Effects of Vitamin D treatment on thyroid autoimmunity

Vitamin D and selenium for type 2 diabetes mellitus with Hashimoto's thyroiditis: Dosage and duration insights

This letter discusses the publication by Feng et al. Iodine, selenium, and vitamin D are closely associated with thyroid hormone production in humans; however, the efficacy of selenium and vitamin D supplementation for type 2 diabetes mellitus (T2DM) patients with Hashimoto's thyroiditis (HT) remains controversial. In the retrospective study we discuss herein, the authors highlighted significant improvements in thyroid function, thyroid antibodies, blood glucose, and blood lipid in T2DM patients with HT following addition of vitamin D and selenium to their antidiabetic regimens, underscoring the value of these supplements. Our team is currently engaged in research exploring the relationship between micronutrients and HT, and we have obtained invaluable insights from the aforementioned study. Based on this research and current literature, we recommend a regimen of 4000 IU/day of vitamin D and 100-200 μg/day of selenium for over three months to six months for patients with HT, particularly for those with concurrent T2DM.

The Effect of Vitamin D Supplementation on Thyroid Hormone Levels in Patients With Autoimmune Thyroid Disease: A Systematic Review

Autoimmune thyroid diseases (AITDs) pose significant challenges in clinical practice, representing one of the most common endocrine abnormalities. Vitamin D deficiency has been linked as one of the contributing factors to the etiology of AITDs. This systematic review evaluates the effects of vitamin D supplementation on thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) levels in adults with AITDs. Using a PICO (population, intervention, comparison, and outcome) framework and adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, seven relevant studies were identified from an initial pool of 1,469 articles. The population comprised individuals with thyroid autoimmunity, as evidenced by at least one elevated positive thyroid autoimmune marker and intervention involved the supplementation of vitamin D, regardless of the dose or method of administration. All randomized clinical trials within the last 10 years, which fit the study criteria, were included. These studies showed varying results based on follow-up duration. Short-term studies (three months or less) demonstrated no significant changes in mean TSH, T3, or T4 levels compared to the control group with vitamin D supplementation. However, all of the long-term studies (greater than three months) indicated significant improvements compared to the control in mean TSH, T3, and T4 levels. Additionally, all long-term studies that compared TSH, T3, and T4 to baseline levels revealed significant changes by the trial's end. Despite these promising findings, the review highlights limitations, including small sample sizes, short study durations, and the need for further research to establish optimal dosing and treatment duration for vitamin D in AITD management. The overall findings suggest that vitamin D supplementation may play a part in thyroid hormone regulation in AITD, particularly with prolonged administration.

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.

Evaluation of vitamin D status in adult patients with newly diagnosed immune thrombocytopenia

It has been shown that 25-OH vitamin D not only preserves calcium and bone homeostasis but also has immunomodulatory effects. The purpose of this study was to assess the association between adult patients with recently diagnosed immune thrombocytopenia (ITP) and vitamin D levels. Retrospective technique was employed in this study. The associations between 25(OH)D value and platelet count, as well as the clinical symptoms of ITP upon diagnosis and 25(OH)D value, were our main findings. A total of 60 patients diagnosed and followed up in our clinic were included in the study. Forty-one patients (68.3%) were female and 19 (31.7%) were male. The median age of the patients was 52.5 (19-88). The median vitamin D level of all patients at diagnosis of ITP was 11.5 (3-86). There was no statistically significant difference between the patients divided into three groups according to their vitamin D levels, in terms of laboratory parameters. There was no statistically significant difference in clinical findings according to vitamin D status in ITP patients. There was no statistically significant difference in terms of relapse-free survival in all three groups (p = 0.71). In conclusion, in our study, no correlation was found between laboratory and clinical findings at diagnosis and vitamin D levels in adult ITP patients. Additional investigations, particularly randomized controlled trials, are required to examine the relationship between 25(OH)D and the incidence and severity of ITP.

Therapeutic effect of vitamin D in Hashimoto's thyroiditis: a prospective, randomized and controlled clinical trial in China

BACKGROUND

The study aims to explore the clinical effects of Vitamin D (VitD) supplements for Hashimoto's Thyroiditis (HT), which are unclear according to other studies.

METHODS

Female patients with newly diagnosed HT from January to June in 2018 were included. This study is registered in the Chinese Clinical Trials Registry with registration number ChiCTR1800014619 (URL: https://www.chictr.org.cn/). Patients were randomly assigned to the treatment group and the control group. The treated group were further randomly assigned to a VitD supplement group or VitD & Levothyroxine (L-T4) supplement group. After 6 months, we recorded and compared various indicators between different groups.

RESULTS

A total of 179 patients, aged 12 to 75, were used for statistical analysis. A significant decrease in Thyroid Peroxidase Antibody (TPOAb) level was observed (351.70±183.25 vs. 246.37±157.39, P<0.001) in the VitD-treated group compared to the control group after 6 months. Free Triiodothyronine (FT3) and Free Thyroxine (FT4) level were increased (FT3: 4.30±0.64 vs. 4.84±0.9, P<0.001; FT4: 15.15±1.93 vs. 17.38±2.97, P<0.001), and Thyroid-Stimulating Hormone (THS) level was decreased (3.58±1.78 vs. 2.25±1.22, P<0.001) in the VitD-treated group compared to the control group.

