Prevalence and risk factors of subclinical thyroid disease

A Clinical Study of Thyroid Abnormalities and Autoantibodies in Patients Diagnosed With Anti-nuclear Antibody Positive Autoimmune Connective Tissue Disorders: An Observational Cross-Sectional Study

INTRODUCTION

Autoimmune connective tissue disorders (CTDs) are characterized by inflammation of the connective tissue structures and immune system aberrations, such as autoantibody production. This study investigates the prevalence and clinical significance of thyroid abnormalities in patients with anti-nuclear antibody (ANA)-positive autoimmune CTDs.

METHODS

This prospective cross-sectional observational study was conducted at Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth (Deemed to be University), Pune, from September 2022 to June 2024. Eighty patients diagnosed with ANA-positive CTDs were included. Comprehensive histories were collected from them and clinical examinations and routine investigations were performed. Blood samples were collected for thyroid function tests and autoantibody tests. Thyroid ultrasound investigations were also performed. Ethical approval and informed consent were obtained.

RESULTS

The study revealed a significant prevalence of thyroid dysfunction among participants, with 39 (48.75%) exhibiting some form of thyroid abnormality. Subclinical hypothyroidism was the most common condition in 18 (22.50%) participants, predominantly affecting females. Thyroid autoantibodies were present in 32 (40%) participants, with thyroid peroxidase antibodies (anti-TPO Ab) being the most common seen in 17 (21.25%) participants. Systemic lupus erythematosus (SLE) was the most prevalent CTD among participants, seen in 44 (55%) participants, followed by Sjogren's syndrome (SS) seen in 19 (23.75%) participants.

CONCLUSION

The study underscores the necessity of routine thyroid function screening in patients with ANA-positive CTDs to facilitate early detection and management of thyroid abnormalities, thereby preventing progression to overt hypothyroidism or hyperthyroidism. The findings highlight the significant association between thyroid dysfunction and autoimmune CTDs, advocating for a holistic approach to patient care.

EMAS position statement: Thyroid disease and menopause

INTRODUCTION

Thyroid diseases are common in women in their late reproductive years; therefore, thyroid disease and menopause may co-exist. Both conditions may present with a wide range of symptoms, leading to diagnostic challenges and delayed diagnosis. Aim To construct the first European Menopause and Andropause Society (EMAS) statement on thyroid diseases and menopause.

MATERIALS AND METHODS

Literature review and consensus of expert opinion (EMAS executive board members/experts on menopause and thyroid disease).

SUMMARY RECOMMENDATIONS

This position paper highlights the diagnostic and therapeutic dilemmas in managing women with thyroid disease during the menopausal transition, aiming to increase healthcare professionals' awareness of thyroid disorders and menopause-related symptoms. Clinical decisions regarding the treatment of both conditions should be made with caution and attention to the specific characteristics of this age group while adopting a personalized patient approach. The latter must include the family history, involvement of the woman in the decision-making, and respect for her preferences, to achieve overall well-being.

Efficacy of Standardized Yoga Asanas as Add-on Therapy in the Management of Hypothyroidism: A Randomized, Open-label, Controlled Clinical Study

Background

Hypothyroidism is an endocrine disorder in which the thyroid gland does not produce an adequate amount of thyroid hormones. This study aimed to determine the efficacy of yoga asanas as an add-on therapy for the management of hypothyroidism.

Materials and Methods

For this interventional clinical study, a total of 450 study participants were screened for eligibility. Out of this, 170 study participants were found fit for preliminary eligibility following stringent inclusion and exclusion criteria. Further, 58 participants were excluded before randomization. A total of 112 hypothyroidism patients (57 in the control group and 55 in the yoga group) participated in this study. The study participants were further followed up for 8 weeks in both the yoga practice (yoga+ standard care of treatment) and control group (standard care of treatment only). The markers of oxidative stress, inflammation, and thyroid hormones were assessed at baseline and after 8 weeks of follow-up/intervention.

Results

After 8 weeks, the study participants in yoga group showed a significant reduction in serum thyroid-stimulating hormone and malondialdehyde levels as compared to baseline (P < 0.05). There was also a positive trend of improvement in other oxidative markers (catalase, superoxide dismutase, and glutathione), and a significant reduction in interleukin-6 levels (P < 0.05) was found in the yoga group as compared to the baseline. However, there was no significant change found in the control group of subjects.

Conclusion

Frequent yoga practice can be an effective lifestyle intervention for hypothyroidism, reducing oxidative stress, inflammation, and potentially improving overall well-being.

Changes in thyroid function and evolution of subclinical thyroid disease in older men

OBJECTIVE

Prevalence of subclinical thyroid disease increases with age, but optimal detection and surveillance strategies remain unclear particularly for older men. We aimed to assess thyroid stimulating hormone (TSH) and free thyroxine (FT4) concentrations and their longitudinal changes, to determine the prevalence and incidence of subclinical thyroid dysfunction in older men.

DESIGN, PARTICIPANTS AND MEASUREMENTS

Longitudinal study of 994 community-dwelling men aged ≥70 years without known or current thyroid disease, with TSH and FT4 concentrations assessed at baseline and follow-up (after 8.7 ± 0.9 years). Factors associated with incident subclinical thyroid dysfunction were examined by logistic regression and receiver operating characteristic analyses.

RESULTS

At baseline, 85 men (8.6%) had subclinical hypothyroidism and 10 (1.0%) subclinical hyperthyroidism. Among 899 men euthyroid at baseline (mean age 75.0 ± 3.0 years), 713 (79.3%) remained euthyroid, 180 (20.0%) developed subclinical/overt hypothyroidism, and 6 (0.7%) subclinical/overt hyperthyroidism. Change in TSH correlated with baseline TSH (r = .16, p < .05). Change in FT4 correlated inversely with baseline FT4 (r = -0.35, p < .05). Only higher age and baseline TSH predicted progression from euthyroid to subclinical/overt hypothyroidism (fully-adjusted odds ratio [OR] per year=1.09, 95% confidence interval [CI] = 1.02-1.17, p = .006; per 2.7-fold increase in TSH OR = 65.4, CI = 31.9-134, p < .001). Baseline TSH concentration ≥2.34 mIU/L had 76% sensitivity and 77% specificity for predicting development of subclinical/overt hypothyroidism.

CONCLUSIONS

In older men TSH concentration increased over time, while FT4 concentration showed little change. Subclinical or overt hypothyroidism evolved in one fifth of initially euthyroid men, age and higher baseline TSH predicted this outcome. Increased surveillance for thyroid dysfunction may be justified in older men, especially those with high-normal TSH.

Appropriateness of Levothyroxine Prescription: A Multicenter Retrospective Study

CONTEXT

Levothyroxine is one of the most prescribed medications in the United States.

OBJECTIVE

This study explores the appropriateness of levothyroxine prescriptions.

METHODS

A retrospective multicenter study was conducted on adult patients who were prescribed levothyroxine for the first time between 2017 and 2020 at three academic centers in the United States. We classified each case of levothyroxine initiation into one of three mutually exclusive categories: appropriate (clinically supported), indeterminate (clinically unclear), or nonevidence based (NEB, not clinically supported).

RESULTS

A total of 977 participants were included. The mean age was 55 years (SD 19), there was female (69%) and White race predominance (84%), and 44% had possible hypothyroid symptoms. Nearly half of the levothyroxine prescriptions were considered NEB (528, 54%), followed by appropriate (307, 31%) and indeterminate (118, 12%). The most common reason for NEB prescription was an index thyrotropin (TSH) value of less than 10 mIU/L without previous TSH or thyroxine values (131/528, 25%), for appropriate prescription, was overt hypothyroidism (163/307, 53%), and for an indeterminate prescription was a nonconfirmed subclinical hypothyroidism with TSH greater than or equal to 10 mIU/L (no confirmatory testing) (51/118, 43%). In multivariable analysis, being female (odds ratio [OR]: 1.3; 95% CI, 1.0-1.7) and prescription by a primary care provider (OR: 1.5; 95% CI, 1.2-2.0) were associated with NEB prescriptions.

CONCLUSION

There is a considerable proportion of NEB levothyroxine prescriptions. These results call for additional research to replicate these findings and to explore the perspective of those prescribing and receiving levothyroxine.

Subclinical thyroid dysfunction and the risk of incident atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Thyroid hormones act on the cardiovascular system directly by modulating its function and indirectly by transcriptional regulation of gene expression in the heart and the vasculature. Studies have shown associations between overt and subclinical thyroid disorders and cardiovascular outcomes. The aim of this study was to perform a systematic review and meta-analysis to assess the potential relationships between subclinical hyper- and hypothyroidism and risk of atrial fibrillation (AF), and post-operative AF.

METHODS

MEDLINE and Scopus databases were searched from inception to 18th February 2023 for randomised controlled trials, case-control studies, and cohort studies which assessed the relationship between subclinical thyroid dysfunction and incident AF events. Risk of bias and the quality of evidence were assessed using the RoBANS tool and GRADE approach, respectively. Meta-analysis was conducted in Review Manager 5.4 using the Mantel-Haenszel statistical method and a random-effects model. Data are presented as risk ratios with 95% confidence intervals. Statistical heterogeneity amongst studies was assessed by the chi-squared (χ2) test and I2 statistic. p≤0.05 were considered significant.

