Serum 25-hydoxyvitamin D concentrations in relation to Hashimoto’s thyroiditis: a systematic review, meta-analysis and meta-regression of observational studies

The immune system in Hashimoto's thyroiditis: Updating the current state of knowledge on potential therapies and animal model construction

Hashimoto's thyroiditis (HT) is one of the most prevalent endocrine disorders worldwide, and it can occur in people of all ages, including children. HT has a multifactorial pathogenesis and develops after a combination of gene regulation, environmental modifiers, and infection triggers. Various coamplifying feedback chronic inflammatory systems are involved in immune mechanisms, including oxidative stress, lymphocyte infiltration, and thyroid cell death. Furthermore, there is no effective treatment for HT at their roots. Thus, this review systematically summarizes and updates the existing etiology and pathogenesis, potential malignant transformation, emerging therapeutic drugs and animal model construction, making it more convenient for researchers to obtain effective information about HT and better explore potential strategies for short-term treatment of the disease.

The development of thyroid autoimmunity is potentially associated with the deficiency of vitamin D3 rather than vitamin D2 in euthyroid men

OBJECTIVE

Vitamin D(VitD) deficiency has been found prevalent among patients with thyroid autoimmunity (TAI). This study aimed to investigate whether low VitD2 or VitD3 potentially contributed to the development of TAI in euthyroid male patients, which had not been reported before.

METHODS

A total of 2882 euthyroid male petroleum workers were recruited from those participants in the healthcare program at the second affiliated hospital of Dalian Medical University in 2021, whose serum VitD levels, thyroid functions, and autoantibody titers were all examined at the same time. Among them, 2587 (89.8%) individuals received the second health follow-up in 2022. Serum VitD including 25(OH)D2 (VitD2) and 25(OH)D3 (VitD3) levels were detected by liquid chromatography-tandem mass spectrometry. Thyroid functions and autoantibody titers were quantified using chemiluminescent immunoassays.

RESULTS

The serum levels of VitD and VitD3 were pronouncedly lower in the male euthyroid subjects with TAI (n = 195) than those non-TAI men (n = 2687, P < 0.05), whereas serum VitD2 was not significantly different based on the data from the initial investigation in 2021. The prevalence of subjects with TAI among the total male euthyroid subjects with TAI population was markedly increased with the decreasing levels of serum VitD and VitD3, respectively (P for trend < 0.05), but not significantly changed with that of serum VitD2. The binary logistic regression analysis revealed that either the deficiency of VitD (serum VitD < 20 ng/mL, VDD) or low VitD3 level was an independent risk factor for the development of TAI, which had been further demonstrated by the follow-up observation in 2022. Among the non-TAI men in 2021, 6.52% (n = 157) individuals became TAI patients after a one-year follow-up, and their serum VitD and VitD3 levels both exhibited significantly more reduction as compared with those of the remained non-TAI ones in 2022. More of those with VDD developed TAI than the non-VDD ones did in 2022 (8.5% vs. 5.6%, P<0.05). Additionally, the change in serum VitD over the two years was more strongly correlated with serum VitD3 (rs = 0.971, P < 0.001) when compared with that of VitD2 (rs = 0.085, P < 0.001) in the whole euthyroid male population.

CONCLUSION

Based on the cross-sectional and prospective investigations, our findings further indicate that VDD may be an independent risk factor for TAI development. Moreover, the latter is potentially associated with the deficiency of VitD3 rather than VitD2 in the euthyroid male population although the related mechanisms await in-depth exploration. Our findings also suggest that VitD3 supplementation might provide more potential benefits than VitD2 among VDD men in terms of preventing TAI development.

STUDY REGISTRATION

the Dalian Health Management Cohort (DHMC) ChiCTR2300073363.

Supplementation with active vitamin D3 ameliorates experimental autoimmune thyroiditis in mice by modulating the differentiation and functionality of intrathyroidal T-cell subsets

Objective

People with Hashimoto's thyroiditis (HT) often have low vitamin D3 concentrations. Some research has suggested that vitamin D3 supplementation reduces thyroid inflammation, but this remains controversial.