CONCLUSION

VitD supplementation can effectively slow progression of hypothyroidism, improve thyroid function, and reduce the anti-thyroid antibody level. This suggests it is useful for HT.

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.

Impact of thyroid autoimmunity and vitamin D on in vitro fertilization/intracytoplasmic sperm injection outcomes among women with normal thyroid function

This prospective cohort study aimed to determine the impact of thyroid autoimmunity and total 25-hydroxyvitamin D concentration on early pregnancy outcomes in women undergoing in vitro fertilization/intracytoplasmic sperm injection who had intact thyroid function. The study included 1,297 women who underwent in vitro fertilization/intracytoplasmic sperm injection cycles, although only 588 patients received fresh embryo transfer. The study endpoints were clinical pregnancy, ongoing pregnancy, ectopic pregnancy, and early miscarriage rates. Our study found that the total 25-hydroxyvitamin D serum concentrations (P<0.001) and anti-Mullerian hormone levels (P=0.019) were lower among patients in the TAI group (n=518) than among those in the non-TAI group (n=779). Additionally, the study population in each group was divided into three subgroups according to the total vitamin D status based on clinical practice guidelines (deficient, <20 ng/mL; insufficient, 21-29 ng/mL; and sufficient, ≥30 ng/mL), TAI group: sufficient, n=144; insufficient, n=187; and deficient, n=187; non-TAI group: sufficient, n=329; insufficient, n=318, and deficient, n=133. In the TAI group, the number of good-quality embryos decreased in patients with vitamin D deficiency (P=0.007). Logistic regression analysis indicated that aging prevented women from achieving clinical (P=0.024) and ongoing pregnancy (P=0.026). The current findings suggest that patients with TAI had reduced serum vitamin D concentration. Furthermore, in the TAI group, the number of good-quality embryos decreased in patients with vitamin D deficiency. Finally, aging adversely impacted achieving clinical and ongoing pregnancy.

Assessment of the reporting quality of randomised controlled trials for vitamin D supplementation in autoimmune thyroid disorders based on the CONSORT statement

BACKGROUND-PURPOSE

Randomized controlled trials (RCTs) are the cornerstone of evidence-based medicine, yet their quality is often suboptimal. The Consolidated Standards of Reporting Trials (CONSORT) statement is a list of advice to upgrade the quality of RCTs. The aim of this study was the assessment of the quality of RCTs for vitamin D supplements in thyroid autoimmunity according to the revised CONSORT 2010 checklist.

METHODS

Databases were searched for RCTs involving patients with autoimmune thyroid disorders (AITDs) who received vitamin D supplements published from 2011 to 2021. A list of 37-items was used and adherence ≥75% was considered of optimal quality. The primary outcome was the mean CONSORT adherence of studies. Secondary outcomes were the estimation of compliance per CONSORT item and the examination for possible determinants of the reporting quality.

RESULTS

Thirteen eligible trials were finally included. The mean compliance was 61.15% ± 14.86%. Only threeof the studies (23%) achieved a good reporting quality (≥75%), while ten (77%) were presented with inadequate reporting (<75%). Randomization and blinding were mainly poorly reported. Impact Factor (IF) of journal was associated with the reporting quality in the univariate analysis [p = 0.033, OR = 1.65, 95%CI = (1316, 1773)]. Sample size (p = 0.067), number of authors (p = 0.118) and number of citations (p = 0.125) were marginally not significant. None of the factors showed significant results in multivariate analysis. Reporting quality and IF were strongly positively correlated [Pearson's r = 0.740, p = 0.04].

CONCLUSION

This study shows that mean CONSORT adherence of RCTs for Vitamin D supplementation in AITDs is moderate, reflecting that study quality and transparency could be improved with better adherence to CONSORT rules.

The relationship between subclinical hypothyroidism and vitamin D

Aim: Vitamin D (vitD) is primarily responsible for bone formation and mineralization. However, in recent years, it has been suggested that vitD may play a role as an immune modulator in the development of numerous diseases, including autoimmune diseases. It has been observed that there is an association between chronic autoimmune thyroiditis (AIT) and vitD levels. This study aims to investigate whether there are differences in the levels of 25-hydroxy vitamin D [25(OH)D], calcium, and phosphorus in patients with subclinical hypothyroidism (SCH) due to AIT, in patients with antibody-negative subclinical hypothyroidism (ANSCH), and in healthy control subjects. Material and Method: Data from 50 newly diagnosed patients with SCH (35 of whom AIT) and 50 euthyroid and antibody-negative healthy controls who presented to the Department of Endocrinology and Internal Medicine at our hospital between 2018 and 2020 were retrospectively reviewed. Calcium, phosphorus, and 25(OH)D levels of patients and controls were compared. Results: Serum 25(OH)D levels were significantly lower in patients compared to controls (16.2±7.8 ng/ml and 20.4±8.2 ng/ml, respectively; p=0.024). Serum levels of calcium (p=0.081) and phosphorus (p=0.712) did not differ between groups. In a subgroup analysis, patients with AIT had significantly lower 25(OH)D values than controls (p=0.009). Compared to controls, 25(OH)D levels were comparable in the ANSCH group (p=0.096). 25(OH)D level was higher in the AIT group than in the ANSCH group (p=0.01). Conclusion: Our results show that patients with SCH have lower 25(OH)D levels than healthy controls. However, this difference is significant in patients with AIT. It is recommended to screen for vitD deficiency in patients with SCH due to AIT.