RESULTS

A total of 6467 records were identified, of which 10 cohort studies met the inclusion criteria. Both subclinical hyperthyroidism and subclinical hypothyroidism were associated with an increased risk of incident AF (risk ratio (RR), 1.99; 95% confidence interval (CI), 1.43-2.77; n = 5 studies; p<0.0001 and RR, 1.19; CI, 1.03-1.39; n = 7 studies; p = 0.02, respectively). Subgroup analysis for post-operative AF revealed marked heterogeneity between studies (I2 = 84%) and association with subclinical hypothyroidism was not significant (RR, 1.41; CI, 0.89-2.22; n = 3 studies; p = 0.15).

CONCLUSIONS

The current evidence suggests that both subclinical hyperthyroidism and subclinical hypothyroidism are associated with increased risk of incident AF. Further investigation is required to determine potential causal links that would guide future clinical practice.

Autoimmune thyroid status in subclinical thyroid disorders in patients attending a tertiary care center in Nepal: a hospital-based cross-sectional study

BACKGROUND

Thyroid dysfunction is the leading endocrine disorder worldwide. Iodine deficiency disorders, which were once the major etiology of thyroid dysfunctions, now have been succeeded by autoimmune thyroid diseases with the rise in aberrant salt ionization protocols. This study endeavors to access the level of thyroid autoantibodies viz. anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (TGA), and anti-thyroid stimulating hormone receptor (TRAb) in individuals with subnormal thyroid profiles.

METHODS

This hospital-based cross-sectional study was conducted at the Department of Clinical Biochemistry, Tribhuvan University for a period of six months. Using non-probability (purposive) sampling method, a total of 60 patients were enrolled with subnormal thyroid profiles to include the population who have not yet started medication. Thyroid hormones (free T3, free T4, TSH) and thyroid antibodies (anti-TPO, TGA, and TRAb) were measured. For non-parametric data, Chi-square test and Kruskal-Wallis test were used. Spearman's correlation was done to determine the association between variables.

RESULTS

Out of 60 participants, the majority of the population between 25 and 44 years were diagnosed with thyroid dysfunction with female preponderance. Among all, 40% (n = 24) had subclinical hyperthyroid states while, 60% (n = 36) had subclinical hypothyroid states, and 75% (n = 45) of the total exhibited positive thyroid antibodies. In subclinical hypothyroid patients with TSH above 10 µIU/ml, anti TPO (58.5%) and TGA (66.7%) positivity were highly prevalent. On the other hand, TRAb was exclusively positive in hyperthyroid condition (50% among the group) which is by far the first of its kind reported in Nepal.

CONCLUSION

The rise in autoimmune thyroid disease among the Nepalese population infers that addressing iodine deficiency simply through salt iodinization may not be adequate to deal with the rising burden of thyroid disorders, especially in iodine-depleted areas. Also, the increasing prevalence of thyroid autoantibodies positivity in subclinical hypothyroidism in the Nepalese population accounts for the arduous screening and monitoring of autoimmune thyroid disorders in Nepal.

The Role of Global Longitudinal Strain in Subclinical Hypothyroid Patients With Heart Failure

Introduction There is considerable evidence to suggest the role of thyroid hormone in acute coronary syndrome (ACS), but less is known about its prognostic role in heart failure (HF). We aimed to assess the role of global longitudinal strain (GLS) in patients hospitalized with HF and underlying subclinical hypothyroidism (SCHS). Methods A retrospective analysis of 161 subjects was conducted by dichotomizing them into HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF) subgroups. SCHS was defined as a thyroid stimulating hormone level >4.50 mIU/L with a normal thyroxine level based on the evaluation of limits for lab markers from prior studies. HFpEF and HFrEF were defined as left ventricular ejection fraction (LVEF)>40% and LVEF≤40%, respectively, based on American College of Cardiology (ACC) guidelines. An abnormal speckled transthoracic echocardiographic (TTE) strain was defined as a left ventricular global longitudinal strain (LVGLS) value of >-15%. Results The mean age of the population was 62±8 years, and 55% were female. LVGLS was present in 121 patients with underlying SCHS (p<0.05). The patients with SCHS and abnormal LVGLS were found to have deranged left ventricular echocardiographic parameters (p<0.05). The derangements were greater for SCHS patients with HFrEF and abnormal LVGLS (p<0.05). Readmission rates at 30 days and in-hospital mortality were higher in SCHS patients with abnormal LVGLS (p<0.05). Conclusion The SCHS is associated with abnormal GLS in HF patients (either HFpEF or HFrEF) that results in remodeling and adverse outcomes, including mortality and readmission rates. Further studies are warranted to validate these findings in a larger population data pool.

The effect of low dose thyroid replacement therapy in patients with episodic migraine and subclinical hypothyroidism: A randomised placebo-controlled trial

INTRODUCTION

Migraine is a common headache syndrome associated with various other comorbidities. Thyroid replacement in migraine patients with hypothyroidism improves headaches; however, thyroid hormone replacement in subclinical hypothyroidism is debatable, and its efficacy is not known.

OBJECTIVE AND METHODOLOGY

This prospective, single-centre, quasi-randomised interventional study was conducted on patients visiting the General Medicine and Neurology outpatient department at a tertiary centre to look at the efficacy of thyroxine in subclinical hypothyroidism.

RESULTS

We assessed 87 patients for analysis; no patients were lost to follow-up. There was a decrease in all parameters evaluated (headache frequency, severity, duration, MIDAS score, MIDAS grade) at three months of follow-up in the treatment group compared to placebo group. There was a significant decrease in headache frequency and severity in the levothyroxine group compared to the placebo group at three months of follow-up. Also, the follow-up MIDAS score (mean ± SD: 6.30 ± 2.455 scores vs. 8.45 ± 5.757 scores) was significantly decreased by treatment at three months follow-up.

CONCLUSION

Treatment of subclinical hypothyroidism effectively reduces migraine headaches, and it is logical to check thyroid function status in patients presenting with migraine headaches. However, a larger randomised controlled trial is required to prove the efficacy of levothyroxine in migraine with subclinical hypothyroidism.

Cardiovascular outcomes in subclinical thyroid disease: an update

PURPOSE OF REVIEW

Subclinical thyroid disease is defined by a thyroid stimulating hormone (TSH) level outside of the normal range with normal circulating thyroid hormone levels. Excess adverse cardiovascular outcomes have been observed in certain patient populations with subclinical hypothyroidism (SCH) and hyperthyroidism (SCHr). The role of thyroid hormone and antithyroid treatments for subclinical thyroid disease remains debated.

RECENT FINDINGS

Cardiovascular disease appears to be a major mediator of all-cause mortality in patients with SCH, in particular those aged at least 60 years of age. In contrast, pooled clinical trial results did not find that levothyroxine reduced the incidence of cardiovascular events or mortality in this patient population. The association between SCHr and atrial fibrillation is well established; however, a 5-year follow-up of older patients with mild (TSH 0.1-0.4 mIU/l) SCHr found no increased incidence of atrial fibrillation. Separately, SCHr was associated with derangements in endothelial progenitor cell function that may underlie vascular disease independent from effects on cardiac function.

SUMMARY

The impact of treatment of subclinical thyroid disease on cardiovascular outcomes remains uncertain. Additional prospective and trial data are needed to evaluate treatment effects on cardiovascular outcomes in younger populations.

The correlation of lipid profile with subclinical and overt hypothyroidism: A cross-sectional study from Syria

We proceeded with this study to investigate the relationship between hypothyroidism and lipid profile disturbance. A cross-sectional study at Al- Mowasat University Hospital in Damascus was conducted from March 2021 to March 2022, and included 324 adults. For each participant with abnormal thyroid stimulating hormone (TSH), free thyroxine (FT4) was requested. The participants were categorized into 3 groups: euthyroid (226 participants), subclinical hypothyroidism (SCH) (75 participants), and overt hypothyroidism (23 participants). Fasting lipid profile was tested as: cholesterol (Chol), triglycerides (TG), low density lipoprotein (LDL), and high density lipoprotein (HDL). A significant relationship between hypothyroidism and dyslipidemia was noticed. LDL, TG, and Chol but not HDL showed a significant difference between study groups (euthyroidism, subclinical, and overt hypothyroidism). The lowest levels of these parameters were in euthyroidism and increased in subclinical and overt hypothyroidism subsequently. Overt hypothyroidism showed a significant difference in LDL, TG, and Chol compared to euthyroidism, however, we did not find a difference in lipid parameters in SCH compared to euthyroidism. LDL and Chol showed significant differences between subclinical and overt hypothyroidism. TSH had a positive weak correlation with LDL, TG, and Chol, however, there was no correlation with HDL. Also, FT4 had a negative weak correlation with LDL, TG, and Chol, however, there was a positive correlation with HDL. Our findings suggest a higher level of lipids (LDL, TG, and Chol) among SCH and overt hypothyroidism compared to general population. A weak correlations of lipid parameters with TSH and FT4 were detected. It is not well evident whether a restoration of euthyroidism might influence the morbidity and mortality, especially cardiovascular comorbidities, in this population, which mandates future studies.

