2013 ETA Guideline: Management of Subclinical Hypothyroidism

Latent Hypothyroidism in Adults

BACKGROUND

The prevalence of latent/subclinical hypothyroidism is between 3% and 10%, according to epidemiologic studies that have been carried out in the USA, the United Kingdom, and Denmark. As persons with latent hypo - thyroidism are often asymptomatic, the diagnosis is often made incidentally in routine laboratory testing.

METHODS

This review is based on a selective search in PubMed for publications on the diagnosis and treatment of latent hypothyroidism. All pertinent articles and guidelines published from 1 January 2000 to 31 July 2016 were included.

RESULTS

The diagnosis of latent hypothyroidism is generally assigned after repeated measurement of a TSH concentration above 4.0 mU/L in a person whose fT4 concentration is in the normal range. The most common cause is autoimmune thyroiditis, which can be detected by a test for autoantibodies. L-thyroxin supplementation is a controversial matter: its purpose is to prevent the development of overt hypothyroidism, but there is a danger of overtreatment, which increases the risk of fracture. To date, no benefit of L-thyroxin supplementation has been demonstrated with respect to morbidity and mortality, health-related quality of life, mental health, cognitive function, or reduction of overweight. There is, however, evidence of a beneficial effect on cardiac function in women, and on the vascular system. At present, treatment is generally considered indicated only if the TSH level exceeds 10.0 mU/L.

CONCLUSION

Limited data are available on the relevant clinical endpoints and undesired side effects of supplementation therapy. Physicians should advise patients about the indications for such treatment on an individual basis after due consideration of the risks and benefits.

The thyroid gland in postmenopausal women: physiology and diseases

The incidence of most thyroid diseases: hypothyroidism, nodular goitre, and cancer is highest among postmenopausal and elderly women. The diagnosis of thyroid dysfunction in this group of patients is difficult because the symptoms can be nonspecific or common with menopausal and ageing complaints. In the interpretation of thyroid function tests the physiological changes in secretion and metabolism of thyrotropin (TSH) and thyroid hormones must be considered, as well as the influence of comorbidities. Unrecognised thyroid dysfunction leads to increased: cardiovascular risk, bone fractures, cognitive impairment, depression, and mortality. Therapy of thyroid dysfunction is different in postmenopausal and elderly women than in young people; hypothyroidism should be treated with caution, because high doses of L-thyroxine can lead to cardiac arrhythmias and increased bone turnover, and hyperthyroidism should be preferentially treated with radioiodine. Thyroid status beneficially influencing longevity relates to low thyroid function. Thyroid nodules and cancer often affect women over 50 years old; the diagnostic and therapeutic approach is the same as in the general population, but the surgical risk and cancer prognosis is worse than in young patients.

MECHANISMS IN ENDOCRINOLOGY: Aging and anti-aging: a Combo-Endocrinology overview

Aging and its underlying pathophysiological background has always attracted the attention of the scientific society. Defined as the gradual, time-dependent, heterogeneous decline of physiological functions, aging is orchestrated by a plethora of molecular mechanisms, which vividly interact to alter body homeostasis. The ability of an organism to adjust to these alterations, in conjunction with the dynamic effect of various environmental stimuli across lifespan, promotes longevity, frailty or disease. Endocrine function undergoes major changes during aging, as well. Specifically, alterations in hormonal networks and concomitant hormonal deficits/excess, augmented by poor sensitivity of tissues to their action, take place. As hypothalamic-pituitary unit is the central regulator of crucial body functions, these alterations can be translated in significant clinical sequelae that can impair the quality of life and promote frailty and disease. Delineating the hormonal signaling alterations that occur across lifespan and exploring possible remedial interventions could possibly help us improve the quality of life of the elderly and promote longevity.

Subclinical hypothyroidism: Should we treat?

Subclinical hypothyroidism (also known as compensated hypothyroidism or mild hypothyroidism) is a condition associated with a raised serum concentration of thyroid stimulating hormone (TSH) but a normal serum free thyroxine (FT4). It is common, affecting about 10% of women above the age of 55 years. Autoimmunity is the commonest cause of subclinical hypothyroidism. About 2.5% of patients with subclinical hypothyroidism progress to clinically overt hypothyroidism each year; the rate of progression is higher in patients with thyroid autoantibodies and higher thyroid stimulating hormone levels. However, thyroid function normalises spontaneously in up to 40% cases. Only a small minority of patients with subclinical hypothyroidism have symptoms, and the evidence to support that levothyroxine ameliorate the symptoms in these patients is weak. Subclinical hypothyroidism in younger patients (<65 years) is associated with an increased risk of coronary heart disease, heart failure and cerebrovascular disease. The risk increases with increasing levels of thyroid stimulating hormone, and is particularly high in patients with TSH levels ≥10.0 mu/L. There is lack of evidence from randomised controlled trials as to whether levothyroxine treatment can prevent these risks, although a large observational study of the UK general practice research database has shown that levothyroxine may reduce the risk of coronary heart disease in younger patients (<70 years). Therefore, the decision whether to treat or not to treat subclinical hypothyroidism should be made after careful consideration of the patient's age, the presence of symptoms, the presence of thyroid antibodies and other risk factors such as cardiovascular disease.

Effect of Thyroxin Treatment on Carotid Intima-Media Thickness (CIMT) Reduction in Patients with Subclinical Hypothyroidism (SCH): a Meta-Analysis of Clinical Trials

Aim: Research shows that subclinical hypothyroidism (SCH) is related to an increased carotid intima –media thickness (CIMT), a surrogate marker of subclinical cardiovascular disease (CVD). It is controversial whether or not SCH should be treated to reduce CVD morbidity and mortality. This meta-analysis aimed to determine whether SCH is associated with an increase in CIMT as compared to Euthyroidism (EU) and whether thyroxin (T4) treatment in SCH can reverse the change in CIMT.

Methods: Two independent reviewers conducted an extensive database research up to December 2016. A total of 12 clinical trials discussed the effect of Thyroxin on CIMT values at pre- and post-treatment in subjects with SCH.

Results: CIMT was significantly higher among SCH (n = 280) as compared to EU controls (n = 263) at baseline; the pooled weighted mean difference (WMD) of CIMT was 0.44 mm [95% confidence interval (CI) 0.14, 0.74], p = 0.004; I² = 65%. After treatment with thyroxin in subjects with SCH (n = 314), there was a statistically significant decrease in CIMT from pre- to post-treatment; the pooled WMD of CIMT decrease was [WMD −0.32; 95% CI (−0.47, −0.16), p = < 0.0001; I² = 2%], and it was no longer different from EU controls [WMD 0.13 mm; 95% CI (−0.04, 0.30); p = 0.14; I² = 27%]. The total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL) were higher in SCH as compared to EU controls and decreased significantly after treatment with thyroxin.

Conclusion: This meta-analysis shows that thyroxin therapy in subjects with SCH significantly decreases CIMT and improves lipid profile, modifiable CVD risk factors. Thyroid hormone replacement in subjects with SCH may play a role in slowing down or preventing the progression of atherosclerosis.