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.

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.

Thyroid autoimmunity and vitamin D: Effects on in vitro fertilization/intracytoplasmic sperm injection laboratory outcomes

This prospective cohort study aimed to determine the effects of thyroid autoimmunity, serum/follicular fluid vitamin D levels, and vitamin D receptor expression in granulosa cells on laboratory outcomes of in vitro fertilization/intracytoplasmic sperm injection. The study included 206 women with or without thyroid autoimmunity undergoing in vitro fertilization/intracytoplasmic sperm injection ovarian stimulation cycles. The primary outcomes in thyroid autoimmunity and non-thyroid autoimmunity patients with high or low follicular fluid vitamin D levels (high vitamin D level, ≥20 ng/mL; low vitamin D level, <20 ng/mL) were the number of oocytes retrieved and quality of embryos. The secondary outcomes were the association between serum and follicular fluid vitamin D levels and vitamin D receptor expression in granulosa cells. Our study revealed that thyroid autoimmunity was associated with fewer good-quality embryos but not oocytes (p = 0.010). The vitamin D level in the follicular fluid was significantly correlated with that in the serum (p < 0.001, r > 0.5). The study populations in the thyroid autoimmunity and non-thyroid autoimmunity groups were divided into two subgroups based on high/low serum/follicular fluid vitamin D levels. There was no significant difference in the number of retrieved oocytes and good-quality embryos between the subgroups with high or low vitamin D levels (p > 0.05), and the incidence of thyroid autoimmunity was comparable between the subgroups (p > 0.05). Linear regression analysis indicated that thyroid autoimmunity had a negative effect on the number of healthy embryos (p = 0.038). Reverse transcription-polymerase chain reaction results indicated that vitamin D receptor expression in granulosa cells was positively correlated with follicular vitamin D levels in the thyroid autoimmunity (p = 0.0002) and non-thyroid autoimmunity (p < 0.0001) groups. The current findings suggest that thyroid autoimmunity may have a more detrimental effect on in vitro fertilization/intracytoplasmic sperm injection laboratory outcomes than vitamin D.

Progress in the Relationship between Vitamin D Deficiency and the Incidence of Type 1 Diabetes Mellitus in Children

Type 1 diabetes mellitus (T1DM) is an autoimmune disease, due to a large number of islet β cells damaged, resulting in an absolute lack of insulin, ultimately relying on insulin therapy. Vitamin D is a fat-soluble sterol derivative that not only participates in calcium and phosphorus metabolism but also acts as an immunomodulatory role by binding to nuclear vitamin D receptors to regulate the expression of transcription factors. Increasing evidence has shown that vitamin D has immunoregulation and anti-inflammatory effects, and it may play a role in T cell regulatory responses due to downregulation in the expression of cathepsin G and inhibition of CD4+ T cell activation and protection of β cells from immune attack and is beneficial in decreasing oxidative stress in T1DM patients. Epidemiologic evidence demonstrates involvement of vitamin D deficiency in T1DM pathogenesis, with the immune system improperly targeting and destroying its own islet β cells. In addition, polymorphisms in genes critical for vitamin D metabolism may increase the risk of islet autoimmunity and T1DM. In this paper, the relationship between vitamin D deficiency and the molecular mechanism of T1DM was discussed.

Bidirectional Mendelian Randomization Analysis for Vitamin D and Thyroid Peroxidase Antibody

PURPOSE

Whether Vitamin D deficiency or insufficiency is associated with thyroid autoimmunity was debated for long time. This study was still to explore the causal relationship of 25 (OH) D with a thyroid peroxidase antibody (TPOAb).

METHODS

The data were obtained from a cross-sectional study, SPECT-China study, which was performed in 23 sites in East China during 2014 to 2016. 10636 participants were finally included in this study. Genotyped four 25 (OH) D-related and four TPOAb-associated single nucleotide polymorphisms (SNPs) created their genetic risk scores (GRS). Bidirectional mendelian randomization (MR) analysis was used in this study.

RESULTS

25 (OH) D GRS was significantly associated with 25 (OH) D (B -0.093, 95% CI -0.111, -0.074) and TPOAb level (B 0.067, 95% CI 0.002 to 0.132). TPOAb GRS was significantly associated with TPOAb concentration (B 0.345, 95% CI 0.135 to 0.556), but not 25 (OH) D (B -0.030, 95% CI -0.091 to 0.030). Using 25 (OH) D_GRS as instrumental variable in the MR analysis, a causal relationship of genetically determined 25 (OH) D with increased TPOAb concentration (B -0.720, 95% CI -1.429 to -0.012). No relation was found between genetically instrumented TPOAb and 25 (OH) D.

CONCLUSION

A higher VD_GRS was associated with higher risk of increased TPOAb concentration, which supports a causal association between decreased vitamin D and increased concentration of TPOAb in an eastern Chinese population.

Effects of vitamin D on thyroid autoimmunity markers in Hashimoto's thyroiditis: systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis of randomized controlled trials to evaluate the efficacy of vitamin D supplementation on thyroid autoimmunity markers in Hashimoto's thyroiditis (HT).