Effects of whole seaweed consumption on humans: current evidence from randomized-controlled intervention trials, knowledge gaps, and limitations

Seaweed is often recognized for its potential health benefits, attributed to its abundance of dietary fibers, protein, and polyphenols. While human observational studies have shown promise, the collective evidence from human intervention trials remains limited. This narrative review aims to comprehensively analyze the effects of seaweed intake on humans, while critically assessing the methodology, including Cochrane risk-of-bias assessment. A search was conducted in online databases, including PubMed, Scopus, and Google Scholar, covering the period from 2000 to May 2023. The focus was on randomized controlled clinical trials (RCTs) evaluating the impact of whole seaweed, either consumed as capsules, integrated into food products or as part of meals. Various health outcomes were examined, including appetite, anthropometric measures, cardiometabolic risk factors, thyroid function, markers of oxidative stress, and blood mineral concentrations. Out of the 25 RCTs reviewed, the findings revealed limited yet encouraging evidence for effects of seaweed on blood glucose metabolism, blood pressure, anthropometric measures, and, to a lesser extent, blood lipids. Notably, these favorable effects were predominantly observed in populations with type-2 diabetes and hypertension. Despite most trials selecting a seaweed dose aligning with estimated consumption levels in Japan, considerable variability was observed in the pretreatment and delivery methods of seaweed across studies. Moreover, most studies exhibited a moderate-to-high risk of bias, posing challenges in drawing definitive conclusions. Overall, this review highlights the necessity for well-designed RCTs with transparent reporting of methods and results. Furthermore, there is a need for RCTs to explore seaweed species cultivated outside of Asia, with a specific emphasis on green and red species. Such studies will provide robust evidence-based support for the growing utilization of seaweed as a dietary component in regions with negligible seaweed consumption, e.g., Europe.

Subclinical Hypothyroidism and Clinical Outcomes After Percutaneous Coronary Intervention: A Meta-Analysis

While subclinical hypothyroidism (SCH) was reportedly associated with an increased risk of cardiovascular mortality, the relationship between SCH and clinical outcomes of patients undergoing percutaneous coronary intervention (PCI) is uncertain. The aim of this study was to assess the association of SCH and cardiovascular outcomes in patients undergoing PCI. We searched PubMed, Embase, Scopus, and CENTRAL databases from its inception until April 1, 2022 for studies comparing the outcomes between SCH and euthyroid patients undergoing PCI. Outcomes of interest include cardiovascular mortality, all-cause mortality, myocardial infarction (MI), major adverse cardiovascular and cerebrovascular events (MACCE), repeat revascularization and heart failure. Outcomes were pooled using the DerSimonian and Laird random-effects model and reported as risk ratios (RR) and 95% confidence intervals (CI). A total of 7 studies involving 1132 patients with SCH and 11,753 euthyroid patients were included in the analysis. Compared with euthyroid patients, patients with SCH had significantly higher risk of cardiovascular mortality (RR 2.16, 95% CI: 1.38-3.38, P < 0.001), all-cause mortality (RR 1.68, 95% CI: 1.23-2.29, P = 0.001) and repeat revascularization (RR 1.96, 95% CI: 1.08-3.58, P = 0.03). However, there were no differences between both groups in terms of incidence of MI (RR 1.81, 95% CI: 0.97-3.37, P = 0.06), MACCE (RR 2.24, 95% CI: 0.55-9.08, P = 0.26) and heart failure (RR 5.38, 95% CI: 0.28-102.35, P = 0.26). Our analysis suggests among patients undergoing PCI, SCH was associated with increased risk of cardiovascular mortality, all-cause mortality and repeat revascularization compared to euthyroid patients.

Preliminary observation of thyroid function changes in subclinical thyroid diseases

BACKGROUND

It is estimated that 1.95% and 5.55% of adults in China suffer from subclinical thyroid diseases, which is difficult to diagnose and treat.

OBJECTIVE

This study aimed to explore the development and prognosis of subclinical thyroid diseases to provide a reference from our single center experience.

METHODS

A total of 240 cases from April 2019 to August 2021 in the laboratory information system database of Huanghua Development Boai Hospital were retrospectively analyzed. Binary logistic regression was conducted to analyze odds ratio (OR) of subclinical thyroid disease types returning to a normal state.

RESULTS

Among the patients hypothyroidism Ia and hyperthyroidism Ia were the most common type with conversion to the normal state (P< 0.001). TSH level of patients with conversion to a normal state was significantly lower than that of those who developed to abnormal disease (P= 0.015). The OR values of hyperthyroidism Ia and hypothyroidism Ia that returned to a normal state compared with hyperthyroidism Ib were 2.659 (1.159 ∼ 6.096, P= 0.021) and 3.138 (1.1.278 ∼ 7.709, P= 0.013), respectively. The OR value of hypothyroidism Ib that returned to normal compared with hyperthyroidism Ib was 0.629 (0.131 ∼ 3.010, P= 0.561). Thyroid hormone levels, age, and gender at first diagnosis were not impact factor for prognosis of subclincal thyroid disease (P> 0.05).

CONCLUSION

Cases with grade hypothyroidism Ia and hyperthyroidism Ia are more likely to revert to normal state than other subclinical thyroid diseases. TSH reference range should be explored for diagnosis and treatment.

Natural history of subclinical hypothyroidism and prognostic factors for the development of overt hypothyroidism: Tehran Thyroid Study (TTS)

OBJECTIVE

The significance of subclinical hypothyroidism (SCH) is largely due to its potential risk for developing overt hypothyroidism (OH). Investigations are still exploring predictive factors contributing to the progression of SCH to OH, particularly in patients with mildly elevated serum thyrotropin (TSH). We aimed to clarify the natural history of SCH and the predictive factors of its progression, based on the grade of SCH severity.

METHODS

This study was conducted within the framework of the Tehran Thyroid Study (TTS), in which 5783 individuals aged ≥ 20 years were followed. After applying exclusion criteria, data of 270 SCH subjects remained for the analysis. Thyroid function tests were assessed at baseline and every 3 years.

RESULTS

Of 270 participants with SCH, 239 (88.5%) had TSH level between 5.06 and 10 mU/L, and 31 (11.4%) had TSH ≥ 10 mU/L. During a median follow-up of 10 years, 40% had TSH within the reference range, 44% maintained elevated TSH, and 16% had added low T4 to the elevated TSH. The annual incidence rate of progression to OH was 22.3 (16.5-101.9) per 1000 person-years [18 (12.6-25.6) for those with TSH 5.07-9.9 mU/L and 57.8 (22.8-101.9) for patients with TSH ≥ 10 mU/L per 1000 person-years (P = 0.001)]. After adjusting age, sex, body mass index (BMI), thyroid peroxidase antibody (TPOAb), and serum TSH, only TPOAb positivity (HR: 2.31; 95% CI 1.10-4.83, P = 0.026) and baseline TSH level ≥ 10 mU/L (HR: 5.14; 95% CI 2.14-12.3, P < 0.001) remained as predictors for development of OH. In patients with TSH 5.07-9.9 mU/L, TPOAb positivity was associated with an increased risk of OH (HR: 2.41; 95% CI 1.10-5.30, P = 0.027). However, in patients with TSH ≥ 10 mU/L, TPOAb positivity was not a predictor (P = 0.49).

CONCLUSION

TPOAb and not TSH are associated with the development of OH in individuals with serum TSH below 10 mU/L, and follow-up at regular intervals is recommended in TPOAb-positive individuals with TSH between 5 and 10 mU/L.

Rosuvastatin potentiates the thyrotropin-lowering effect of metformin in men with non-autoimmune subclinical hypothyroidism and prediabetes

WHAT IS KNOWN AND OBJECTIVE

Metformin treatment decreases thyrotropin levels in individuals with hypothyroidism and this effect seems to be mediated by the 5'-adenosine monophosphate-activated protein kinase pathway in the pituitary. The activity of this pathway is also stimulated by statins. The current study was aimed at investigating whether the impact of metformin on hypothalamic-pituitary-thyroid axis activity is affected by statin use.

METHODS

The study included three matched groups of men with non-autoimmune hypothyroidism and prediabetes: patients treated for at least 6 months with high-intensity rosuvastatin therapy (20-40 mg daily) [groups A (n = 24) and C (n = 19)] and men not receiving statin therapy [group B (n = 24)]. Over the entire study period (6 months), groups A and B received metformin (2.55-3 g daily). Moreover, groups A and C continued rosuvastatin therapy. The lipid profile, glucose homeostasis markers, and plasma concentrations of thyrotropin, total and free thyroid hormones, prolactin, FSH, LH, ACTH and insulin-like growth factor-1 were determined at baseline and 6 months later.

