Vitamin D and Hashimoto's Thyroiditis: Observations from CROHT Biobank

Genetically predicted circulating concentrations of micronutrients and risk of autoimmune thyroiditis: a Mendelian randomized study

Background

Micronutrients play pivotal roles in modulating various aspects of the immune response. However, the existing literature on the association between micronutrients and autoimmune thyroiditis (AIT) remains limited and contentious. To address this gap, we conducted Mendelian randomization (MR) to investigate potential links between genetically predicted concentrations of six micronutrients (Copper (Cu), Iron (Ir), Calcium (Ca), Vitamin D (VD), Vitamin C (VC), Zinc (Zn)) and the risk of AIT.

Method

Utilizing summary statistics from genome-wide association studies (GWAS) in individuals of European descent, we employed MR methodologies to elucidate the interplay between micronutrients and AIT. Three distinct MR techniques were employed: Inverse Variance Weighted (IVW), MR-Egger regression, and Weighted Median Estimator (WME). Additionally, we evaluated outcome heterogeneity using Cochran's Q statistic and assessed pleiotropy using the MR-Egger intercept.

Result

IVW analysis revealed no substantial evidence supporting a significant impact of genetically predicted micronutrient concentrations on AIT risk (Cu: OR = 0.918, P = 0.875; Ir: OR = 0.653, P = 0.264; Ca: OR = 0.964, P = 0.906; VD: OR = 0.717, P = 0.378; VC: OR = 0.986, P = 0.875; Zn: OR = 0.789, P = 0.539). Cochran's Q test for IVW indicated no notable heterogeneity. Moreover, the MR-Egger intercept method suggested the presence of horizontal pleiotropy between serum VC levels and AIT (MR-Egger intercept = -0.037, p = 0.026), while no such pleiotropy was observed for other micronutrients.

Conclusion

Our MR analysis does not support a causal relationship between genetically predicted concentrations of six micronutrients (Cu, Ir, Ca, VD, VC, and Zn) and the risk of AIT.

The Impact of Environmental Factors on the Development of Autoimmune Thyroiditis-Review

Autoimmune thyroiditis (Hashimoto's thyroiditis) is the most common autoimmune disease. It most often manifests itself as hypothyroidism but may also present with euthyroidism or even hyperthyroidism. The etiopathogenesis of autoimmune thyroiditis is still unclear. However, in addition to genetic and epigenetic factors, many environmental factors are known to increase the risk of developing AIT. In this review, we aimed to collect and analyze data connected with environmental factors and autoimmune thyroiditis development. Our review indicates iodine intake, vitamin D deficiency, selenium deficiency, viral infections caused by Epstein-Barr Virus (EBV), Human parvovirus B19 (PVB19), Human herpesvirus 6A (HHV-6A) and Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), bacterial infection caused by Helicobacter pylori, microbiome disruption, medications such as interferon-alpha and tyrosine kinase inhibitors, as well as stress, climate, and smoking can influence the risk of the occurrence of autoimmune thyroiditis. Having knowledge of risk factors allows for making changes to one's diet and lifestyle that will reduce the risk of developing the disease and alleviate the course of autoimmune thyroiditis.

The Role of Nutrition on Thyroid Function

Thyroid function is closely linked to nutrition through the diet-gut-thyroid axis. This narrative review highlights the influence of nutritional components and micronutrients on thyroid development and function, as well as on the gut microbiota. Micronutrients such as iodine, selenium, iron, zinc, copper, magnesium, vitamin A, and vitamin B12 influence thyroid hormone synthesis and regulation throughout life. Dietary changes can alter the gut microbiota, leading not just to dysbiosis and micronutrient deficiency but also to changes in thyroid function through immunological regulation, nutrient absorption, and epigenetic changes. Nutritional imbalance can lead to thyroid dysfunction and/or disorders, such as hypothyroidism and hyperthyroidism, and possibly contribute to autoimmune thyroid diseases and thyroid cancer, yet controversial issues. Understanding these relationships is important to rationalize a balanced diet rich in essential micronutrients for maintaining thyroid health and preventing thyroid-related diseases. The synthetic comprehensive overview of current knowledge shows the importance of micronutrients and gut microbiota for thyroid function and uncovers potential gaps that require further investigation.