Harmonization of Serum Thyroid-Stimulating Hormone Measurements Paves the Way for the Adoption of a More Uniform Reference Interval

BACKGROUND

The IFCC Committee for Standardization of Thyroid Function Tests developed a global harmonization approach for thyroid-stimulating hormone measurements. It is based on a multiassay method comparison study with clinical serum samples and target setting with a robust factor analysis method. Here we describe the Phase IV method comparison and reference interval (RI) studies conducted with the objective to recalibrate the participating assays and demonstrate the proof-of-concept.

METHODS

Fourteen manufacturers measured the harmonization and RI panel; 4 of them quantified the harmonization and first follow-up panel in parallel. All recalibrated their assays to the statistically inferred targets. For validation, we used desirable specifications from the biological variation for the bias and total error (TE). The RI measurements were done with the assays' current calibrators, but data were also reported after transformation to the new calibration status. We estimated the pre- and postrecalibration RIs with a nonparametric bootstrap procedure.

RESULTS

After recalibration, 14 of 15 assays met the bias specification with 95% confidence; 8 assays complied with the TE specification. The CV of the assay means for the harmonization panel was reduced from 9.5% to 4.2%. The RI study showed improved uniformity after recalibration: the ranges (i.e., maximum differences) exhibited by the assay-specific 2.5th, 50th, and 97.5th percentile estimates were reduced from 0.27, 0.89, and 2.13 mIU/L to 0.12, 0.29, and 0.77 mIU/L.

CONCLUSIONS

We showed that harmonization increased the agreement of results from the participating immunoassays, and may allow them to adopt a more uniform RI in the future.

Sub-Clinical Hypothyroidism and Its Association With Increased Cardiovascular Mortality: Call for Action

Thyroid hormones play an important role in regulating different functions regarding metabolism and performance in multiple organs. Any change in the thyroid hormones axis can lead to profound effect on the vital organ stability especially the cardiovascular system. Hypothyroidism is classified according to the clinical presentation as overt and subclinical. Currently, there exists a paucity of evidence on the beneficial effects of thyroxine hormone replacement on cardiovascular mortality outcomes in subclinical hypothyroidism. Also, the clinical relevance of measuring and treating supra-normal thyroid-stimulating hormone levels in newly diagnosed heart failure patients with preserved ejection fraction requires further study. Here we review the current evidence regarding the prognostic significance of sub-clinical hypothyroidism in patients with heart failure with preserved ejection fraction.

Natural history of mild subclinical hypothyroidism in a middle-aged and elderly Chinese population: a prospective study

Subclinical hypothyroidism (SCH) has a high global prevalence. Most SCH patients have mild cases (thyrotropin ≤10 mIU/L). Treatment recommendations for mild SCH are controversial, which raises concerns about the natural history of mild SCH. We aimed to clarify the natural history of mild SCH. This is a prospective population-based study. We measured thyroid function in 11,000 participants in the REACTION study and followed 505 newly diagnosed mild SCH patients aged 40-years or older between 2011 and 2014. Logistic regression analysis was used to seek baseline parameters associated with the natural outcomes of mild SCH. Among 505 mild SCH patients, 221 (43.8%) had persistent SCH, 251 (49.7%) reverted to euthyroidism, and 17 (3.4%) progressed to overt hypothyroidism (OH). Patients with higher baseline total cholesterol (TC, between 201.0-240.0 mg/dL or >240.0 mg/dL vs. <201.0 mg/dL, p = 0.048 and 0.006, respectively) or positive thyroid peroxidase antibodies (TPOAb, p = 0.009) had higher risks of progression to OH, while those with higher baseline creatinine (CR, between 0.71-0.80 mg/dL or >0.80 mg/dL vs. ≤0.65 mg/dL, p = 0.031 and 0.004, respectively), higher baseline thyrotropin (≥7 mIU/L, p < 0.001) or older (>60 years vs. ≤50 years, p = 0.012) had lower odds of reverting to euthyroidism. In conclusion, TPOAb and TC seem to be more important predictors of progression to OH than initial thyrotropin, whereas high baseline thyrotropin or CR were negative correlated with reversion to euthyroidism. The prognostic value of TC and CR in mild SCH should be considered.

The Effect of Early Substitution of Subclinical Hypothyroidism on Biochemical Blood Parameters and the Quality of Life

BACKGROUND

Subclinical hypothyroidism (SCH) is defined as high TSH and normal thyroxine. Data on the effects of early substitution by levothyroxine on psychophysical health in SCH are still not consistent enough to support its introduction.

METHODS

Clinical parameters, biochemical data and quality of life (Short Form 36 questionnaire) were measured before the intervention and 3 months after the euthyroid state had been achieved in SCH patients.

RESULTS

Significant reduction in body weight (p=0.030), systolic and diastolic blood pressure (p=0.024, p=0.019), homocysteine (p<0.001), leukocytes and neutrophils (p=0.011, p=0.001), INR (p=0.049), K levels (p=0.040, p=0.013), HbA1c (p=0.001), fasting insulin (p<0.001) and insulin resistance measured by HOMA index (p<0.001), lipid parameters (total cholesterol (p<0.001), LDL-cholesterol (p<0.001), triglycerides (p=0.007), apoB (p=0.022), Lp(a) (p<0.001), LDL/HDL (p=0.008), LAP (p=0.04) and apoB/apoA1 ratios (p<0.023)), TSH (p<0.001) and tAbs (p<0.001) was recorded. Frequency of fatty liver (20% to 2.9%, p=0.016), hyperlipidemia (85% to 65.7%, p=0.001) and metabolic syndrome (34.3% to 2.9%, p=0.070) significantly decreased. A statistically significant positive association was found between the average dose of levothyroxine and changes in physical functioning (r=0.391, p=0.020), vitality (r=0.393, p=0.020), mental health (r=0.374, p=0.027) and overall dimensions of mental health (r=0.376, p=0.026). With increasing doses of levothyroxine, the previously listed scores of SF 36 grew (r=0.296, p=0.084).

CONCLUSIONS

Early substitution of SCH improved the many clinical and biochemical parameters related to cardiovascular risk. Quality of life was also improved, and correlated only with thyroxine doses suggesting an indirect relationship between the degree of hypothyroidism and quality of life.

Thyroid Status and Mortality Risk in Older Adults With Normal Thyrotropin: Sex Differences in the Milan Geriatrics 75+ Cohort Study

BACKGROUND

Thresholds of optimal thyroid status in old age are controversial. We investigated the longitudinal association between thyroid parameters and 10-year all-cause mortality risk in older outpatients with normal thyrotropin (TSH) and modification by sex and age.

METHODS

Baseline TSH, free thyroxine (fT4), and free triiodothyronine (fT3) were assessed in the Milan Geriatrics 75+ Cohort Study. 324 men and 609 women older than 75 years had normal TSH. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for the associations between thyroid parameters and mortality risk using Cox regression. Sex-stratified analyses were adjusted for sociodemographic factors and comorbidities.