RESULTS AND DISCUSSION

Fifty-nine patients completed the study. There were differences between groups A and C and group B in baseline values of total cholesterol, LDL-cholesterol, gonadotropins and ACTH. Although observed in both groups of metformin-treated patients, the effect on thyrotropin levels was more pronounced in group A than in group B. The impact on fasting glucose and insulin sensitivity was stronger in group B than group A. In turn, only in group A metformin tended to reduce gonadotropin levels. There were no differences between follow-up and baseline values of lipids, total and free thyroid hormones, prolactin, ACTH and insulin-like growth factor-1 in both these groups. In group C, all assessed variables remained at a similar level.

WHAT IS NEW AND CONCLUSION

The results of the current study suggest that rosuvastatin potentiates the inhibitory effect of metformin on thyrotrope secretory function.

Interplay between cardiovascular and thyroid dysfunctions: A review of clinical implications and management strategies

Cardiovascular diseases (CVD) and thyroid dysfunction are two of the most prevailing disorders in the world that are closely interlinked. Actions of thyroid hormones are mediated via thyroid receptors present in the myocardium and the vascular tissue. Primary mechanism that links thyroid dysfunction with CVD is the modification of cardiovascular risk factors (dyslipidemia, blood pressure, coagulation parameters, etc.) resulting in endothelial and left ventricular systolic and diastolic dysfunction.

Both overt and subclinical hyperthyroidism and hypothyroidism may cause adverse alterations in cardiac function. Hyperthyroidism gives rise to palpitation, atrial fibrillation, systolic hypertension, and heart failure, whereas hypothyroidism increases diastolic hypertension, pericardial effusion, and the risk of ischemic heart disease via altering lipid and coagulation parameters. Early recognition and treatment of thyroid dysfunction may prevent adverse cardiovascular events in patients with or without pre-existing CVD.

Certain cardiac conditions and medications can cause alterations in thyroid function that may predispose an individual to higher morbidity and mortality. In certain situations, thyroid dysfunction treatment may have cardiovascular benefits. This study deals with the interplay between cardiovascular and thyroid dysfunctions associated with clinical implications and management strategies.

Subclinical Hypothyroidism and Cognitive Impairment

BACKGROUND

Although thyroid dysfunction has been considered as a cause of reversible cognitive impairment, association between subclinical hypothyroidism and cognitive impairment is controversial.

OBJECTIVE

We compared cognitive profiles of patients in an euthyroid or subclinical hypothyroid (sHypo) state, as well as their disease progression from mild cognitive impairment (MCI) to dementia within 3 years.

METHODS

We included 2,181 patients in a euthyroid and 284 in a sHypo state over 60 years of age who underwent an extensive cognitive assessment at Seoul National University Bundang Hospital but were not prescribed levothyroxine, methimazole, carbimazole, or propylthiouracil. After propensity score matching for age, sex, and education level, 1,118 patients in a euthyroid and 283 patients in a sHypo state were included. Attention, language, memory, visuocontructive, and executive functions were compared between the groups using Student's t-test or the Mann-Whitney U test. To investigate the association between disease progression and subclinical hypothyroidism, a Cox regression analyses was performed in 1,265 patients with MCI. Patients with thyroid-stimulating hormone levels over 10 mlU/L was classified as the "sHypo10", and hazard ratios for sHypo or sHypo10 were assessed.

RESULTS

There was no difference in attention, language, memory, visuoconstructive, and executive functions between the patient groups. Progression from MCI to dementia was not associated with sHypo or sHypo10.

CONCLUSION

There was no difference in cognitive profile between euthyroid and sHypo patients, and no association between subclinical hypothyroidism and disease progression. This might suggest a clue of strategies regarding hormone therapy in subclinical hypothyroidism with cognitive impairment.

Androgen deprivation therapy for prostate cancer and the risk of thyroid diseases

BACKGROUND

Androgen deprivation therapy (ADT) is the major treatment for metastatic prostate cancer (PCa), but few studies have investigated the effects of ADT on thyroid diseases.

METHODS

This population-based, nationwide cohort study utilized the Taiwan National Health Insurance Research Database (NHIRD) with 17,192 PCa patients between 1997 and 2013. We used the Cox proportional hazards models and propensity score-matched analysis to analyze the association between ADT and the development of thyroid diseases.

RESULTS

A total of 17,192 newly diagnosed men with PCa were selected from the NHIRD. There were 6200 ADT users and 6200 non-ADT users after 1:1 propensity score matching. There was a significantly decreased risk of thyroid diseases among ADT users compared with non-ADT users (adjusted hazard ratio (aHR): 0.79, 95% confidence interval (CI): 0.65-0.95, p < 0.001). Further analysis showed a significantly decreased risk of thyroid diseases with increasing ADT duration (p < 0.001).

CONCLUSIONS

The result showed that ADT use in men with PCa was associated with a decreased risk of thyroid disease development.

Subclinical hypothyroidism in women's health: from pre- to post-menopause

OBJECTIVE

Subclinical hypothyroidism (SCH) is a quite frequent condition among women, affecting 3-12% of the general population. Its consequences on women's health in reproductive age, pregnancy and menopause have been extensively investigated but data about the effective impact of treatment with levothyroxine (LT4) remain conflicting.

METHODS

This is a narrative review and analysis of the most relevant data until June 2021.

RESULTS

SCH may affect reproduction. Evidence suggests that women with SCH undergoing assisted reproductive technique (ART) may benefit from LT4 therapy whereas there are no conclusive data regarding women attempting natural conception. SCH may be associated with several negative pregnancy outcomes, that is to say recurrent pregnancy loss (RPL), preterm delivery, preeclampsia and neurocognitive disturbances of offspring. However, the protective role of LT4 treatment has been established in selected cases, for instance in thyroid peroxidase antibody (TPOAb) -positive women with TSH greater than the pregnancy specific reference range and/or in TPOAb-negative women with TSH >10.0 mIU/L. In menopause, SCH can worsen the negative cardio-metabolic effects of hormonal loss and/or aging, by exacerbating dyslipidaemia and hypertension. Nevertheless, robust data about the benefits of LT4 therapy are still lacking and treatment should be encouraged with caution.

CONCLUSIONS

SCH represents a challenging condition during pre- and post- menopause. An aware knowledge of its possible principal consequences could help all clinicians who are involved in women's health to manage more properly it, preventing its sequelae.

Relationship Between Thyroid Hormonal Status in Patients with a Hypothyroid Form of Hashimoto's Thyroiditis and Iodine Concentrations in Drinking Water

The current study aimed to identify correlative and regressive dependencies between the water iodine concentration and the levels of TSH (thyroid-stimulating hormone), thyroglobulin antibodies (TgAbs), and thyroid peroxidase (TPOAb) in the serum of 168 in patients (34 men and 134 women) with a hypothyroid form of Hashimoto's thyroiditis who use water from the supply network and individual wells. Based on the water iodine concentration, low and moderate degrees of iodine endemia in the location of the patients were determined. In the groups of men and women using water from different water supply sources, there were direct correlations between the water iodine concentrations and the TgAbs and TPOAb titers as well as an inverse dependence between iodine and TSH levels. Multivariate regressive analysis indicated that TgAb and TSH in the group of women using water from a supply network and TPOAb titers in the group of women using well water were independent factors associated with water iodine concentrations. Statistically significant correlations and regressive dependencies between the water iodine concentrations and the biomarkers of the thyroid status of the patients indicate the risk of Hashimoto's thyroiditis progression, especially among women with additional iodine intake.

Subclinical Hypothyroidism: Prevalence, Health Impact, and Treatment Landscape

Subclinical hypothyroidism (sHypo) is defined as normal serum free thyroid hormone levels coexisting with elevated serum thyroid-stimulating hormone (TSH) levels. sHypo is a common condition observed in clinical practice with several unique features. Its diagnosis should be based on an understanding of geographic and demographic differences in biochemical criteria versus a global reference range for TSH that is based on the 95% confidence interval of a healthy population. During the differential diagnosis, it is important to remember that a considerable proportion of sHypo cases are transient and reversible in nature; the focus is better placed on persistent or progressive forms, which mainly result from chronic autoimmune thyroiditis. Despite significant evidence documenting the health impacts of sHypo, the effects of levothyroxine treatment (LT4-Tx) in patients with sHypo remains controversial, especially in patients with grade 1 sHypo and older adults. Existing evidence suggests that it is reasonable to refrain from immediate LT4-Tx in most patients if they are closely monitored, except in women who are pregnant or in progressive cases. Future research is needed to further characterize the risks and benefits of LT4-Tx in different patient cohorts.

