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

Vitamin D and thyroid function: A mendelian randomization study

BACKGROUND

Numerous organs, including the thyroid gland, depend on vitamin D to function normally. Insufficient levels of serum 25-hydroxyvitamin D [25(OH)D] are seen as a potential factor contributing to the emergence of several thyroid disorders, however, the causal relationship remains unclear. Here we use a Mendelian randomization (MR) approach to investigate the causal effect of serum 25(OH)D concentration on the indicators of thyroid function.

METHODS

We conducted a two-sample MR analysis utilizing summary data from the most extensive genome-wide association studies (GWAS) of serum 25(OH)D concentration (n = 443,734 and 417,580), thyroid-stimulating hormone (TSH, n = 271,040), free thyroxine (fT4, n = 119,120), free triiodothyronine (fT3, n = 59,061), total triiodothyronine (TT3, n = 15,829), as well as thyroid peroxidase antibody levels and positivity (TPOAb, n = 12,353 and n = 18,297), low TSH (n = 153,241), high TSH (n = 141,549), autoimmune hypothyroidism (n = 287,247) and autoimmune hyperthyroidism (n = 257,552). The primary analysis was conducted using the multiplicative random-effects inverse variance weighted (IVW) method. The weighted mode, weighted median, MR-Egger, MR-PRESSO, and Causal Analysis Using Summary Effect estimates (CAUSE) were used in the sensitivity analysis.

RESULTS

The IVW, as well as MR Egger and CAUSE analysis, showed a suggestive causal effect of 25(OH)D concentration on high TSH. Each 1 SD increase in serum 25(OH)D concentration was associated with a 12% decrease in the risk of high TSH (p = 0.02). Additionally, in the MR Egger and CAUSE analysis, we found a suggestive causal effect of 25(OH)D concentration on autoimmune hypothyroidism. Specifically, each 1 SD increase in serum 25(OH)D concentration was associated with a 16.34% decrease in the risk of autoimmune hypothyroidism (p = 0.02).

CONCLUSIONS

Our results support a suggestive causal effect which was negative in direction across all methods used, meaning that higher genetically predicted vitamin D concentration possibly lowers the odds of having high TSH or autoimmune hypothyroidism. Other thyroid parameters were not causally influenced by vitamin D serum concentration.

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The association of gluten-free diet with thyroid autoimmunity in patients with celiac disease: a meta-analysis

Background: Thyroid autoimmunity is an immune response to thyroid antigens that causes varying degrees of thyroid dysfunction. The sole effective treatment for Celiac Disease (CD) is a gluten-free diet (GFD). However, the association between GFD and thyroid autoimmunity in patients with CD has not been confirmed. Methods: A comprehensive search of several databases, involving PubMed, Embase, Web of Science, Medline, and Cochrane databases, was conducted to identify studies that primarily addressed the effects of GFD on thyroid autoimmunity in CD subjects. The meta-analysis involved studies that compared the risk of ATPO and ATG antibody positivity in CD patients with GFD, the risk of developing AITD, and the risk of developing thyroid dysfunction. Fixed-effects models or random-effects models were used to calculate the odds ratios (ORs) and their 95% confidence intervals (95% CIs). Results: A total of 10 observational studies met the inclusion criteria and included 6423 subjects. The results indicated that GFD is positively associated with thyroid autoimmunity in the children subgroup of CD patients (OR = 1.61, 95%CI 1.06-2.43, P = 0.02). However, there was no significant difference in thyroid autoimmunity between the group adhering to GFD and the control group in the total CD population. Conclusion: The results seem to indicate that subjects with a more pronounced autoimmunity (such as to have an early onset of CD) appear to have a greater risk of thyroid autoimmunity.