RESULTS

233 men and 367 women died during follow-up. After adjustment, each 1-mU/L higher TSH was associated with decreased mortality risk in men (HR 0.83, 95% CI 0.69-0.98), but not in women (HR 1.09, 95% CI 0.95-1.24) (p for sex interaction = .006). Each 1-ng/L higher fT4 was associated with increased mortality risk in men (HR 1.11, 95% CI 1.02-1.22), but not in women (HR 0.98, 95% CI 0.93-1.04) (p for sex interaction = .013). Each 1-pg/mL higher fT3 was associated with decreased mortality risk in women (HR 0.77, 95% CI 0.60-0.98), but not in men (HR 0.80, 95% CI 0.57-1.13). The inverse association between TSH and mortality was most pronounced in men older than 85 years.

CONCLUSIONS

Among older outpatients with normal TSH, higher TSH and lower fT4 were associated with decreased mortality risk in men but not in women. When assessing thyroid status, sex and age should be taken into account.

Undertreated hypothyroidism due to calcium or iron supplementation corrected by oral liquid levothyroxine

PURPOSE

The aim of this study was to assess whether oral liquid levothyroxine would correct tablet levothyroxine malabsorption induced by calcium or iron, two sequestrants of levothyroxine.

METHODS

Nineteen adult hypothyroid patients with tablet levothyroxine malabsorption caused by calcium and/or iron supplements were switched from tablet to liquid levothyroxine at the same dose. Primary outcomes were: (1) significantly lower mean serum thyroid-stimulating hormone with the liquid compared with the tablet formulation, and (2) significantly greater rate of serum thyroid-stimulating hormone less than or equal to 4.12 or 2.5 mU/L.The mean follow-up was 25.2 ± 16.5 weeks.

RESULTS

TSH was lower with liquid levothyroxine compared with tablet levothyroxine (7.48 ± 5.8 vs. 1.95 ± 1.3 mU/L, P < 0.001), both in the calcium group (8.74 ± 7.2 vs. 2.15 ± 1.4, P < 0.001) and iron group (8.74 ± 7.2 vs. 1.68 ± 0.9, P < 0.001). Thyroid-stimulating hormone levels ≤4.12 mU/L in all patients, calcium group and iron group were more frequent post-switch (95, 87 and 100%) compared to pre-switch (26, 22 and 29%, P < 0.001), and so were thyroid-stimulating hormone levels ≤2.50 mU/L (66, 59 and 76% compared to 5, 9 and 0%, P < 0.001). The pattern held comparing the first liquid levothyroxine thyroid-stimulating hormone levels and the first tablet levothyroxine thyroid-stimulating hormone levels or the corresponding rates of thyroid-stimulating hormone levels below the target.

CONCLUSIONS

Liquid levothyroxine is resistant to the sequestration by calcium or iron. The high rate of thyroid-stimulating hormone normalization already at the first check (6-8 weeks) should avoid frequent adjustments in levothyroxine doses and assays of thyroid-stimulating hormone, with consequent financial savings.

Subclinical hypothyroidism, lipid metabolism and cardiovascular disease

Subclinical hypothyroidism is defined by elevated serum thyrotropin in presence of normal free thyroid hormones. Lipid metabolism is influenced by thyroid hormone and many reports showed that lipids status worsen along with TSH level. Subclinical hypothyroidism has been also linked to other cardiovascular risk factors such as alteration in blood pressure and increased atherosclerosis. Further evidences suggested that mild dysfunction of thyroid gland is associated with metabolic syndrome and heart failure. Thyrotropin level seems the best predictor of cardiovascular disease, in particular when its levels are above 10mU/L. However, despite these observations, there is no clear evidence that levothyroxine therapy in subjects with milder form of subclinical hypothyroidism could improve lipid status and the other cardiovascular risk factors. In this review, we address the effect of thyroid hormone and cardiovascular risk, with a focus on lipid metabolism.

Is metabolic dysregulation associated with antidepressant response in depressed women in climacteric treated with individualized homeopathic medicines or fluoxetine? The HOMDEP-MENOP Study

BACKGROUND

Climacteric is associated with both depression and metabolic dysregulation. Scarce evidence suggests that metabolic dysregulation may predict poor response to conventional antidepressants. Response to depression treatment has not been studied in homeopathic medicine. The aim of this study was to investigate the prevalence of metabolic disorders in depressed climacteric women treated with homeopathic medicines, fluoxetine or placebo, and if these alterations have any association with response to depression treatment.

METHODS

One hundred and thirty-three Mexican women (40-65 years) with depression, enrolled in the HOMDEP-MENOP study, a randomized, placebo-controlled, double-blind, double-dummy, three-arm trial with a 6 week follow-up, underwent a complete medical history and clinical examination. Metabolic parameters were assessed at baseline. Association between baseline metabolic parameters and response to depression treatment was analyzed with bivariate analysis in the three groups. Odds ratios (OR) with their 95% confidence interval (95% CI) were calculated. Metabolic parameters were considered for inclusion in the logistic regression model if they had a statistically significant relationship with response rate on bivariate analysis at p<0.05 or if they were clinically relevant.

RESULTS

Overall combined prevalence (obesity and overweight) was 86.5%; 52.3% had hypertriglyceridemia; 44.7% hypercholesterolemia; 46.7% insulin resistance; and 16% subclinical hypothyroidism. There was no statistically significant association between dyslipidemia, overweight, or insulin resistance and non-response in the homeopathy group [OR (95% CI) 1.57 (0.46-5.32), p=0.467; 0.37 (0.003-1.11), p=0.059; 0.67 (0.16-2.7), p=0.579, respectively].

CONCLUSION

Metabolic dysregulation was not significantly associated with response to depression treatment in depressed climacteric women treated with individualized homeopathic treatment (IHT), fluoxetine or placebo. Due to the high prevalence of metabolic disorders and its relationship with depression in the climacteric, further investigation should be focused on whether individualized prescriptions based on classical homeopathy for depressed climacteric women have an effect on metabolic parameters, and/or if treating the metabolic disorders at the same time could lead to higher response rates. ClinicalTrials.gov Identifier: NCT01635218 URL: http://clinicaltrials.gov/ct2/show/NCT01635218?term=depression+homeopathy&rank=1.

Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

BACKGROUND

Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model.

METHODS

A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure.

RESULTS

Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels.

CONCLUSION

Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.