Stroke in SARS-CoV-2 Infection: A Pictorial Overview of the Pathoetiology

Since the early days of the pandemic, there have been several reports of cerebrovascular complications during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Numerous studies proposed a role for SARS-CoV-2 in igniting stroke. In this review, we focused on the pathoetiology of stroke among the infected patients. We pictured the results of the SARS-CoV-2 invasion to the central nervous system (CNS) via neuronal and hematogenous routes, in addition to viral infection in peripheral tissues with extensive crosstalk with the CNS. SARS-CoV-2 infection results in pro-inflammatory cytokine and chemokine release and activation of the immune system, COVID-19-associated coagulopathy, endotheliitis and vasculitis, hypoxia, imbalance in the renin-angiotensin system, and cardiovascular complications that all may lead to the incidence of stroke. Critically ill patients, those with pre-existing comorbidities and patients taking certain medications, such as drugs with elevated risk for arrhythmia or thrombophilia, are more susceptible to a stroke after SARS-CoV-2 infection. By providing a pictorial narrative review, we illustrated these associations in detail to broaden the scope of our understanding of stroke in SARS-CoV-2-infected patients. We also discussed the role of antiplatelets and anticoagulants for stroke prevention and the need for a personalized approach among patients with SARS-CoV-2 infection.

Prognosis of papillary thyroid carcinoma in relation to preoperative subclinical hypothyroidism

INTRODUCTION

It has been established that thyroid-stimulating hormone (TSH) stimulates the growth and development of thyroid malignancy, and a higher serum TSH level is associated with the incidence of thyroid cancer and an advanced tumour stage. This study aimed to evaluate the association of preoperative subclinical hypothyroidism with the prognosis of papillary thyroid cancer (PTC).

METHODS

A total of 466 patients who underwent surgery for PTC between December 2006 and June 2009 were enrolled. Among them, 44 patients had subclinical hypothyroidism, while 422 did not have subclinical hypothyroidism, as diagnosed using the preoperative thyroid function test. We compared the recurrence rate and association with clinicopathological features in the two groups.

RESULTS

The median patient age was 46.9 years (17-74 years). There were 420 female and 46 male patients. The median follow-up duration was 81.4 months. There were no statistical differences between the two groups with respect to age, sex, tumour size, extrathyroidal extension, multifocality, lymph node metastasis, TNM stages, recurrence and disease-free survival, despite a significant difference in the average TSH concentrations of the two groups.

CONCLUSIONS

Our results suggest that preoperative subclinical hypothyroidism was not associated with tumour aggressiveness and recurrence in PTC.

Routine Measurement of Thyroid Stimulating Hormone in Patients Presenting With Third-Degree Atrioventricular Block: Do We Really Need It?

Background Hypothyroidism can be a cause of sinus bradycardia. However, thyroid laboratory evaluation is often performed routinely in patients with complete heart block (CHB) though there is little data to support this practice. This study aimed to assess the frequency of thyroid dysfunction in patients presenting with CHB without clinical features of hypothyroidism. Methodology All patients referred for permanent pacemaker implantation for CHB were included in this cross-sectional study. Patients with known thyroid disorder or clinical features of thyroid disorder were excluded. Demographic, electrocardiography (EKG), and routine thyroid stimulating hormone (TSH) screening results were recorded. Results A total of 102 patients with complete atrioventricular (AV) block were enrolled in the study of which 50.0% (51) were male. The mean age was 61.09 ± 11.74. Co-morbidities included diabetes mellitus 44.1% (45), smoking 36.3% (37), and hypertension 55.9% (57). Mean EKG atrial rate was 82.97 ± 31.31 mmHg with a mean ventricular escape rate of 36.17 ± 5.93. Permanent pacemakers were implanted in all of the patients. Only one patient had an abnormal TSH. Conclusions We found a very low prevalence of thyroid dysfunction among patients without clinical features of thyroid dysfunction presenting with third-degree AV block. This calls for cautious prescription of thyroid testing in clinically euthyroid patients.

Does Hypothyroidism Increase Complications, Lengths of Stay, Readmissions, and Costs Following Primary 1- to 2-Level Lumbar Fusion?

STUDY DESIGN

Level III-retrospective review.

OBJECTIVE

To evaluate the impact of hypothyroidism in patients undergoing 1- to 2-level lumbar fusion (1-2LF).

SUMMARY OF BACKGROUND DATA

Hypothyroidism is a common cause of morbidity and mortality following surgery. Studies have demonstrated the effects of hypothyroidism following orthopedic surgery, but not 1-2LF.

MATERIALS AND METHODS

Patients undergoing 1-2LF with hypothyroidism were identified within the Medicare population, and served as the study group. Study group patients were randomly matched to controls in a 1:5 ratio by age, sex, and medical comorbidities. Primary outcomes analyzed included in-hospital lengths of stay (LOS), 90-day readmission rates, 90-day medical complications, and costs of care. Pearson χ tests were used to compare patient demographics. Logistic regression analyses were used to calculate odds ratios (OR) for medical complications and readmissions. Welch t test was used to test for significance in cost between the cohorts. An α value <0.002 was considered statistically significant.

RESULTS

The query yielded 417,483 patients who underwent 1-2LF with (n=69,584) and without (n=347,899) hypothyroidism. Hypothyroid patients had significantly longer in-hospital LOS (8 vs. 4 d; P<0.0001) compared with controls. In addition, study group patients had significantly higher incidence and odds of 90-day readmissions (20.22% vs. 17.62%; OR, 1.18; P<0.0001) and 90-day medical complications (6.38% vs. 1.89%; OR, 3.53; P<0.0001) compared with controls. Study group patients had higher day of surgery costs ($97,304.01 vs. $95,168.35; P=0.014) and 90-day costs of care ($113,514.15 vs. $108,860.60; P=0.0001) compared with controls.

CONCLUSIONS

After adjusting for age, sex, and medical comorbidities, the study demonstrates patients who have hypothyroidism have longer in-hospital LOS and higher rates of readmissions, complications, and costs. The study is vital as it can allow orthopedic surgeons to adequately counsel and educate these patients of the potential complications that may occur following their procedure.

Importance of thyroid-stimulating hormone levels in liver disease

Objectives Recently, several studies have reported the association between elevation of thyroid-stimulating hormone (TSH) levels and liver disease, especially, non-alcoholic fatty liver disease (NAFLD). We aimed to evaluate the incidence and risk factors of TSH elevation in patients with liver disease. Methods We retrospectively reviewed the data of patients aged <18 years who were diagnosed with liver disease between January 2015 and March 2019. Results Among the 77 patients, 17 (22.1%) had subclinical hypothyroidism and 3 (17.6%) progressed to overt hypothyroidism. A total of 26 (33.8%) patients had NAFLD, and 6 (23.1%) had subclinical hypothyroidism. The ultrasound grade of liver steatosis was not related to the elevation of TSH levels. The median age was significantly younger in patients with TSH elevation (5 vs. 9 years, p = 0.017). Albumin levels were significantly decreased (3.9 vs. 4.3 g/dL, p = 0.007), and total bilirubin levels were elevated (2.2 vs. 0.6 mg/dL, p = 0.001) in patients with subclinical hypothyroidism. Conclusions TSH elevation commonly occurs in patients with liver disease, especially those with younger age. The cause of liver disease was not a risk factor for TSH elevation.

Update of hypothyroidism and its management in Unani medicine

Hypothyroidism is a clinical syndrome caused by thyroid hormone deficiency due to reduced production, deranged distribution, or lack of effects of thyroid hormone. The prevalence of hypothyroidism in developed countries is around 4-5%, whereas it is about 11% in India, only 2% in the UK, and 4·6% in the USA. It is more common in women than in men. Hypothyroidism has multiple etiologies and manifestations. The most common clinical manifestations are weight gain, loss of hair, cold intolerance, lethargy, constipation, dry skin, and change in voice. The signs and symptoms of hypothyroidism differ with age, gender, severity of condition, and some other factors. The diagnosis is based on clinical history, physical examination and serum level of FT3, FT4, and thyroid-stimulating hormone, imaging studies, procedures, and histological findings. The treatment of choice for hypothyroidism is levothyroxine, however; in this review article, we have discussed the epidemiology, etiology, clinical sign and symptoms, diagnosis, complications, and management of hypothyroidism in modern medicine and a comparative treatment by the Unani system of medicine (USM). In the USM, the main emphasis of the principle of treatment (Usool-e-Ilaj) is to correct the abnormal constitution (Su-e-Mizaj) and alter the six prerequisites for existence (Asbab-e-Sitta Zarooriya) to restore normal health. It is a packaged treatment, that is, different components of treatment are given as a package form which includes different drugs, dosages form, and regimens.

S, Dande P. Protective effect of a polyherbal bioactive fraction in propylthiouracil-induced thyroid toxicity in ratsby modulation of the hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal axes

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Hypothyroidism is the most frequent toxic effect of a large variety of chemical compounds.

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The polyherbal bioactive fraction exhibited a pro-thyroid effect in hypothyroidic rats.

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The polyherbal fraction restored the propylthiouracil-depleted thyroid hormone levels significantly.

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The polyherbal fraction may act through multiple mechanisms to exhibit a pro-thyroid effect.

