil, and TKIs. We hope our unique method will contribute to analyzing various targets and lists of hit compounds will promote understanding of DIOs.

Effects of meteorin-like hormone on endocrine function of hypothalamo-hypophysial system and peripheral uncoupling proteins in rats.

Meteorin-like hormone (Metrnl) is a peptide secreted from the adipose tissue and modulates the whole-body energy metabolism. Metrnl release into the circulation is influenced by obesity, cold exposure, and exercise. Thyroid hormones also exert many of their effects on metabolism through uncoupling proteins (UCPs). This study aimed to determine effect of Metrnl on hypothalamo-hypophysier-thyroid axis and energy metabolism and reveal the possible involvement of UCPs in this process. Fourty male Sprague-Dawley rats were divided into 4 groups with 10 animals in each group: control, sham, 10 and 100nM Metrnl. Hypothalamus, muscle, white adipose tissue (WAT) and brown adipose tissue (BAT) samples were collected to detect thyrotropin-releasing hormone (TRH), and UCP1 and UCP3 protein levels by western blot analysis. Serum thyroid-stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4) hormone levels were determined by enzyme-linked immunosorbent assay. Central infusion of Metrnl caused significant increase in serum TSH, T3 and T4 levels compared to control (p < 0.05). After Metrnl treatment, there were significant increases in TRH in hypothalamus tissue, UCP1 in WAT and BAT; and UCP3 protein in the muscle tissue (p < 0.05). The findings that Metrnl induced increases in the peripheral UCPs and hypothalamus-pituitary-thyroid axis hormones implicate a role for this hormone in body energy homeostasis through UCP-mediated mechanisms.

Effect of Levothyroxine Replacement on Cognitive Function Impairment in a Sample of Egyptian Population with Subclinical Hypothyroidism

Introduction: Subclinical hypothyroidism (SHT) is characterized by a normal range of free thyroxin concentrations together with increased serum TSH levels. SHT is defined as serum thyroid-stimulating hormone (TSH) concentration above the upper limit of the reference range in the face of normal free FT4 and FT3 levels. The effect of SHT on cognitive function has been investigated in several preclinical studies, and a growing body of evidence has suggested a relevant link between thyroid hormones and the central nervous system. Objectives: This study aimed to investigate the effect of levothyroxine replacement on cognitive impairment in a sample of Egyptian patients with SHT. Methods: A prospective cohort study conducted on 30 patients with cognitive impairment and SHT attending an endocrine outpatient clinic at the Ain Shams University Hospital to study the effect of levothyroxine supplementation on cognitive impairment in patients with SHT. The study was conducted on 30 patients. All participants were subjected to a full history taking; thorough clinical examination; laboratory investigations including thyroid profile (FT3, FT4, TSH), anti-thyroid peroxidase antibodies, anti-thyroglobulin antibodies, and lipid profile; imaging tests as neck ultrasound, echocardiography, and carotid duplex; and finally Addenbrooke’s questionnaire used to diagnose mild cognitive impairment. Results: A highly statistically significant difference was found before, 3 months and 6 months after treatment with levothyroxine regarding all clinical data, TSH, LDL, T. cholesterol, FT3, FT4 and HDL, carotid intima-media thickness, and Addenbrooke’s questionnaire. Our study showed a statistically significant inverse correlation between TSH level and mild cognitive impairment before and after treatment with levothyroxine at 3 and 6 months intervals as when TSH increased, results of Addenbrooke’s questionnaire decreased and, so, cognitive impairment increased, while when TSH decreased in response to thyroxine replacement, cognitive impairment improved as detected by an increase in the patient’s score. Conclusion: SHT has a great effect on cognitive impairment, as normalization in TSH level results in improvement in cognitive function. Also, there was a significant reduction in carotid intima-media thickness, which may contribute to improvement of cognitive function in addition to a great improvement in lipid profile, which in turn positively affects cardiac and cognitive function.

