Natural history of autoimmune thyroiditis

Clonal hematopoiesis of indeterminate potential and risk of autoimmune thyroid disease

BACKGROUND

Autoimmune thyroid disease (AITD) is the most common organ-specific autoimmune disease, often remaining asymptomatic until the thyroid is significantly affected. Clonal hematopoiesis of indeterminate potential (CHIP) has been reported to drive many inflammatory diseases and autoimmune diseases. The association between CHIP and AITD is scarcely reported. This study aims to investigate whether CHIP is associated with the risk of AITD.

METHODS

We conducted a prospective community-based cohort study at the UK Biobank. CHIP, defined as the exposure, was identified using whole-exome sequencing (WES) data. AITD was sourced from the inpatient hospitalization register, the death register, and the primary healthcare register. Cox regression models were utilized to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the association between CHIP and AITD. Next, we conducted a subgroup analysis to investigate the role of specific gene mutations (DNMT3A, TET2, ASXL1, PPM1D, SRSF2, and JAK2) in the investigated association. Finally, we assessed the association across small CHIP clones (variant allele frequency, VAF: 2-10%) and large CHIP clones (VAF ≥ 10%). All models were adjusted for sex, age, ethnicity, education, Townsend deprivation index, body mass index, smoking status, and drinking status.

RESULTS

A total of 454,618 individuals were included in the final analysis. We identified 14,059 (3.1%) participants with CHIP. Compared with individuals without CHIP, those with CHIP were generally older and more likely to be smokers. Over a median follow-up of 12.7 years (interquartile range, IQR: 11.9-13.5), 21,708 cases with AITD were diagnosed. CHIP was associated with an increased risk of AITD (HR 1.11, 95% CI 1.03-1.19). Specifically, individuals with TET2-mutant CHIP (HR 1.23, 95% CI 1.07-1.41) had an elevated risk of AITD. A large CHIP clone (HR 1.17, 95% CI 1.08-1.27) was associated with an increased risk of AITD. Focusing on large CHIP clone, we also observed an association between TET2-mutant (HR 1.27, 95% CI 1.10-1.47) and ASXL1-mutant (HR 1.33, 95% CI 1.02-1.73) CHIP and risk of AITD.

CONCLUSIONS

Individuals with CHIP were associated with a modestly increased risk of AITD, especially TET2-mutant CHIP. Future studies are needed to verify current findings and elaborate potential mechanisms.

Identification and Preliminary Clinical Validation of Key Extracellular Proteins as the Potential Biomarkers in Hashimoto's Thyroiditis by Comprehensive Analysis

Hashimoto's thyroiditis (HT) is an autoimmune disruption manifested by immune cell infiltration in thyroid tissue and the production of antibodies against thyroid-specific antigens, such as the thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb). TPOAb and TGAb are commonly used in clinical tests; however, handy indicators of the diagnosis and progression of HT are still scarce. Extracellular proteins are glycosylated and are likely to enter body fluids and become readily available and detectable biomarkers. Our research aimed to discover extracellular biomarkers and potential treatment targets associated with HT through integrated bioinformatics analysis and clinical sample validations. A total of 19 extracellular protein-differentially expressed genes (EP-DEGs) were screened by the GSE138198 dataset from the Gene Expression Omnibus (GEO) database and protein annotation databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the function and pathway of EP-DEGs. STRING, Cytoscape, MCODE, and Cytohubba were used to construct a protein-protein interaction (PPI) network and screen key EP-DEGs. Six key EP-DEGs (CCL5, GZMK, CXCL9, CXCL10, CXCL11, and CXCL13) were further validated in the GSE29315 dataset and the diagnostic curves were evaluated, which all showed high diagnostic accuracy (AUC > 0.95) for HT. Immune profiling revealed the correlation of the six key EP-DEGs and the pivotal immune cells in HT, such as CD8+ T cells, dendritic cells, and Th2 cells. Further, we also confirmed the key EP-DEGs in clinical thyroid samples. Our study may provide bioinformatics and clinical evidence for revealing the pathogenesis of HT and improving the potential diagnosis biomarkers and therapeutic strategies for HT.

Associated autoimmune thyroid diseases in children and adolescents with type one diabetes in Jordan

OBJECTIVES

To investigate the prevalence of thyroid autoimmunity and related thyroid disorders among children and adolescents with type 1 diabetes in Jordan.

METHODS

In a retrospective study, thyroid stimulating hormone and thyroid hormone (Free T4) levels were measured in 684 children with type 1 diabetes who presented to Jordan University Hospital between January 2012 and February 2021. Anti-thyroid peroxidase (TPOAb) and anti-thyroglobulin (TGAb) antibodies were measured in 526 and 438 subjects with type 1 diabetes, respectively.

RESULTS

681 children were included in the study (52.4 % females, average current age 14.3 years, average age at diagnosis 8.0 years, and average diabetes duration 6.2 years). Of the whole group, 18 children (2.6 %) were diagnosed with subclinical hypothyroidism and 31 children (4.4 %) had overt hypothyroidism. Of those who were tested for TPOAb and TGAb, 22.6 and 23.1 % were positive respectively. Predictors for developing hypothyroidism were female sex and positive antibodies to glutamic acid decarboxylase.

CONCLUSIONS

Screening for associated thyroid autoimmunity in children and adolescents with type one diabetes from Jordan is advised with a special focus on females and those with positive antibodies to glutamic acid decarboxylase.

Relationships between the serum TPOAb and TGAb antibody distributions and water iodine concentrations, thyroid hormones and thyroid diseases: a cross-sectional study of 2503 adults in China

The aim of this study was to explore the status of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in three areas with differing water iodine concentrations; and to discuss the relationships between these two thyroid antibodies and thyroid diseases in the three areas. We investigated 2503 adults from three areas. Urinary iodine concentrations, thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), TPOAb, TGAb and thyroid volume (TV) were measured, and thyroid ultrasonography was performed. The positivity rates of TGAb(+), TPOAb(+) and TGAb(+) and TPOAb(+) or TGAb(+) were significantly higher in iodine fortification (IF) areas than iodine adequate (IA) areas (all P < 0·05). In IF and iodine excess areas, the positivity rates of TPOAb(+), TGAb(+) and TPOAb(+) or TGAb(+) significantly increased with age (all P for trend < 0·05). The levels of TSH, TV and the prevalence of overt hypothyroidism, subclinical hypothyroidism and goitre were significantly elevated in the thyroid antibody-positive groups in the three areas, but the FT3 was diminished (all P < 0·010). Positivity for TPOAb and TGAb was associated with an increased risk of subclinical hypothyroidism in the three areas. In areas with different median water iodine, positivity for both TPOAb and TGAb was associated with elevated TSH values. Notably, with the increased levels of TPOAb, the frequency of abnormally elevated TSH increased dramatically in the three areas.

Transient high thyroid stimulating hormone and hypothyroidism incidence during follow up of subclinical hypothyroidism

Objectives. Given the high prevalence of subclinical hypothyroidism (SCH), defined as high thyroid stimulating hormone (TSH) and normal free thyroxine (FT4), and uncertainty on treatment, one of the major challenges in clinical practice is whether to initiate the treatment for SCH or to keep the patients under surveillance. There is no published study that has identified predictors of short-term changes in thyroid status amongst patients with mild elevation of TSH (4.5-10 mIU/L). Subjects and Results. A cohort study was conducted on patients with SCH detected through a general population screening program, who were followed for six months. This project identified factors predicting progression to hypothyroid status, persistent SCH and transient cases. A total of 656 participants joined the study (431 controls and 225 were patients with SCH). A part of participants (12.2%) developed biochemical hypothyroidism during the follow-up, while 73.8% of the subjects became euthyroid and the remained ones (13.4%) stayed in the SCH status. The incidence of overt hypothyroidism for participants with TSH above 6.9 mIU/L was 36.7%, with incidence of 42.3% for females. Anti-thyroid peroxidase antibodies (TPO) positivity is an important predictor of development of hypothyroidism; however, it could be also positive due to transient thyroiditis. Conclusions. It can be concluded that females with TSH above 6.9 mIU/L, particularly those with free triiodothyronine (FT3) and FT4 in the lower half of the reference range, are more likely to develop biochemical hypothyroidism. Therefore, it is recommended to give them a trial of levothyroxine replacement. It is also recommended to repeat TSH after six months for male subjects and participants with baseline TSH equal or less than 6.9 mIU/L.