METHODS

This meta-analysis included randomized controlled clinical trials identified by a systematic search of electronic databases (PubMed®, MEDLINE®, EMBASE, The Cochrane Library, China National Knowledge Infrastructure) from inception to August 2020. All studies included patients with HT that received vitamin D supplementation irrespective of the doses administered or the duration of treatment. The primary and secondary outcome measures were thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TGAb) titres.

RESULTS

Eight studies (n = 652) were included. There was significant heterogeneity between the studies. Using a random-effect model, vitamin D supplementation reduced TPOAb titre (standardized mean difference [SMD]: -1.11; 95% confidence interval [CI]: 1-1.92, -0.29) and TGAb titre (SMD: -1.12; 95% CI: -1.96, -0.28). A subgroup analysis demonstrated that vitamin D supplementation for >3 months resulted in a decrease in TPOAb titre (SMD: -1.66, 95% CI: -2.91, -0.41) but treatment ≤3 months was ineffective. Treatment with vitamin D₃ decreased TPOAb titre (SMD: -1.48; 95% CI: -2.53, -0.42) whereas vitamin D did not.

CONCLUSION

These data suggest that vitamin D reduces autoantibody titre in patients with HT.

Vitamin D, Thyroid Hormones and Cardiovascular Risk: Exploring the Components of This Novel Disease Triangle

The role of thyroid hormones (THs) in the cardiovascular (CV) system, through several direct and indirect effects is recognized. Even very small modification in TH levels (as those observed in subclinical hypothyroidism or hyperthyroidism, and low triiodothyronine syndrome) may adversely affect the CV system, whereas thyroid hormones benefit the CV system and improve the prognosis. There is also evidence of vitamin D effects on cardiometabolic disease (e.g., through modulation of endothelial and smooth muscle cell activity, renin-angiotensin-aldosterone system, nitric oxide, oxidative stress, and inflammatory response), as well as an association between vitamin D [25(OH)D] deficiency and autoimmune thyroid diseases or cancer, and a relationship between vitamin D concentration and titers of antibodies and thyroid autoimmunity replacement. Interestingly, experimental data indicate a direct effect of vitamin D on Type 2 deiodinase expression causing subsequential peripheral conversion of T4 into T3. However, the functional links among THs, vitamin D and the cardiovascular system, and clinical effects of coexisting abnormalities in this new troublesome triad, have not yet been reviewed. The main aim of this review is to discuss pathophysiology of this relationship, proposing new mechanistic insights involving vitamin D in the modulation of cardiometabolic disease and thyroid profile.

Vitamin D deficiency is associated with thyroid autoimmunity: results from an epidemiological survey in Tianjin, China

PURPOSE

The pathogenesis of Hashimoto's thyroiditis (HT) is unclear, although some studies have identified an association between vitamin D deficiency and thyroid autoantibody positivity. This study aimed to investigate vitamin D status, and its relationships with thyroid autoantibody positivity and HT, via a large epidemiological survey.

METHODS

The epidemiological survey was conducted in Tianjin, China. All participants underwent testing for serum 25-hydroxyvitamin D (25OHD), thyroid function, and thyroid autoantibodies, and some participants underwent testing to evaluate CD4⁺ T-cell differentiation and concentrations of related cytokines.

RESULTS

The study included 1812 participants and revealed prevalences of 13.1% for thyroid peroxidase antibodies (i-TPOAb) and 14.0% for thyroglobulin antibodies (i-TgAb). Logistic regression analysis revealed that thyroid autoantibody positivity was associated with sex, age, and 25OHD classification. An increased likelihood of i-TPOAb positivity was associated with 25OHD deficiency (odds ratio [OR]: 2.428, 95% confidence interval [CI]: 1.383-4.261) and 25OHD inadequacy (OR: 1.198, 95% CO: 0.828-1.733; p = 0.008). An increased likelihood of i-TgAb positivity was associated with 25OHD deficiency (OR: 2.366, 95% CI: 1.366-4.099) and 25OHD inadequacy (OR: 1.263, 95% CI: 0.883-1.807; p = 0.009). Relative to healthy subjects, patients with HT had significantly higher proportions of Th1 and Th17 cells, as well as higher concentrations of related cytokines.

CONCLUSIONS

This study revealed that vitamin D deficiency was associated with thyroid autoantibody positivity, and that vitamin D deficiency seems to be involved in the pathological mechanism underlying HT. Large randomized controlled trials are needed to investigate the effects of vitamin D supplementation on HT.

Pleiotrope Wirkung von Vitamin D mit Berücksichtigung von COVID-19

Vitamin D wird aus der Nahrung aufgenommen oder in der Haut unter Einwirkung von UV-Licht gebildet. In der Leber wird 25(OH)-Vitamin D gebildet und in der Niere 1,25(OH)2-Vitamin D, welches als Hormon den Knochen- und Mineralstoffwechsel reguliert.

Außerhalb der Niere besitzen viele Organe Enzyme, um 1,25(OH)2-Vitamin D zu bilden für autokrine und parakrine Wirkungen. Für diese pleiotropen Effekte erscheint eine gleichmäßige Vitamin-D-Versorgung (tägliche Vitamin-D-Supplementation) mit mäßiger Dosierung besser wirksam als hoch dosierte Bolusapplikationen. Neben der klassischen Wirkung von 1,25(OH)2-Vitamin D auf das muskuloskelettale System sind unter den extraskelettalen Wirkungen insbesondere die immunregulatorischen Effekte mittlerweile sehr gut belegt. So kann durch eine gute Vitamin-D-Versorgung das Risiko für respiratorische Infekte vermindert werden, was gerade im Hinblick auf die aktuelle COVID-19(Coronavirus-Erkrankung-19)-Pandemie von Bedeutung erscheint.