Criteria for assigning laboratory measurands to models for analytical performance specifications defined in the 1st EFLM Strategic Conference

This paper, prepared by the EFLM Task and Finish Group on Allocation of laboratory tests to different models for performance specifications (TFG-DM), is dealing with criteria for allocating measurands to the different models for analytical performance specifications (APS) recognized in the 1st EFLM Strategic Conference Consensus Statement. Model 1, based on the effect of APS on clinical outcome, is the model of choice for measurands that have a central role in the decision-making of a specific disease or clinical situation and where cut-off/decision limits are established for either diagnosing, screening or monitoring. Total cholesterol, glucose, HbA

Recent Advances in Thyroid Hormone Regulation: Toward a New Paradigm for Optimal Diagnosis and Treatment

In thyroid health, the pituitary hormone thyroid-stimulating hormone (TSH) raises glandular thyroid hormone production to a physiological level and enhances formation and conversion of T4 to the biologically more active T3. Overstimulation is limited by negative feedback control. In equilibrium defining the euthyroid state, the relationship between TSH and FT4 expresses clusters of genetically determined, interlocked TSH-FT4 pairs, which invalidates their statistical correlation within the euthyroid range. Appropriate reactions to internal or external challenges are defined by unique solutions and homeostatic equilibria. Permissible variations in an individual are much more closely constrained than over a population. Current diagnostic definitions of subclinical thyroid dysfunction are laboratory based, and do not concur with treatment recommendations. An appropriate TSH level is a homeostatic concept that cannot be reduced to a fixed range consideration. The control mode may shift from feedback to tracking where TSH becomes positively, rather than inversely related with FT4. This is obvious in pituitary disease and severe non-thyroid illness, but extends to other prevalent conditions including aging, obesity, and levothyroxine (LT4) treatment. Treatment targets must both be individualized and respect altered equilibria on LT4. To avoid amalgamation bias, clinically meaningful stratification is required in epidemiological studies. In conclusion, pituitary TSH cannot be readily interpreted as a sensitive mirror image of thyroid function because the negative TSH-FT4 correlation is frequently broken, even inverted, by common conditions. The interrelationships between TSH and thyroid hormones and the interlocking elements of the control system are individual, dynamic, and adaptive. This demands a paradigm shift of its diagnostic use.

Prevalence of hypothyroidism in nondiabetic chronic kidney disease and effect of thyroxine replacement on estimated glomerular filtration rate

Reduced T3 and free T4, elevated thyroid stimulating hormone, and hyporesponsiveness to thyrotropin releasing hormone raise questions about the presence of hypothyroidism in chronic kidney disease (CKD) and raise the possibility of benefit from thyroxine supplementation. A prospective cohort study was conducted on 73 nondiabetic CKD cases. Hypothyroid patients were started on levothyroxine and were reviewed after 3 and 6 months. The mean age of study population was 42.3 ± 16.8 years. Of the total population, 32 (43.8%) cases had hypothyroidism, among whom 2 (2.7%) had overt hypothyroidism and 30 (41.1%) had subclinical hypothyroidism. Prevalence of hypothyroidism increased with increasing severity of CKD. There were 1 (3.1%) case with hypothyroidism in stage 3b, 8 (25%) cases in stage 4, and 23 (71.9%) cases in stage 5. The mean estimated glomerular filtration rate (ml/min/1.73 m²) at baseline was 13.7 ± 8.9 which increased to 17.5 ± 6.8 and 22.4 ± 9.3 after 3 and 6 months of thyroid hormone replacement therapy (THRT), respectively (P < 0.001). Hypothyroidism is commonly associated with nondiabetic CKD and its prevalence increases with declining renal function. THRT significantly improves renal function in nondiabetic CKD with hypothyroidism.

Subclinical hypothyroidism in childhood - current knowledge and open issues

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range, in the presence of normal concentrations of total T₄ or free T₄. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease recorded among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.

Clinical Update in Aspects of the Management of Autoimmune Thyroid Diseases

Aspects of autoimmune thyroid disease updated in this review include: immunoglobulin G4 (IgG4)-related thyroid disease (Riedel's thyroiditis, fibrosing variant of Hashimoto's thyroiditis, IgG4-related Hashimoto's thyroiditis, and Graves' disease with elevated IgG4 levels); recent epidemiological studies from China and Denmark indicating that excess iodine increases the incidence of Hashimoto's thyroiditis and hypothyroidism; immunomodulatory agents (ipilimumab, pembrolizumab, nivolumab) activate immune response by inhibiting T-cell surface receptors which down-regulate immune response, i.e., cytotoxic T-lymphocyte antigen 4 and programmed cell death protein 1 pathways; alemtuzumab is a humanised monoclonal antibody to CD52 which causes immune depletion and thyroid autoimmune disease especially Graves' hyperthyroidism; small molecule ligand (SML) agonists which activate receptors, SML neutral antagonists, which inhibit receptor activation by agonists, and SML inverse agonists which inhibit receptor activation by agonists and inhibit constitutive agonist independent signaling have been identified. SML antagonism of thyroid-stimulating hormone-receptor stimulatory antibody could treat Graves' hyperthyroidism and Graves' ophthalmopathy; and thyroxine treatment of subclinical hypothyroidism can produce iatrogenic subclinical hyperthyroidism with the risk of atrial fibrillation and osteoporosis. The increased risk of harm from subclinical hyperthyroidism may be stronger than the potential benefit from treatment of subclinical hypothyroidism.

Thyroid hormones and cardiovascular disease

Myocardial and vascular endothelial tissues have receptors for thyroid hormones and are sensitive to changes in the concentrations of circulating thyroid hormones. The importance of thyroid hormones in maintaining cardiovascular homeostasis can be deduced from clinical and experimental data showing that even subtle changes in thyroid hormone concentrations - such as those observed in subclinical hypothyroidism or hyperthyroidism, and low triiodothyronine syndrome - adversely influence the cardiovascular system. Some potential mechanisms linking the two conditions are dyslipidaemia, endothelial dysfunction, blood pressure changes, and direct effects of thyroid hormones on the myocardium. Several interventional trials showed that treatment of subclinical thyroid diseases improves cardiovascular risk factors, which implies potential benefits for reducing cardiovascular events. Over the past 2 decades, accumulating evidence supports the association between abnormal thyroid function at the time of an acute myocardial infarction (MI) and subsequent adverse cardiovascular outcomes. Furthermore, experimental studies showed that thyroid hormones can have an important therapeutic role in reducing infarct size and improving myocardial function after acute MI. In this Review, we summarize the literature on thyroid function in cardiovascular diseases, both as a risk factor as well as in the setting of cardiovascular diseases such as heart failure or acute MI, and outline the effect of thyroid hormone replacement therapy for reducing the risk of cardiovascular disease.

Prevalence of hypothyroidism in diabetic kidney disease and effect of thyroid hormone replacement on estimate glomerular filtration rate

AIMS

To determine the prevalence of subclinical and overt hypothyroidism in diabetic kidney disease (DKD) and effect of thyroid hormone replacement on progression of DKD.

MATERIALS AND METHODS

A prospective cohort study on 41 adult DKD patients who were screened for hypothyroidism. Hypothyroid DKD patients were started on levothyroxine replacement and were reviewed after 3 and 6 months.

RESULTS

Of the total population, 14 (34.1%) cases were hypothyroid, among whom 12 (29.3%) cases were subclinical, and 2 (4.8%) were overt hypothyroidism. Prevalence of hypothyroidism and mean thyroid stimulating hormone levels increased with increasing severity of DKD. There were 2 (14.3%) hypothyroid cases in stage 3b, 4 (28.5%) cases in stage 4, and 8 (57.2%) in stage 5 DKD. The mean estimate glomerular filtration rate (ml/min/1.73 m²) at baseline was 13.6 ± 13.3 which increased to 16.4 ± 14.5 and 21.2 ± 15.3 after 3 and 6 months of thyroid hormone replacement therapy (THRT), respectively (P < 0.001).