Switching of Hashimoto Thyroiditis Into Graves’ Disease: A Case Report and Literature Review

Background: Hashimoto thyroiditis (HT) and Graves’ disease (GD) are autoimmune inflammatory thyroid disorders. The evolution from GD into HT is the most common scenario while the conversion from HT into GD seems to be less common. Case Presentation: A 20-year-old female patient referred to the endocrinology clinic with a three-month history of fatigue, lethargy, lack of appetite, constipation, menorrhagia, cold intolerance, and 5 kg weight gain in the last two months. Clinical examination showed dry skin, scalp hair loss, and painless hard goiter whereas thyroid ultrasound revealed generalized homogeneous hypoechoic thyroid hypertrophy. Laboratory tests demonstrated increased serum thyroid-stimulating hormone (TSH) 210 µIU/L (normal: 0.25-4.50), decreased free thyroxine (FT4) 0.37 ng/L (normal: 0.8-1.8) and free triiodothyronine (FT3) 1.94 pg/mL (normal: 1.8-4.6), and finally, increased thyroid peroxidase antibodies (anti-TPO) 462 IU/mL (normal: up to 34). Based on observations, HT was diagnosed and thus daily treatment with levothyroxine 75 mcg was started for the patient. Two months later, she referred with symptoms suggestive of hyperthyroidism with reduced TSH levels, which did not improve after levothyroxine cessation, thus more laboratory tests were conducted and revealed decreased TSH levels, increased T3 and T4, and TSH receptor stimulating antibody (TSAb)levels, and increased radioactive iodine uptake at 24 hours. Therefore, the diagnosis of GD was made. Five weeks after treatment, she was in full remission. Conclusion: Although the switch from HT into GD is rare, it can occur at any time during the disease. Nonetheless, early diagnosis and treatment would improve the quality of care.

Effects of pesticide NeemAzal-T/S on thyroid, stress hormone and some cytokines levels in freshwater common carp, Cyprinus carpio L

In this study, the effects of azadirachtin (AZA) on thyroid axis hormones [thyroid stimulating hormone (TSH), free/total triiodothyronine (FT3/TT3), free/total thyroxine (FT4/TT4)], stress axis [cortisol, adrenocorticotropic hormones (ACTH)] and cytokines [tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6)] levels in carp fish exposed to 1.20 ppm and 2.40 ppm AZA for 4 days and 30 days were investigated. As a result of our study, the increase in serum TSH, FT3, FT4, ACTH, cortisol, TNF-α, IL-1β and IL-6 levels and decreases in serum TT3 and TT4 levels were found to be statistically significant depending on the dose and time (p < 0.05).

Subclinical Hypothyroidism (SH) and Atherogenic Index of Plasma (AIP) in Women: A Case-Control Study From a Tertiary Care Hospital in South India.

IntroductionSubclinical hypothyroidism (SH) is defined as an increase in serum-thyroid stimulating hormone (S-TSH) above the normal level with free triiodothyronine (T4) and free thyroxine (T3) within the normal range. It is more common in females. The association between SH and dyslipidemia is unclear. There are many controversial studies regarding the same. This is the single largest study of Atherogenic index of plasma (AIP) in SH among women from our country. Our aim is to study the lipid profile and AIP in SH patients. We will also study the correlation between AIP and S-TSH levels in SH patients.Materials and methodsIt was a retrospective study conducted in a tertiary care center. A total of 97 females with SH were taken as cases and 86 normal females were taken as euthyroid (ET) controls. They were matched for demographic characteristics. T3, T4, S-TSH, total cholesterol, S-triglycerides (S-TG), high-density lipoprotein - cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and AIP were compared between the two groups. Spearman’s correlation between TSH and AIP was studied in the SH group. Mann-Whitney U test was performed.ResultsThe TG, HDL, AIP levels were significantly different between both groups. TG, AIP was higher in the SH group compared to the ET group (p value of TG= 0.01, p value of AIP <0.0001). HDL was lower in the ET group compared to the SH group (p value <0.0001). AIP showed a significant positive correlation with S-TSH levels in the SH group. (r value=0.72, p value=<0.001).ConclusionIt is important to regularly monitor SH patients for dyslipidemia, in order to start early therapy with levothyroxine/statins. Emphasis should be laid on lifestyle changes such as diet and exercise from the time of diagnosis. Community level education and awareness should be encouraged. Also, AIP is a better parameter to assess cardiovascular risk in SH patients than a conventional lipid profile.