Methods

EAT was induced in female NOD/ShiLtJ mice by giving them water containing 0.05% sodium iodide, and 1μg/kg of 1α,25-(OH)2D3 was injected intraperitoneally every other day. After 8 weeks, the morphological architecture of the mouse thyroid follicles was examined by histological sections, thyroid autoantibodies and thyroid hormone concentrations were determined by enzyme-linked immunosorbent assays (ELISAs), and the major functions and subsets of B- and T-lymphocytes in the mouse thyroid were determined by tissue multiple immunofluorescence technology and ELISA.

Results

EAT caused thyroiditis follicle destruction and interfollicular lymphocyte infiltration in mice, increased concentrations of circulating thyroid autoimmune antibodies TG-Ab and TPO-Ab, and abnormal thyroid hormone levels. EAT also increased the number and functionality of CD4+ Tfh, Th17,Th1 and Th2 cells in the thyroid, while decreasing the number and functionality of CD4+ Treg cells and CD19+B10 cells. Treatment with VD3 reversed these changes.

Conclusion

Vitamin D3 supplementation can effectively treat autoimmune thyroiditis in mice. VD3 reduces autoimmune thyroid damage and decreases serum thyroid antibody levels in mice by inhibiting the differentiation and functionality of pro-inflammatory Tfh, Th17, Th1 and Th2 cells and by facilitating the differentiation and functionality of anti-inflammatory B10 cells and Treg.

Mediating role of triglyceride-glucose index and its derivatives in the relationship between central obesity and Hashimoto thyroiditis in type 2 diabetes

BACKGROUND

Obesity and insulin resistance (IR) may be risk factors for thyroid disease, but there is no clinical-based consensus on this topic. Therefore, this study aims to evaluate the associations between the triglyceride-glucose index (TyG) and its derivatives and Hashimoto thyroiditis (HT) in type 2 diabetes mellitus (T2DM) patients, and explore the relationships between the central obesity indicators and HT risk to provide a reliable basis for the early prevention of HT.

METHODS

A total of 1071 T2DM patients aged ≥ 20 years were selected from a tertiary hospital in Tianjin, all of them had normal thyroid function (including free triiodothyronine, free thyroxine, total triiodothyronine, total thyroxine, and thyroid-stimulating hormone). HT was assessed via thyroid-associated antibodies and thyroid colour Doppler ultrasound. TyG and its derivatives were measured via IR. Restricted cubic spline (RCS) models, multivariable logistic regression, and receiver operating characteristic (ROC) curve analysis were used to explore the correlations and predict HT. Mediation analysis explored the mediating role of TyG and its derivatives in the associations between the central obesity indicators and HT.

RESULTS

RCS models revealed that increases in waist circumference (WC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR), TyG-WC, TyG-WHR, and TyG-WHtR were associated with increased HT risk. Logistic regression revealed that participants in the fourth quartile of TyG-WC, TyG-WHR, and TyG-WHtR had approximately 3.38 times greater HT risk (odds ratio range: 2.807 to 3.375). ROC analysis revealed that WC, WHtR, WHR, TyG-WC, TyG-WHtR and TyG-WHtR could distinguish the presence of HT. In females, the WHR had the highest predictive power, with an area under the ROC curve of 0.651 (95% confidence interval 0.611-0.691, P < 0.001). Mediation analysis revealed that high IR, as assessed by the TyG-body mass index (TyG-BMI), significantly mediated the effects of WC, WHtR, and WHR on the risk of HT. Among them, the TyG-BMI had the highest proportion of mediating effect of WC on HT risk, reaching 74.08%.

CONCLUSION

IR significantly mediates the increased risk of HT associated with central obesity. In clinical practice, WC, WHtR, WHR, TyG-WC, TyG-WHR, and TyG-WHtR serve as sensitive indicators for predicting HT risk in adult T2DM patients.