CONCLUSIONS

Hypothyroidism is commonly associated with DKD. Prevalence of hypothyroidism increased with declining renal function. THRT significantly improved renal function in DKD patients with hypothyroidism after 3 and 6 months of therapy.

Thyroid function and risk of type 2 diabetes: a population-based prospective cohort study

BACKGROUND

The association of thyroid function with risk of type 2 diabetes remains elusive. We aimed to investigate the association of thyroid function with incident diabetes and progression from prediabetes to diabetes in a population-based prospective cohort study.

METHODS

We included 8452 participants (mean age 65 years) with thyroid function measurement, defined by thyroid-stimulating hormone (TSH) and free thyroxine (FT4), and longitudinal assessment of diabetes incidence. Cox-models were used to investigate the association of TSH and FT4 with diabetes and progression from prediabetes to diabetes. Multivariable models were adjusted for age, sex, high-density lipoprotein cholesterol, and glucose at baseline, amongst others.

RESULTS

During a mean follow-up of 7.9 years, 798 diabetes cases occurred. Higher TSH levels were associated with a higher diabetes risk (hazard ratio [HR] 1.13; 95 % confidence interval [CI], 1.08-1.18, per logTSH), even within the reference range of thyroid function (HR 1.24; 95 % CI, 1.06-1.45). Higher FT4 levels were associated with a lower diabetes risk amongst all participants (HR 0.96; 95 % CI, 0.93-0.99, per 1 pmol/L) and in participants within the reference range of thyroid function (HR 0.96; 95 % CI, 0.92-0.99). The risk of progression from prediabetes to diabetes was higher with low-normal thyroid function (HR 1.32; 95 % CI, 1.06-1.64 for TSH and HR 0.91; 95 % CI, 0.86-0.97 for FT4). Absolute risk of developing diabetes type 2 in participants with prediabetes decreased from 35 % to almost 15 % with higher FT4 levels within the normal range.

CONCLUSIONS

Low and low-normal thyroid function are risk factors for incident diabetes, especially in individuals with prediabetes. Future studies should investigate whether screening for and treatment of (subclinical) hypothyroidism is beneficial in subjects at risk of developing diabetes.

Recent Advances in Autoimmune Thyroid Diseases

Autoimmune thyroid disease (AITD) includes hyperthyroid Graves disease, hypothyroid autoimmune thyroiditis, and subtle subclinical thyroid dysfunctions. AITD is caused by interactions between genetic and environmental predisposing factors and results in autoimmune deterioration. Data on polymorphisms in the AITD susceptibility genes, related environmental factors, and dysregulation of autoimmune processes have accumulated over time. Over the last decade, there has been progress in the clinical field of AITD with respect to the available diagnostic and therapeutic methods as well as clinical consensus. The updated clinical guidelines allow practitioners to identify the most reasonable and current approaches for proper management. In this review, we focus on recent advances in understanding the genetic and environmental pathogenic mechanisms underlying AITD and introduce the updated set of clinical guidelines for AITD management. We also discuss other aspects of the disease such as management of subclinical thyroid dysfunction, use of levothyroxine plus levotriiodothyronine in the treatment of autoimmune hypothyroidism, risk assessment of long-standing antithyroid drug therapy in recurrent Graves' hyperthyroidism, and future research needs.

A Worthy Finding: Decrease in Total Cholesterol and Low-Density Lipoprotein Cholesterol in Treated Mild Subclinical Hypothyroidism

BACKGROUND

Mild subclinical hypothyroidism (SCH) affects a large number of people and is known to be a risk factor for dyslipidemia. However, whether mild SCH patients should be treated with L-thyroxine to improve lipid profiles remains controversial. In addition, it is also unclear whether all mild SCH patients can benefit from L-thyroxine treatment, regardless of basal thyrotropin or lipid levels. This study aimed to assess the effects of L-thyroxine replacement therapy on the lipid profiles of mild SCH patients.

METHODS

This open-label randomized controlled trial was performed in Ningyang County, Shandong Province, China. A total of 378 mild SCH patients with diagnoses confirmed by two thyroid function tests were randomly assigned to either the intervention group (L-thyroxine replacement therapy) or the control group (no treatment). The primary outcome was a change in serum total cholesterol (TC) concentration.

RESULTS

In all, 369 participants completed the 15-month follow-up period. Reduced TC concentrations were more prominent in the intervention group than they were in the control group (-0.41 mmol/L vs. -0.17 mmol/L; p = 0.012), and changes in low-density lipoprotein cholesterol levels exhibited the same trend. Subgroup analyses were performed to assess the effects of L-thyroxine in patients with different thyrotropin or TC levels. When the study population was stratified according to basal thyrotropin concentration, all patients who had received L-thyroxine showed reduced TC levels (p < 0.001). The treatment was similarly beneficial for all patients, regardless of basal TC level. Even for subjects with TC levels <5.18 mmol/L, serum TC concentrations remained unchanged in the intervention group (p = 0.936) but increased by 0.35 mmol/L in the control group (p = 0.004).

CONCLUSIONS

The findings suggest that mild SCH patients could benefit from L-thyroxine treatment to improve lipid profiles, regardless of basal thyrotropin or TC concentrations.

Menopause modulates the association between thyrotropin levels and lipid parameters: The SardiNIA study

OBJECTIVE

Thyroid hormone influences lipoprotein metabolism. The role of menopausal status in this association has not been extensively studied. The aim of the present study is to evaluate the association between lipid parameters and mild elevations of thyrotropin (TSH), and whether menopause influences this relationship.

STUDY DESIGN

A cross-sectional study was conducted with a sample of 2,914 women (aged 14-102 years) from the SardiNIA study.

MAIN OUTCOME MEASURES

The association of TSH with blood lipid levels was examined using regression analyses, according to menopausal status.

RESULTS

Postmenopausal women had lower serum TSH concentrations and higher levels of total cholesterol, low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), and triglycerides than did premenopausal women (p=0.001 or less for all). In premenopausal women, after adjusting for the confounders age, BMI, smoking, insulin and glycaemia, TSH showed a direct relation to the levels of total cholesterol (β=0.046, p=0.010), LDLc (β=0.044, p=0.016) and triglycerides (β=0.085, p<0.001), but no association with HDLc level. In the postmenopausal group, TSH was directly associated only with triglyceride levels (β=0.103, p=0.014).

CONCLUSIONS

The association between mild elevation of TSH and lipid levels is influenced by menopausal status. Further research is needed to clarify this finding.

Natural history of subclinical hypothyroidism with TSH ≤10 mIU/l: a prospective study

OBJECTIVE

The risk of progression of subclinical hypothyroidism (SCH) to clinical dysfunction is one of the factors considered in the decision to treat this condition. This study evaluated the natural history of SCH in women with TSH ≤10 mIU/l.

DESIGN

This is a prospective study.

PATIENTS

Two hundred and fifty-two women with SCH and TSH levels ranging from 4·5 to 10 mIU/l were followed up for a period of 5 years.