Autoimmune thyroid disease and type 1 diabetes mellitus: same pathogenesis; new perspective?

Autoimmune thyroid disease (AITD) and type 1 diabetes mellitus (T1DM) are two common autoimmune diseases that can occur concomitantly. In general, patients with diabetes have a high risk of AITD. It has been proposed that a complex genetic basis together with multiple nongenetic factors make a variable contribution to the pathogenesis of T1DM and AITD. In this paper, we summarize current knowledge in the field regarding potential pathogenic factors of T1DM and AITD, including human leukocyte antigen, autoimmune regulator, lymphoid protein tyrosine phosphatase, forkhead box protein P3, cytotoxic T lymphocyte-associated antigen, infection, vitamin D deficiency, and chemokine (C-X-C motif) ligand. These findings offer an insight into future immunotherapy for autoimmune diseases.

Vitamin D and Autoimmune Thyroid Disease-Cause, Consequence, or a Vicious Cycle?

Vitamin D is a steroid hormone traditionally connected to phosphocalcium metabolism. The discovery of pleiotropic expression of its receptor and of the enzymes involved in its metabolism has led to the exploration of the other roles of this vitamin. The influence of vitamin D on autoimmune disease-namely, on autoimmune thyroid disease-has been widely studied. Most of the existing data support a relationship between vitamin D deficiency and a greater tendency for development and/or higher titers of antibodies linked to Hashimoto's thyroiditis, Graves' disease, and/or postpartum thyroiditis. However, there have also been some reports contradicting such relationships, thus making it difficult to establish a unanimous conclusion. Even if the existence of an association between vitamin D and autoimmune thyroid disease is assumed, it is still unclear whether it reflects a pathological mechanism, a causal relationship, or a consequence of the autoimmune process. The relationship between vitamin D's polymorphisms and this group of diseases has also been the subject of study, often with divergent results. This text presents a review of the recent literature on the relationship between vitamin D and autoimmune thyroid disease, providing an analysis of the likely involved mechanisms. Our thesis is that, due to its immunoregulatory role, vitamin D plays a minor role in conjunction with myriad other factors. In some cases, a vicious cycle is generated, thus contributing to the deficiency and aggravating the autoimmune process.

Vitamin D effects and endocrine diseases

A lack of vitamin D has been linked to autoimmune diseases including type 1 diabetes, autoimmune thyroiditis and to obesity. The prevalence of vitamin D deficiency is higher in diabetic or obese children and patients with thyroiditis compared to healthy controls. Moreover, low vitamin D values seem to be associated with major complications and poor glycemic control, in particular in obese children. Supplementation with vitamin D, which has immune-regulatory properties, may support our therapies and improve the outcomes in different diseases. Although some studies suggest a possible role of vitamin D in the etiology of autoimmune diseases and obesity, data on supplementation benefits are inconclusive and further studies are needed. In this paper, we focus on the current evidence regarding vitamin D function in endocrine diseases and possible benefits of its supplementation in pediatric age.

Immunomodulatory Effects of Vitamin D in Thyroid Diseases

Vitamin D is a secosteroid with a pleiotropic role in multiple physiological processes. Besides the well-known activity on bone homeostasis, recent studies suggested a peculiar role of vitamin D in different non-skeletal pathways, including a key role in the modulation of immune responses. Recent evidences demonstrated that vitamin D acts on innate and adaptative immunity and seems to exert an immunomodulating action on autoimmune diseases and cancers. Several studies demonstrated a relationship between vitamin D deficiency, autoimmune thyroid disorders, and thyroid cancer. This review aims to summarize the evidences on the immunomodulatory effect of vitamin D on thyroid diseases.

Immunomodulatory effect of vitamin D and its potential role in the prevention and treatment of thyroid autoimmunity: a narrative review

The main role of vitamin D is to control mineral homeostasis. However, recent studies suggested the existence of a number of extraskeletal effects. Among the latter, preclinical studies provided consistent data on the involvement of vitamin D in innate and adaptive immunity and autoimmunity. Molecular biology studies showed that both vitamin D receptor and vitamin D enzymatic complexes are expressed in a large number of cells and tissues unrelated to mineral homeostasis. In contrast, only a few randomized clinical trials in humans investigated the possible role of vitamin D in the prevention or treatment of immunological disorders. In this regard, low serum vitamin D levels have been reported in observational trials in human autoimmune disorders. The aim of the present paper was to review the potential implications of vitamin D in immune modulation, with special focus on thyroid autoimmune disorders.

Pathophysiological Role and Therapeutic Implications of Vitamin D in Autoimmunity: Focus on Chronic Autoimmune Diseases

Vitamin D is a pleiotropic secosteroid yielding multiple actions in human physiology. Besides the canonical regulatory activity on bone metabolism, several non-classical actions have been described and the ability of vitamin D to partake in the regulation of the immune system is particularly interesting, though far stronger and convincing evidence has been collected in in vitro as compared to in vivo studies. Whether vitamin D is able to regulate at physiological concentrations the human immune system remains unproven to date. Consequently, it is not established if vitamin D status is a factor involved in the pathogenesis of immune-mediated diseases and if cholecalciferol supplementation acts as an adjuvant for autoimmune diseases. The development of autoimmunity is a heterogeneous process, which may involve different organs and systems with a wide range of clinical implications. In the present paper, we reviewed the current evidences regarding vitamin D role in the pathogenesis and management of different autoimmune diseases.