Incidence of TPOAb over a 4-year follow-up period: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Objective

Although some previous data have suggested a high iodine intake in Brazil, the prevalence of antithyroperoxidase antibodies (TPOAb) in the country is compatible with rates from countries with adequate iodine intake. This observation emphasizes the importance of knowing the incidence of TPOAb in Brazil.

Methods

This prospective analysis included euthyroid participants with negative TPOAb at baseline and a thyroid function assessment at a 4-year follow-up. TPOAb was measured by electrochemiluminescence and considered positive when titers were ≥34 IU/mL. TSH and free T4 (FT4) levels were determined by a third-generation immunoenzymatic assay. The incidence of TPOAb is expressed in percentage per year or as a cumulative incidence within the 4-year follow-up period.

Results

Of 8,922 euthyroid participants (mean age 51.1 years; 50.9% women) with a negative TPOAb test at baseline, 130 presented incident TPOAb at the 4-year follow-up, yielding an annual incidence of TPOAb of 0.38%/year (95% confidence interval [95% CI], 0.37-0.39%/year) and a cumulative incidence over 4 years of 1.46% (95% CI, 1.21-1.71%). In men, the annual incidence was 0.32% (95% CI, 0.31-0.33%), and the cumulative incidence over 4 years was 1.23% (95% CI, 0.90-1.56%). In women, the annual incidence was 0.43%/year (95% CI, 0.42-0.44%/year) and the cumulative incidence over 4 years was 1.67% (95% CI, 1.30-2.04%). The only factor associated with incident TPOAb was the occurrence of thyroid diseases at follow-up. No differences in TPOAb incidence were detected across ELSA-Brasil research centers.

Conclusion

Based on the results of this study, the incidence of TPOAb per year and at a 4-year follow-up period are compatible with those of a country with adequate iodine intake.

Human immunodeficiency virus, diabetes mellitus and thyroid abnormalities: Should we be screening?

BACKGROUND

Diabetes mellitus (DM) and human immunodeficiency virus (HIV) are associated with thyroid abnormalities. Scarce literature exists on the prevalence of thyroid abnormalities in people living with HIV (PLWH) and DM (PLWHD). Guidelines vary regarding thyroid-stimulating hormone (TSH) screening in PLWH and/or DM.

OBJECTIVES

This study describes thyroid abnormalities in PLWHD and HIV-uninfected people living with DM (PLWD).

METHOD

This was a cross-sectional analysis of demographic, clinical and biochemical data including TSH results of first-visit patients to the Edendale Hospital diabetes clinic between January 2016 and December 2017.

RESULTS

A total of 915 patients were enrolled: 165 PLWHD and 750 PLWD. Overall prevalence of thyroid disorders in PLWD was 8.53% (64/750). The occurrence of 'total' thyroid disorders and of 'subclinical-hypothyroidism' (SCH) was higher in PLWHD than PLWD (23.03% vs. 8.53% and 20.61% vs. 4%, p < 0.001; respectively). People living with HIV and diabetes with thyroid disorders had lower CD4 counts than PLWHD without thyroid disorders (376.08 ± 333.30 vs. 509 ± 341.7 cells/mm3; p = 0.004). Subclinical-hypothyroidism was more common in patients on antiretroviral therapy [ART] (27/136 [19.85%] vs. 4/27 [14.81%], p < 0.001). A significant number of PLWHD acquired HIV before the onset of DM (107/165 [64.85%] vs. 58/165 [35.15%], p < 0.001). Patients on ART were more likely to develop DM, OR 2.66 (95% CI 1.11-6.38).

CONCLUSION

Our study showed an increased prevalence of thyroid disorders (especially SCH) in PLWD and a higher prevalence in PLWHD. Young, overweight, female PLWHD were at risk of SCH. People living with HIV and DM on ART demonstrated an increased prevalence of thyroid dysfunction and poor lipaemic control. The introduction of combined communicable-non-communicable disease clinics might provide an integrated patient screening option.

Hashimoto's thyroiditis: An update on pathogenic mechanisms, diagnostic protocols, therapeutic strategies, and potential malignant transformation

Hashimoto's thyroiditis, characterized by thyroid-specific autoantibodies, is one of the commonest autoimmune disorders. Although the exact etiology has not been fully elucidated, Hashimoto's thyroiditis is related to an interaction among genetic elements, environmental factors and epigenetic influences. Cellular and humoral immunity play a key role in the development of the disease; thus, a T and B cells inflammatory infiltration is frequently found. Histopathologic features of the disease include lymphoplasmacytic infiltration, lymphoid follicle formation with germinal centers, and parenchymal atrophy. Moreover, the occurrence of large follicular cells and oxyphilic or Askanazy cells is frequently associated to Hashimoto's thyroiditis. Clinically, Hashimoto's thyroiditis is characterized mainly by systemic manifestations due to the damage of the thyroid gland, developing a primary hypothyroidism. Diagnosis of Hashimoto's thyroiditis is clinical and based on clinical characteristics, positivity to serum antibodies against thyroid antigens (thyroid peroxidase and thyroglobulin), and lymphocytic infiltration on cytological examination. The mainstream of treatment is based on the management of the hypothyroidism with a substitution therapy. A relationship between Hashimoto's thyroiditis and a possible malignant transformation has been proposed in several studies and involves immunological/hormonal pathogenic links although specific correlation is still debated and needs to be further investigated with prospective studies.

Latent autoimmune thyroid disease

Objective

To determine the prevalence of thyroid autoantibodies and the associated factors in euthyroid subjects.

Methods

300 euthyroid subjects, chosen by stratified sampling from an inception cohort of 1335 individuals, were included. Thyroid function was evaluated by measuring the serum levels of TSH (0.3–4.5 μIU/mL) and FT4 (5.2–12.7μg/dL). Anti-peroxidase (TPOAbs), anti-thyroglobulin (TgAbs), and anti-TSH receptor (TrAbs) antibodies were evaluated with 23 additional autoantibodies as well as vitamin D (VitD) levels. The analysis included sociodemographic, clinical, and environmental characteristics. Data were analyzed by bivariate and multivariate tests.

Results

Thyroid autoimmunity was observed in 15.3% of the subjects (TPOAbs 11.3% and TgAbs 2.0%). In six individuals, both autoantibodies were positive. TrAbs were not detected in any individual. Familial thyroid disease (β ​= ​3.4, 95% CI: 1.2–9.5, P ​= ​0.021), the presence of other autoimmune diseases (β ​= ​10.8, 95% CI: 1.6–72.9, P ​= ​0.014) VitD insufficiency (P ​= ​0.030), never smoke (β ​= ​6.9, 95% CI: 1.6–30.4, P ​= ​0.010), drinking more than 4 cups of coffee (β ​= ​3.8, 95% CI: 1.1–13.1, P ​= ​0.036), and a higher number of years exposed to wood smoke (P ​= ​0.04) were associated with thyroid autoimmunity. In the case of TPOAbs, familial thyroid disease (β ​= ​4.9, 95% CI: 1.7–14.0, P ​= ​0.003), never smoke (β ​= ​5.7, 95% CI: 1.4–21.0, P ​= ​0.002), and drinking more than 4 cups of coffee (β ​= ​3.6, 95% CI: 1.1–13.1, P ​= ​0.047) were associated with their positivity. In addition, the presence of anti–SS–A/Ro52 (β ​= ​36.7, 95% CI: 2.5–549.9, P ​= ​0.009) and anti-Ku antibodies (β ​= ​10.2, 95% CI: 1.1–100.7, P ​= ​0.046) was also associated with TPOAbs. The presence of African ancestry (β ​= ​10.5, 95% CI: 1.7–63.2, P ​= ​0.01), anti–SS–A/Ro52 (β ​= ​15.8, 95% CI: 1.2–198.6, P ​= ​0.03), and anti-CENP-B antibodies (β ​= ​31.2, 95% CI: 1.8–565.9 ​P ​= ​0.02) were associated with TgAbs.

Conclusion

Latent thyroid autoimmunity is not rare. Environmental, genetic, and immunological factors as well as ancestry are associated risk factors. These results would facilitate the implementation of screening strategies in order to provide timely diagnosis and treatment.

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Latent autoimmunity is common in colombian eutyrhoid subjects.

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Autoimmune diseases and familial autimmunity are associated to thyroid autoimmunity.

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Tobacco, cofee compsumption and VitD insufficiency influence thyroid autoimmunity.