Food temperature altered macronutrients induced changes in satiety hormones; glucagon - like peptide -1 and cholecystokinin and their correlation with subjective satiety

BACKGROUND

The benefits of dietary macronutrients for weight management depend on the integrity of gut hormones. The role of food temperature in the release of satiety hormones and satiety needs elucidation. We aimed to determine the impact of different food temperatures with varying macronutrient compositions on satiety-related gut hormones glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) and find the correlation of satiety hormones with appetite scores and remainder-day food (energy) intake.

MATERIALS AND METHODS

Thirteen healthy participants (eight males and five females) aged 25-35 years with body mass index 18.5-24.9 kg/m2 with no medical illnesses or eating disorders consumed three compositions of meals (high carbohydrate, high fat, and high protein meals) each at three temperatures (cold, warm, and hot) in a randomized, double-blinded, controlled crossover design. Plasma concentrations of peptide hormones were determined at 0, 30, and 240 minutes by enzyme-linked immunosorbent assay, and 24-hours food recall was used for remainder-day food intake (remainder energy). Data were analyzed using SPSS version 27.0. The change in plasma levels of gut hormones with time was assessed using Friedman test; Kruskal-Wallis test was employed to compare GLP-1 and CCK hormonal levels across nine meals.

RESULTS

A comparison of the three meals at the three temperatures (total of nine groups), showed that the GLP-1 and CCK plasma concentrations were significantly different (P < 0.001). GLP-1 and CCK responses increased more after hot meals than cold meals. Overall, high-fat meals had more effective gut hormone secretions. The area under the curve was increased for GLP-1 in high-fat meals and for CCK in hot meals. The peptide hormones (GLP-1 and CCK) were positively correlated with satiety scores and inversely with remainder food intake.

CONCLUSION

The temperature of food was found to be an effective stimulus for the regulation of CCK and GLP-1 secretion. Hot food temperature increased satiety hormones (CCK and GLP-1), independent of food macronutrient composition.

The Impact of Vitamin D on Immune Function and Its Role in Hashimoto's Thyroiditis: A Narrative Review

Vitamin D, an essential nutrient, plays a crucial role in numerous biological functions, acting as a hormone and being important for the proper functioning of the immune system. This review illustrates the interactions between adequate vitamin D levels and an appropriate immune response, highlighting the implications for Hashimoto's thyroiditis (HT), a chronic inflammation of the thyroid characterized by the production of autoantibodies. A comprehensive review of the existing literature shows that vitamin D inhibits the secretion of pro-inflammatory cytokines, leading to an improvement in the clinical picture in HT by switching from a pro-inflammatory to immune balance. Vitamin D supplementation has been shown to reduce elevated serum levels of thyroid peroxidase antibodies, a key marker of HT. Although the results are conflicting, the evidence suggests that an adequate vitamin D intake supports the immune function and counteracts autoimmune conditions such as HT by improving their symptoms. There is evidence of vitamin D's key role in supporting the immune system function and managing autoimmunity, such as in HT. An adequate vitamin D intake is crucial for improving the clinical picture and the symptoms of HT.

Assessment of Vitamin Concentrations in Patients with Hashimoto's Thyroiditis and Their Relationships with Thyroid Function, Biochemical Status, and Anthropometric Parameters-A Preliminary Study

Hashimoto's thyroiditis (HT) is the leading cause of hypothyroidism, affecting mainly the female population. Many patients with HT have metabolic disorders and nutritional deficiencies. The aim of this study was to evaluate vitamin D, A, E, B2, and B6 concentrations, thyroid function, metabolic profile, and anthropometric parameters of patients with Hashimoto's thyroiditis. In 81 female patients with HT (study group), vitamin A and B2 concentrations were significantly lower than in 34 healthy women (control group). No differences were noted in vitamin D, E, and B6 concentrations between groups. Moreover, HT patients had similar anthropometric parameters, lipid profiles, and glucose and insulin concentrations compared to controls. This study showed some relationships between vitamin concentrations and anthropometric or biochemical profiles in HT patients. Among others, in the HT group, the concentration of vitamin D was positively correlated with the level of HDL and negatively correlated with BMI, total fat mass, and insulin level, which influence cardiovascular risk. The results indicate that patients with HT should be routinely tested for vitamin concentrations to prevent nutritional deficiencies. Further studies are also needed on the role of vitamins in the development and progression of HT and the presence of metabolic complications in this population.