Assessing vitamin D levels in an anti-DFS70 positive population: New insights emerging

Background: Anti-dense fine speckled 70 (DFS70) autoantibodies have more often been described in apparently healthy individuals than in patients with systemic autoimmune rheumatic diseases (SARD). The aim of this study was to explore the link between anti-DFS70 autoantibodies and vitamin D (25(OH)D) levels in an Italian adult cohort.Methods: Serum samples from 34 (five males and 29 females) anti-DFS70 positive patients (index cases), 34 ANA-negative healthy controls, 34 ANA-positive anti-DFS70 negative SLE patients, both groups age- and gender-matched with the index cases, 23 ANA-positive anti-DFS70 negative healthy blood donors and six female SARD patients showing mixed DFS positive pattern were collected and tested for 25(OH)D levels. Relevant demographics and lifestyle practices, body mass index (BMI), comorbidities, and use of medication were recorded for patients and healthy controls.Results: Mean serum levels of 25(OH)D were significantly higher in anti-DFS70 positive subjects (mean ± SD: 22.1 ± 9.8 ng/ml) than in ANA-negative healthy controls (mean ± SD: 17.3 ± 6.7 ng/ml; p = .03), ANA-positive healthy controls (mean ± SD: 15.2 ± 6.8 ng/ml; p = .01), SLE patients (16.6 ± 11.0 ng/ml; p = .01) and in patients with SARD (15.0 ± 5.6 ng/ml; p = .01). No statistically relevant differences in BMI, clinical, or demographic parameters were found.Conclusions: Our findings showed higher levels of vitamin D in anti-DFS70 positive subjects than in the controls, which is compatible with the hypothesis of the "benign" nature of anti-DFS70 antibodies.

Hypovitaminosis D Influences the Clinical Presentation of Immune Thrombocytopenia in Children with Newly Diagnosed Disease

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by isolated thrombocytopenia defined as platelet count in peripheral blood <100 × 10⁹/L. Hypovitaminosis D is very common in children with autoimmune diseases. To analyze whether hypovitaminosis D is associated with the clinical presentation of ITP in children, medical records of 45 pediatric patients with newly diagnosed immune thrombocytopenia in the coastal region of Croatia were evaluated. The severity of bleeding was assessed using two bleeding scores. Children with lower 25-hydroxyvitamin D (25(OH)D) values had higher values of the skin-mucosa-organ-gradation (SMOG) bleeding score and respectively more severe bleeding on diagnosis of ITP. With further analysis of the main domains of that score, we found that patients with a lower 25(OH)D value had more severe bleeding in the skin and organs. When 25(OH)D and ITP Bleeding Scale (IBLS) score were analyzed, a negative correlation was found, but it was not significant. Our findings suggest that hypovitaminosis D influences the severity of the clinical presentation of ITP in children on initial diagnosis of the disease. Therefore, therapy with 25(OH)D could be a new potential option for treatment of ITP. To investigate the connection between 25(OH)D and the incidence and severity of ITP, further studies, especially randomized controlled studies, are needed.

Vitamin D, Thyroid Autoimmunity and Cancer: An Interplay of Different Factors

BACKGROUND AND AIMS

In spite of large volume of data linking Vitamin D with cardiovascular morbidity, autoimmunity, cancer, and virtually every organ system, Vitamin D and thyroid is a lesser-known aspect of Vitamin D in clinical practice. This article intends to highlight the current literature on the impact of Vitamin D status and supplementation on thyroid autoimmunity and cancer.

METHODS

References for this review were identified through searches of PubMed for articles published to from 1950 to August 2019 using the terms "thyroid" [MeSH Terms] AND "Vitamin D" [MeSH Terms] OR "thyroid" [All Fields] AND "Vitamin D" [All Fields].

RESULTS

Significant inverse correlation was documented between anti-thyroid peroxidase antibody (TPOAb) and serum 25-hydroxy-Vitamin D (25OHD). TPOAb positivity is more prevalent in Vitamin D deficient individuals. A large volume of medical literature is available from observational studies linking Vitamin D with thyroid autoimmunity. Data from interventional studies documenting beneficial effects of Vitamin D on thyroid autoimmunity is also available, but lesser than that from observational studies. Short-term high dose oral Vitamin D supplementation reduces TPOAb titers. Certain Vitamin D receptor (VDR) gene polymorphism have been linked to increased occurrence of autoimmune thyroid disorders (AITD). Vitamin D deficiency, decreased circulating calcitriol has been linked to increased thyroid cancer. Certain VDR gene polymorphisms have been linked with increased as well as decreased occurrence of thyroid cancer. Data is scant on use of Vitamin D and its analogues for treating thyroid cancer.

CONCLUSION

In spite of large volume of medical literature from observational studies linking Vitamin D with thyroid autoimmunity and cancer, meaningful concrete clinical data on impact of Vitamin D supplementation on hard clinical end points in these disorders is lacking, and should be the primary area of research in the next decade.