Active Vitamin D Ameliorates Arsenite-Induced Thyroid Dysfunction in Sprague-Dawley Rats by Inhibiting the Toll-like Receptor 4/NF-KappaB-Mediated Inflammatory Response

Arsenic, a well-known environmental endocrine disruptor, exerts interference on the body's endocrine system. Our previous investigations have demonstrated that chronic exposure to sodium arsenite (NaAsO2) can induce thyroid damage and dysfunction in Sprague-Dawley (SD) rats. Vitamin D (VD) is an indispensable fat-soluble vitamin that plays a crucial role in maintaining thyroid health. In recent years, numerous studies have demonstrated the association between VD deficiency and the development of various thyroid disorders. However, the precise intervention roles and mechanisms of VD in arsenic-induced thyroid injury remain elusive. This study aimed to investigate the intervention effect of VD on NaAsO2-induced thyroid dysfunction in SD rats. The results demonstrated that exposure to NaAsO2 activates the TLR4/NF-κB signaling pathway in thyroid tissue of rats, leading to apoptosis of thyroid cells and subsequent inflammatory damage and disruption of serum thyroid hormone secretion. Supplementation with TAK-242 (a TLR4 inhibitor) and VD effectively inhibits the activation of the TLR4/NF-κB signaling pathway in rat thyroid tissue exposed to NaAsO2, thereby reducing the inflammatory damage and dysfunction caused by arsenic exposure. In conclusion, the findings of this study offer innovative insights into the application of VD in the prevention and treatment of thyroid dysfunction caused by arsenic exposure.

Anti-inflammatory diets

ABSTRACT

This article reviews inflammatory versus anti-inflammatory foods, autoimmune and inflammatory disorders, the benefits of specific anti-inflammatory diets, and strategies for nurses to partner with individuals, while considering culture and food preferences, to promote healthy eating habits and prevent diseases.

Clinical comparative efficacy and therapeutic strategies for the Hashimoto's thyroiditis: A systematic review and network meta-analysis

Ethnopharmacological relevance

Vitamin D (VD), selenium preparations (Se), and thyroid hormone replacement therapy are commonly used to treat Hashimoto thyroiditis (HT). Increasing evidence suggests that traditional Chinese medicine (TCM) is an effective therapeutic strategy in the treatment of HT.

Aim of the study

This study aimed to investigate the efficacy and safety of commonly-used drugs for HT.

Materials and methods

A literature search was performed using PubMed, Web of Science, Cochrane Library, EMBASE, Chinese China National Knowledge Infrastructure (CNKI), Clinical Trial Registry (Chi CTR), China Science and Technology Journal Database (the VIP), Wanfang Database, and China Chinese Biomedical Database (CBM) from January 1, 2003, to December 31, 2022. The outcomes included TPOAb, TgAb, TSH, FT3, FT4, and adverse events. Our study was registered in PROSPERO (CRD42023449705).

Results

Sixty trials and 4719 participants were included, comparing 16 treatments: VD, Se, LT-4, Se + LT-4, HM, placebo + LT-4, HM + LT-4, Se + myolnositol, Se + VD, HM + Se, mannan peptide, LT-4+prednisone, Methimazole, Methimazole + HM, Tapazole + Propranolol, and placebo. We found that Chinese herbal medicine has significant effect vs. LT-4 [MD 0.10, 95 % confidence interval 0.02 to 0.50]) and LT-4+placebo [MD 0.10, 95 % confidence interval 0.01 to 0.77]) in reducing TPOAb. Although receiving LT-4+prednisone was not statistically significant, the treatment ranking showed that this combination therapy had the highest probability of reducing TPOAb levels (72.8 %). In addition, the effect of Se plus LT-4 was not statistically significant; however, the treatment ranking showed that this combination therapy had the highest probability (78.6 %) of reducing TgAb levels, followed by HM (64.0 %). Reports on side effects have mainly focused on the digestive and cardiovascular systems.

Conclusion

Our analyses showed that HM alone or in combination with other treatments for patients with HT can improve the side effects of other drugs, enhance efficacy, and maybe the most effective option for treating HT. However, there still need further verified using high-quality evidence.

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.