Vitamin D, selenium in type 2 diabetes and Hashimoto's thyroiditis: Is it effective?

The study by Feng et al, explores treatment approaches for these coexisting conditions. It emphasizes the potential advantages of selenium and vitamin D supplementation but also raises methodological and patient selection concerns. Findings indicate a complex interplay between interventions and disease markers, prompting the need for further research. Despite limitations, the study offers valuable insights into managing the intricate relationship between type 2 diabetes mellitus and Hashimoto's thyroiditis. The authors' contributions shed light on potential treatment avenues, although careful consideration of study design and patient characteristics is warranted for future investigations in this domain.

Impaired Sensitivity to Thyroid Hormones Is Associated With Decreased Vitamin D Levels in the Euthyroid Population

CONTEXT

The relationship between vitamin D and thyroid profiles lacks consensus despite extensive investigations. Whether vitamin D levels correlate with thyroid hormone sensitivity remains largely unexplored.

OBJECTIVE

To explore the relationship between vitamin D levels and thyroid hormone sensitivity among euthyroid individuals.

METHODS

This study involved 6452 euthyroid participants. Clinical parameters, including TSH, free thyroxine, 25-hydroxyvitamin D [25(OH)D], and other relevant indicators were extracted from the National Health and Nutrition Examination Survey 2007-2012. To quantify thyroid hormone sensitivity, we calculated the Thyroid Feedback Quantile-based Index (TFQI), the TSH index (TSHI), and the thyrotropin thyroxine resistance index (TT4RI).

RESULTS

Subjects with impaired thyroid hormone sensitivity have decreased 25(OH)D levels (TFQI, TT4RI: P < 0.05; TSHI: P = .05574) following adjustment of confounding variables. Age-specific analysis found negative correlations between thyroid hormone sensitivity indices and 25(OH)D within the 20 to 60 years subgroup, turning positive in the 60 to 80 years subgroup. In females, thyroid hormone sensitivity indices and vitamin D levels were negatively linked, while in males, vitamin D's relationships with TFQI, TT4RI, and TSHI shifted from negative to positive when 25(OH)D levels exceeded 63.5 nmol/L, 56.7 nmol/L, and 56.7 nmol/L, respectively. Stratification by race revealed U-shaped curvilinear patterns resembling those found in the males. In body mass index (BMI) subanalysis, vitamin D had differing associations with thyroid hormone sensitivity indices: negative in the <25 kg/m2 and ≥30 kg/m2 subgroups and U-shaped in the 25-30 kg/m2 subgroup.

CONCLUSION

Impaired thyroid hormone sensitivity correlates with decreased vitamin D levels among euthyroid subjects, with associations varying by age, sex, race, and BMI.

Vitamin D, selenium, and antidiabetic drugs in the treatment of type 2 diabetes mellitus with Hashimoto's thyroiditis

BACKGROUND

Diabetes and thyroiditis are closely related. They occur in combination and cause significant damage to the body. There is no clear treatment for type-2 diabetes mellitus (T2DM) with Hashimoto's thyroiditis (HT). While single symptomatic drug treatment of the two diseases is less effective, combined drug treatment may improve efficacy.

AIM

To investigate the effect of a combination of vitamin D, selenium, and hypo-glycemic agents in T2DM with HT.

METHODS

This retrospective study included 150 patients with T2DM and HT treated at The Central Hospital of Shaoyang from March 2020 to February 2023. Fifty patients were assigned to the control group, test group A, and test group B according to different treatment methods. The control group received low-iodine diet guidance and hypoglycemic drug treatment. Test group A received the control treatment plus vitamin D treatment. Test group B received the group A treatment plus selenium. Blood levels of markers of thyroid function [free T3 (FT3), thyroid stimulating hormone (TSH), free T4 (FT4)], autoantibodies [thyroid peroxidase antibody (TPOAB) and thyroid globulin antibody (TGAB)], blood lipid index [low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triacylglycerol (TG)], blood glucose index [fasting blood glucose (FBG), and hemoglobin A1c (HbA1c)] were measured pre-treatment and 3 and 6 months after treatment. The relationships between serum 25-hydroxyvitamin D3 [25 (OH) D3] level and each of these indices were analyzed.