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Early recognition of latent autoimmunity allows prediction of overt autoimmunity.

The antigenic link between thyroid autoimmunity and breast cancer

The association between breast cancer and benign thyroid disorders, in particular thyroid autoimmunity, has been debated for decades. Autoantibodies to thyroid peroxidase, the hallmark of thyroid autoimmunity, have a higher prevalence among patients with breast cancer compared with the general population. Furthermore a correlation between their positivity and a better prognosis of breast cancer was found in several independent small-scale studies, even if such observation was not confirmed in a subsequent retrospective study conducted on the largest patient cohort to date. The thyroid and mammary glands present several biological similarities, therefore the hypothesis of an immune response to shared thyroid/breast antigens could in part explain the association between thyroid autoimmunity and breast cancer. The sodium iodide symporter is expressed in both glands, however it seems unlikely to be the key common antigen, considering that autoantibodies targeting it are rare. Instead thyroid peroxidase, one of the major thyroid autoantigens, is also expressed in breast tissue and therefore represents the main antigenic link between thyroid autoimmunity and breast cancer. Furthermore lactoperoxidase, an enzyme of the same family that shares structural similarities with thyroid peroxidase, is expressed in neoplastic breast cells and is responsible for the cross-reactivity with some autoantibodies to thyroid peroxidase. Novel strategies for the diagnosis and treatment of breast cancer might take advantage of the antigenic link between thyroid and breast tissues.

Prevalence of antithyroperoxidase antibodies in a multiethnic Brazilian population: The ELSA-Brasil Study

OBJECTIVE

In this study, we aimed to describe the prevalence and distribution of positive antithyroperoxidase antibodies (TPOAb) according to sex, age strata, and presence of thyroid dysfunction using baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

MATERIALS AND METHODS

Thyroid hormone tests were obtained from each study participant at baseline. Levels of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) were measured using a third-generation immunoenzymatic assay. Antithyroperoxidase antibodies were measured by electrochemiluminescence and were considered to be positive when ≥ 34 IU/mL.

RESULTS

The prevalence of TPOAb among 13,503 study participants was 12%. Of participants with positive TPOAb, 69% were women. Almost 60% of the individuals with positive TPOAb were white. The presence of positive TPOAb was associated with the entire spectrum of thyroid diseases among women, but only with overt hyperthyroidism and overt hypothyroidism in men.

CONCLUSION

The distribution of positive TPOAb across sex, race, age, and thyroid function in the ELSA-Brasil study is aligned with the worldwide prevalence of positive TPOAb reported in iodine-sufficient areas. In women, the presence of TPOAb was related to the entire spectrum of thyroid dysfunction, while in men, it was only related to the occurrence of overt thyroid disease.

Elevated neutrophil-to-lymphocyte ratio in the diagnosis of Hashimoto's thyroiditis

OBJECTIVE

Hashimoto's thyroiditis (HT) is an autoimmune inflammatory disorder. The purpose of this study was to determine the neutrophil-to-lymphocyte ratio (NLR), a novel marker of inflammation, in patients with HT and to compare these values with those from healthy subjects.

METHOD

A total of 154 participants were included in the study, 90 HT patients and 64 healthy volunteers. Retrospectively, demographic and laboratory data of the subjects were obtained from our institution's database. Patients with active infection, diabetes mellitus, malignancy, other chronic inflammatory diseases, hematologic disorders and patients on aspirin or steroid treatment were excluded from the study. Values for complete blood count (CBC) and serum laboratory parameters of HT patients were the baseline values obtained at the time of HT diagnosis. Control subjects consisted of healthy volunteers who visited our institution for a routine check-up.

RESULTS

Age, gender and CBC parameters were not different between the HT group and the control group; however, the NLR of HT group (2.1 [1.3-5.8]) was significantly higher than the control group (1.9 [0.6-3.3]), p=0.04.

CONCLUSION

Increased NLR may be useful as an indicator of the presence of HT, especially in complicated cases. NLR is inexpensive and easy to determine. Larger, prospective studies are required to determine its usefulness in assessing diagnostic potential and treatment outcomes in HT patients.

TPOAb and Thyroid Function Are Not Associated with Breast Cancer Outcome: Evidence from a Large-Scale Study Using Data from the Taxotere as Adjuvant Chemotherapy Trial (TACT, CRUK01/001)

BACKGROUND

Small-scale studies correlated the presence of thyroid autoimmunity with both improved or worsened breast cancer outcome.

OBJECTIVES

We aimed to clarify this association in a large cohort using the phase III, randomized, controlled Taxotere as Adjuvant Chemotherapy Trial (TACT, CRUK01/001).

METHODS

TACT women >18 years old with node-positive or high-risk node-negative early breast cancer (pT1-3a, pN0-1, M0), with stored plasma (n = 1,974), taken 15.5 (median; IQR 7.0-24.0) months after breast surgery were studied. Patients had also received chemotherapy (100%), radiotherapy (1,745/1,974; 88.4%), hormonal therapy (1,378/ 1,974; 69.8%), or trastuzumab (48/1,974; 2.4%). History of thyroid diseases and/or related treatments was not available. The prognostic significance of autoantibodies to thyroid peroxidase (TPOAb; positive ≥6 kIU/L), free-thyroxine and thyrotropin (combined: euthyroid, hypothyroid, hyperthyroid) was evaluated for disease-free survival (DFS), overall-survival (OS), and time-to-recurrence (TTR), with Cox regression models in univariate and multivariable analyses. The extended median follow-up was 97.5 months.

RESULTS

No difference in DFS was found by TPOAb status (unadjusted hazard ratio [HR]: 0.97, 95%CI: 0.78-1.19; p = 0.75) and/or thyroid function (unadjusted HR [hypothyroid vs. euthyroid]: 1.15, 95% CI: 0.79-1.68; p = 0.46; unadjusted HR [hyperthyroid vs. euthyroid]: 1.14, 95% CI: 0.82-1.61; p = 0.44). Similar results were obtained for OS, TTR, multivariable analyses, when TPOAb titre by tertiles was considered, and in a subgroup of 123 patients with plasma collected before adjuvant treatments.

CONCLUSIONS

No evidence for a prognostic role of TPOAb and/or thyroid function in moderate-to-high-risk early breast cancer was found in the largest and longest observational study to date.

The Prevalence, Incidence and Natural Course of Positive Antithyroperoxidase Antibodies in a Population-Based Study: Tehran Thyroid Study

OBJECTIVE

Thyroid peroxidase antibody (TPOAb), the most common antibody frequently measured in population surveys is a protein expressed in the thyroid gland. We conducted the present study to analyze the prevalence and incidence of thyroid auto immunity and natural course of TPOAb in a population based study.

MATERIAL AND METHODS

This prospective study was conducted within the framework of the Tehran Thyroid Study (TTS) on 5783 (2376 men and 3407 women) individuals aged ≥ 20 years who had thyroid function tests at baseline and were followed up for median 9.1 year with TPOAb measurements at approximately every 3 years.

RESULTS

The mean age of total population at baseline was 40.04±14.32. At baseline, of the 5783 participants, 742 (12.8%) were TPOAb positive, with higher prevalence among women than in men (16.0 vs. 8.5%, p = 0.001). The prevalence of TPOAb positivity in the total population was 11.9, 14.9 and 13.6% in the young, middle age and elderly respectively. The total incidence rate (95%CI) of TPOAb positivity in the total population (5020) was 7.1 (6.36-7.98) per 1000 person-years of follow-up, with higher incidence of TPOAb positivity among young participants, i.e. 8.5 (7.5-9.7) per 1000 person-years. Sex specific incidence rate demonstrated that TPOAb positivity was higher in women, 9.3 (8.2-10.7) per 1000 person-years. The Cox's proportional hazard model analysis showed that the hazard ratio of developing TPOAb positivity was higher in women than men (P<0.0001) and tended to increase slightly with serum TSH levels (P<0.0001) but declined with increasing age (P<0.0001) in the total population. Our findings demonstrate that individuals, who became TPOAb positive in each phase, had significant elevation of TSH levels at the phase of seroconversion, compared to baseline values.

CONCLUSION

Gender, age and elevated serum TSH were found to be risk factors for developing TPOAb positivity. Furthermore, compared to baseline a significant elevation of TSH levels during seroconversion phase was observed in TPOAb positive individuals.