Study of evaluation of renal function in subclinical hypothyroid patients

Subclinical hypothyroidism (SCH) is evaluated as an increased serum thyroid-stimulating hormone (TSH) above the given upper limit of the reference range, with free thyroxine (free T) and free triiodothyronine (free T) within the reference range. Thyroid hormones play major role in the growth, development and physiology of the renal system. The study was performed to evaluate renal functions in SCH cases. The study was conducted at Smt SMS Multispecialty hospital. 50 SCH and 50 overt hypothyroidism (OHT) cases, 100 euthyroid patients (ET) were enrolled in the study. Thyroid function test, serum creatinine and eGFR were measured in all the three groups. The result shows that there was a definitive trend of increased serum creatinine from euthyroid group to SCH group and finally to OHT group and definitive trend of decreased eGFR from euthyroid group to SCH group and finally to OHT group. Among the three groups, there are higher percentage of patients having high serum creatinine and low eGFR belongs to SCH and OHT group in comparison to ET group. Our result showed a significant positive correlation of TSH with serum creatinine in cases of SCH and OHT and significant negative correlation of TSH with eGFR in cases of SCH and OHT. Finding of our study suggests that renal function and thyroid function are interrelated with each other in SCH cases. SCH patients should be monitored for renal parameters regularly to prevent long term complications. Early diagnosis and early treatment of the disease and can increase the quality of life.

Glycemic status in patients with primary hypothyroidism and its relation to disease severity

Background: Primary hypothyroidism can be defined as an increase in serum thyroid-stimulating hormone (TSH) level, and the concentration of free T3, free T4, T3, and T4 is low. Hypothyroidism is a prevalent disease mostly affecting middle-aged women. One of the most important determinants of glucose homeostasis is thyroid hormones. Hypothyroid patients have a higher prevalence of insulin resistance and tendency to Type 2 diabetes mellitus than the normal individual. Objective: To investigate the correlation between TSH and hemoglobin A1c (HbA1C) in patients with primary hypothyroidism; so, to study the effects of hypothyroidism on glucose metabolism. Subjects and Methods: Ninety-five Iraqi primary hypothyroidism patients and 40 healthy persons taken as control were selected from Specialized Centre for Endocrinology and Diabetes during the period from June 2017 to January 2018. The patients were diagnosed previously as cases of primary hypothyroidism, and they were on treatment and still on treatment. All patients were sent to investigate TSH, T4, T3, and HbA1c. The patients were subdivided into three main groups: first is uncontrolled nondiabetic primary hypothyroid group (36 patients), second is controlled nondiabetic primary hypothyroid group (43) and third is the diabetic primary hypothyroid group (16 patients). Results: A significant difference (P