RESULTS

The levels of 25 (OH) D3, FT3, FT4, and LDL-C increased in the order of the control group, test group A, and test group B (all P < 0.05). The TPOAB, TGAB, TC, TG, FBG, HbA1c, and TSH levels increased in the order of test groups B, A, and the control group (all P < 0.05). All the above indices were compared after 3 and 6 months of treatment. Pre-treatment, there was no divergence in serum 25 (OH) D3 level, thyroid function-related indexes, autoantibodies level, blood glucose, and blood lipid index between the control group, test groups A and B (all P > 0.05). The 25 (OH) D3 levels in test groups A and B were negatively correlated with FT4 and TGAB (all P < 0.05).

CONCLUSION

The combination drug treatment for T2DM with HT significantly improved thyroid function, autoantibody, and blood glucose and lipid levels.

A Mendelian randomization study of the effect of serum 25-hydroxyvitamin D levels on autoimmune thyroid disease

Objective

The influence of vitamin D on autoimmune thyroid disease (AITD) remains a subject of ongoing debate. This study employs Mendelian randomization (MR) to investigate the causal correlations of serum 25-hydroxyvitamin D (25[OH]D) levels with autoimmune thyroiditis (AIT), autoimmune hyperthyroidism (AIH), and Graves disease (GD).

Methods

Data on single nucleotide polymorphisms related to serum 25(OH)D levels, AIT, AIH, and GD were sourced from UK Biobank and FinnGen. Inverse variance weighted, MR-Egger, and weighted median were employed to test the exposure-outcome causal relationship. Assessments of horizontal pleiotropy, heterogeneity, and stability were performed using the MR-Egger intercept, Cochran's Q test, and leave-one-out sensitivity analysis, respectively.

Results

The results of MR analysis showed increased serum 25(OH)D levels was associated with a reduced risk of AIT (OR 0.499, 95% CI 0.289 to 0.860, p = 0.012) but not causal associated with AIH (OR 0.935, 95% CI 0.695 to 1.256, p = 0.654) and GD (OR 0.813, 95% CI 0.635 to 1.040, p = 0.100). Intercept analysis showed no horizontal pleiotropy (p > 0.05), and Cochran's Q test showed no heterogeneity (p > 0.05). Sensitivity analysis suggested that these results were robust.

Conclusion

An increased serum 25(OH)D level is associated with AIT risk reduction but unrelated to AIH and GD. This finding suggests that vitamin D supplementation can be valuable for preventing and treating AIT.

Association between serum vitamin D levels and sensitivity to thyroid hormone indices: a cross-sectional observational study in NHANES 2007-2012

Objective

We designed this study to determine whether there is a link between vitamin D levels and sensitivity to thyroid hormone and to provide a new perspective for studying the relationship between vitamin D and thyroid disease.

Methods

Our study included 8,126 participators from the National Health and Nutrition Examination Survey (NHANES) database between 2007 and 2012. We used weighted multiple linear regression models to enquire the connection between serum vitamin D levels and thyroid hormone sensitivity indicators, including the following: Thyroid-stimulating hormone index (TSHI), Free Triiodothyronine/Free thyroxine (FT3/FT4), Thyroid Feedback Quantile-based Index (TFQI), and Thyrotroph Thyroxine Resistance Index (TT4RI). Finally, we used constrained cubic splines to explore possible nonlinear relationships. All data cleaning and statistical analyses were performed using R software.

Results

The final Results were reached after adjusting for various confounding factors. We found a U-shaped relationship between TFQI and serum vitamin D, and the lowest TFQI appeared when the serum vitamin D concentration was 25.77ng/ml. However, an inverse U-shaped relationship was found between FT3/FT4 and vitamin D levels. When the serum vitamin D concentration was 25.43ng/ml, the ratio of FT3/FT4 was the highest.

Conclusion

In the US population, our study concluded that FTQI and FT3/FT4 were U-shaped or inverse-U-shaped with serum vitamin D levels respectively after several adjustments. Therefore, FTQI and FT3/FT4 are considered indicators of the complex relationship between thyroid hormone resistance and vitamin D metabolism. In the future, more complex prospective investigations are needed to confirm these findings and find a causal link between them.