RESULTS

Among the 241 patients followed up until the completion of the study, 46 (19%) required levothyroxine (L-T4) therapy, 55 (22·8%) had spontaneous normalization of serum TSH, and 140 (58·1%) continued to meet the criteria for mild SCH. In multivariate analysis, only initial TSH >8 mIU/l was a predictor of the need for L-T4. In contrast, initial TSH ≤8 mIU/l and the absence of thyroiditis [negative antithyroid peroxidase antibodies (TPOAb) and ultrasonography (US)] were predictors of TSH normalization. Of note, the natural history was similar in TPOAb-positive patients and patients with negative TPOAb but with positive US.

CONCLUSIONS

Most women with mild elevation of serum TSH, ranging from 4·5 to 10 mIU/l, do not progress to overt hypothyroidism and even normalize their TSH. However, initial TSH seems to be a more important predictor of progression than the presence of antibodies or ultrasonographic appearance.

The impact of thyroid hormone replacement therapy on left ventricular diastolic function in patients with subclinical hypothyroidism

OBJECTIVE

Subclinical hypothyroidism (SH) is associated with a moderately elevated risk of heart failure events among older adults. The objective of our prospective study was to assess the impact of thyroid hormone replacement therapy (HRT) with low doses of L-thyroxine (6.25-25 µg/day) on left ventricular diastolic function in patients with SH.

MATERIALS AND METHODS

33 patients with SH and 25 healthy controls were involved. All participants underwent standard echocardiography and Doppler imaging at baseline and, the patient group, also after a course of HRT.

RESULTS

At baseline, patients with SH showed significantly lower E (0.79 ± 0.22 vs. 0.93 ± 0.19, p < 0.001), E/A ratio (1.19 ± 0.29 vs. 1.31 ± 0.25, p < 0.003), and higher intraventricular septum thickness (IVST) (0.99 ± 0.14 vs. 0.89 ± 0.18, p < 0.001) in comparison with healthy controls. After 6 months of therapy, the E/A ratio underwent significant increase (1.28 ± 0.21 vs. 1.19 ± 0.29, p < 0.001), while the IVS displayed a robust reduction (0.92 ± 0.16 vs. 0.99 ± 0.14, p < 0.001).

CONCLUSIONS

HRT with low-dosed L-thyroxine may improve left ventricular diastolic function in patients with SH.

Effect of steroid replacement on thyroid function and thyroid autoimmunity in Addison's disease with primary hypothyroidism

BACKGROUND

Steroid replacement without thyroxine supplementation normalizes thyroid function test (TFT) in some but not all Addison's disease patients with primary hypothyroidism. Both autoimmune and nonautoimmune mechanisms contribute to this improvement in TFT. However, the documentation of the change in thyroid autoimmunity after cortisol replacement is very limited in the literature. The aim of this study was to determine the effect of steroid replacement on TFT and anti-thyroid peroxidase antibody (anti-TPO-Ab) titer in Addison's disease with primary hypothyroidism.

MATERIALS AND METHODS

This observational study was conducted in a tertiary care center in South India. Six Addison's disease patients with primary hypothyroidism, who were only on steroid replacement, were included in the study. Low serum cortisol (<83 nmol/L) with high plasma adrenocorticotropic hormone (>22 pmol/L) and/or hyperpigmentation of skin/mucous membranes was considered as the diagnostic criteria for Addison's disease. Primary hypothyroidism (both overt and subclinical) was defined as high thyroid stimulating hormone (TSH) with/without low free thyroxine (fT4). TFT and anti-TPO-Ab were performed before and after steroid replacement in all of them.

RESULTS

Poststeroid replacement, there was a normalization of TSH in all but one subjects. In overt hypothyroidism patients, fT4 also normalized. The improvement in TFT was not associated with decreasing titer of the anti-TPO-Ab in all six patients. However, there was a significant difference in TSH after steroid replacement compared to the baseline status.

CONCLUSIONS

The concept of normalization of primary hypothyroidism with cortisol replacement in patients with Addison's disease should be recognized to avoid iatrogenic thyrotoxicosis caused by thyroxine replacement. Both autoimmune and nonautoimmune mechanisms contribute to these alterations.

Thyroid disease in pregnancy: A review of diagnosis, complications and management

Malfunction of the thyroid gland is the second most common endocrine disorder encountered during pregnancy. It is well known that overt disease of the thyroid gland, either hyper or hypo can adversely affect pregnancy outcome. There is also an ongoing debate surrounding the issue of subclinical hypothyroidism and its effect on the cognitive development of the unborn child. The goal of this paper is to present a systematic review of the literature and the current recommendations for diagnosis and treatment of thyroid disease in pregnancy and postpartum.

Levothyroxine replacement in primary congenital hypothyroidism: the higher the initial dose the higher the rate of overtreatment

BACKGROUND

Congenital hypothyroidism (CH) is the most frequent endocrine disorder during the neonatal period, and a delay in diagnosis and treatment leads to irreversible complications. A high L-thyroxine (LT4) dose is recommended for treatment, while the optimal starting dose is still a matter of debate. The objective of this study was to determine the effects of various starting doses of LT4 on serum thyroid stimulating hormone (TSH) and thyroxine (fT4) at the end of the first month of treatment.

METHODS

A total of 71 patients (37 males, 52.1%) with CH were included in the study. The patients were designated into three sets of subgroups according to the following categorical variables: (i) initial LT4 doses: 6-9.9 μg/kg/day, 10-11.9 μg/kg/day and 12-17 μg/kg/day; (ii) initial TSH levels: 6-9.99 μIU/mL, 10-75 μIU/mL and >75 μIU/mL; and (iii) etiology: dyshormonogenesis and dysgenesis. A fT4 level >2.3 ng/dL±a TSH level <0.5 μIU/mL were considered as overtreatment.

RESULTS

The mean age of the study population was 22.3±13.2 days at diagnosis. At diagnosis, the mean fT4 was 0.84±0.32 ng/dL, and TSH was 39.3±30 μIU/mL. The mean initial dose of LT4 was 10.9±2.9 μg/kg/day. Overtreatment rates were significantly higher in the highest dose group (12-17 μg/kg/day) compared with the lowest dose group (6-9.9 μg/kg/day) (61.5% and 25%, respectively, p<0.05). None of the patients was undertreated.

CONCLUSIONS

In this study, we found that the rate of overtreatment was significantly higher in patients who were given LT4 doses of 12-17 μg/kg/day. Thus, monitoring thyroid functions earlier than one month of treatment is necessary.