Role of Vitamin D Beyond the Skeletal Function: A Review of the Molecular and Clinical Studies

The classical function of Vitamin D, which involves mineral balance and skeletal maintenance, has been known for many years. With the discovery of vitamin D receptors in various tissues, several other biological functions of vitamin D are increasingly recognized and its role in many human diseases like cancer, diabetes, hypertension, cardiovascular, and autoimmune and dermatological diseases is being extensively explored. The non-classical function of vitamin D involves regulation of cellular proliferation, differentiation, apoptosis, and innate and adaptive immunity. In this review, we discuss and summarize the latest findings on the non-classical functions of vitamin D at the cellular/molecular level and its role in complex human diseases.

The effect of vitamin D supplementation on thyroid autoantibody levels in the treatment of autoimmune thyroiditis: a systematic review and a meta-analysis

PURPOSE

Although observational studies suggested that vitamin D plays a role in autoimmune thyroiditis (AIT), intervention trials yielded inconsistent findings. We therefore conducted a systematic review and a meta-analysis to evaluate the effects of Vitamin D on decreasing autoantibodies in patients with AIT.

METHOD

We identified all studies that assessed the changes of TPO-Ab and Tg-Ab in patients with AIT under the treatment of vitamin D from PubMed, Embase, The Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, and VIP Database.

RESULTS

Six randomized controlled trials (RCTs) were included in this systematic review representing a total of 344 patients with AIT. The results showed that Vitamin D supplementation significantly dropped TPO-Ab titers [three studies, random effects standardized mean difference (SMD): -1.11, 95% CI -1.52 to -0.70, P < 0.01] at six months, but not at no more than 3 months [random effects SMD: -0.12, 95% CI: -0.69 to 0.44, P = 0.67]. As compared with control group, participants who received vitamin D supplementation demonstrated significantly lower Tg-Ab [random effects SMD: -0.55, 95% CI: -1.05 to -0.04, P = 0.033]. In addition, no serious adverse effect was reported.

CONCLUSIONS

The current evidence suggests that vitamin D supplementation could decrease serum TPO-Ab and Tg-Ab titers of patients with AIT in the short-term (about six months). More high quality studies are needed to further confirm the effects, especially the long-term effects of Vitamin D supplementation on thyroid autoantibodies levels in the treatment of AIT.

Physiological serum 25-hydroxyvitamin D concentrations are associated with improved thyroid function-observations from a community-based program

PURPOSE

Vitamin D deficiency has been associated with an increased risk of hypothyroidism and autoimmune thyroid disease. Our aim was to investigate the influence of vitamin D supplementation on thyroid function and anti-thyroid antibody levels.

METHODS

We constructed a database that included 11,017 participants in a health and wellness program that provided vitamin D supplementation to target physiological serum 25-hydroxyvitmain D [25(OH)D] concentrations (>100 nmol/L). Participant measures were compared between entry to the program (baseline) and follow-up (12 ± 3 months later) using an intent-to-treat analysis. Further, a nested case-control design was utilized to examine differences in thyroid function over 1 year in hypothyroid individuals and euthyroid controls.

RESULTS

More than 72% of participants achieved serum 25(OH)D concentrations >100 nmol/L at follow-up, with 20% above 125 nmol/L. Hypothyroidism was detected in 2% (23% including subclinical hypothyroidism) of participants at baseline and 0.4% (or 6% with subclinical) at follow-up. Serum 25(OH)D concentrations ≥125 nmol/L were associated with a 30% reduced risk of hypothyroidism and a 32% reduced risk of elevated anti-thyroid antibodies. Hypothyroid cases were found to have higher mean serum 25(OH)D concentrations at follow-up, which was a significant positive predictor of improved thyroid function.

CONCLUSION

The results of the current study suggest that optimal thyroid function might require serum 25(OH)D concentrations above 125 nmol/L. Vitamin D supplementation may offer a safe and economical approach to improve thyroid function and may provide protection from developing thyroid disease.

SEASONAL VARIATION OF VITAMIN D AND SERUM THYROTROPIN LEVELS AND ITS RELATIONSHIP IN A EUTHYROID CAUCASIAN POPULATION

OBJECTIVE

It is unclear whether seasonal variations in vitamin D concentrations affect the hypothalamo-pituitary-thyroid axis. We investigated the seasonal variability of vitamin D and serum thyrotropin (TSH) levels and their interrelationship.

METHODS

Analysis of 401 patients referred with nonspecific symptoms of tiredness who had simultaneous measurements of 25-hydroxyvitamin D3 (25[OH]D3) and thyroid function. Patients were categorized according to the season of blood sampling and their vitamin D status.

RESULTS

25(OH)D3 levels were higher in spring-summer season compared to autumn-winter (47.9 ± 22.2 nmol/L vs. 42.8 ± 21.8 nmol/L; P = .02). Higher median (interquartile range) TSH levels were found in autumn-winter (1.9 [1.2] mU/L vs. 1.8 [1.1] mU/L; P = .10). Across different seasons, 25(OH)D3 levels were observed to be higher in lower quartiles of TSH, and the inverse relationship was maintained uniformly in the higher quartiles of TSH. An independent inverse relationship could be established between 25(OH)D3 levels and TSH by regression analysis across both season groups (autumn-winter: r = -0.0248; P<.00001 and spring-summer: r = -0.0209; P<.00001). We also observed that TSH varied according to 25(OH)D3 status, with higher TSH found in patients with vitamin D insufficiency or deficiency in comparison to patients who had sufficient or optimal levels across different seasons.