Efficacy of Combined Photobiomodulation Therapy with Supplements versus Supplements alone in Restoring Thyroid Gland Homeostasis in Hashimoto Thyroiditis: A Clinical Feasibility Parallel Trial with 6-Months Follow-Up

Hashimoto thyroiditis (HT) is a thyroid-specific autoimmune disorder, triggering hypothyroidism in a population with an adequate dietary intake. Despite the current conventional treatment focuses on the permanent replacement of levothyroxine (LT4) deficiency, it appears that thyroid autoimmunity remains the cause of persistent symptoms in patients with HT, even when they achieve to be euthyroid from a biochemical standpoint. Photobiomodulation (PBM) showed to be an effective therapy in the management of autoimmune diseases, but with limited evidence. Hence, our study was conducted to appraise the efficacy of PBM therapy with supplements in restoring thyroid gland homeostasis in patients with HT compared with supplements alone. Seventy-four female subjects aged between 20 and 50 years old were recruited and divided equally into two groups: PBM and supplements group (group 1); and supplements alone group (group 2). The PBM dosimetry and treatment protocols were as follows: wavelength, 820 nm; power output, 200 mW; continuous emission mode; irradiating time, 20 s per point; fluence, 32 J/cm2 per point; treatment frequency, twice a week (excluding weekends); and treatment duration, three consecutive weeks. Whereas, the supplements protocol for both groups was the same, as follows: subjects with a serum level of vitamin D3 <40 ng/dL, who received replacement according to their serum levels, and all the subjects had a daily intake of 100 µg of oral selenium. The biochemical (FT3, FT4, antiTPO and antiTG) and anthropometric measurements were evaluated. Our findings showed significant improvement in group 1 parameters (PBM+ supplements) compared with group 2 (supplements only) in terms of weight loss and reduction in the following parameters: BMI, hip and waist circumference, waist/hip ratio, TSH, antiTPO, antiTG and treatment dose of LT4 (p < 0.05). Our results, for the first time, demonstrated an efficacy of PBM delivered at a lower fluence with supplements in restoring thyroid function, anthropometric parameters and lifestyle factors in patients with HT. Hence, extensive studies with a longer follow-up period are warranted.

Impact of Vitamin D on Immunopathology of Hashimoto's Thyroiditis: From Theory to Practice

Hashimoto's thyroiditis (HT) is a common autoimmune disease affecting the thyroid gland, characterized by lymphocytic infiltration, damage to thyroid cells, and hypothyroidism, and often requires lifetime treatment with levothyroxine. The disease has a complex etiology, with genetic and environmental factors contributing to its development. Vitamin D deficiency has been linked to a higher prevalence of thyroid autoimmunity in certain populations, including children, adolescents, and obese individuals. Moreover, vitamin D supplementation has shown promise in reducing antithyroid antibody levels, improving thyroid function, and improving other markers of autoimmunity, such as cytokines, e.g., IP10, TNF-α, and IL-10, and the ratio of T-cell subsets, such as Th17 and Tr1. Studies suggest that by impacting various immunological mechanisms, vitamin D may help control autoimmunity and improve thyroid function and, potentially, clinical outcomes of HT patients. The article discusses the potential impact of vitamin D on various immune pathways in HT. Overall, current evidence supports the potential role of vitamin D in the prevention and management of HT, although further studies are needed to fully understand its mechanisms of action and potential therapeutic benefits.

Associations between vitamin D levels and dietary patterns in patients with Hashimoto's thyroiditis

Introduction

Vitamin D insufficiency is a global health problem affecting healthy and diseased individuals, including patients with Hashimoto's thyroiditis (HT). Identifying dietary factors that may affect vitamin D levels and providing dietary guidelines accordingly can alleviate this problem. We therefore aimed to identify still unknown associations of dietary patterns, assessed through the Food Frequency Questionnaire (FFQ) with vitamin D blood levels.

Materials and methods

FFQ was collected from 459 patients from Croatian Biobank of Patients with Hashimoto's thyroiditis (CROHT), while total 25(OH)D was measured from their stored serum samples. We performed linear regression analysis between vitamin D levels and weekly intake of 24 food groups in 459 patients with HT (ALL), and in two disease-severity groups (MILD and OVERT).

Results

The main results of our study are observations of: (1) an inverse association between vitamin D levels and coffee consumption (ALL: β = -0.433, p = 0.005; OVERT: β = -0.62, p = 0.008); (2) an inverse association between vitamin D levels and sweets consumption (ALL: β = -0.195, p = 0.034; OVERT: β = -0.431, p = 0.006); (3) positive association between vitamin D levels and vegetable consumption (ALL: β = 0.182, p = 0.019; OVERT, β = 0.311, p = 0.009). Importantly, effect sizes of all three associations were more prominent in HT patients with prolonged and more severe disease (OVERT).

