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

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.

How Does Vitamin D Affect Immune Cells Crosstalk in Autoimmune Diseases?

Vitamin D is a secosteroid hormone that is highly involved in bone health. Mounting evidence revealed that, in addition to the regulation of mineral metabolism, vitamin D is implicated in cell proliferation and differentiation, vascular and muscular functions, and metabolic health. Since the discovery of vitamin D receptors in T cells, local production of active vitamin D was demonstrated in most immune cells, addressing the interest in the clinical implications of vitamin D status in immune surveillance against infections and autoimmune/inflammatory diseases. T cells, together with B cells, are seen as the main immune cells involved in autoimmune diseases; however, growing interest is currently focused on immune cells of the innate compartment, such as monocytes, macrophages, dendritic cells, and natural killer cells in the initiation phases of autoimmunity. Here we reviewed recent advances in the onset and regulation of Graves' and Hashimoto's thyroiditis, vitiligo, and multiple sclerosis in relation to the role of innate immune cells and their crosstalk with vitamin D and acquired immune cells.

VITAMIN D LEVEL AND ITS RELATIONSHIP WITH CANCER STAGE IN PATIENTS WITH DIFFERENTIATED THYROID CARCINOMA

BACKGROUND

Differentiated thyroid carcinoma (DTC) has witnessed an increase in incidence and although it is considered to have a slow grow potential and a 90% 10-year survival rate, local or distant metastases can be observed in 20%. It is essential to recognize other factors associated with malignancy and poor prognosis. Vitamin D and its deficiency has proven useful as a prognostic biomarker for many types of cancer, including thyroid cancer.

AIM

Evaluate the relationship between vitamin D status in DTC and benign thyroid disorders patients and correlation between vitamin D and histopathological findings in DTC group.

METHODS

Study included 170 patients with confirmed DTC and 200 with benign thyroid pathology. Evaluation included 25-hydroxy vitamin D [25(OH)D], ultrasound and histopathologic features.

RESULTS

In DTC patients, mean value of vitamin D was significantly lower (17.86 ng/mL ± 9.31 DS versus 20.26 ng/mL ± 9.31 DS, p=0.029). Statistical analysis confirmed a negative correlation between vitamin D levels and tumor size (T) according to TNM classification (r=-0.176, p=0.02).

CONCLUSIONS

Vitamin D level was significantly lower in the DTC group and 25(OH)D levels may be correlated with histopathology features like tumor size and aggressiveness according to TNM classification.

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.

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.

Migration health research in Norway: a scoping review

Aims: To provide an overview of published research on migration and health conducted in Norway and identify gaps in the research field. Methods: Applying a scoping review methodology, we searched Medline for articles on migration health in Norway published between 2008 and 2020, and assessed them according to research topic, methodology, user-involvement and characteristics of the populations studied (country or area of origin, type of migrant/immigrant status). Results: Of the 707 articles retrieved, 303 met the inclusion criteria. Most studies (77%) were within the clinical disciplines reproductive health, mental health, infectious diseases and cardiovascular diseases, or on socio-cultural aspects and the use of healthcare services. One third of the papers (36%) pulled participants from various geographic backgrounds together or did not specify the geographic background. Among those who did so, participants were mostly from The Middle East, South and Southeast Asia and sub-Saharan Africa. Only 14% of the articles specified the type of migrant/immigrant status and those included refugees, asylum seekers and undocumented migrants. A total of 80% of the papers used quantitative methods, of which 15 described an intervention; 15 papers (5%) described different types of user-involvement. Conclusions: Our findings suggest gaps in research related to migrant subgroups, such as those from Eastern-Europe and labour and family reunification migrants. Future studies should further investigate the self-identified health needs of different migrant groups, and might also benefit from a methodological shift towards more intervention studies and participatory approaches.

"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.

Effect of Vitamin D Supplementation on Thyroid Autoimmunity among Subjects of Autoimmune Thyroid Disease in a Coastal Province of India: A Randomized Open-label Trial

OBJECTIVE

Hashimoto's thyroiditis (HT) is a variant of autoimmune thyroid disorders (AITD) which has been associated with vitamin D (vit-D) deficiency. However, whether vit-D supplementation is linked to reduction of thyroid autoantibodies and improvement of thyroid function is not well characterized. The present study was planned to evaluate the effect of vit-D supplementation on possible improvement of thyroid autoantibody titer and thyroid hormone profile in patients with AITD subjects.

METHODS

Twenty-three patients of HT were given weekly supplementation of 60,000 IU vit-D for 8 weeks followed by once a month for another 4 months. After 6 months of vit-D supplementation, thyroid autoantibody titer (TPO antibody) and thyroid hormone profile was rechecked.

RESULTS

Mean serum vit-D was increased significantly from 15.33 ± 5.71 to 41.22 ± 12.24 ng/mL (normal levels) after supplementation. There was significant increase in thyroid autoantibody titre (from 746.8 ± 332.2 to 954.1 ±4 59.8 IU/ml; P = 0.006) and TSH level (7.23 ± 3.16 to 3.04 ± 2.62 (mIU/L); P = 0.01) following 6 months of vit-D supplementation.

CONCLUSION

Vitamin-D levels were low in AITD patients in eastern India and, its supplementation in HT patients increased thyroid antibody titer and there was significant reduction in serum TSH and increased in free T4.

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.

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.

Hepatitis B virus downregulates vitamin D receptor levels in hepatoma cell lines, thereby preventing vitamin D-dependent inhibition of viral transcription and production

Background

Vitamin D is a key immune-modulator that plays a role in the innate and adaptive immune systems. Certain pathogens impair the immune defense by downregulating the vitamin D receptor (VDR) pathway. Low serum levels of vitamin D are associated with increased hepatitis B virus (HBV) replication. Our study aimed to assess the in-vitro relationship between HBV production and Vitamin D signaling pathway and to explore the associated mechanism(s).

Methods

HBV transcription and replication was evaluated by qRT-PCR of the HBV-RNA and covalently closed circular DNA (cccDNA). Furthermore, we have transfected the 1.3 X HBV-Luc plasmid to the cells and measured the Luciferase activity using Luminometer. Vitamin D signaling pathway activation was evaluated by measuring the expression levels of VDR, CYP24A1, Tumor necrosis factor α (TNFα) and cathelicidin (CAMP) by qRT-PCR. All assays were performed on HepG2.2.15, HepG2, and HepAD38 cells treated with or without Vitamin D active metabolite: calcitriol.

Results

Calcitriol did not suppress HBV transcription, cccDNA expression or HBV RNA levels in HepG2.2.15 cells. However, VDR transcript levels in HepG2.215 cells were significantly lower compared to HepG2 cells. Similar results were obtained in HepAD38 cell where VDR expression was down-regulated when HBV transcript level was up-regulated. In addition, calcitriol induced VDR-associated signaling, resulting in upregulation of CYP24A1, TNFα and CAMP expression level in HepG2 cells but not in the HepG2.2.15 cells.

Conclusions

These findings indicate that VDR expression is downregulated in HBV-transfected cells, thereby preventing vitamin D from inhibiting transcription and translation of HBV in vitro. HBV might use this mechanism to avoid the immunological defense system by affecting both TNFα and CAMP signaling pathways.

Electronic supplementary material

The online version of this article (10.1186/s10020-018-0055-0) contains supplementary material, which is available to authorized users.