Regulation of Dendritic Cell Functions by Vitamins as Promising Therapeutic Strategy for Immune System Disorders

A functional immune system is crucial for a healthy life, protecting from infections, tumors, or autoimmune disorders; these are accomplished by the interaction between various immune cells. Nourishment, particularly micronutrients, are very important components in the immune system balance, therefore this review emphasizes the vitamins (D, E, A, C) and Dendritic cells' subsets due to vitamins' roles in immune processes, especially on dendritic cells' functions, maturation, and cytokine production. Current studies reveal significant benefits related to vitamins, including vitamin E, which can contribute to the control of dendritic cells' function and maturation. Furthermore, vitamin D plays an immunoregulatory and anti-inflammatory role in the immune system. Metabolite of vitamin A which is called retinoic acid leads to T cells' differentiation to T helper 1 or T helper 17, so low levels of this vitamin exacerbate the menace of infectious diseases, and vitamin C has anti-oxidant effects on dendritic cells and modulate their activation and differentiation program. Additionally, the correlation between the amount of vitamin and the occurrence or progression of allergic diseases and autoimmunity disorders is discussed according to the results of previous studies.

Vitamin D Deficiency Is Associated with Impaired Sensitivity to Thyroid Hormones in Euthyroid Adults

The relationship between vitamin D deficiency and sensitivity to thyroid hormones was unclear. We aimed to explore the association of 25-hydroxyvitamin D (25(OH)D) levels with thyroid hormone sensitivity in euthyroid adults. A total of 3143 subjects were included. The serum 25(OH)D, free thyroxine (FT3), free thyrotropin (FT4), thyroid-stimulating hormone (TSH), and other clinical variables were measured. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. Thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI), thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI), and FT3/FT4 were calculated to assess thyroid hormone sensitivity. Results showed that 58.8% of the participants had vitamin D deficiency. They had significantly higher levels of triglyceride, insulin, FT3, FT4, TSH, TFQI, PTFQI, TSHI, and TT4RI and lower levels of high-density lipoprotein cholesterol than those with sufficient vitamin D (all p < 0.05). Logistic regression analysis showed that the risk of impaired sensitivity to thyroid hormones evaluated by TFIQ, PTFQI, TSHI, and TT4RI increased by 68% (OR: 1.68; 95%CI: 1.45-1.95; and p < 0.001), 70% (OR: 1.70; 95%CI: 1.46-1.97; and p < 0.001), 66% (OR: 1.66; 95%CI: 1.43-1.92; and p < 0.001), and 50% (OR: 1.50; 95%CI: 1.30-1.74; and p < 0.001), respectively, in participants with vitamin D deficiency compared with those with sufficient vitamin D after adjusting for multiple confounders. In conclusion, in euthyroid populations, vitamin D deficiency was associated with impaired sensitivity to thyroid hormones.

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.

Exposure to a Vitamin D Best Practices Toolkit, Model, and E-Tools Increases Knowledge, Confidence, and the Translation of Research to Public Health and Practice

Preventable vitamin D deficiency (VDD) is a global health concern. The prevention, early detection, and treatment of vitamin D deficiency aligning with serum 25-hydroxyvitamin D concentration recommendations of 40-60 ng/mL (100-150 nmol/L), provided by an international panel of 48 vitamin D researchers, would result in significant health benefits and cost savings to individuals and society. However, research shows that healthcare professionals lack knowledge and confidence in best practices with respect to vitamin D. A vitamin D toolkit was developed that included a model for decision-making support, e-tools, and accompanying resources and was implemented using an online, asynchronous learning management system. This pre-test, post-test, and follow-up survey study design aimed to increase nurses' and dietitians' levels of knowledge and confidence regarding vitamin D, aid in their translation of evidence into spheres of practice and influence, and help them identify translation barriers. The completion of the toolkit increased the participants' (n = 119) knowledge from 31% to 65% (p < 0.001) and their confidence from 2.0 to 3.3 (p < 0.001) on a scale of 1-5. Respondents reported using the model (100%) as a framework to successfully guide the translation of vitamin D knowledge into their sphere of influence or practice (94%) and identifying translation barriers. The toolkit should be included in interdisciplinary continuing education, research/quality improvement initiatives, healthcare policy, and institutions of higher learning to increase the movement of research into practice.