Electrocardiographic changes in subclinical hypothyroidism

Background: Subclinical hypothyroidism (SCH) is an apparently asymptomatic condition defined by increased serum thyrotropin (thyroid-stimulating hormone) concentrations, but normal serum free T3 and free T4 hormone levels. Thyroid hormones are known to affect the heart and vasculature. The effect of SCH on cardiovascular system is not much studied. Aims and Objectives: The objectives of this study were to study the electrocardiogram (ECG) changes in a group of newly diagnosed subclinical hypothyroid females and to compare the ECG changes in subclinical hypothyroid females with normal healthy euthyroid individuals. Materials and Methods: We studied 30 non-pregnant females with primary SCH in the age group of 20–40 years, who were newly diagnosed and untreated. Thirty age- and body mass index-matched healthy individuals were taken as controls. Clinical and biochemical parameters and ECG were studied. Statistical software, “GraphPad QuickCalcs,” was used for the statistical analysis. Results: Mean QTc interval of the study group was significantly longer than those of the control group (P = 0.037). Other parameters of ECG were comparable in both the groups. Conclusion: ECG changes in SCH showed increase in the QTc interval as compared to controls, which predisposes to the potentially life-threatening ventricular arrhythmias. However, the other parameters of ECG such as QRS interval, PR interval, and QRS axis were similar to the controls.

Associations Between Thyroid Hormones Within the Euthyroid Range and Indices of Obesity in Obese Chinese Women of Reproductive Age.

Background: A number of researches have reported that thyroid hormones are associated with obesity. However, the relationship of serum levels of thyroid hormones in the normal range with obesity and parameters of obesity in women of childbearing age remains controversial. The purpose of this study was to examine serum levels of thyroid hormones within the normal range in obese Chinese women of reproductive age and to investigate the relationship between concentration of thyroid hormones and indices of obesity, including body mass index (BMI), waist-to-hip ratio (WHR), insulin resistance, blood glucose, blood lipids, and blood pressure. Methods: One hundred fifty-one obese women of reproductive age and 160 nonobese women of reproductive age were enrolled in this study. Serum levels of thyroid-stimulating hormone (TSH) of all subjects were within the normal reference range (0.35-4.94 mIU/L). The serum levels of free triiodothyronine (FT3), free thyroxine (FT4), and TSH, height, body weight, BMI, waist and hip circumferences, WHR, fasting blood glucose (FBG), fasting insulin (FI), homeostasis model assessment of insulin resistance (HOMA-IR), total triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured in all subjects. Quantile regression analysis was used to analyze the associations of serum levels of FT3, FT4, and TSH with values of BMI, WHR, FBG, FI, HOMA-IR, TG, TC, LDL-C, HDL-C, SBP, and DBP. Results: In the group of obese women, serum levels of FT4 were lower (P < 0.001) and serum levels of TSH were higher (P < 0.001) compared with nonobese controls. After adjusting for covariables, quantile regression analysis showed that serum levels of FT4 were inversely associated with BMI values between the quantile levels of 0.29 and 0.60 of BMI (i.e., BMI level of 22.49 and 28.31 kg/m2, respectively). Meanwhile, we found that serum levels of TSH positively correlated with BMI values after the quantile level of 0.51 (i.e., BMI level of 27.06 kg/m2), positively associated with TC after the quantile level of 0.6 (i.e., TC level of 4.86 mM), and positively associated with LDL-C after the quantile level of 0.39 (i.e., LDL level of 1.96 mM). No significant associations were found between serum levels of thyroid hormones and values of WHR, FBG, FI, HOMA-IR, TG, HDL-C, SBP, and DBP. Conclusions: FT4 and TSH play an important role in regulating the weight in women with normal thyroid function during their reproductive years. Women with decreased serum FT4 or increased serum TSH levels have a higher risk of developing obesity. Besides, TSH has a significant influence on metabolism of blood lipids. Women with higher serum levels of TSH have a higher risk of incidence of lipid metabolism disorders.