Hypothyroidism is the most frequent consequence of the interaction of a large variety of drugs, environmental pollutants and industrial chemicals with the thyroid gland. It is associated with diminished endocrine function which may lead to hyperlipidemia, diabetes, Alzheimer’s disease, weight gain, and other metabolic disorders. The present study evaluates the pro-thyroid activity of a bioactive fraction from a polyherbal teabag in rats with hypothyroidism induced by propylthiouracil. The teabag was formulated to stimulate synthesis and/or release of T4 and affectthe conversion of T4 to T3. Phytoconstituents of the polyherbal teabag are potent antioxidants that may be responsible for the pro-thyroid activity. The tea-extract (1000 mg) was found to contain 1076 μg of gallic acid and 1131 μg of rutin from HPTLC analysis. Rats received propylthiouracil (8 mg/kg) for the first 15days followed by the polyherbal tea-extract (500, 1000 and 1500 mg/kg), the standard drug levothyroxine (0.1 mg/kg), aerobic exercise, and a combination of tea-extract (1000 mg/kg) and aerobic exercise daily along with propylthiouracil for the next 30 days. Finally, rats received their respective treatments alone without propylthiouracil for 15 more days. Lipid profile and levels of glucose, insulin, T3, T4, TSH, cortisol, homocysteine, creatinine, uric acid, malondialdehyde, glucose-6 phosphatase, and endogenous antioxidants were determined. All treatments attenuated significantly the propylthiouracil-elevated TSH, homocysteine, creatinine, uric acid, glucose-6-phosphatase, insulin, and malondialdehyde levels, and restored favorably the propylthiouracil-altered lipid profile, T3, T4, and endogenous antioxidant levels. The polyherbal tea-extract (1000 and 1500 mg/kg) treatment and thecombination treatment of tea-extract (1000 mg/kg) with aerobic exercise displayed significant restoration of the suboptimalthyroid function. This may be due to a favorablemodulation ofthe hypothalamic-pituitary–thyroid and the hypothalamic–pituitary–adrenal axes.

Subclinical Hypothyroidism Affects the Long-Term Outcomes of Patients Who Undergo Coronary Artery Bypass Grafting Surgery but Not Heart Valve Surgery

BACKGROUND

The aim of this study was to determine the associations between subclinical hypothyroidism (SCH) and long-term cardiovascular outcomes after coronary artery bypass grafting (CABG) or heart valve surgery (HVS).

METHODS

We retrospectively reviewed and compared all-cause mortality, cardiovascular mortality, and cardiovascular events in 461 patients who underwent CABG and 104 patients who underwent HVS.

RESULTS

During a mean±standard deviation follow-up duration of 7.6±3.8 years, there were 187 all-cause deaths, 97 cardiovascular deaths, 127 major adverse cardiovascular events (MACE), 11 myocardial infarctions, one unstable angina, 70 strokes, 30 hospitalizations due to heart failure, 101 atrial fibrillation, and 33 coronary revascularizations. The incidence of all-cause mortality after CABG was significantly higher in patients with SCH (n=36, 55.4%) than in euthyroid patients (n=120, 30.3%), with a hazard ratio of 1.70 (95% confidence interval, 1.10 to 2.63; P=0.018) after adjustment for age, sex, current smoking status, body mass index, underlying diseases, left ventricular dysfunction, and emergency operation. Interestingly, low total triiodothyronine (T3) levels in euthyroid patients who underwent CABG were significantly associated with increased risks of all-cause mortality, cardiovascular mortality, and MACE, but those associations were not observed in HVS patients. Both free thyroxine and thyroid-stimulating hormone levels in euthyroid patients were not related with any cardiovascular outcomes in either the CABG or HVS group.

CONCLUSION

SCH or low total T3 might be associated with a poor prognosis after CABG, but not after HVS, implying that preoperative thyroid hormonal status may be important in ischemic heart disease patients.

Thyroid Function and Nutrient Status in the Athlete

Thyroid disease is common in the general population, especially in women, and also may be prevalent among athletes. Autoimmune disorders are the most common cause of thyroid disorders in countries with iodine-fortification programs; however, thyroid dysfunction can be brought on by nutritional factors, including insufficient energy intake and iodine, selenium, iron, and vitamin D deficiency. Additionally, strenuous exercise may be associated with transient alterations in thyroid hormones. While the development of thyroid related disorders has the potential to impact health and peak performance, typical clinical manifestations are highly variable, lack specificity, and are frequently confused with other health problems. The assessment process should focus on anthropometric changes, biochemical tests (thyroid panel), personal and family history, examination for appropriate signs and symptoms, and diet and environmental assessment that includes adequacy of energy, iodine, iron, selenium, and vitamin D intake/status along with excess stress and exposure to environmental contaminants and dietary goitrogens.

Clinical and subclinical maternal hypothyroidism and their effects on neurodevelopment, behavior and cognition

Clinical and subclinical hypothyroidism are the most common hormonal dysfunctions during pregnancy. Insufficient maternal thyroid hormones (THs) in the early stages of pregnancy can lead to severe impairments in the development of the central nervous system because THs are critical to central nervous system development. In the fetus and after birth, THs participate in neurogenic processes, cell differentiation, neuronal activation, axonal growth, dendritic arborization, synaptogenesis and myelination. Although treatment is simple and effective, approximately 30% of pregnant women in Brazil with access to prenatal care have their first consultation after the first trimester of pregnancy, and any delay in diagnosis and resulting treatment delay may lead to cognitive impairment in children. This review summarizes the effects of clinical and subclinical hypothyroidism on fetal neurodevelopment, behavior and cognition in humans and rodents. Arch Endocrinol Metab. 2020;64(1):89-95.

Screening for thyroid dysfunction and treatment of screen-detected thyroid dysfunction in asymptomatic, community-dwelling adults: a systematic review

BACKGROUND

This systematic review was conducted to inform the Canadian Task Force on Preventive Health Care recommendations on screening for thyroid dysfunction (TD). The review sought to answer key questions on the benefits and harms of screening for TD, patients' values and preferences for screening, and the benefits and harms of treating screen-detected TD.

METHODS

This review followed Canadian Task Force on Preventive Health Care methods, which include the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The search strategy used for benefits and harms of screening and treatment was an update to the 2014 review by the US Preventive Services Task Force and searched MEDLINE and the Cochrane Library. MEDLINE, Embase, ProQuest Public Health, and SCOPUS were searched for patients' values and preferences for screening. Outcomes of interest included all-cause mortality, deaths due to cardiovascular diseases, fatal and non-fatal cardiovascular events, atrial fibrillation, fractures, quality of life, cognitive function, and harms due to TD treatment. Two reviewers independently screened abstracts and full texts according to pre-determined inclusion criteria and assessed the risk of bias for each study included. Strength and quality of the evidence was assessed for each outcome. A narrative synthesis was conducted due to heterogeneity of the included studies.

RESULTS

No studies were found on screening for TD, treatment of subclinical hyperthyroidism, or patients' values and preferences for screening for TD. Twenty-two studies (from 24 publications) on the treatment of TD in patients with screen-detected subclinical hypothyroidism were included. Results from the included randomized controlled trials suggested no benefit of treatment for subclinical hypothyroidism for the large majority of outcomes. We found very low-quality evidence (from two cohort studies) for a small reduction in all-cause mortality among adults < 65 or 40-70 years who were treated for TD compared to those who were not.

CONCLUSIONS

This review found moderate to very low-quality evidence on the benefits and harms of treatment for subclinical hypothyroidism, with most of the evidence showing no benefit of treatment.

Overprescribed Medications for US Adults: Four Major Examples

To understand possible medication overprescribing, it would be important to know which classes are the most prescribed, for which indications, for what duration, and for which age groups. Among the 10 most frequently prescribed medication classes for US adults, four were evaluated for overprescribing, and systematically assessed in relation to their primary indication. The assessment included usage patterns, trends, age of recipients, treatment duration, and benefits versus adverse consequences. The findings in this selective review are supported by an extensive search of the medical literature. The four selected medication categories and their most common indication included opioids for chronic pain, proton pump inhibitors for indigestion, levothyroxine for subclinical hypothyroidism, and antidepressants for subsyndromal levels of depression. These medications, grouped by their most frequent indication along with polypharmacy, have experienced major prescription increases in recent years, particularly among older patients. Most concerning is that they have been frequently prescribed for extended periods, usually with inadequate evidence of benefit. High drug usage patterns can aid in quantifying overprescribing within polypharmacy by age group.

Association between subclinical hypothyroidism and metabolic disorders: A retrospective chart review study in an emerging university hospital

Background

Subclinical hypothyroidism is defined as an increase in serum levels of Thyroid Stimulating Hormone (TSH) above the normal range, without alteration of total T4 concentrations that is reported to have association with various metabolic conditions. The study aimed to investigate any association between subclinical hypothyroidism and metabolic disorders in Al Kharj city.

Methods

This is a cross‐sectional study that included review of patients’ charts from prince Sattam bin Abdul‐Aziz University, Al Kharj, Saudi Arabia, from August 1 to November 30, 2016. Data were analyzed with SPSS version 21. Descriptive statistics were obtained as frequencies. Pearson chi‐square analysis was used to assess any differences between disease status and study variables. P‐value < 0.05 was considered significant.

Results

The mean age was 30.65 ± 13.3 with a female predominance. The average BMI was 29.5 ± 7.71; 46 (11.5%) had hypertension, 52 (46.8%) had diabetes, 173 (44%) had anemia, and 192 (56%) had vitamin D deficiency. Due to increased TSH levels, male gender had higher prevalence of subclinical hypothyroidism with P‐value < 0.001 and 0.011, respectively.