The Effect of Vitamin D Adequacy on Thyroid Hormones and Inflammatory Markers after Bariatric Surgery

Vitamin D status affects the clinical and corporal outcomes of postoperative patients who undergo a Roux-en-Y gastric bypass (RYGB). The aim of this study was to evaluate the effect of adequate vitamin D serum concentrations on thyroid hormones, body weight, blood cell count, and inflammation after an RYGB. A prospective observational study was conducted with eighty-eight patients from whom we collected blood samples before and 6 months after surgery to evaluate their levels of 25-hydroxyvitamin D 25(OH)D, thyroid hormones, and their blood cell count. Their body weight, body mass index (BMI), total weight loss, and excess weight loss were also evaluated 6 and 12 months after surgery. After 6 months, 58% of the patients achieved an adequate vitamin D nutritional status. Patients in the adequate group showed a decrease in the concentration of thyroid-stimulating hormone (TSH) (3.01 vs. 2.22 µUI/mL, p = 0.017) with lower concentrations than the inadequate group at 6 months (2.22 vs. 2.84 µUI/mL, p = 0.020). Six months after surgery, the group with vitamin D adequacy showed a significantly lower BMI compared with the inadequate group at 12 months (31.51 vs. 35.04 kg/m², p = 0.018). An adequate vitamin D nutritional status seems to favor a significant improvement in one's thyroid hormone levels, immune inflammatory profile, and weight loss performance after an RYGB.

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 categories and postpartum thyroid function in women with hypothyroidism

Objective

To analyze the related factors of the postpartum thyroid function in women with overt hypothyroidism (OH)/subclinical hypothyroidism (SCH) and explore the effects of vitamin D categories.

Methods

Thyroid hormones, thyroid autoantibody, and serum 25OHD levels were continuously recorded from the first trimester of pregnancy (T1) to the 12th postpartum month. Logistic regression analysis and Cox regression analysis were used to screen the related factors of postpartum thyroid function, and the Latent Class Growth Model was performed to analyze the trajectory characteristics of serum 25OHD levels.

Results

Totally, 252 pregnant women with OH/SCH were enrolled in the study. In the 12th month postpartum, 36.5% of the patients improved thyroid function, 37.3% continued hypothyroidism, and 26.2% developed thyroid dysfunction. Vitamin D sufficiency, positive TPOAb, and positive TgAb in T1 were independent prognostic factors of postpartum thyroid function. Vitamin D sufficiency in T1 was illustrated as an independent factor of the improved postpartum thyroid function, but the protective effect for the developed postpartum thyroid dysfunction was only confirmed in TPOAb-positive patients. Cox regression analysis further confirmed the effects of vitamin D categories. Notably, the high-level 25OHD trajectory during pregnancy and postpartum could predict improved postpartum thyroid function and decrease the risk of developed postpartum thyroid dysfunction.

Conclusion

Appropriate vitamin D nutrition during pregnancy and postpartum may be beneficial to postpartum thyroid function.

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.

Association between vitamin D deficiency and hypothyroidism: results from the National Health and Nutrition Examination Survey (NHANES) 2007-2012

PURPOSE

Many smaller studies have previously shown a significant association between thyroid autoantibody induced hypothyroidism and lower serum vitamin D levels. However, these finding have not been confirmed by large-scale studies. In this study, we evaluated the relationship between hypothyroidism and vitamin D levels using a large population-based data.

METHODS

For this study, we used National Health and Nutrition Examination Survey (NHANES) during the years 2007-2012. We categorized participants into three clinically relevant categories based on vitamin D levels: optimal, intermediate and deficient. Participants were also split into hypothyroid and hyperthyroid. Weighted multivariable logistic regression analyses were used to calculate the odds of being hypothyroid based on vitamin D status.

RESULTS

A total of 7943 participants were included in this study, of which 614 (7.7%) were having hypothyroidism. Nearly 25.6% of hypothyroid patients had vitamin D deficiency, compared to 20.6% among normal controls. Adjusted logistic regression analyses showed that the odds of developing hypothyroidism were significantly higher among patients with intermediate (adjusted odds ratio [aOR], 1.7, 95% CI: 1.5-1.8) and deficient levels of vitamin D (aOR, 1.6, 95% CI: 1.4-1.9).

CONCLUSION

Low vitamin D levels are associated with autoimmune hypothyroidism. Healthcare initiatives such as mass vitamin D deficiency screening among at-risk population could significantly decrease the risk for hypothyroidism in the long-term.