Bipolar disorder and antithyroid antibodies: review and case series

Mood disorders and circulating thyroid antibodies are very prevalent in the population and their concomitant occurrence may be due to chance. However, thyroid antibodies have been repeatedly hypothesized to play a role in specific forms of mood disorders. Potentially related forms include treatment-refractory cases, severe or atypical depression, and depression at specific phases of a woman’s life (early gestation, postpartum depression, perimenopausal). With regard to bipolar disorder, studies of specific subgroups (rapid cycling, mixed, or depressive bipolar) have reported associations with thyroid antibodies. Offspring of bipolar subjects were found more vulnerable to develop thyroid antibodies independently from the vulnerability to develop psychiatric disorders. A twin study suggested thyroid antibodies among possible endophenotypes for bipolar disorder. Severe encephalopathies have been reported in association with Hashimoto’s thyroiditis. Cases with pure psychiatric presentation are being reported, the antithyroid antibodies being probably markers of some other autoimmune disorders affecting the brain. Vasculitis resulting in abnormalities in cortical perfusion is one of the possible mechanisms.

Radiation-Induced Thyroid Cancer: Gender-Related Disease Characteristics and Survival

BACKGROUND

Radiation exposure is a well-known risk factor for well-differentiated thyroid cancer (WDTC). However, gender disparity in disease characteristics is not completely understood. The purpose of this study was to determine the behavior of radiation-induced thyroid cancer according to gender.

METHODS

Charts of all patients diagnosed with WDTC after radiation exposure between the years 1985 and 2013 in a tertiary referral center were retrieved.

RESULTS

Forty-three patients were reviewed, 29 females and 14 males. Mean age of exposure for women and men were 17.1 ± 19.5 and 15.5 ± 12.5 years, respectively (P = .78). Age at diagnosis were 47.5 ± 15.5 and 41.5 ± 15 years for women and men, respectively (P = .18). Mean disease-specific survival was 44.1 and 43.7 years for women and men, respectively (P = .50).

CONCLUSIONS

Similar disease characteristics, tumor pathology, disease-free survival, and overall survival in both genders. In sporadic well-differentiated thyroid carcinoma, female gender is associated with better tumor behavior and prognosis. However, our results suggest that women are more affected by radiation than men and therefore have the same prognosis as men.

Subclinical Hypothyroidism and Type 2 Diabetes: A Systematic Review and Meta-Analysis

Background

Abundant evidence suggests an association between subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (T2DM), but small sample sizes and inconclusive data in the literature complicate this assertion.

Objective

We measured the prevalence of SCH in T2DM population, and investigated whether T2DM increase the risk of SCH and whether SCH was associated with diabetic complications.

METHODS

We conducted a meta-analysis using PubMed, EMBASE, Web of Science, Wan Fang, CNKI and VIP databases for literature search. We obtained studies published between January 1, 1980 to December 1, 2014. The studies were selected to evaluate the prevalence of SCH in T2DM subjects, compare the prevalence of SCH in T2DM subjects with those non-diabetics, and investigate whether diabetic complications were more prevalent in SCH than those who were euthyroid. Fixed and random effects meta-analysis models were used, and the outcome was presented as a pooled prevalence with 95% confidence interval (95% CI) or a summary odds ratio (OR) with 95% CI.

RESULTS

Through literature search, 36 articles met the inclusion criteria and these articles contained a total of 61 studies. Funnel plots and Egger’s tests showed no publication bias in our studies, except for the pooled prevalence of SCH in T2DM (P = 0.08) and OR for SCH in T2DM (P = 0.04). Trim and fill method was used to correct the results and five potential missing data were replaced respectively. The adjusted pooled prevalence of SCH in T2DM patients was 10.2%, meanwhile, T2DM was associated with a 1.93-fold increase in risk of SCH (95% CI: 1.66, 2.24). Furthermore, SCH might affect the development of diabetic complications with an overall OR of 1.74 (95% CI: 1.34, 2.28) for diabetic nephropathy, 1.42 (95% CI: 1.21, 1.67) for diabetic retinopathy, 1.85 (95% CI: 1.35, 2.54) for peripheral arterial disease, and 1.87 (95% CI: 1.06, 3.28) for diabetic peripheral neuropathy.

Conclusions

T2DM patients are more likely to have SCH when compared with healthy population and SCH may be associated with increased diabetic complications. It is necessary to screen thyroid function in patients with T2DM, and appropriate individualized treatments in addition to thyroid function test should be given to T2DM patients with SCH as well.

Clinical, biochemical & cytomorphologic study on Hashimoto's thyroiditis

BACKGROUND & OBJECTIVES

Despite, the extensive salt iodization programmes implemented in India, the prevalence of goiter has not reduced much in our country. The most frequent cause of hypothyroidism and goiter in iodine sufficient areas is Hashimoto's thyroiditis (HT). This study records the clinical presentation, biochemical status, ultrasonographic picture and cytological appearance of this disease in a coastal endemic zone for goiter.

METHODS

Case records of patients with cytological diagnosis of HT were studied in detail, with reference to their symptoms, presence of goiter, thyroid function status, antibody levels and ultrasound picture. Detailed cytological study was conducted in selected patients.

RESULTS

A total of 144 patients with cytological proven HT/lymphocytic thyroiditis were studied. Ninety per cent of the patients were females and most of them presented within five years of onset of symptoms. Sixty eight per cent patients had diffuse goiter, 69 per cent were clinically euthyroid and 46 per cent were biochemically mildly hypothyroid. Antibody levels were elevated in 92.3 per cent cases. In majority of patients the sonographic picture showed heterogeneous echotexture with increased vascularity. Cytological changes were characteristic.

INTERPRETATION & CONCLUSIONS

Our study showed predominance of females in the study population in 21-40 yr age group with diffuse goiter. We suggest that in an endemic zone for goiter, all women of the child bearing age should be screened for HT.

Efficacy of homeopathic intervention in subclinical hypothyroidism with or without autoimmune thyroiditis in children: an exploratory randomized control study

INTRODUCTION

The decision to treat subclinical hypothyroidism (SCH) with or without autoimmune thyroiditis (AIT) in children, presents a clinical dilemma. This study was undertaken to evaluate the efficacy of individualized homeopathy in these cases.

METHODS

The study is an exploratory, randomized, placebo controlled, single blind trial. Out of 5059 school children (06-18 years) screened for thyroid disorders, 537 children had SCH/AIT and 194 consented to participate. Based on primary outcome measures (TSH and/or antiTPOab) three major groups were formed: Group A - SCH + AIT (n = 38; high TSH with antiTPOab+), Group B - AIT (n = 47; normal TSH with antiTPOab+) and Group C - SCH (n = 109; only high TSH) and were further randomized to two subgroups-verum and control. Individualized homeopathy or identical placebo was given to respective subgroup. 162 patients completed 18 months of study.

RESULTS

Baseline characteristics were similar in all the subgroups. The post treatment serum TSH (Group A and C) returned to normal limits in 85.94% of verum and 64.29% of controls (p < 0.006), while serum AntiTPOab titers (Group A and B) returned within normal limits in 70.27%of verum and 27.02%controls (p < 0.05). Eight children (10.5%) progressed to overt hypothyroidism (OH) from control group.

CONCLUSION

A statistically significant decline in serum TSH values and antiTPOab titers indicates that the homeopathic intervention has not only the potential to treat SCH with or without antiTPOab but may also prevent progression to OH.

Interferon-γ inhibits integrin-mediated extracellular signal-regulated kinase activation stimulated by fibronectin binding in thyroid cells

Hashimoto's thyroiditis (HT) is an autoimmune disorder characterized by the presence of specific antibodies and by a lymphocytic infiltration of the thyroid secreting inflammatory cytokines. Macrophages, lymphocytes, and cytokines play a pivotal role in both development and progression of Th1-mediated autoimmune diseases, and a direct role in the destruction of thyroid follicles and follicular cell function in autoimmune thyroiditis. Integrins are integral membrane receptors involved in cell-extra-cellular matrix (ECM) interaction with both structural and signaling functions. The integrin- ECM interaction is necessary for the correct function and survival of thyroid follicular cells. The purpose of this study was to determine the effect of cytokine stimulation on integrin expression and signaling in the thyroid cell. Primary cultures from normal thyroids were treated with interferon-γ (IFN-γ), INF-α, tumor necrosis factor-α, interleukin 1a or these cytokines all together. Integrin expression, cell adhesion to fibronectin (FN) and FN-stimulated extracellular signal-regulated kinase (ERK) phosphorylation were determined after cytokine treatment. IFN-γ and IFN-α were the most effective, reducing the expression of the integrin αvβ3 and slightly increasing the α3β1. Cell treatment with IFN-γ strongly impaired cell adhesion to FN. At the same time, the treatment with IFN-γ dramatically inhibited the stimulation of ERK phosphorylation induced by cell adhesion to FN. In conclusion, IFN-γ inhibits the expression of the integrin αvβ3, reducing the cell adhesion to FN and the following intracellular signaling in thyroid cells in culture. These results suggest that integrins may be a target of the infiltrating lymphocytes and have a role in the pathogenesis of autoimmune thyroiditis.