Conclusion

Subclinical hypothyroidism is a significant topic worldwide whose prevalence is rising. In this study, we could not find any significant association between subclinical hypothyroidism and metabolic disorder. Further longitudinal studies with large sample size are needed to study this association.

Reference Range and Sociodemographic Characteristics of TSH among Reproductive Age Women in Rural China

Appropriate reference range of thyroid-stimulating hormone (TSH) is important to interpreting the results of thyroid functional tests. However, the reference range and sociodemographic characteristics of TSH based on large-scale studies are yet to be declared in rural China. To clarify reference range and sociodemographic characteristics of TSH in reproductive age of women from rural China. A nationwide population-based study was conducted as The National Free Preconception Health Examination Project (NFPHEP). Nearly 400,000 (n = 392,659) of Chinese rural women aged 15-55 years were randomly recruited. Predetermined strict exclusion criteria made a number of 359,895 as the reference population. Serum TSH was evaluated with enzyme-linked immunosorbent assay (ELISA). The reference range of TSH on overall and reference population was 0.39-5.20 and 0.39-5.13 uIU/ml (2.5th-97.5th percentiles), respectively. In the reference population, the range (2.5th to 97.5th percentile) of serum TSH in different age groups was 0.40-5.03 uIU/ml, 0.39-5.15 uIU/ml, 0.37-6.10 uIU/ml, and 0.44-7.03 uIU/ml, respectively. The mean TSH value in women aged 26-35 years was 2.26 uIU/ml, significantly lower than those aged 36-45 (p < 0.001). The mean TSH values for eastern, central, and western regions were 2.28 uIU/ml, 2.29 uIU/ml, and 2.24 uIU/ml respectively. The mean of serum TSH concentration was significantly higher in central region than that in western region (p ≤ 0.001). The TSH value 0.39-5.13 uIU/ml (2.5th-97.5th percentiles) was derived as a reference range of reproductive age women from rural China. We use the TSH ranges from reference population to diagnose hyperthyrotropinemia or hypothyroidism in different areas in China. The reference ranges for eastern, central, and western regions were 0.33-5.61 uIU/ml, 0.40-5.04 uIU/ml, and 0.40-4.98 uIU/ml (2.5th-97.5th percentiles) respectively. The value of serum TSH was associated with age, living region, smoking, drinking, educational level, and interpersonal tension, as well as life and economic pressure, but irrelevant to ethnicity or occupation.

Subclinical Hypothyroidism and Coronary Revascularization After Coronary Artery Bypass Grafting

We aimed to investigate long-term cardiovascular sequelae after coronary artery bypass grafting (CABG) in patients with subclinical hypothyroidism (SCH). All-cause and cardiovascular-related mortality, and cardiovascular events were retrospectively reviewed in 222 euthyroid and 36 SCH patients who underwent CABG. During a mean follow-up period of 8.2 ± 4.1 years, there were 90 incidents of all-cause deaths, 20 cardiovascular-related deaths, 70 major cardiovascular adverse events, 6 myocardial infarctions, 12 unstable anginas, 31 strokes, 23 hospitalizations due to heart failure, 15 atrial fibrillation (AF) events, and 27 coronary revascularizations. The incidence rate of coronary revascularization was significantly higher in patients with SCH (n = 6, 16.6%) than in euthyroid patients (n = 20, 9.0%), with a hazard ratio (HR) of 3.179 (95% confidence interval [CI] 1.174, 8.605; p = 0.023) after adjustment. In subgroup analysis, SCH patients who experienced postoperative AF within 3 months after CABG surgery had a significantly higher risk of coronary revascularization (n = 4, 25.0%) than euthyroid patients without AF (n = 14, 8.9%) after adjustment (HR 11.759, 95% CI 2.747, 50.343, p = 0.001). The frequency of fatal or nonfatal unstable angina was also higher in patients with SCH (n = 2, 12.5%) than in euthyroid patients (n = 4, 2.5%) (HR 16.999, 95% CI 2.242, 128.860, p = 0.006). In conclusion, preoperative SCH is associated with less favorable cardiovascular outcomes, especially coronary revascularization after CABG. Moreover, SCH patients who develop postoperative AF exhibit significantly increased risks of unstable angina and coronary revascularization. Preoperative evaluation of thyroid function may be helpful for predicting long-term outcomes after CABG.

Subclinical Hypothyroidism and the Risk of Cardiovascular Disease and All-Cause Mortality: A Meta-Analysis of Prospective Cohort Studies

OBJECTIVES

To determine the impact of subclinical hypothyroidism (SCH) on the risk of cardiovascular disease (CVD) and all-cause mortality, a comprehensive meta-analysis was performed according to the age or coexisting CVD risk status of the participants.

METHODS

Studies regarding the association of SCH with all-cause mortality from PubMed and Embase databases were included. The pooled relative risk (RR) of CVD and all-cause mortality was calculated using the Mantel-Haenszel method. A subgroup analysis of participants with high CVD risk was conducted, including history of coronary, cerebral, or peripheral artery disease; dilated cardiomyopathy; heart failure; atrial fibrillation; venous thromboembolism; diabetes mellitus; or chronic kidney disease.

RESULTS

In total, 35 eligible articles incorporating 555,530 participants were included. SCH was modestly associated with CVD and all-cause mortality (RR for CVD = 1.33 [confidence interval (CI) 1.14-1.54]; RR for all-cause mortality = 1.20 [CI 1.07-1.34]). However, the association was not observed in participants aged ≥65 years. Subgroup analysis showed that participants with SCH and high CVD risk showed a significantly higher risk of all-cause mortality (RR for CVD = 2.20 [CI 1.28-3.77]; RR for all-cause mortality = 1.66 [CI 1.41-1.94]), whereas those with SCH and low CVD risk did not. Additional subgroup analysis of six studies with a mean participant age of ≥65 years and high CVD risk showed a significant high risk of all-cause mortality in the SCH group (RR = 1.41 [CI 1.08-1.85]; I² = 0%).

CONCLUSIONS

SCH is associated with an increased CVD risk and all-cause mortality, particularly in participants with high CVD risk.

Relation of Subclinical Hypothyroidism is Associated With Cardiovascular Events and All-Cause Mortality in Adults With High Cardiovascular Risk

The aim of this study was to determine the association between subclinical hypothyroidism and cardiovascular (CVD) events, and mortality using the atherosclerotic CVD risk score. We carried out an observational study in a prospective cohort that was followed up for 12 years. The study included 3,021 participants aged ≥ 40 years at baseline from the Ansung cohort, part of the Korean Genome and Epidemiology Study. Cox regression models were constructed to evaluate the hazards ratio (HR) and 95% confidence interval (CI) for all-cause mortality and CVD events in groups classified according to thyroid status. Subgroup analysis was performed with a cut-off age of 65 years or 7.5% of the 10-year atherosclerotic CVD risk score. The subclinical hypothyroidism group in the highest quartile of thyroid-stimulating hormone (>6.57 mIU/L) had a significantly increased risk of all-cause mortality (HR 2.12, 95% CI 1.27 to 3.56) and CVD events (HR 1.92, 95% CI 1.21 to 3.04) compared with euthyroid participants. Subgroup analysis by CVD risk revealed that participants with high CVD risk only had a high risk of all-cause mortality (HR 2.18, 95% CI 1.22 to 3.87) and CVD events (HR 2.42, 95% CI 1.35 to 4.33). Further analysis showed that participants aged <65 years with high CVD risk had the highest risk of all-cause mortality (HR 3.50, 95% CI 1.50 to 8.16) and CVD events (HR 3.37, 95% CI 1.46 to 9.57). Our results demonstrated that high thyroid-stimulating hormone levels were associated with a greater risk of mortality and new CVD risks, particularly among subjects with high CVD risk.

Age-sex disparities and sub-clinical hypothyroidism among patients in Tikur Anbesa Specialized Hospital, Addis Ababa, Ethiopia

BACKGROUND

Subclinical hypothyroidism is an elevation in serum thyroid-stimulating hormone above the upper limit of the reference range (0.45-4.5 mIU/L) with normal serum TT4 and TT3 concentration. The most important implication of subclinical hypothyroidism is high likelihood of progression of clinical hypothyroidism.

METHODS

Institution-based cross-sectional study was conducted on medical records of patients referred at endocrine clinic Tikur Anbesa Specialized Hospital, Addis Ababa from 2010 to 2016. This study was conducted from normal ambulatory patients who have come in the hospital outpatient department since they experienced abnormality on their health status. During the study period, patients were complaining about their clinical symptoms. A total number of 9000 patients were included. Patients' card was retrieved by using standard extracted formats to collect socio-demographic and clinical information and laboratory measurements. Serum TSH, TT4, and TT3 levels were determined by electro-chemiluminescence immunoassay method on ECLIA 2010 fully automatic analyzer at TASH nuclear medicine. SPSS 20 version software was used for analysis, and chi-square test was used to check the association between dependent and independent variables.