Vitamin D and thyroid disorders: a systematic review and Meta-analysis of observational studies

BACKGROUND

The contribution of vitamin D to thyroid disorders has received paramount attention; however, results are mixed. Hence, we designed a systematic review and meta-analysis to obtain a definitive conclusion.

METHODS

The search included PubMed, ISI Web of Science, Scopus, and Google Scholar databases up to March 2021 to collect available papers reporting the relationship between serum levels of vitamin D and thyroid disorders. The pooled effect was reported as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

Out of 6123 datasets, 42 were eligible to get into this systematic review and meta-analysis. Serum vitamin D was markedly lower in autoimmune thyroid diseases (AITD) (WMD - 3.1 ng/dl; 95% CI, - 5.57 to - 0.66; P = 0.013; I² = 99.9%), Hashimoto's thyroiditis (HT) (WMD - 6.05 ng/dl; 95% CI, - 8.35 to - 3.75; P < 0.001; I² = 91.0%) and hypothyroidism patients (WMD - 13.43 ng/dl; 95% CI, - 26.04 to - 0.81; P = 0.03; I² = 99.5%), but not in subjects with Graves' disease (GD) (WMD - 4.14 ng/dl; 95% CI, - 8.46 to 0.17; P = 0.06; I² = 97.5%).

CONCLUSIONS

Our findings suggested lower vitamin D levels in patients with hypothyroidism, AITD, and HT compared to healthy subjects. However, the link between serum vitamin D and GD was only significant among subjects ≥40 years old.

The role of T2E mediated CBF-1/RBP-Jκ signaling in metastatic thyroid cancer

OBJECTIVE

Cancer has been shown to be an independent risk factor for 2019-nCoV. Expression of transmembrane serine protease 2 (TMPRSS2) is abnormal in many cancers. Nevertheless, system analysis of TMPRSS2-ERG (T2E) abnormalities in metastatic thyroid cancer remains to be elucidated.

METHOD

Using genomic and chromatin data, we demonstrate a unique cis-regulatory landscape between non-T2E and T2E-positive metastatic thyroid cancers, including clusters of regulatory elements (COREs). We attempt to describe the effect of T2E silencing on the cis-regulatory structure in metastatic thyroid cancers and its phase with the obvious phenotype characteristics of T2E-positive metastatic thyroid cancers.

RESULTS

These differences were linked by the ERG (erythroblast transformation-specific related gene) co-opts of FoxA1 and HOXB13, which realized T2E specific transcription profile. The study also demonstrated the T2E-specific CORE in an ERG site of structural rearrangement, which is due to the expansion of the T2E locus and contributes to its up-expression. Ultimately, we demonstrate that T2E-specific transcription profile is the basis of vulnerability of CBF-1/RBP-Jκ pathway. In fact, CBF-1/RBP-Jκ pathway inhibits the invasion and growth of T2E-positive thyroid tumors.

CONCLUSION

This study indicates that the overexpression of ERG co-option has a unique cis-regulatory structure in T2E positive thyroid tumors, which induces drug dependence on CBF-1/RBP-Jκ signal. Our study solved the genetic and epigenetic variation of T2E in metastatic thyroid cancer for the first time. It is worth noting that further functional and clinical validation is needed as our study is a bioinformatics analysis.

A Clinical Trial for the Identification of Metabolic Biomarkers in Hashimoto's Thyroiditis and in Psoriasis: Study Protocol

Hashimoto's thyroiditis and psoriasis are inflammatory disorders that significantly impact patients' quality of life, stressing the need for novel biomarkers of early diagnosis. This randomized clinical trial (NCT04693936) aims to identify Hashimoto's thyroiditis' and psoriasis' metabolic biomarkers and to investigate the effect of environmental factors on the disease-related metabolic imprint and quality of life. Patients with Hashimoto's thyroiditis, patients with psoriasis, and healthy individuals aged 18-60 will be recruited, enrolled according to eligibility criteria (medical history, clinical thyroid markers and the PASI score) and randomized to two groups. The intervention group will receive a combination of nutraceuticals for 6 months as part of a Mediterranean diet, and the control group will follow their usual diet. Data will be collected at baseline and the end of the study, including metabolite levels, lifestyle and anthropometric measurements, adherence to the Mediterranean diet (through the Mediterranean Diet Score) and disease-specific quality of life (through the Thyroid Patient Report Outcome for Hashimoto's group, and the Dermatology Life Quality Index for the psoriasis group). This study will investigate metabolic biomarkers and related changes in Hashimoto's thyroiditis and psoriasis and evaluate the association of metabolic changes with dietary factors and quality of life.