Vitamin D: An Essential Nutrient in the Dual Relationship between Autoimmune Thyroid Diseases and Celiac Disease-A Comprehensive Review

Autoimmune thyroid diseases (AITD) are among the most frequent autoimmune disorders, with a multifactorial etiology in which both genetic and environmental determinants are probably involved. Celiac disease (CeD) also represents a public concern, given its increasing prevalence due to the recent improvement of screening programs, leading to the detection of silent subtypes. The two conditions may be closely associated due to common risk factors, including genetic setting, changes in the composition and diversity of the gut microbiota, and deficiency of nutrients like vitamin D. This comprehensive review discussed the current evidence on the pivotal role of vitamin D in modulating both gut microbiota dysbiosis and immune system dysfunction, shedding light on the possible relevance of an adequate intake of this nutrient in the primary prevention of AITD and CeD. While future technology-based strategies for proper vitamin D supplementation could be attractive in the context of personalized medicine, several issues remain to be defined, including standardized assays for vitamin D determination, timely recommendations on vitamin D intake for immune system functioning, and longitudinal studies and randomized controlled trials to definitely establish a causal relationship between serum vitamin D levels and the onset of AITD and CeD.

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.

Effects of vitamin D supplementation on autoantibodies and thyroid function in patients with Hashimoto's thyroiditis: A systematic review and meta-analysis

BACKGROUND

Hashimoto's thyroiditis (HT) is the prevailing form of autoimmune thyroiditis and the leading cause of hypothyroidism in iodine-sufficient regions worldwide. This study aims to evaluate the efficacy of vitamin D supplementation on HT through a meta-analysis of randomized controlled trials (RCTs).

METHODS

The databases searched included PubMed, and others. We included RCTs that the treatment group received vitamin D, while the control group received either a placebo or no treatment. The studies measured the baseline and endpoint levels of 25-hydroxyvitamin D [25(OH)D], thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), anti-thyroid peroxidase antibody (TPO-Ab), and thyroglobulin antibody (TG-Ab). We performed a meta-analysis to calculate the standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

A total of 12 studies involving 862 individuals were included. Vitamin D supplementation has a significant impact on reducing the titers of TPO-Ab (SMD = -1.084, 95% CI = -1.624 to -0.545) and TG-Ab (SMD = -0.996, 95% CI = -1.579 to -0.413) in patients with HT, and it also improves thyroid function by decreasing TSH level (SMD = -0.167, 95% CI = -0.302 to 0.031) and increasing FT3 (SMD = 0.549, 95% CI = 0.077-1.020) and FT4 (SMD = 0.734, 95% CI = 0.184-1.285) levels. Active vitamin D (calcitriol) significantly reduces the titer of TPO-Ab compared to naive forms of vitamin D (vitamin D2 or D3); treatment durations > 12 weeks result in a more effective reduction of TPO-Ab levels and a more significant increase in FT4 and FT3 levels in patients with HT (meta-regression P < .05).

CONCLUSION

Vitamin D supplementation may have beneficial effects on HT patients by modulating immune responses and improving thyroid function.

Assessment of the Impact of Nutritional Intervention with the Probiotic Lactiplantibacillus plantarum 299v on Nutritional Status and Quality of Life of Hashimoto's Thyroiditis Patients-A Randomized Double-Blind Study Protocol

The current treatment for the autoimmune disease of hypothyroidism (AIDH) is based on pharmacotherapy with levothyroxine. A non-pharmacological supplementary element of therapy could be the implementation of an individualized balanced diet and probiotics. Lactiplantibacillus plantarum 299v (Lp299v), with its anti-inflammatory effects, may also support the therapy. However, the number of studies on personalized dietary interventions with probiotics in AIDH is limited, and no clear conclusions can be drawn from the results so far. Therefore, this trial will analyze the effect of Lp299v supplementation in conjunction with nutrition education on the quality of life and nutritional status of patients with Hashimoto's. Methods: This double-blind, 12-week intervention study will include 100 female patients with AIDH. They will be divided into two groups: (1) individual personalized nutrition education + Lp299v and (2) individual personalized nutrition education + placebo. Before and after the education intervention, selected elements in the diet, eating behavior, quality of life, nutritional status (anthropometric parameters, body composition), blood pressure, and anti-TPO (antibodies against thyroid peroxidase) titer will be assessed. Hypothesis: It is expected that this study will provide deeper knowledge on the validity of using proper nutritional principles and Lp299v in AIDH. Specifically, the impact on the subjective assessment of the quality of life, selected elements in the diet, and the state of nutrition and health will be assessed.