Conclusion

Further research into the functional and causal relationships of the observed associations is important to provide guidance regarding coffee/sugar intake on vitamin D status. A well-balanced diet can help prevent vitamin D deficiency and improve the quality of life of patients with HT, especially those in later stages of disease characterized by greater metabolic imbalance.

Vitamin D and Autoimmune Rheumatic Diseases

Vitamin D is a steroid hormone with potent immune-modulating properties. It has been shown to stimulate innate immunity and induce immune tolerance. Extensive research efforts have shown that vitamin D deficiency may be related to the development of autoimmune diseases. Vitamin D deficiency has been observed in patients with rheumatoid arthritis (RA) and has been shown to be inversely related to disease activity. Moreover, vitamin D deficiency may be implicated in the pathogenesis of the disease. Vitamin D deficiency has also been observed in patients with systemic lupus erythematosus (SLE). It has been found to be inversely related to disease activity and renal involvement. In addition, vitamin D receptor polymorphisms have been studied in SLE. Vitamin D levels have been studied in patients with Sjogren's syndrome, and vitamin D deficiency may be related to neuropathy and the development of lymphoma in the context of Sjogren's syndrome. Vitamin D deficiency has been observed in ankylosing spondylitis, psoriatic arthritis (PsA), and idiopathic inflammatory myopathies. Vitamin D deficiency has also been observed in systemic sclerosis. Vitamin D deficiency may be implicated in the pathogenesis of autoimmunity, and it may be administered to prevent autoimmune disease and reduce pain in the context of autoimmune rheumatic disorders.

The Role of Vitamin D in Autoimmune Thyroid Diseases: A Narrative Review

Vitamin D (VitD) deficiency has garnered significant attention in contemporary medical research. Although the canonical biological activity of VitD manifests itself mainly in the regulation of calcium-phosphorus metabolism, recent studies show that, thanks to the presence of numerous receptors, VitD may also play an important role in regulating the immune system. VitD deficiency has been demonstrated to impact autoimmune disease, coeliac disease, infections (including respiratory/COVID-19), and patients with cancer. Recent studies also show that VitD plays a significant role in autoimmune thyroid diseases (AITDs). Many studies have shown a correlation between low VitD levels and chronic autoimmune thyroiditis - Hashimoto thyroiditis (HT), Graves' disease (GD), and postpartum thyroiditis (PPT). This review article, therefore, describes the current state of knowledge on the role of VitD in AITDs, including HT, GD, and PTT.

Vitamin D and the Thyroid: A Critical Review of the Current Evidence

Vitamin D is necessary for the normal functioning of many organs, including the thyroid gland. It is, therefore, not surprising that vitamin D deficiency is considered a risk factor for the development of many thyroid disorders, including autoimmune thyroid diseases and thyroid cancer. However, the interaction between vitamin D and thyroid function is still not fully understood. This review discusses studies involving human subjects that (1) compared vitamin D status (primarily determined by serum calcidiol (25-hydroxyvitamin D [25(OH)D]) levels) with thyroid function assessed by thyroid stimulating hormone (TSH), thyroid hormones, and anti-thyroid antibody levels; and (2) evaluated the effect of vitamin D supplementation on thyroid function. Due to the many inconsistencies in the results between the studies, it is still difficult to draw a definite conclusion on how vitamin D status affects thyroid function. Studies in healthy participants observed either a negative correlation or no association between TSH and 25(OH)D levels, while the results for thyroid hormones showed high variability. Many studies have observed a negative association between anti-thyroid antibodies and 25(OH)D levels, but equally many studies have failed to observe such an association. Regarding the studies that examined the effect of vitamin D supplementation on thyroid function, almost all observed a decrease in anti-thyroid antibody levels after vitamin D supplementation. Factors that could contribute to the high variability between the studies are the use of different assays for the measurement of serum 25(OH)D levels and the confounding effects of sex, age, body-mass index, dietary habits, smoking, and the time of year when the samples were collected. In conclusion, additional studies with larger numbers of participants are needed to fully understand the effect of vitamin D on thyroid function.