Thyroid autoantibodies in pregnancy: their role, regulation and clinical relevance

Autoantibodies to thyroglobulin and thyroid peroxidase are common in the euthyroid population and are considered secondary responses and indicative of thyroid inflammation. By contrast, autoantibodies to the TSH receptor are unique to patients with Graves' disease and to some patients with Hashimoto's thyroiditis. Both types of thyroid antibodies are useful clinical markers of autoimmune thyroid disease and are profoundly influenced by the immune suppression of pregnancy and the resulting loss of such suppression in the postpartum period. Here, we review these three types of thyroid antibodies and their antigens and how they relate to pregnancy itself, obstetric and neonatal outcomes, and the postpartum.

Consenso brasileiro para a abordagem clínica e tratamento do hipotireoidismo subclínico em adultos: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

INTRODUÇÃO: O hipotireoidismo subclínico (HSC), definido por concentrações elevadas do TSH em face de níveis normais dos hormônios tireoidianos, tem elevada prevalência no Brasil, particularmente entre mulheres e idosos. Embora um número crescente de estudos venha associando o HSC com maior risco de doença arterial coronariana e de mortalidade, não há ensaio clínico randomizado sobre o benefício do tratamento com levotiroxina na redução dos riscos e o tratamento permanece controverso. OBJETIVO: Este consenso, patrocinado pelo Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia e desenvolvido por especialistas brasileiros com vasta experiência clínica em tireoide, apresenta recomendações baseadas em evidências para uma abordagem clínica do paciente com HSC no Brasil. MATERIAIS E MÉTODOS: Após estruturação das questões clínicas, a busca das evidências disponíveis na literatura foi realizada inicialmente na base de dados do MedLine-PubMed e posteriormente nas bases Embase e SciELO - Lilacs. A força da evidência, avaliada pelo sistema de classificação de Oxford, foi estabelecida a partir do desenho de estudo utilizado, considerando-se a melhor evidência disponível para cada questão e a experiência brasileira. RESULTADOS: Os temas abordados foram definição e diagnóstico, história natural, significado clínico, tratamento e gestação, que resultaram em 29 recomendações para a abordagem clínica do paciente adulto com HSC. CONCLUSÃO: O tratamento com levotiroxina foi recomendado para todos os pacientes com HSC persistente com níveis séricos do TSH > 10 mU/L e para alguns subgrupos especiais de pacientes.

Inflammation and increased myxovirus resistance protein A expression in thyroid tissue in the early stages of Hashimoto's thyroiditis

BACKGROUND

The role of viruses as environmental triggers for Hashimoto's thyroiditis (HT) is controversial. Thyroid epithelial cells express a variety of molecules involved in antiviral responses. This study combined histological, immunological, and virological tests to describe changes in tissue from patients with newly diagnosed and untreated HT. To study the early events, patients with positive thyroid peroxidase antibodies (TPO-Ab) and normal thyroid function were also included. This stage was defined as "prethyroiditis."

METHODS

Thyroid tissue was collected from 47 patients with high titers of TPO-Ab and from 24 controls. Seventeen patients had prethyroiditis, 17 had subclinical hypothyroidism, and 13 had overt hypothyroidism. The interferon (IFN)-α/β-inducible myxovirus resistance protein 1 (myxovirus resistance protein A; MxA) was used as a surrogate marker for type I IFN expression. Inflammation, expression of MxA, and the presence of the enteroviralcapsid protein (VP1) were characterized by immunohistochemistry. The presence of enterovirus (EV) RNA was examined by in situ hybridization.

RESULTS

The density of CD4+ T cells was increased in all three patient groups, while CD8+ T cells were increased only in patients with overt hypothyroidism. The density of plasma cells increased as the disease progressed. The density of plasmacytoid dendritic cells and the expression of MxA were significantly increased in all patient groups compared with controls (p<0.01). EV RNA was present in 11% of HT patients, but in none of the control subjects, whereas the enteroviral protein was detected in 19% and 16%, respectively.

CONCLUSION

The inflammatory reaction in the thyroid gland is a very early event in the pathogenesis of HT. The increased expression of MxA in the inflamed tissue suggests that type I IFN plays a role in disease development. Whether this is virus-dependent needs to be explored in further studies.

Surgical Indications for Goiter with Background Hashimoto's Thyroiditis: Institutional Experience

Hashimoto's thyroiditis (HT) is usually treated conservatively with thyroxine. Its incidence is higher in Iodine sufficient areas and may require surgery for associated nodularity or complications. A retrospective study on surgically treated HT cases was conducted in a teritiary care teaching hospital in an Iodine sufficient area of Southern India. 34 cases of goiter with associated HT, who underwent thyroidectomy between 2007 and 2010 were analysed for indications of surgery. Minimum follow-up period was 6 months. F:M ratio was 31:3 with mean age of 41.3 years. Goiter was diffuse in 41% and nodular in 59%. 16 (47%) of patients were hypothyroid. Autoimmune association was found in 35%. Commonest surgery done was hemithyroidectomy in 12 (35%) followed by subtotal thyroidectomy in 10 cases. Most frequent indication for surgery was nodular goiter in 12 (35%) followed by associated malignancy, persistent goiter, pressure symptoms and painful thyroiditis. Histopathology showed diffuse HT alone in 12 (35%) and rest of the cases had HT as a component synchronous with other pathologies. Associated pathologies were benign multinodular goiter (6), colloid nodule (6), papillary cancer (5), follicular adenoma (4), cyst (1). Surgery for HT is primarily indicated for associated pathologies like dominant nodule, suspicious or proven malignancy, persistent goiter, painful thyroiditis, pressure symptoms and rarely for HT perse. Rate of surgery for HT associated goiter appears to be higher in Iodine sufficient areas, the cause of which needs to be studied further.

Interferon-γ inhibits integrin-mediated adhesion to fibronectin and survival signaling in thyroid cells

Hashimoto's thyroiditis is the most frequent autoimmune disorder, characterized by the presence of a large lymphocytic infiltration and secretion of inflammatory cytokines in the thyroid. Infiltrating lymphocytes and cytokines play a pivotal role in the progression of HT, characterized by the progressive destruction of the normal follicular architecture of the gland and death of follicular cells, ending with loss of thyroid function. Integrins are plasma membrane receptors for the cell-extra-cellular matrix components, with both structural and signaling functions. Integrin-mediated fibronectin (FN) binding is necessary for the correct function and survival of thyroid follicular cells. The purpose of this study was to determine the effect of interferon-γ (IFN-γ) stimulation on integrin expression and signaling in the thyroid cell. Cytotoxicity, integrin expression, cell adhesion to FN, and FN-stimulated ERK and AKT phosphorylation were determined in a normal human thyroid cell line treated with IFN-γ. IFN-γ induced apoptosis and reduced the expression of the integrin αvβ3. Integrin-mediated cell adhesion to FN was strongly impaired. Similarly, FN-stimulated ERK and AKT phosphorylation were inhibited. In conclusion, our study in a thyroid cell model demonstrates that IFN-γ induces apoptosis and inhibits the expression of the integrin αvβ3, reducing cell adhesion to FN and the succeeding outside-in signaling. These results suggest that integrins mediate the cytotoxic effect of IFN-γ and are involved in the destructive mechanism of autoimmune thyroiditis.

The incidence and prevalence of thyroid autoimmunity

The thyroid gland is the most common organ affected by autoimmune disease. Other autoimmune diseases, most notably type 1 diabetes mellitus, are increasing in incidence. It is unknown whether autoimmune thyroid diseases are following the same pattern. This review summarizes studies of autoimmune thyroid disease incidence and prevalence since 1950, not only for these measures of occurrences, but also for commenting on identified risk factors for thyroid autoimmunity. We find that incidence of autoimmune thyroid disease is currently higher than in historic series although the studies are so variable in design, patient population, disease definition, and laboratory methods that it is impossible to tell whether this difference is real. Further research is required to assess the possibility of changing disease patterns of autoimmune thyroid disease as opposed to simple changes in diagnostic thresholds.