Oxidative stress as a key feature of autoimmune thyroiditis: an update

INTRODUCTION

Oxidative stress has been proposed as one of the factors concurring in the pathophysiology of autoimmune thyroid diseases. Reactive oxygen species are the main expression of oxidative stress in biological systems, and their production can overcome antioxidant defenses ultimately leading to cell damage, apoptosis, and death. The present review was aimed at describing the state of the art of the relationships between oxidative stress and autoimmune thyroiditis. The most used biomarkers of oxidative stress and their correlation with thyroid function are reported.

EVIDENCE ACQUISITION

We conducted a search of the literature in the English language starting from 2000, using the following search terms: "Hashimoto thyroiditis," "autoimmune thyroiditis," "hypothyroidism," "hyperthyroidism," "oxidative stress," "oxidants," "antioxidant," "advanced glycation end products." Both clinical studies and animal models were evaluated.

EVIDENCE SYNTHESIS

Data form clinical studies clearly indicate that the balance between oxidants and antioxidants is shifted towards the oxidative side in patients with autoimmune thyroiditis, suggesting that oxidative stress may be a key event in the pathophysiology of the disease, irrespective of thyroid function. Studies in animal models, such as the NOD.H2h4 mouse, confirm that thyroidal accumulation of ROS plays a role in the initiation and progression of autoimmune thyroiditis.

CONCLUSIONS

Oxidant/antioxidant imbalance represent a key feature of thyroid autoimmunity. Oxidative stress parameters could be used as biochemical markers of chronic inflammation, to better predict the disease evolution along its natural history. Dietary habits and antioxidant supplements may provide protection from autoimmunity, opening new perspectives in the development of more tailored therapies.

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.

<p>Associations Between Serum 25-Hydroxyvitamin D Levels and Thyroid Function Parameters in Previously Healthy Children Aged 6 to 24 Months</p>

Purpose

Vitamin D deficiency has been linked to overt thyroid diseases. Data on the effects of vitamin D status on thyroid function in children are less examined. The goal of the present study was to explore the association between serum 25-hydroxyvitamin D [25(OH)D] levels and thyroid function parameters in early childhood.

Patients and Methods

This was a cross-sectional study involving record-linkage of children’s data of routine health check-ups for promoting early childhood development at Guangdong Women and Children’s Hospital; 2869 children aged 6–24 months were included from January 2015 to May 2017. Serum 25(OH)D, thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels were measured using the electrochemiluminescence immunoassay.

Results

The study population had a mean serum 25(OH)D level of 79.7 ± 28.1 nmol/L and 12.5% vitamin D deficiency and 36.0% insufficiency rates. The rates of thyroid dysfunctions detected were 2.9% hypothyroidism, 4.2% subclinical hypothyroidism, 0.9% hyperthyroidism, and 1.7% subclinical hyperthyroidism among the previously healthy children aged 6 to 24 months. Serum 25(OH)D levels had no significant correlation with TSH (r = 0.022, P = 0.236), FT3 (r = 0.014, P = 0.440) and FT4 (r = −0.059, P = 0.056) levels. No significant difference in the levels of thyroid hormones was found between the different quartiles of 25(OH)D level. Vitamin D deficiency [25(OH)D < 50 nmol/L] was associated with hypothyroidism (adjusted odds ratio = 2.16, 95% confidence interval: 1.18–3.94) but not with subclinical hypothyroidism, hyperthyroidism, and subclinical hyperthyroidism.

Conclusion

Vitamin D deficiency is slightly associated with hypothyroidism. No associations were found between serum 25(OH)D levels and thyroid-related measures (TSH, FT3, and FT4) in previously healthy children aged 6–24 months.