Systematic vitamin D supplementation is associated with improved outcomes and reduced thyroid adverse events in patients with cancer treated with immune checkpoint inhibitors: results from the prospective PROVIDENCE study

BACKGROUND

Hypovitaminosis D can have a negative prognostic impact in patients with cancer. Vitamin D has a demonstrated role in T-cell-mediated immune activation. We hypothesized that systematic vitamin D repletion could impact clinical outcomes in patients with cancer receiving immune-checkpoint inhibitors (ICIs).

METHODS

We planned a prospective observational study (PROVIDENCE) to assess serum vitamin D levels in patients with advanced cancer receiving ICIs (cohort 1 at treatment initiation, cohort 2 during treatment) and the impact of systematic repletion on survival and toxicity outcomes. In an exploratory analysis, we compared the clinical outcomes of cohort 1 with a control cohort of patients followed at the participating centers who did not receive systematic vitamin D repletion.

RESULTS

Overall, 164 patients were prospectively recruited in the PROVIDENCE study. In cohort 1, consisting of 101 patients with 94.1% hypovitaminosis (≤ 30 ng/ml) at baseline, adequate repletion with cholecalciferol was obtained in 70.1% at the three months re-assessment. Cohort 2 consisted of 63 patients assessed for vitamin D at a median time of 3.7 months since immunotherapy initiation, with no patients having adequate levels (> 30 ng/ml). Even in cohort 2, systematic supplementation led to adequate levels in 77.8% of patients at the three months re-assessment. Compared to a retrospective control group of 238 patients without systematic vitamin D repletion, PROVIDENCE cohort 1 showed longer overall survival (OS, p = 0.013), time to treatment failure (TTF, p = 0.017), and higher disease control rate (DCR, p = 0.016). The Inverse Probability of Treatment Weighing (IPTW) fitted multivariable Cox regression confirmed the significantly decreased risk of death (HR 0.55, 95%CI: 0.34-0.90) and treatment discontinuation (HR 0.61, 95%CI: 0.40-0.91) for patients from PROVIDENCE cohort 1 in comparison to the control cohort. In the context of longer treatment exposure, the cumulative incidence of any grade immune-related adverse events (irAEs) was higher in the PROVIDENCE cohort 1 compared to the control cohort. Nevertheless, patients from cohort 1 experienced a significantly decreased risk of all grade thyroid irAEs than the control cohort (OR 0.16, 95%CI: 0.03-0.85).

CONCLUSION

The PROVIDENCE study suggests the potential positive impact of early systematic vitamin D supplementation on outcomes of patients with advanced cancer receiving ICIs and support adequate repletion as a possible prophylaxis for thyroid irAEs.

Vitamin D: immune function, inflammation, infections and auto-immunity

Vitamin D plays an active role beyond mineral metabolism and skeletal health, including regulation of the immune system. Vitamin D deficiency is widely prevalent, and observational studies link low vitamin D status to a risk of infections and auto-immune disorders. Reports indicate an inverse relationship between vitamin D status and such conditions. This review details vitamin D signalling interactions with the immune system and provides experimental and clinical evidence evaluating vitamin D status, vitamin D supplementation and host susceptibility to infections, inflammation and auto-immunity. The published literature including related reviews, systematic reviews, meta-analyses, randomised controlled trials (RCTs), observational studies and basic science reports have been synthesised. Meta-analyses of observational studies have demonstrated a link between low vitamin D status and risk of acute respiratory infections, COVID-19 disorders, multiple sclerosis, type 1 diabetes (T1DM), inflammatory bowel disease (IBD), systemic lupus erythematosus and other auto-immune disorders. Observational studies suggest that vitamin D supplementation may protect against several infectious and auto-immune conditions. Meta-analyses of RCTs had mixed results, demonstrating a small protective role for vitamin D supplementation against acute respiratory infections, especially in those with vitamin D deficiency and children, and providing modest benefits for the management of T1DM and IBD. Vitamin D status is inversely associated with the incidence of several infectious and auto-immune conditions. Supplementation is recommended for those with vitamin D deficiency or at high risk of deficiency, and it might provide additional benefit in acute respiratory infections and certain auto-immune conditions.