Thyroid involvement in ankylosing spondylitis and relationship of thyroid dysfunction with anti-TNF α treatment

Association between rheumatological and autoimmune thyroid disorders has been demonstrated by many studies. However, a few data exist indicating the association between thyroid disorders and ankylosing spondylitis (AS). In this study, the frequency of thyroid disorders in patients with AS and the impact of anti-TNF α therapy on this were investigated. Data of 108 patients (female/male (F/M) 27/81) were analyzed. Data on free T3, free T4, thyroid-stimulating hormone, anti-thyroid peroxidase antibodies (TPO), anti-thyroglobulin antibodies, and thyroid ultrasound were assessed retrospectively. 44 (F/M 15/29) patients were receiving anti-TNF α, while 64 (F/M 12/52) were receiving other drugs [(sulfasalazine, anti-inflammatory drug (NSAIDs)]. Among those not receiving anti-TNF α therapy, TPO level was high in 23 patients (mean TPO value 86.69 ± 65.28 U/ml), while it was high only in nine receiving anti-TNF α (mean TPO 36.61 ± 14.02 U/ml) (p < 0.05). Investigating the data regarding gender in both populations, autoimmune thyroid disease frequency was found to be lower in the patient group receiving anti-TNF α treatment. Subclinical hyperthyroidism was discovered in three patients (one female two male), and subclinical hypothyroidism in two (two male). Thyroid nodule was detected in 29 patients. It was concluded that the frequency of thyroid autoimmune disease was higher in our study than that reported in the literature, and the frequency of thyroid disorder in patients with AS was lower in those receiving anti-TNF α compared to those not. This may arise from the role of TNF α on pathogenesis of thyroid disorders.

The TSH upper reference limit: where are we at?

The diagnosis of subclinical hypothyroidism--serum TSH levels above and T(4) levels within the laboratory reference ranges--depends critically on the upper limit of the TSH reference interval. Calls have been made to lower the current upper TSH reference limit of 4.0 mU/l to 2.5 mU/l to exclude patients with occult hypothyroidism. However, data from population studies do not indicate that the distribution of TSH is altered owing to inclusion of such individuals. The opposite suggestion has also been put forward; the TSH upper reference limit is often too low, especially in the elderly, in women and in white individuals, which may lead to unnecessary or even harmful therapy. Studies in elderly individuals have shown that although aging may be associated with increased TSH levels, paradoxically, overt hypothyroidism in this population may be associated with a less robust TSH response than in young individuals. This Review highlights the interindividual and intraindividual variability of TSH levels and discusses the current controversy that surrounds the appropriateness of reference ranges defined on the basis of age, race, sex and amount of iodine intake. Moreover, the current evidence on lowering or increasing the upper limit of the TSH reference interval is reviewed and the need to individualize levothyroxine treatment in patients with elevated TSH levels is discussed.

Screening of an elderly female population for hypo- and hyperthyroidism by use of a thyroid hormone panel

The elderly female population living in a rural primary health care district in the south of Sweden was screened for hypo- and hyperthyroidism. A total of 1 442 (97.3%) of the 1 482 women 60 years of age or older attended the study. By use of a computer-evaluated thyroid hormone panel, 178 women (12.3%) were identified as probably abnormal. Among them, 8 women (0.55% of total) with previously unknown thyroid disease were detected as overtly hypothyroid. If also 13 women with spontaneous subclinical hypothyroidism were included, the prevalence of earlier unknown hypothyroidism was 21/1 442 (1.5%). The number of subjects with hyperthyroidism discovered by screening was 28/1 442 (1.9%). Although much remains to be elucidated regarding medical, social and economic factors, the high figures obtained for newly discovered abnormal thyroid function suggest that screening for hyper- and hypothyroidism may be worthwhile in such an elderly female population.

Interval between tests and thyroxine estimation method influence outcome of monitoring of subclinical hypothyroidism

CONTEXT/OBJECTIVE

Most patients with subclinical hypothyroidism are regularly monitored when treatment is not started. We have studied how interval between follow-up visits and how different T(4) estimates influence diagnostic outcome in a cohort of patients with untreated subclinical hypothyroidism, and studied whether assessment of clinical symptoms and signs aids evaluation of an individual subclinical hypothyroidism patient.

DESIGN/PATIENTS

During 1 yr, monthly measurements of TSH and three different T(4) estimates, and recording of hypothyroid symptoms and signs were performed in 21 patients with subclinical hypothyroidism confirmed on two occasions 3 months apart.

RESULTS

One patient was euthyroid at all visits, and one started treatment for profound overt hypothyroidism. The remaining patients were subclinical hypothyroidism at 74%, overtly hypothyroid at 22%, and had normal thyroid function tests in 4% of the visits. Increasing frequency of visits associated significantly with decreasing number of patients characterized as subclinical hypothyroidism after 1 yr (P = 0.016). Diagnosis of overt hypothyroidism differed between T(4) estimates (P = 0.005) and was highly dependent on T(4) reference limits. The hypothyroid clinical score did not differ between biochemical diagnoses (P = 0.29).

CONCLUSIONS

The monitoring procedure itself may influence the outcome of control of subclinical hypothyroidism. Specifically, the interval between visits, type of T(4) estimate used, and lower T(4) reference limit influenced the outcome when untreated subclinical hypothyroidism patients were followed for 1 yr. The hypothyroid clinical score did not aid the evaluation in individual subclinical hypothyroidism patients.

Antithyroperoxidase and antithyroglobulin antibodies in a five-year follow-up survey of populations with different iodine intakes

OBJECTIVE

In a follow-up study, we determined the prevalence, incidence, and natural course of positive antithyroperoxidase antibodies (TPOAbs) and antithyroglobulin antibodies (TgAbs) in the general population and examined the influences of iodine intake.

DESIGN

The study was conducted in Panshan, Zhangwu, and Huanghua, regions with mildly deficient, more than adequate, and excessive iodine intake, respectively. Of the 3761 unselected subjects who were enrolled at baseline, 3018 participated in the 5-yr follow-up study. Serum TSH, TPOAb, and TgAb levels were measured.

RESULTS

Among subjects in Panshan, Zhangwu, and Huanghua, the prevalence of positive TPOAbs was 11.23, 11.83 and 12.02%, respectively, whereas 11.23, 11.17, and 11.26% of subjects were TgAb positive, respectively. In the older population (> or =45 yr), TgAb-positive individuals were more frequent in Huanghua than Panshan and Zhangwu (P < 0.05). The 5-yr cumulative incidence of positive TPOAb was 2.08, 3.84, and 2.84% in Panshan, Zhangwu, and Huanghua, respectively, whereas 2.91, 3.64, and 5.07% of subjects were TgAb positive, respectively (P < 0.05), corresponding to the increase in iodine intake. Subjects who were TPOAb and/or TgAb positive at baseline developed thyroid dysfunctions more frequently than those without antibodies (14.44 vs. 3.31%, P < 0.01); their incidence of elevated TSH levels was 1.32, 8.46, and 15.38% in Panshan, Zhangwu, and Huanghua, respectively (P < 0.05).

CONCLUSIONS

Subjects who were TPOAb and TgAb positive at baseline developed thyroid dysfunctions more frequently than seronegative subjects. High iodine intake was a risk factor for developing hypothyroidism in antibody-positive subjects. A constant exposure to excessive iodine intake increased the incidence of positive TgAb.

Variation in thyroid function tests in patients with stable untreated subclinical hypothyroidism

OBJECTIVE

Knowledge of variation in thyroid function is important for interpretation of thyroid function tests. We aimed to describe intra-individual variation in thyroid function in patients with stable, untreated subclinical hypothyroidism (SCH) compared to euthyroid individuals to assess the importance of monitoring SCH patients.

DESIGN

We measured thyrotropin (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) monthly for 1 year in a longitudinal study of 15 untreated SCH patients with initial TSH 5-12 mU/L, without trends in TSH, and compared findings with results from 15 euthyroid individuals.

MAIN OUTCOME

CV% was 17.0, 6.1, and 6.2 for TSH, fT4, and fT3, respectively. Overall CV% for TSH was lower in SCH patients than controls. Contrary to euthyroid individuals, CV% in SCH patients increased with rising mean TSH (r2 = 0.29, p = 0.04). Individual disease set points were established with 45, 6, and 6 tests for TSH, fT4, and fT3, with 95% confidence. Differences required between two test results were 40%, 15%, and 15%, respectively, with 90% confidence.