The Effect of Vitamin D Replacement on Patient with Subclinical Hypothyroidism: A Pilot Randomized Clinical Trial

Background:

Subclinical hypothyroidism (SCH) is characterized by an elevated Thyroid Stimulating Hormone (TSH) with a normal T4. The prevalence of Vitamin D deficiency in patients SCH is high. Some studies suggested that Vitamin D supplements could be reduced serum concentration of TSH so improve SCH and prevent overt hypothyroidism. This study aims to explore the effect of vitamin D replacement on subclinical hypothyroidism.

Materials and Methods:

Fifty-nine patients, diagnosed with both subclinical hypothyroidism and Vitamin D deficiency by the Endocrinology outpatient clinics between January 2018 and March 2019, were included in this trial. The patients with overt hypothyroidism, cardiovascular risk factors, or positive TPO antibody, abnormal T4, and pregnant women were excluded from this study. The 40 subjects were investigated who received vitamin D supplements for two months. Analyses were conducted through paired-samples t-test and independent-samples t-test using SPSS 24 (Armonk, NY: IBM Corp).

Results:

The mean serum levels of TSH was decreased from 6.89 mIU/l in the pre-test to 3.34 mIU/l in the post-test, and the difference was found to be statistically significant at P<0.001.

Conclusion:

We found that the TSH mean level significantly dropped through the use of vitamin D supplements. Thus, it is recommended that all the patients with subclinical hypothyroidism be screened and treated with vitamin D supplements.

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.

Vitamin D deficiency and thyroid autoantibody fluctuations in patients with Graves' disease - A mere coincidence or a real relationship?

PURPOSE

The aim of this study was to evaluate the association between vitamin D (vitD) and changes in the titers of anti-TSH receptor (TSHR-Abs), antithyroglobulin (Tg-Abs), and antiperoxidase (TPO-Abs) autoantibodies.

MATERIALS/METHODS

The study involved 269 patients with Graves' disease (GD), divided into four subgroups (1-4), i.e. 65 smokers treated with vitD(+) (1), 76 smokers not treated with vitD(-) (2), 61 non-smokers treated with vitD(+) (3) and 67 non-smokers with vitD(-) (4). All thyroid parameters were analyzed at entry and 1, 3, 6, 9 and 12 months later.

RESULTS

The titer of TSHR-Abs in group 3 was significantly lower than in groups 1 and 2 across all time points. At 3, 6 and 12 months, the titers of TSHR-Abs were also lower in group 4 compared to groups 1 and 2. At 9 months, the titers in group 3 were lower than in all other groups. There was a significant inverse correlation between baseline levels of vitD and baseline titers of Tg-Abs (in group 1 only), Tg-Abs after 12 months (in group 1 only), TPO-Abs after 12 months (in groups 1 and 3), fT4 (in group 4 only), and a significant positive correlation with TPO-Abs (in group 2 only). VitD levels at 12 months were inversely correlated with Tg-Abs in group 1.

CONCLUSIONS

VitD measurements in patients with GD, especially smokers with an increased TSHR-Ab titers before 131I therapy, are recommended. Immunological remission is more likely in patients with GD who receive vitD, particularly smokers.

Retrospective Analysis of Cardiovascular Disease Risk Parameters in Participants of a Preventive Health and Wellness Program