Levothyroxine treatment of mild subclinical hypothyroidism: a review of potential risks and benefits

Subclinical hypothyroidism (SCH) is defined as elevated thyroid stimulating hormone (TSH) with normal levels of free triiodothyronine (FT3) and free thyroxine (FT4). SCH is further classified into a milder condition with TSH levels between 4.0 and 10.0 milli-international units (mIU)/l (mild-SCH) and a severe form with TSH >10.0 mIU/l (severe-SCH). SCH is a common problem (prevalence is greater in women than men), which increases further with increasing age and TSH levels. Even though the risk of progression to overt hypothyroidism is higher in patients with severe-SCH, the risk is also significant in patients having mild-SCH; it has been suggested that every twofold rise in serum TSH would increase the risk from 1 to 4%, which further increases to 38% if thyroid antibodies are positive. Current data have shown increased cardiovascular risk in patients with mild-SCH and have demonstrated some benefits of levothyroxine treatment in reducing these events. However, evidence on the association of mild-SCH and musculoskeletal system, cognitive dysfunction, mood disorders, dyslipidaemia, diabetes and goitre is conflicting. Similarly, the discussion regarding the exact upper limit of normal for serum TSH remains controversial. The data have also shown increased risk of adverse pregnancy outcomes in patient with mild-SCH, with some benefits of thyroxine treatment. The recent available guidelines related to management of patients with serum TSH <10 mIU/l have suggested decisions should be made taking into account the age of the patient, associated risk factors and comorbid conditions. This chronicle review assesses current evidence regarding the risks associated and the recommendations related to benefits of levothyroxine treatment in patients having mild-SCH.

MECHANISMS IN ENDOCRINOLOGY: Impact of isolated TSH levels in and out of normal range on different tissues

Routine treatment of thyroid cancer (TC) includes long-term suppression of TSH. The necessity of this treatment in low- and intermediate-risk patients as well as the extent of TSH suppression is currently under discussion. A literature search was performed to illustrate the role of TSH in extrathyroidal cells and to identify potential reasons for different effects of exogenously suppressed and endogenously low TSH levels. Although adverse effects of subnormal and supranormal TSH blood levels on heart and brain have not been consistently found, studies show a clear negative effect of suppressed TSH levels on bone mineral density. Experimental data also support an important role of TSH in the immune system. The ability of levothyroxine (l-T4) to regulate TSH levels and triiodothyronine levels in a physiological manner is limited. Reduction of circadian changes in TSH levels, decrease of thyroid hormone-binding proteins, prevention of potential compensatory increases of TSH levels (e.g., in old age), and unresponsiveness of TSH-producing cells to TRH on l-T4 treatment might cause adverse effects of suppressed TSH levels. In view of the adverse effects of aggressive TSH suppression, achieving the suggested levels of TSH between 0.9 and 1 mU/l in the treatment of low-to-intermediate risk TC patients appears justified.

Subclinical Thyroid Dysfunction and Depressive Symptoms among the Elderly: A Prospective Cohort Study

BACKGROUND

Subclinical hypothyroidism has been associated with depressive symptoms in cross-sectional studies, but prospective data and data on subclinical hyperthyroidism are scarce.

METHODS

In the Leiden substudy of the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), thyroid-stimulating hormone and free T4 levels were measured at baseline and repeated after 6 months in adults aged 70-82 years with preexisting cardiovascular disease or known cardiovascular risk factors to define persistent thyroid functional status. Main outcome measures were depressive symptoms, assessed with the Geriatric Depression Scale 15 (GDS-15) at baseline and after 3 years. All analyses were adjusted for age, gender and education.

RESULTS

In 606 participants (41% women; mean age 75 years) without antidepressant medication, GDS-15 scores at baseline did not differ for participants with subclinical hypothyroidism (n = 47; GDS-15 score 1.75, 95% CI 1.29-2.20, p = 0.53) or subclinical hyperthyroidism (n = 13; GDS-15 score 1.64, 95% CI 0.78-2.51, p = 0.96) compared to euthyroid participants (n = 546; mean GDS-15 score 1.60, 95% CI 1.46-1.73). After 3 years, compared to the euthyroid participants, changes in GDS-15 scores did not differ for participants with subclinical hypothyroidism (x0394;GDS-15 score -0.03, 95% CI -0.50 to 0.44, p = 0.83), while subclinical hyperthyroidism was associated with an increase in GDS scores (x0394;GDS-15 score 1.13, 95% CI 0.32-1.93, p = 0.04). All results were similar for persistent subclinical thyroid dysfunction.

CONCLUSIONS

In this largest prospective study on the association of persistent subclinical thyroid dysfunction and depression, subclinical hypothyroidism was not associated with increased depressive symptoms among older adults at high cardiovascular risk. Persistent subclinical hyperthyroidism might be associated with increased depressive symptoms, which requires confirmation in a larger prospective study.

Thyroid Stimulating Hormone Is Increased in Hypertensive Patients with Obstructive Sleep Apnea

Purpose. To evaluate alteration in serum TSH in hypertensives with OSA and its relation with cardiometabolic risk factors. Methods. 517 hypertensives were cross-sectionally studied. OSA was determined by polysomnography and thyroid function by standard methods. Results. OSA was diagnosed in 373 hypertensives (72.15%). Prevalence of subclinical hypothyroidism was significantly higher in OSA hypertensives than in non-OSA ones (15.0% versus 6.9%, P = 0.014). Serum LnTSH in hypertensives with severe OSA was significantly higher (0.99 ± 0.81 versus 0.74 ± 0.77 μIU/mL, P < 0.05) than in those without OSA. AHI, LSaO₂, ODI₃, and ODI₄ were independently associated with serum TSH for those aged 30-65 years. Dividing subjects into four groups as TSH < 1.0 μIU/mL, 1.0 ≤ THS ≤ 1.9 μIU/mL, 1.91 ≤ TSH < 4.5 μIU/mL, and TSH ≥ 4.5 μIU/mL, only 26.3% of OSA subjects exhibited TSH between 1.0 and 1.9 μIU/mL, significantly less than non-OSA subjects (26.3% versus 38.2%, P = 0.01). DBP and serum LDL-c elevated with TSH increasing and were only significantly higher in TSH ≥ 4.5 μIU/mL group than in 1.0 ≤ TSH ≤ 1.9 μIU/mL group (96.32 ± 14.19 versus 92.31 ± 12.86 mmHg; P = 0.040; 0.99 ± 0.60 versus 0.87 ± 0.34 mmol/L, P = 0.023). Conclusion. OSA might be a risk factor for increased TSH even within reference range in hypertensive population.

Study on Subclinical Hypothyroidism and its Association with Various Inflammatory Markers

INTRODUCTION

Subclinical hypothyroidism shows the mimic reaction more like to frank hypothyroidism which creates the dilemma. Inflammatory markers can be helpful in assessment of adverse effects of subclinical hypothyroidism, are not very well studied in the past. So the aim of this study was to investigate the role of inflammatory markers in Subclinical hypothyroidism patients.

MATERIALS AND METHODS

The study population consisted of 154 patients with recently diagnosed subclinical hypothyroidism and 100 healthy controls. TSH, FT4 & T3 were estimated by enzyme linked Immunosorbent assay (ELISA) for diagnosis of subclinical hypothyroidism. Total cholesterol, triglycerides, and HDL-C were estimated by spectrophotometric method. LDL - C was calculated by Friedewald formula. Inflammatory markers (ESR, C-reactive protein & Interleukin 6) were also estimated by enzyme linked Immunosorbent assay (ELISA).