CONCLUSION

Percent variation in TSH was lower in SCH than in euthyroid controls, but increased with higher mean TSH. The number of tests needed to establish disease set points was high. The difference required between two tests to be truly different was 40% for TSH and 15% for fT4 and fT3.

Fifteen-year follow-up of thyroid function in lithium patients

OBJECTIVE

To study prospectively the course of clinically relevant thyroid dysfunction in a cohort of patients on long-term lithium treatment.

METHOD

Patients (no.=150) who had undergone a cross-sectional evaluation of their thyroid function in 1989, when they were at different stages of lithium treatment, were followed up for thyroid circulating thyroid antibodies, hypothyroidism, hyperthyroidism, and thyroidectomy, during a further period of lithium exposure of up to 15 yr.

RESULTS

Annual rates of newly developed circulating thyroid antibodies and hypothyroidism were 1.7 and 1.5%, respectively. Subjects with thyroid antibodies had a higher chance of requiring substitution treatment with levothyroxine for hypothyroidism compared with subjects with no evidence of thyroid antibodies (6.4% annual rate compared to 0.8%; relative risk: 8.4; 95% confidence interval: 2.9-24.0). One case of hyperthyroidism was observed over 976 patient-yr. Three patients underwent thyroidectomy during followup (two for multinodular goiter and one for multicentric papillary carcinoma).

CONCLUSIONS

Lithium may be associated with hypothyroidism in particular in the presence of circulating thyroid antibodies. Incidence of thyroid antibodies is comparable with that reported for the general population. Hyperthyroidism and thyroid cancer are rare.

Lithium treatment and thyroid abnormalities

Background

Although the interactions between lithium treatment and thyroid function have long been recognised, their clinical relevance is still controversial. This paper sets out a review of the literature to date, considering that lithium still represents the gold standard among prophylactic treatments of manic-depression several decades after its introduction.

Method

PubMed database was used to search for English-language articles relating to lithium treatment and thyroid function. As the amount of relevant papers totalled several hundreds, this review refers to previous reviews, especially with regard to older literature. Moreover, the authors particularly refer to a series of studies of thyroid function performed in a cohort of patients at different stages of lithium treatment, who were followed up by their group from 1989 onwards.

Results

The main findings from this review included: a) lithium definitely affects thyroid function as repeatedly shown by studies on cell cultures, experimental animals, volunteers, and patients; b) inhibition of thyroid hormone release is the critical mechanism in the development of hypothyroidism, goitre, and, perhaps, changes in the texture of the gland which are detected by ultrasonic scanning; c) compensatory mechanisms operate and prevent the development of hypothyroidism in the majority of patients; d) when additional risk factors are present, either environmental (such as iodine deficiency) or intrinsic (immunogenetic background), compensatory potential may be reduced and clinically relevant consequences may derive; e) hypothyroidism may develop in particular during the first years of lithium treatment, in middle-aged women, and in the presence of thyroid autoimmunity; f) thyroid autoimmunity is found in excess among patients suffering from affective disorders, irrespective of lithium exposure; g) in patients who have been on lithium for several years, the outcome of hypothyroidism, goitre, and thyroid autoimmunity do not much differ from those observed in the general population; h) hyperthyroidism and thyroid cancer are observed rarely during lithium treatment.

Recommendations

Thyroid function tests (TSH, free thyroid hormones, specific antibodies, and ultrasonic scanning) should be performed prior to starting lithium prophylaxis. A similar panel should be repeated at one year. Thereafter, annual measurements of TSH may be sufficient to prevent overt hypothyroidism. In the presence of raised TSH or thyroid autoimmunity, shorter intervals between assessments are advisable (4–6 months). Measurement of antibodies and ultrasonic scanning may be repeated at 2-to-3-year intervals. The patient must be referred to the endocrinologist if TSH concentrations are repeatedly abnormal, and/or goitre or nodules are detected. Thyroid function abnormalities should not constitute an outright contraindication to lithium treatment, and lithium should not be stopped if a patient develops thyroid abnormalities. Decisions should be made taking into account the evidence that lithium treatment is perhaps the only efficient means of reducing the excessive mortality which is otherwise associated with affective disorders.

Efectos del tratamiento sustitutivo con levotiroxina en el perfil lipídico de pacientes con hipotiroidismo subclínico leve

BACKGROUND AND OBJECTIVE

To evaluate the effects of levothyroxine (L-T4) replacement on lipoprotein profile in patients with mild subclinical hypothyroidism, defined as a serum TSH level between 5 to 10 mU/l with a normal serum free thyroxine level.

PATIENTS AND METHOD

We have prospectively studied 89 patients with mild subclinical hypothyroidism -10 male, 79 female; mean (standard deviation) TSH: 7.9 (1.3) mU/l-. The thyroperoxidasa antibodies were positive in 46 subjects and were treated with L-T4. The 43 patients with thyroperoxidasa antibodies negative were used as controls. In both groups fasting lipid profiles were measured at baseline and 40 weeks.

RESULTS

There were no significant differences in the age, serum concentrations of TSH, free thyroxine and lipid profile between 2 groups at baseline. After therapy, serum TSH levels had returned within the normal range in the L-T4 group and were now significantly lower than in the control group (p < 0.001). There were no significant differences in the changes from baseline to 40 weeks between patients in the L-T4 group and the control group for any of the lipid variables measured, expressed as the mean change in the L-T4 group minus the mean change in the control group and the 95% confidence interval (CI): total cholesterol, -0.27 mmol/l (95% CI, -0.69 to 0.16 mmol/l); LDLc, -0.27 mmol/l (95% CI -0.61 to 0.05 mmol/l).

CONCLUSIONS

Forty weeks L-T4 treatment does not significantly improve the lipid profile in patients with mild subclinical hypothyroidism.

Association of the TSHR gene with Graves' disease: the first disease specific locus

The development of autoimmune thyroid disease (AITD) is associated with autoantibodies directed against the thyroid stimulating hormone receptor (TSHR). Previous studies have failed to demonstrate a consistent association between the TSHR and AITD, or any of its sub-phenotypes. In the present study, we analysed the linkage disequilibrium (LD) structure encompassing the TSHR, to identify LD 'blocks' and SNPs, which capture the majority of intra-block haplotype diversity. The haplotype tagging SNPs, plus all common SNPs reported in previous studies were genotyped in 1,059 AITD Caucasian cases and 971 Caucasian controls. A haplotype, across two LD blocks, showed association (P<1 x 10(-6), OR 1.7) with Graves' disease (GD) but not autoimmune hypothyroidism (AIH). We replicated these findings by genotyping the most associated GD SNP, rs2268458, in a separate UK Caucasian cohort of 1,366 AITD cases and 1,061 controls (GD, P=2 x 10(-6), OR 1.3; AIH, P=NS). These results in two independent Caucasian data sets suggest that the TSHR is the first replicated GD-specific locus meriting further fine mapping and functional analysis to identify the aetiological variants.

Natural course of autoimmune thyroiditis in type 1 diabetes: association with gender, age, diabetes duration, and puberty

AIMS

To investigate the natural history and incidence of autoimmune thyroiditis (AIT) in paediatric patients with type 1 diabetes (T1D).

METHODS

Since 1990, annual screening for thyroid disease has been performed in children and adolescents with T1D. Antibodies against thyroperoxidase (anti-TPO) and thyroglobulin (anti-TG) as well as TSH were measured in 659 patients (54.3% boys). In 126 patients, anti-TPO and anti-TG levels were followed at yearly intervals from onset up to five years of T1D. Anti-TPO above 30 U/ml and anti-TG above 20 U/ml were considered positive, values above 100 U/ml as significantly raised and indicative of AIT. L-thyroxine treatment was started if TSH was higher than 4.5 microU/ml and/or thyroid gland enlargement on thyroid ultrasound was present.

RESULTS

At initial screening, 15.4% of patients had raised anti-TPO and 14.4% anti-TG. Girls had more frequently raised antibodies than boys. Sixty two patients (9.4%, 61% girls) required treatment with L-thyroxine. The cumulative incidence (SE) of AIT after 10 years of diabetes was 0.14 (0.02), being significantly higher in females (0.18 (0.03)), particularly after the age of 12 years. At T1D onset, positive anti-TPO and anti-TG were present in 21 of 126 patients (16.7%), each. All patients with significantly increased values of anti-TPO (n = 17, 148-5340 U/ml) and anti-TG (n = 11, 140-2000 U/ml) at T1D onset remained positive during the following five years.