Lifestyle, dietary, and nutritional choices are important influencing parameters of cardiovascular disease (CVD) risk, the number one cause of morbidity and mortality globally. Our aims were to i) characterize CVD risk parameters using data from 7939 participants enrolled in a preventive health and wellness program between March 2010 and January 2017; and ii) evaluate intervention effects in 3,020 participants who returned for follow-up. Blood measurements (nutrient markers), CVD risk parameters (abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, low high-density lipoprotein (HDL), insulin resistance, and inflammation), glycemic status (HbA1c), and insulin resistance (HOMA-IR) were assessed. Framingham and Reynold's risk scores were also calculated. After approximately one year of treatment (n = 3 020), mean arachidonic acid:eicosapentaenoic acid (AA:EPA) ratio, homocysteine, and HbA_lc concentrations were significantly reduced; other risk parameters did not improve but mean values remained within reference ranges. Excluding participants taking related medications, 38.8%, 37.2%, 38.0%, 42.5%, and 59.7% of those with hyperglycemia, hypertriglyceridemia, low HDL, insulin resistance, or prediabetes, respectively, at baseline no longer had the condition at follow-up. In contrast, of individuals within the reference range at baseline, new cases at follow-up were found for 10.1%, 12.2%, 6.3%, 8.2%, and 7.6% (as above, respectively). Regression models revealed a significant association between serum 25-hydroxyvitamin D concentrations ≥100 nmol/L and reductions in many CVD risk parameters after adjustment for confounding variables. These findings suggest that a preventive approach to health and wellness focused on nutrients, optimal serum 25-hydroxyvitamin D concentrations, and lifestyle changes has the potential to reduce the risk of CVD.

Second edition of SIMPAR's "Feed Your Destiny" workshop: the role of lifestyle in improving pain management

This review is aimed to summarize the latest data regarding pain and nutrition, which have emerged during the second edition of Feed Your Destiny (FYD). Theme presentations and interactive discussions were held at a workshop on March 30, 2017, in Florence, Italy, during the 9th Annual Meeting of Study in Multidisciplinary Pain Research, where an international faculty, including recognized experts in nutrition and pain, reported the scientific evidence on this topic from various perspectives. Presentations were divided into two sections. In the initial sessions, we analyzed the outcome variables and methods of measurement for health claims pertaining to pain proposed under Regulation EC No 1924/2006 of the European Parliament and of the Council of 20 December 2006 on nutrition and health claims made on foods. Moreover, we evaluated how the Mediterranean diet can have a potential impact on pain, gastrointestinal disorders, obesity, cancer, and aging. Second, we discussed the evidence regarding vitamin D as a nutraceutical that may contribute to pain control, evaluating the interindividual variability of pain nature and nurture, and the role of micro-RNAs (miRNAs), polyunsaturated omega 3 fatty acids, and phenolic compounds, with a final revision of the clinical role of nutrition in tailoring pain therapy. The key take-home message provided by the FYD workshop was that a balanced, personalized nutritional regimen might play a role as a synergic strategy that can improve management of chronic pain through a precision medicine approach.

Stress-Axis Regulation by Vitamin D3 in Multiple Sclerosis

Introduction

Multiple sclerosis (MS) has been associated with both a poor vitamin D status and hyperactivity of the hypothalamus–pituitary–adrenal (HPA) axis. Since nuclear receptor ligands may regulate each other, we explored the association of vitamin D₃ supplements with circadian cortisol levels in a double-blind and placebo-controlled supplementation study.

Methods

Female patients with relapsing-remitting MS received vitamin D₃ supplements (4,000 IU/day; n = 22) or placebo (n = 19) during 16 weeks. Salivary cortisol levels, repeatedly measured during the day, and serum 25(OH)D levels were assessed before (T0) and after (T1) this treatment period.

Results

Median 25(OH)D levels at T1 were 139.9 (interquartile range 123.5–161.2) and 74.5 nmol/L (58.6–88.1) in the vitamin D₃ and placebo group, respectively (p < 0.001). Comparisons within and between groups showed no differences in area under the curve (AUC) and slope of the cortisol day curve. Although the AUC of the cortisol awakening response (CAR, sampling each 15 min the first hour after awakening) showed a reduction over time in the vitamin D₃ group [39.16 nmol/L (27.41–42.07) at T0 to 33.37 nmol/L (26.75–38.08) at T1] compared to the placebo group [33.90 nmol/L (25.92–44.61) at T0 to 35.00 nmol/L (25.46–49.23) at T1; p = 0.044], there was no significant difference in AUC of CAR at T1 corrected for baseline AUC of CAR (p = 0.066).

Conclusion

Suppression of HPA-axis activity by vitamin D₃ supplements in non-depressed MS patients may be best reflected by CAR as primary outcome measure. Further studies should address this interaction and its potential implications for the disease course of MS.

Registration

This study was registered on ClinicalTrials.gov (NCT02096133) and EudraCT (2014-000728-97).