RESULTS

In this study the level of TSH Mean ± SD (11.12±4.17 vs 2.73±0.80) and T3 Mean ± SD (0.96±0.17 vs 1.08±0.26) were significantly higher (<0.001) in subclinical hypothyroidism. Serum concentration of FT4 was not significantly different between the groups. Total cholesterol, triglycerides, and LDL-C were significantly higher in patients group. While the level of HDL-C was significantly lower in SCH patients compared to euthyroid group. TSH level was positively correlated with inflammatory markers in subclinical hypothyroidism, which were significantly different in subclinical hypothyroidism.

CONCLUSION

This study suggests that subclinical hypo-thyroidism patients have increased inflammatory markers along with dyslipidemia and due to that future risk of further development of cardiovascular disorder can occur. Level of inflammatory markers increases in patients as disease progress if left untreated.

Factors associated with growth disturbance at celiac disease diagnosis in children: a retrospective cohort study

Background

Impaired growth is a well-known complication in celiac disease, but factors associated with it are poorly known. We investigated this issue in a large cohort of children.

Methods

530 children with biopsy-proven celiac disease were included. The participants were divided into two groups on the basis of the presence (n = 182) or absence (n = 348) of growth disturbance at diagnosis. Histological, serological and clinical characteristics were compared between children with growth failure and those with normal growth. Further, patients with growth failure as the sole clinical presentation were compared to those with poor growth and concomitant other symptoms.

Results

Children with growth failure were younger (p < 0.001) and had lower hemoglobin (p = 0.016) and higher celiac antibody (p < 0.001), alanine aminotransferase (p = 0.035) and thyroid-stimulating hormone values (p = 0.013) than those with normal growth. Significantly associated with growth failure at diagnosis were age <3 years (OR 4.3 (95 % CI 2.5-7.5) vs older age), diagnosis before the year 2000 and in 2000–09 (OR 3.1 (1.8-5.4) and OR 1.8 (1.1-2.8) vs diagnosis in 2010–2013), presence of total and subtotal villous atrophy (OR 4.2 (2.5-7.0) and OR 2.0 (1.3-3.2) vs partial atrophy), severe symptoms (OR 3.4 (1.8-6.7) vs mild symptoms) and vomiting (OR 3.1 (1.5-6.3). The presence of abdominal pain reduced the risk (OR 0.5 (0.3-0.7)), while there was no effect of gender, diarrhea, constipation, other chronic diseases and celiac disease in the family. Children evincing poor growth as the sole clinical presentation were older (p < 0.001) and had higher hemoglobin (P < 0.001) and total iron (p = 0.010) values and lower TG2ab values (p = 0.009) than those with growth disturbance and other symptoms.

Conclusions

In particular young age and severe clinical and histological presentation were associated with growth disturbance at celiac disease diagnosis. Children with only poor growth are markedly different from those with other concomitant symptoms, suggesting different pathogenic mechanisms.

Subclinical hypothyroidism: a 'laboratory-induced' condition?

OBJECTIVE

In current literature and guidelines, there is a tendency to define absolute TSH concentrations at which patient follow-up or even pharmaceutical intervention should be initiated. As TSH concentrations depend on the analytical method/platform used for TSH quantification, absolute cut-off values may pose threats for uniform clinical decision-making. In this study we therefore set out to clarify to what extent the method/platform and the reference values applied for TSH influence the clinical interpretation of thyroid parameters.

DESIGN AND METHODS

We retrospectively analyzed anonymous TSH results from the Dutch external quality assessment program (EQAS) in relation to reference values advised by different manufacturers. We also examined TSH/free thyroxin (fT4) reference ranges and prevalence of thyroid pathology among different Dutch laboratories, including four cases in which a switch in the measuring platform was made.

RESULTS

Our data show that interpretation of thyroid parameters is not only influenced by between-method/platform variation, but is also substantially affected by the variation in TSH/fT4 reference intervals applied in individual laboratories. Additionally, we show that the transition to a novel analytical method/platform can result in a shift in the prevalence of thyroid pathology, especially for subclinical hypothyroidism.

CONCLUSIONS

Subclinical hypothyroidism can be a 'laboratory-induced' condition. This is an undesirable situation in regard to the clinical implications such a diagnosis can have for patients.

STUDY OF THE PREVALENCE OF AUTOIMMUNE THYROID DISEASE IN WOMEN WITH BREAST CANCER

OBJECTIVE

The aim of this study was to analyze the prevalence of thyroid disorders in patients with a positive biopsy for breast cancer prior to specific antitumor treatment.

METHODS

The frequency and pattern of thyroid disorders were evaluated in 112 patients with breast cancer (G1) and 125 control patients (G2) by analyzing serum thyroid-stimulating hormone (TSH), anti-thyroid peroxidase antibodies, and anti-thyroglobulin antibodies. In addition, the expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) was assessed in the breast biopsies by immunohistochemistry.

RESULTS

The frequency of thyroid disorders, such as changes in TSH levels and/or the presence of thyroid antibodies, was not different between the 2 groups examined (30.4% in G1 versus 28.0% in G2) (P = .69). However, a family history of thyroid disease was more frequent in patients with breast cancer (50.5% in G1 versus 28.2% in G2) (P = .001). Regarding the clinical stage of breast cancer, there was no difference between women with autoimmune thyroiditis and those without thyroid dysfunction (P = .316). Similarly, there were no differences in hormone receptor (estrogen or progesterone) and HER2 expression between patients who tested positive and those who tested negative for anti-thyroid antibodies (P = .052 and P = .549, respectively).

CONCLUSION

The data obtained in this study did not reveal a higher frequency of autoimmune thyroid disease in patients with breast cancer compared to controls. A family history of thyroid disease was more common in those with breast cancer.

Changes in the before and after thyroxine treatment levels of adipose tissue, leptin, and resistin in subclinical hypothyroid patients

BACKGROUND

Subclinical hypothyroidism (SH) occurs when serum thyroid stimulating hormone (TSH) concentrations are raised and serum thyroid hormone concentrations are normal. The effect of SH on the proinflammatory adipose cytokine releasing visceral adipose tissue (VAT) is not clear. The aim of this study is to identify the difference between the pre and posttreatment levels of VAT, leptin, and resistin in SH patients.

METHODS

There were 51 SH patients and 43 age- and gender-matched healthy subjects included in the study. Thyroid functions, biochemical tests, leptin, resistin, and visceral and subcutaneous fat measurements were made. The measurements were repeated in the SH group in the third month following L-thyroxin treatment.

RESULTS

Initially, high sensitivity C-reactive protein, carotid artery intima-media thickness (mm), leptin, and resistin levels were significantly higher in the SH group compared to the controls, while the other parameters were similar. While no correlation was observed between TSH levels and adipokines, a positive correlation was detected between waist circumference and leptin levels (r = 0.549, p < 0.01). Visceral adipose tissue was positively correlated to age, waist circumference, and leptin levels, but negatively correlated to free thyroxin (T4) levels (r = 0.419, p = 0.009; r = 0.794, p < 0.01; r = 0.515, p < 0.01 and r = - 0.416, p = 0.009, respectively). A significant decrease was observed in VAT volume, leptin, and resistin levels of SH patients following levothyroxine treatment. Conclusion The reduced VAT volume, leptin, and resistin levels in SH patients following treatment may support the idea that TSH affects adipose tissue functions.