CONCLUSION

Our study shows seasonal variability in 25(OH)D3 production and TSH secretion in euthyroid subjects and that an inverse relationship exists between them. Further studies are needed to see if vitamin D replacement would be beneficial in patients with borderline thyroid function abnormalities.

ABBREVIATIONS

25(OH)D2 = 25-hydroxyvitamin D2; 25(OH)D3 = 25-hydroxyvitamin D3; AITD = autoimmune thyroid disease; FT4 = free thyroxine; TFT = thyroid function test; TSH = thyrotropin; UVB = ultraviolet B.

Effect of Vitamin D deficiency treatment on thyroid function and autoimmunity markers in Hashimoto's thyroiditis: A double-blind randomized placebo-controlled clinical trial

Background:

The link between autoimmune thyroid diseases and Vitamin D deficiency has been reported. However, there are controversies in this regard. We conducted a double-blind randomized placebo-controlled clinical trial to investigate the effect of Vitamin D deficiency treatment on thyroid function and autoimmunity marker (thyroid peroxidase antibody [TPO-Ab]) in patients with Hashimoto's thyroiditis.

Materials and Methods:

Fifty-six patients with Hashimoto's thyroiditis and Vitamin D deficiency (25-hydroxyvitamin D level ≤20 ng/mL) were randomly allocated into two groups to receive Vitamin D (50000 IU/week, orally) or placebo for 12 weeks, as Vitamin D-treated (n = 30) and control (n = 26) groups, respectively. TPO-Ab, thyroid-stimulating hormone (TSH), parathormone, calcium, albumin, and creatinine concentrations were compared before and after trial between and within groups. The data were presented as mean (standard error [SE]) and analyzed by appropriate tests.

Results:

Mean (SE) of Vitamin D was increased in Vitamin D-treated group (45.5 [1.8] ng/mL vs. 12.7 [0.7] ng/mL, P = 0.01). Mean (SE) of TPO-Ab did not significantly change in both groups (734 [102.93] IU/mL vs. 820.25 [98.92] IU/mL, P = 0.14 in Vitamin D-treated and 750.03 [108.7] [IU/mL] vs. 838.07 [99.4] [IU/mL] in placebo-treated group, P = 0.15). Mean (SE) of TSH was not changed in both groups after trial, P = 0.4 and P = 0.15 for Vitamin D-treated and control groups, respectively. No significant difference was observed between two study groups in none studied variables (P > 0.05).

Conclusion:

Vitamin D treatment in Vitamin D deficient patients with Hashimoto's thyroiditis could not have significant effect on thyroid function and autoimmunity.

The Role of Vitamin D in Thyroid Diseases

The main role of vitamin D is regulating bone metabolism and calcium and phosphorus homeostasis. Over the past few decades, the importance of vitamin D in non-skeletal actions has been studied, including the role of vitamin D in autoimmune diseases, metabolic syndromes, cardiovascular disease, cancers, and all-cause mortality. Recent evidence has demonstrated an association between low vitamin D status and autoimmune thyroid diseases such as Hashimoto’s thyroiditis and Graves’ disease, and impaired vitamin D signaling has been reported in thyroid cancers. This review will focus on recent data on the possible role of vitamin D in thyroid diseases, including autoimmune thyroid diseases and thyroid cancers.

Effect of Vitamin D on Thyroid Autoimmunity: A Randomized, Double-Blind, Controlled Trial Among Ethnic Minorities

Context

Autoimmune thyroid disorders have been linked to vitamin D deficiency, but an effect of vitamin D supplementation is not established.

Objective

Our objective was to test whether vitamin D compared with placebo could reduce thyroid autoantibodies.

Design

Predefined additional analyses from a randomized, double-blind, placebo-controlled trial.

Setting

The study was conducted in different community centers in Oslo, Norway.

Participants

A total of 251 presumed healthy men and women, aged 18 to 50 years, with backgrounds from South Asia, the Middle East, and Africa were included.

Intervention

Daily supplementation with 25 µg (1000 IU) vitamin D₃, 10 µg (400 IU) vitamin D₃, or placebo for 16 weeks.

Outcome Measure

Difference in preintervention and postintervention antithyroid peroxidase antibody (TPOAb) levels. Additional outcomes were differences in thyroid-stimulating hormone (TSH) and free fraction of thyroxine (fT4).

Results

There were no differences in change after 16 weeks on TPOAb (27 kU/L; 95% CI, -17 to 72; P = 0.23), TSH (-0.10 mU/L; 95% CI, -0.54 to 0.34; P = 0.65), or fT4 (0.09 pmol/L; 95% CI, -0.37 to 0.55; P = 0.70) between those receiving vitamin D supplementation or placebo. Mean serum 25(OH)D₃ increased from 26 to 49 nmol/L in the combined supplementation group, but there was no change in the placebo group.

Conclusion

Vitamin D₃ supplementation, 25 µg or 10 µg, for 16 weeks compared with placebo did not affect TPOAb level in this randomized, double-blind study among participants with backgrounds from South Asia, the Middle East, and Africa who had low vitamin D levels at baseline.