RESULTS

The overall prevalence of subclinical hypothyroidism evaluated to be 582 (6.47%), 4.6% in females and 1.9% in males. Four hundred and thirty-one (74%) patients had serum TSH levels between 5 and 10 mIU/L, and the average TSH level of subclinical hypothyroid patients whose age was ≥ 40 differ significantly from that of subclinical hypothyroid patients whose age was < 40. The average TSH level among female patients whose age are ≥ 40 differed significantly from their counterparts. Subclinical hypothyroidism patients more often reported having dry skin, poor memory, fatigue, cold intolerance, constipation, and hoarseness.

CONCLUSION

The overall prevalence of ScHt was 6.5% where females showed higher level than males. Age ≥ 40 became independent factor of subclinical hypothyroidism. The higher prevalence of subclinical hypothyroidism in this study could become a predictor for overt hypothyroidism, so screening for subclinical hypothyroidism prevents the later development of complicated overt hypothyroidism.

Evaluation of Thyroid Hormone Levels and Urinary Iodine Concentrations in Koreans Based on the Data from Korea National Health and Nutrition Examination Survey VI (2013 to 2015)

No nationwide data have been published about thyroid hormone levels and urinary iodine concentrations (UICs) in Korea. The Korea Centers for Disease Control and Prevention and the Korean Thyroid Association established a project to evaluate the nationwide thyroid hormone profile and UICs in healthy Koreans as part of the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2013 to 2015), a nationwide, cross-sectional survey of the Korean population that enrolled 7,061 individuals who were weighted to represent the entire Korean population. Based on the KNHANES VI, the geometric mean value of serum thyroid stimulating hormone was 2.16 mIU/L, and its reference interval was 0.59 to 7.03 mIU/L. The mean value of serum free thyroxine was 1.25 ng/dL, and its reference interval was 0.92 to 1.60 ng/dL. The median UIC in the Korean population was reported to be 294 μg/L, corresponding to 'above requirements' iodine intake according to the World Health Organization recommendations. A U-shaped relationship of UIC with age was found. The prevalence of overt hyperthyroidism and overt hypothyroidism in the Korean population based on the KNHANES VI was 0.54% and 0.73%, respectively.

Transcriptome Network Analysis Reveals Aging-Related Mitochondrial and Proteasomal Dysfunction and Immune Activation in Human Thyroid

BACKGROUND

Elucidating aging-related transcriptomic changes in human organs is necessary to understand the aging physiology and mechanisms, but little is known regarding the thyroid gland. We investigated aging-related transcriptomic alterations in the human thyroid gland and characterized the related molecular functions.

METHODS

Publicly available RNA sequencing data of 322 thyroid tissue samples from the Genotype-Tissue Expression project were analyzed. In addition, our own 64 RNA sequencing data of normal thyroid tissue samples were used as a validation set. To comprehensively evaluate the associations between aging and transcriptomic changes, we performed a weighted gene coexpression network analysis and pathway enrichment analysis. The thyroid differentiation score was then used for further analysis, defining the correlations between thyroid differentiation and aging.

RESULTS

The most significant aging-related transcriptomic change in thyroid was the downregulation of genes related to the mitochondrial and proteasomal functions (p = 3 × 10^-6). Moreover, genes that are associated with immune processes were significantly upregulated with age (p = 3 × 10^-4), and all of them overlapped with the upregulated genes in the thyroid glands affected by lymphocytic thyroiditis. Furthermore, these aging-related changes were not significantly different according to sex, but in terms of the thyroid differentiation, females were more susceptible to aging-related changes (p for trend = 0.03).

CONCLUSIONS

Aging-related transcriptomic changes in the thyroid gland were associated with mitochondrial and proteasomal dysfunction, loss of differentiation, and activation of autoimmune processes. Our results provide clues to better understanding the age-related decline in thyroid function and higher susceptibility to autoimmune thyroid disease.

Sex differences in risk factors for subclinical hypothyroidism

OBJECTIVE

To investigate the prevalence of subclinical hypothyroidism (SCH) in Korean adults and identify the risk factors for the occurrence of SCH by sex.

DESIGN AND METHODS

This study used data from the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI), a cross-sectional, nationally representative survey, which comprises a health interview survey, a health examination survey and a nutrition survey. To examine SCH, the reference range of thyroid-stimulating hormone (TSH) was defined using both the range provided by the test kit manufacturer (SCH-M) and a population-based range (SCH-P). We investigated the prevalence of SCH and its risk factors by sex using both reference ranges.

RESULTS

The prevalence of SCH in Koreans according to SCH-M (0.35-5.5 µIU/mL) was 5.6%, and 3.3% with SCH-P (0.62-6.68 µIU/mL). For men, smoking significantly reduced the incidence of SCH, positive anti-thyroid peroxidase antibody (TPOAb) significantly increased the risk of SCH, and in an adjusted model, the risk of SCH in all quartiles increased as the urine iodine creatinine ratio (UICR) quartile increased. For women, positive TPOAb was confirmed as a risk factor for SCH, as was the highest UICR quartile. Furthermore, the odds ratio for SCH in urban vs rural residence was 1.78.

CONCLUSIONS

The prevalence rates of SCH were similar to those reported in the literature and previously known risk factors were confirmed using both TSH reference ranges. The notable findings from this study are that the increased risk of SCH with increased iodine intake was more marked in men than in women and that residential area may be a risk factor for SCH in women.

Graves Disease in Central Ghana: Clinical Characteristics and Associated Factors

Background

Graves disease (GD) has increased in prevalence over the past decade in Africa. Despite this, the condition is not well described, especially in sub-Saharan Africa.

Objective

We have described the clinical characteristics and associated factors of GD in a cohort of patients attending a resource-limited setting tertiary hospital.

Methods

Patients were examined thoroughly and systematically tested for the degree of clinical and biochemical thyroid status. Thyroid volume, characteristics, and blood flow were assessed at presentation using ultrasonography. Factors associated with an inability to achieve clinical and biochemical thyroid remission were evaluated using multiple logistic regression analysis.

Results

Overall, 182 patients were studied, 152 (83.5%) were women with a female:male ratio of 5.1:1.0. The mean age at presentation was 39.9 ± 14.7 years with women significantly older than men. Thyroid-associated orbitopathy (TAO) was observed in 56% of the participants and pretibial myxoedema in 6%. About 84% of the participants were hyperthyroid at presentation, 9% were euthyroid, 4% were hypothyroid, and 3% had subclinical hyperthyroidism. Inability to achieve biochemical and clinical remission at 24 months was associated with increased thyroid volume (odds ratio [OR]: 2.35, 95% confidence interval [CI]: 1.85-2.52, P < .001), presence of TAO (OR: 2.15, 95% CI: 2.12-2.33, P < .001), increased FT3/FT4 ratio (OR: 1.33, 95% CI: 1.24-2.56, P = .004), and missed clinic appointment (OR: 5.2, 95% CI: 4.55-7.89, P < .001).

Conclusions

Graves disease among Ghanaians is associated with significant signs at presentation. Inability to achieve remission within the first 24 months is associated with increased thyroid volume, TAO, an increased FT3/FT4 ratio, as well as missed clinic appointment.

Age- and gender-specific reference intervals of TSH and free T4 in an iodine-replete area: Data from Korean National Health and Nutrition Examination Survey IV (2013-2015)

BACKGROUND

Establishment of the reference interval of thyroid-stimulating hormone (TSH) is critical in the diagnosis of thyroid dysfunction and is affected by age, gender, iodine nutrition, and ethnicity. The aim of this study was to determine the reference intervals of TSH and free thyroxin (FT4) from a large, nationwide data of Korea where iodine intake is more than adequate.

METHODS

We analyzed data from the Korea National Health and Nutrition Examination Survey VI that measured serum TSH, FT4, and thyroid peroxidase antibody from 7,061 individuals (urinary iodine measurement in 6,565). Age- and gender-specific reference intervals were established from 95% confidence limits from the 2.5 to 97.5 percentile of TSH (log-transformed) and FT4 in reference populations.

RESULTS

The geometric mean of TSH was 2.16 ± 0.01 mIU/L, with the lowest value found in the middle aged group (2.04 ± 0.02 mIU/L) and higher values noted in age groups of 10-19 and over 70 years (2.38 ± 0.02 and 2.32 ± 0.07 mIU/L, respectively). The association of TSH and age was U-shaped. The overall reference interval of TSH was 0.59-7.03 mIU/L. Mean FT4 was 1.25 ± 0.003 ng/dL (16.09 ± 0.039 pmol/L), and it showed a small but continuous decrease after 20 years of age (P < 0.001). There was a significant positive correlation between TSH and urine iodine concentration (r = 0.154, P < 0.001).

CONCLUSIONS

The reference interval of TSH in Korea, where iodine intake is above the requirement, was 0.59-7.03 mIU/L and showed U-shaped change with age, which was a similar pattern to iodine intake. The reference interval of FT4 was 0.92-1.60 ng/dL. The geometric mean and upper limit of TSH were higher than those of Western populations, reflecting the paramount importance of iodine intake on thyroid function.