Thyroid dysfunction prevalence and relation to glycemic control in patients with type 2 diabetes mellitus

ObjectiveIt is usually difficult to clinically identify thyroid abnormalities in diabetics as features of thyroid dysfunction may simulate diabetes symptoms or complications. So, assessing thyroid dysfunction prevalence in patients with type 2 diabetes mellitus (DM) would help better control of DM and its complications. Several studies reported this prevalence, however, some included small sample size or lacked a control group. We aimed to determine thyroid dysfunction prevalence in diabetic patients as well as its relation to glycemic control. MethodsA cross-sectional study included 200 patients having type 2 DM and 200 apparently healthy controls. Each participant was tested for fasting and 2-h post-prandial blood glucose, glycated haemoglobin (HbA1C), thyroid function tests: thyroid-stimulating hormone (TSH), free tri-iodothyronine (FT3), free thyroxine (FT4), serum total cholesterol and triglycerides and thyroid antibodies; anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) for hypothyroidism only. ResultsThere was a significant increase in serum TSH and T3 levels in diabetics when compared with the controls, (P < 0.001, P = 0.001), respectively. Thyroid dysfunction was significantly more prevalent in patients with HbA1c ≥ 8%, (P = 0.0001), and in those having longer diabetes duration, (P < 0.001). ConclusionThere was a higher prevalence of thyroid dysfunction among patients with type 2 DM. This dysfunction increased with the rise of HbA1c. This could suggest that poor glycemic control may have a role in the development of thyroid dysfunction in type 2 DM patients. Subclinical hypothyroidism was the most prevalent type of thyroid dysfunction in diabetic patients.

Thyroid Function in Health Care Workers Exposed to Ionizing Radiation.

To analyze possible alterations of thyroid function related to dosimetric values in health care workers exposed to ionizing radiation. Forty-six health care workers exposed to ionizing radiation at a tertiary hospital previously exposed to ionizing radiation were included in the study. Age, sex, history of thyroid diseases, thyroid hormones, work post, service, dosimetric values of previous year, and 5 y period were considered. Alterations of thyroid function and other variables were analyzed by exact logistic regression univariate model. 7.1% workers showed an increased serum thyroid-stimulating hormone without free T3 or free T4 alteration. A significant relationship between workers with increased thyroid-stimulating hormone and dosimetric values of previous year (odds ratio 6.35, 95% confidence interval 1.20-98.1, p = 0.021) and previous 5 y period of radiation exposure (odds ratio 1.72, 95% confidence interval 1.12-3.34, p = 0.007) was obtained. An increased risk of subclinical hypothyroidism related to radiation doses was observed in this pilot study on a group of health care workers exposed to ionizing radiation.

Prevalence of iatrogenic hypothyroidism in hyperthyroid cats treated with radioiodine using an individualised scoring system.

The aim of this study was to report the prevalence of iatrogenic hypothyroidism, with or without azotaemia, based on the measurement of serum total thyroxine (T4), thyroid-stimulating hormone (TSH) and creatinine concentrations, in hyperthyroid cats undergoing radioiodine (131I) treatment where the 131I dose was calculated using a previously described scoring system. A secondary aim of the study was to determine the positive and negative predictive values of serum T4 and TSH concentrations obtained 19 days after treatment in order to predict the development of iatrogenic hypothyroidism 6-9 months after 131I treatment. Serum T4, TSH and creatinine concentrations were measured 19 days and 6-9 months after 131I treatment. The prevalence of iatrogenic hypothyroidism was assessed with the results obtained 6-9 months after 131I treatment. The prevalence of overt and subclinical hypothyroidism 6-9 months after 131I treatment was 40.0% (22/55 cats) and 12.7% (7/55 cats). Overt hypothyroidism with azotaemia was diagnosed in 8/55 (14.5%) cats. The positive and negative predictive values for the prediction of the development of iatrogenic hypothyroidism 6-9 months after 131I treatment were 72.2% and 80.0%, respectively, for a low serum T4 concentration, and 75.0% and 44.6%, respectively, for an increased serum TSH concentration. The use of an individualised scoring system is effective in determining the 131I dose for the treatment of hyperthyroid cats. However, the prevalence of overt hypothyroidism was higher in comparison with other studies using different dosing protocols. Further studies comparing the efficacy of individualised scoring systems and different fixed doses to determine which method is superior are warranted.