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.

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.

The Influence of Nutritional Intervention in the Treatment of Hashimoto's Thyroiditis-A Systematic Review

Diet can be a complementary treatment for Hashimoto's disease by affecting thyroid function and anti-inflammatory properties. It is still unclear which dietary strategy would be the most beneficial. The aim of this systematic review is to examine all the data currently available in the literature on the effects of nutritional intervention on biochemical parameters (anti-thyroid antibody and thyroid hormones levels) and characteristic symptoms in the course of Hashimoto's thyroiditis. This systematic review was prepared based on PRISMA guidelines. Articles in PubMed and Scopus databases published up to November 2022 were searched. As a result of the selection, out of 1350 publications, 9 were included for further analysis. The nutritional interventions included the following: elimination of gluten (3 articles) or lactose (1 article), energy restriction with or without excluding selected foods (n = 2), consumption of Nigella sativa (n = 2), or dietary iodine restriction (n = 1). The intervention duration ranged from 21 days to 12 months and included individuals with various thyroid function. Of the nine studies, three studies were female only. An improvement was observed during an energy deficit and after the elimination of selected ingredients (e.g., gluten, lactose, or goitrogens), as well as after the intervention of Nigella sativa. These interventions improved antibody levels against peroxidase (anti-TPO), (thyrotropin) TSH, and free thyroxine (fT4). No improvement was seen on the iodine-restricted diet. Varied outcomes of analyzed dietary interventions may be due to the heterogeneous thyroid condition, high variability between patients, and differences in habitual intake of critical nutrients (e.g., iodine, selenium, and iron) in different populations. Therefore, there is a great need for further experimental studies to determine whether any nutritional interventions are beneficial in Hashimoto's disease.

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.

Vitamin D and Multiple Health Outcomes: An Umbrella Review of Observational Studies, Randomized Controlled Trials, and Mendelian Randomization Studies

Observational studies, randomized controlled trials (RCTs), and Mendelian randomization (MR) studies have yielded inconsistent results on the associations of vitamin D concentrations with multiple health outcomes. In the present umbrella review we aimed to evaluate the effects of low vitamin D concentrations and vitamin D supplementation on multiple health outcomes. We summarized current evidence obtained from meta-analyses of observational studies that examined associations between vitamin D concentrations and multiple health outcomes, meta-analyses of RCTs that investigated the effect of vitamin D supplementation on multiple health outcomes, and MR studies that explored the causal associations of vitamin D concentrations with various diseases (international prospective register of systematic reviews PROSPERO registration number CRD42018091434). A total of 296 meta-analyses of observational studies comprising 111 unique outcomes, 139 meta-analyses of RCTs comprising 46 unique outcomes, and 73 MR studies comprising 43 unique outcomes were included in the present umbrella review. Twenty-eight disease outcomes were identified by both meta-analyses of observational studies and MR studies. Seventeen of these reported disease outcomes had consistent results, demonstrating that lower concentrations of vitamin D were associated with a higher risk for all-cause mortality, Alzheimer's disease, hypertension, schizophrenia, and type 2 diabetes. The combinations of consistent evidence obtained by meta-analyses of observational studies and MR studies together with meta-analyses of RCTs showed that vitamin D supplementation was associated with a decreased risk for all-cause mortality but not associated with the risk for Alzheimer's disease, hypertension, schizophrenia, or type 2 diabetes. The results indicated that vitamin D supplementation is a promising strategy with long-term preventive effects on multiple chronic diseases and thus has the potential to decrease all-cause mortality. However, the current vitamin D supplementation strategy might not be an efficient intervention approach for these diseases, suggesting that new strategies are highly needed to improve the intervention outcomes.

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.