On the Centennial of Vitamin D-Vitamin D, Inflammation, and Autoimmune Thyroiditis: A Web of Links and Implications

The 100th anniversary of the discovery of vitamin D3 (VitD3) coincides with significant recent advances in understanding its mechanism of action along with accumulating knowledge concerning its genomic and nongenomic activities. A close relationship between VitD3 and the immune system, including both types of immunity, innate and adaptive, has been newly identified, while low levels of VitD3 have been implicated in the development of autoimmune thyroiditis (AIT). Active 1,25(OH)₂ D3 is generated in immune cells via 1-α-hydroxylase, subsequently interacting with the VitD3 receptor to promote transcriptional and epigenomic responses in the same or adjacent cells. Despite considerable progress in deciphering the role of VitD3 in autoimmunity, its exact pathogenetic involvement remains to be elucidated. Finally, in the era of coronavirus disease 2019 (COVID-19), brief mention is made of the possible links between VitD3 deficiency and risks for severe COVID-19 disease. This review aims to commemorate the centennial of the discovery of VitD3 by updating our understanding of this important nutrient and by drawing up a framework of guidance for VitD3 supplementation, while emphasizing the necessity for personalized treatment in patients with autoimmune thyroid disease. A tailored approach based on the specific mechanisms underlying VitD3 deficiency in different diseases is recommended.

Emerging trends and hot spots in autoimmune thyroiditis research from 2000 to 2022: A bibliometric analysis

Background

Autoimmune thyroiditis (AIT) is the most common autoimmune disease, affecting 3-5% patients worldwide. In recent years, approximately 200 articles on AIT have been published annually in various journals. However, to date, no article has systematically assessed the related literature. Therefore, we conducted a bibliometric analysis on AIT to reveal the dynamic scientific developments and help researchers gain a global perspective while exploring the hotspots and development trends.

Methods

AIT-related articles and reviews from 2000 to 2022 were retrieved from the Web of Science Core Collection (WoSCC). The following search terms were used to extract document data: TS= (“ autoimmune thyroiditi*”) OR TI= (“chronic lymphocytic thyroiditi*”) OR TI=(hashimoto*) OR TI= (“postpartum thyroiditis”). We selected articles and reviews published in English from 2000 to 2022. Three software programs (VOSviewer, CiteSpace, Pajek) were employed to analyze the contribution and co-occurrence relationships of different references, countries/regions, institutes, journals and also keywords in this field.

Results

This scientometric study included 2290 English papers published in 723 journals with 39661 co-cited references from 561 institutions in 120 countries/regions. Based on the reference and keyword analysis, researchers used to focus on “apoptosis”, “insulin resistance”, “encephalopathy”, “IFN-γ” related to AIT during the past 20 years. However, with the development of other novel directions such as “papillary thyroid cancer” (2018-2022), “Vitamin D” (2016-2022), “oxidative stress” (2018-2022), “polymorphism” (2019-2022) and “association” (2020-2022), researchers are more interested in the relationship between papillary thyroid carcinoma and AIT, the effect of vitamin D supplementation on AIT, the oxidative stress in thyroid disease as well as the influence of polymorphism.

Conclusion

Bibliometric analysis of the outputs of AIT shows an overview of the current status of the research on AIT. The associations between papillary thyroid carcinoma, vitamin D, oxidative stress, polymorphism and AIT are major research frontiers. However, further research and collaboration are still required worldwide. Our findings can help researchers grasp the research status of AIT and quickly determine new directions for future research.

Metabolic Characteristics of Hashimoto's Thyroiditis Patients and the Role of Microelements and Diet in the Disease Management-An Overview

Hashimoto’s thyroiditis (HT) is the most common autoimmune disease and the leading cause of hypothyroidism, in which damage to the thyroid gland occurs due to the infiltration of lymphocytes. It is characterized by increased levels of antibodies against thyroid peroxidase and thyroglobulin. In this review, we present the metabolic profile, the effectiveness of micronutrient supplementation and the impact of dietary management in patients with HT. For this current literature review, the databases PubMed, Cochrane, Medline and Embase were reviewed from the last ten years until March 2022. This article provides a comprehensive overview of recent randomized controlled trials, meta-analyses, and clinical trials. Many patients with HT, even in the euthyroid state, have excess body weight, metabolic disorders, and reduced quality of life. Due to frequent concomitant nutritional deficiencies, the role of vitamin D, iodine, selenium, magnesium, iron and vitamin B12 is currently debated. Several studies have underlined the benefits of vitamin D and selenium supplementation. There is still no specific diet recommended for patients with HT, but a protective effect of an anti-inflammatory diet rich in vitamins and minerals and low in animal foods has been suggested. There is insufficient evidence to support a gluten-free diet for all HT patients. Pharmacotherapy, along with appropriate nutrition and supplementation, are important elements of medical care for patients with HT. The abovementioned factors may decrease autoantibody levels, improve thyroid function, slow down the inflammatory process, maintain proper body weight, relieve symptoms, and prevent nutritional deficiencies and the development of metabolic disorders in patients with HT.