CONCLUSIONS

For early detection of autoimmune thyroiditis in children with T1D, measurement of anti-TPO and TSH at T1D onset and in yearly intervals after the age of 12 years is recommended.

The relationship between iron status and thyroid hormones in adolescents living in an iodine deficient area

BACKGROUND

Iron may be only one of many nutritional factors that influence thyroid hormone metabolism in iodine-deficient areas.

OBJECTIVE

To evaluate the effect of iron status on thyroid hormone profile in adolescents living in a mild iodine-deficient area in Turkey.

SUBJECTS

Three hundred and thirty school-aged children with mean age 14 years were examined.

METHODS

Free triiodothyronine, free tetraiodothyronine and thyrotropin levels were analyzed by chemiluminescent enzyme immunoassay. Hemoglobin and mean corpuscular volume were measured with a Hemocounter. Iron and total iron binding capacity concentration were determined by colorimetric photometric methods. Ferritin level was determined by immunoturbidimetry.

RESULTS

Thyroid hormone levels of the children with anemia were not significantly different compared to children without anemia. No significant correlation was found between thyroid hormones and iron status.

CONCLUSION

The thyroid hormone profile was not significantly affected in this area. This survey showed no correlation between iron status and thyroid hormone levels.

Patterns of autoimmunity in primary biliary cirrhosis patients and their families: a population-based cohort study

BACKGROUND

Primary biliary cirrhosis (PBC) is a chronic liver disease with autoimmune features but uncertain aetiology. Increased risk of PBC among relatives of patients may reflect common environmental factors, or inherited immunogenetic susceptibility. Associations between PBC and other autoimmune diseases have been reported, but their true extent and pattern is unknown.

AIM

To examine the prevalence and association patterns of autoimmune disease in a representative group of PBC patients.

DESIGN

Clinical cohort study.

METHODS

We clinically assessed members of a geographically-based PBC patient cohort (n = 160) for the presence of additional autoimmune disease, using established specific diagnostic criteria.

RESULTS

Some 53% of patients had at least one additional autoimmune condition, and 63% had serum autoantibodies other than AMA or ANA. AMA+ patients had a significantly lower prevalence of additional autoimmunity than AMA- patients (49% vs. 79%; p < 0.01). The greatest relative increase in disease prevalence was for scleroderma (8% of patients). Autoimmune disease was present in 14% of first-degree relatives.

DISCUSSION

PBC patients and their families have a wide susceptibility to autoimmunity. This observation supports an autoimmune aetiology and suggests that the genetic basis of PBC is likely to be expressed, at least in part, through factors controlling immune tolerance in general.

Disfunções mínimas da tiróide: hipotiroidismo subclínico e hipertiroidismo subclínico

Hipotiroidismo subclínico (SHT) e hipertiroidismo subclínico (SCH) são definidos pelas concentrações normais de T4 e T3 livres séricos associadas com valores de TSH elevado (SHT) ou suprimido (SCH). As prevalências são baixas e sintomas e sinais de disfunção tiroideana escassos. No SHT, colesterol total e LDL-C estão ligeiramente elevados, e tratamento com levotiroxina pode influir nos valores dos lipídeos. Ocorre diminuição da contratilidade do miocárdio e aumento da resistência vascular periférica, que melhoram com o tratamento. Fibrilação atrial é mais freqüente no SCH, e há aumento do índice de massa do ventrículo esquerdo, da contratilidade cardíaca, disfunção diastólica e indução de batimentos atriais ectópicos que regridem com uso de beta-bloqueadores. No SCH, ocorre diminuição da densidade óssea. Depressão, doença do pânico e alterações de testes cognitivos são freqüentes no SHT. O tratamento do SHT é indicado com TSH sérico maior do que 8mU/L e presença de anticorpos antitiroideanos, e do SCH endógeno, quando existem sintomas, em idosos ou concentração de TSH menor do que 0,1mU/L.

The prevalence of undiagnosed thyroid disorders in a previously iodine-deficient area

OBJECTIVE

The aim of the present study was to analyze the current status of morphologic and functional thyroid abnormalities in a previously iodine-deficient area.

METHODS

The population based Study of Health in Pomerania (SHIP) comprised 4310 participants, aged 20-79 years. Thyroid function (thyrotropin [TSH] free triiodothyronine [FT(3)], and free thyroxine [FT(4)]) and serum autoantibodies to thyroperoxidase (TPOAb) were evaluated from blood samples. Thyroid structure and size were measured by ultrasound. Data from 3941 participants with no known thyroid disorders were analyzed.

RESULTS

The median iodine urine excretion was 12.4 microg/dL. The rate of decreased serum TSH levels (<0.3 mIU/L) was 11.3%; 2.2% of participants had suppressed serum TSH levels (<0.1 mIU/L). The prevalence of subclinical hyperthyroidism was 1.8%, the prevalence of overt hyperthyroidism 0.4%. Elevated TSH levels were found in 1.2% of individuals. Subclinical hypothyroidism was observed in 0.5%, overt hypothyroidism in 0.7% of the sample. Elevated TPOAb were detected in 7% of subjects, 4.1% of participants had TPOAb greater than 200 IU/mL. The prevalence of goiter was 35.9%. An inhomogeneous echo pattern was detected in 35.2% and nodules in 20.2% of participants. Diffuse autoimmune thyroiditis was diagnosed in 47 subjects (1.2%).

CONCLUSION

There are a number of thyroid disorders in this previously iodine-deficient region. Further studies are required to investigate the change of thyroid disorders during iodine supplementation programs.

Estudo da Função Tiroideana em Uma População com Mais de 50 Anos

Com objetivo de analisar a freqüência de disfunção tiroideana e de identificar possíveis alterações hormonais decorrentes do envelhecimento, estudamos 198 indivíduos com idade variando de 50 a 85 anos e 106 filhos com idade entre 11 e 49 anos. A prevalência de disfunção tiroideana foi semelhante em ambos grupos (12,6% no grupo de estudo e 14,1% entre os filhos). A presença de um ou dois anticorpos antitiroideanos positivos foi também semelhante entre os grupos (9,1% e 12,3% para os idosos e filhos respectivamente), embora sem correlação disfunção tiroideana. nos idosos. Os níveis séricos de T3 e FT4 foram significantemente menores entre os indivíduos mais velhos quando comparados com os filhos (1,27±0,27 x 1,39±0,31 ng/ml e 0,97±0,29 x 1,18±0,76 ng/dl, respectivamente). Não houve diferença entre os grupos quanto aos níveis de TSH, T4 total e TBG. Concluímos que a prevalência de disfunção tiroideana não foi diferente entre os grupos e que a presença de anticorpos antitiroideanos esteve associada com disfunção da tiróide apenas nos indivíduos mais jovens. A correlação inversa dos níveis de T3 e FT4 com a idade pode refletir uma adaptação à menor necessidade dos hormônios com o envelhecimento.

Epidemiology and prevention of clinical and subclinical hypothyroidism

Iodine deficiency is the most common cause of hypothyroidism worldwide. In persons living in iodine-replete areas, causes are congenital, spontaneous because of chronic autoimmune disease (atrophic autoimmune thyroiditis or goitrous autoimmune thyroiditis [Hashimoto's thyroiditis]), or iatrogenic because of goitrogens, drugs, or destructive treatment for thyrotoxicosis. Screening for congenital hypothyroidism exists and its use prevents mental retardation. The prevalence of spontaneous hypothyroidism is between 1% and 2% and is more common in older women and 10 times more common in women than in men. A significant proportion of subjects have asymptomatic chronic autoimmune thyroiditis and 8% of women (10% of women over 55 years of age) and 3% of men have subclinical hypothyroidism. Approximately one third of patients with newly diagnosed overt hypothyroidism have received destructive therapy for hyperthyroidism and indefinite surveillance is required. There is not much that can be done to prevent the occurrence of spontaneous autoimmune hypothyroidism, but if identified early, something can be done to prevent progression to overt disease. Controversy exists as to whether healthy adults would benefit from screening for autoimmune thyroid disease because a significant proportion of subjects tested will have evidence of mild thyroid failure. Case finding in women at menopause or visiting a primary care physician with nonspecific symptoms appears justified.