Vitamin D Implications and Effect of Supplementation in Endocrine Disorders: Autoimmune Thyroid Disorders (Hashimoto’s Disease and Grave’s Disease), Diabetes Mellitus and Obesity

Background and Objectives: Vitamin D deficiency is involved in numerous pathologies, including endocrine pathology. The purpose of this review consists of presenting the role of vitamin D in the pathophysiology of certain endocrine disorders, autoimmune thyroid disorders (Hashimoto’s disease and Grave’s disease), diabetes mellitus, and obesity, and whether its supplementation can influence the outcome of these diseases. Materials and Methods: Review articles and original articles from the literature were consulted that corresponded with the thematic. Results: Vitamin D deficiency is frequently encountered in endocrine disorders and supplementation restores the normal values. In Hashimoto’s disease, vitamin D deficiency appears to be correlated with a higher titer of anti-TPO antibodies and with thyroid volume, and supplementation was associated with reduction of antibodies in some studies. In other studies, supplementation appeared to reduce TSH levels. In Grave’s disease, there was a significant correlation regarding vitamin D levels and thyroid volume respective to the degree of exophthalmos. In diabetes mellitus type 2 patients, supplementation led to some improvement of the HOMA-IR index and HbA1c, whereas obesity data from literature do not report significant beneficial findings. Conclusions: Vitamin D deficiency is highly prevalent in endocrine disorders and its supplementation appears to have numerous beneficial effects.

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.

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 and Hashimoto's Thyroiditis: Observations from CROHT Biobank

The aims of this study were to evaluate: (1) associations of vitamin D with the presence/severity of Hashimoto’s thyroiditis (HT) and (2) correlations of vitamin D with thyroid-related phenotypes. Total 25(OH)D (vitamin D in the text) was measured from stored serum samples of 461 HT patients and 176 controls from a Croatian Biobank of HT patients (CROHT). (1) Vitamin D levels, and proportions of vitamin D deficiency, were compared between HT cases and controls. HT patients were additionally divided into two groups (MILD and OVERT) to take into account HT severity. (2) Correlations between vitamin D and 10 clinical phenotypes in all HT patients and two subgroups of HT patients were tested using the Spearman correlation test. Our analyses were adjusted for age, gender, BMI, smoking status and seasonality of blood sampling. (1) No significant differences in vitamin D levels, or proportions of vitamin D deficiency, were detected between HT patients of all disease stages and controls. However, a nominally significant difference in vitamin D levels between MILD and OVERT subgroups (OR = 1.038, p = 0.023) was observed. Proportions of individuals with vitamin D deficiency during winter–spring were high: all HT cases (64.69%), MILD (60.64%), OVERT (68.7%), controls (60.79%). (2) A nominally significant negative correlation between vitamin D and TSH in all HT patients (r = −0.113, p = 0.029) and a positive correlation between vitamin D and systolic blood pressure in OVERT HT patients (r = 0.205, p = 0.025) were identified. Our study indicates that there is no association between vitamin D and HT; however, there may be a subtle decrease in vitamin D levels associated with overt hypothyroidism.

Application of Dried Blood Spots and Serum Samples for the Determination of Vitamin D Metabolites in the Group of Healthy Women and with Hashimoto’s Thyroiditis

Purpose

The relationship between Hashimoto's thyroiditis and vitamin D concentration was already presented in many studies. The aim of this study was to analyze the differences in the concentration of vitamin D metabolites between healthy women and women with Hashimoto's thyroiditis (HT).

Methods

The quantitative analysis of five vitamin D metabolites was carried out using liquid chromatography coupled with tandem mass spectrometry. The analyzed materials were serum and dried blood spots (DBS). The results obtained for the two materials were also compared.

Results

No statistically significant differences were found in the mean concentration of the 25(OH)D3, 25(OH)D2, 24,25(OH)2D3, 1,25(OH)2D3 metabolites between the test and the control groups. However, a strong correlation was found between the 25(OH)D3 and 24,25(OH)2D3 metabolites.

Conclusion

The study showed that healthy women and women with Hashimoto's disease had similar concentration of vitamin D metabolites. Research also proved that DBS is a good alternative to serum. The differences in 25(OH)D concentration were not statistically significant (17.0 and 15.5 ng mL−1 for serum and DBS, respectively). DBS can be successfully used in research on a large group of people, since the process of material collection, as well as sample preparation, is fast and simple. It is also easy to transport and store, and requires small volume of blood.