Association Between Vitamin D Deficiency and Autoimmune Thyroid Disorder: A Systematic Review

Despite recent evidence that low serum 25-hydroxyvitamin D (25(OH)D) levels and deflects may influence the emergence of autoimmune thyroid disorders (AITD), the relationship between vitamin D deficiency and Graves’ disease (GD) and Hashimoto's thyroiditis (HT), which comprise AITD, remains unclear. We retrieved studies that described vitamin D association with HT and GD from PubMed/Medline, Google Scholar, and the Cochrane Library. We included research studies that compared vitamin D levels and deficiency or sufficiency between AITD cases such as HT and GD cases and control subjects. The final assessment comprised 11 studies that recruited 1952 AITD cases (HT and GD) that were published between 2011 and 2021; these were included in the final review. All the included studies were observational, and more precisely, case-control studies that recruited healthy subjects as well as controls. The majority of the studies reviewed indicated that HT and GD patients have a greater prevalence of vitamin D deficiency or low serum 25 (OH)-D levels. Two studies failed to establish an association between vitamin D deficiency and HT and GD disease. In conclusion, vitamin D deficiency or insufficiency can increase the rate of autoimmune diseases such as HT and GD. Randomized controlled trials with a longer follow-up period are needed to confirm the causal relationship between autoimmune thyroid disorder and vitamin D and to provide more reliable insights into the relevance of treatment effects of vitamin D therapy or supplementation.

Relationship Between Vitamin D and Thyroid: An Enigma

Hypothyroidism is a frequently encountered endocrine disorder in clinical practice. Besides its traditional role in bone health, vitamin D has been shown to have favorable effects in a variety of different systems due to its pleiotropic qualities and ubiquitous receptor expression. Over the years, researchers have been fascinated by the intricate molecular interplay between vitamin D and thyroid. In this regard, attempts have emerged to demonstrate the role of vitamin D in thyroid disorders. This article has reviewed the existing literature on the role of vitamin D in hypothyroidism. We explored studies discussing the physiological interactions between vitamin D and thyroid, as well as the clinical consequences, supplemental and prognostic relevancy of vitamin D in auto-immune thyroid disease (AITD) and hypothyroidism.

Potential Risk Factors for Isolated Hypothyroxinemia in Women of Childbearing Age-Results from Retrospective Analysis

Isolated hypothyroxinemia (IH) unfavorably affects reproduction. This study aimed to evaluate retrospectively if any routinely measured clinical/laboratory parameters are associated with IH among women of childbearing age hospitalized in the endocrine department. A group of 466 female non-pregnant inpatients (age range 13-57 years) was considered. IH (decreased free thyroxine (FT4) with normal TSH) was found in 8/466 patients (1.72%). Vitamin D deficiency (<30 ng/mL) was found in all patients with IH, whereas severe Vitamin D deficiency (<20 ng/mL) was found in 5/6. Vitamin D concentration was lower in IH females. FT4 concentration was lower in patients with severe vitamin D deficiency and correlated positively with vitamin D concentration. Insulin resistance index (IRI) was increased (>1.25) in 5/6 patients with IH. IRI was higher in IH patients and it was the only independent linear factor for IH in the univariate regression. FT4 concentration was lower in patients with increased IRI and correlated negatively with IRI. FT4 concentration correlated negatively with body mass index (BMI) and LDL cholesterol or triglycerides, and positively with HDL cholesterol or HDLC/cholesterol ratio. Vitamin D deficiency, insulin resistance and increased BMI (as potential causative factors), and abnormal lipid profile (as a possible consequence), are associated with IH in women of childbearing age. Eliminating risk factors for hypothyroxinemia may improve reproductive health.