"Vitamin D Deficiency Is More Common in Women with Autoimmune Thyroiditis: A Retrospective Study"

BACKGROUND

Vitamin D is a hormone that is mainly produced in the skin upon ultraviolet B radiation exposure and has important influence on various organs. In recent years, data have been collected that vitamin D deficiency plays an important role in the development of various nonskeletal diseases, including autoimmune diseases. Chronic autoimmune thyroiditis (Hashimoto's thyroiditis) is one of the most common organ-specific autoimmune endocrine diseases. It is characterized by increased level of antithyroid peroxidase and/or antithyroglobulin antibodies in blood, which often leads to thyroid dysfunction and structural changes of the gland. There is an opinion that vitamin D deficiency may be considered as an important risk factor for development of chronic autoimmune thyroiditis, but data of various small studies are controversial. Despite the fact that Georgia is a sunny country, vitamin D deficiency is a widespread problem here. Thyroid diseases, including the chronic autoimmune thyroiditis, are also very common in Georgia. The aim of our research was to compare the level of vitamin D between the patients with chronic autoimmune thyroiditis and the healthy subjects.

METHODS

This retrospective study enrolled subjects, who were 18-70 years old and visited the clinics "Cortex" and "National Institute of Endocrinology" in 2018 or in 2019 from mid-spring to mid-summer. Data of thyroid-stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, antithyroglobulin antibodies, thyroid ultrasonography, and 25(OH) vitamin D were retrospectively analysed based on medical history. In total, data of 1295 patients were collected. The statistical processing of data was performed through the SPSS 20 program.

RESULTS

The negative association between thyroid-stimulating hormone, antithyroid peroxidase antibodies, antithyroglobulin antibodies, heterogeneous parenchyma of thyroid gland, and vitamin D was found in women. Statistically significant association was not detected in men.

CONCLUSIONS

Serum vitamin D is lower in women with autoimmune thyroiditis and primary hypothyroidism. Further studies are needed to evaluate the influence of vitamin D supplementation on thyroid autoantibody positivity or primary hypothyroidism.

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.

The exploration of Hashimoto's Thyroiditis related miscarriage for better treatment modalities

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disease (ATD) worldwide and is strongly associated with miscarriage and even recurrent miscarriage (RM). Moreover, with a deepening understanding, emerging evidence has shown that immune dysfunctions caused by HT conditions, including imbalanced subsets of CD4+ T-helper cells, B regulatory (Breg) cells, high expression levels of CD56dim natural killer (NK) cells, and cytokines, possibly play an important role in impairing maternal tolerance to the fetus. In recent years, unprecedented progress has been made in recognizing the specific changes in immune cells and molecules in patients with HT, which will be helpful in exploring the mechanism of HT-related miscarriage. Based on these findings, research investigating some potentially more effective treatments, such as selenium (Se), vitamin D3, and intravenous immunoglobulin (IVIG), has been well developed over the past few years. In this review, we highlight some of the latest advances in the possible immunological pathogenesis of HT-related miscarriage and focus on the efficacies of treatments that have been widely introduced to clinical trials or practice described in the most recent literature.

Vitamin D and autoimmune disease

Vitamin D as a part of the endocrine system is an important component in the interaction between the kidney, bone, parathyroid hormone, and the intestine, which maintains extracellular calcium level within normal limits, in order to keep the vital physiologic process and skeletal integrity. Vitamin D is also associated with hypertension, muscular function, immunity, and ability to encounter infection, autoimmune disease, and cancer. The role of vitamin D in immunity is a feedback reaction of paracrine to eliminate inflammation or to influence CD4 T-cell differentiation and or to increase the function of T suppressor cell or combination between both. The active form of vitamin D produces and maintains self immunologic tolerance, some studies show that 1,25(OH)2D inhibits induction of disease in autoimmune encephalomyelitis, thyroiditis, type-1 diabetes mellitus, inflammatory bowel disease (IBD), systemic lupus erythematosus, and collagen-induced arthritis and Lyme arthritis.