Vitamin D and thyroid diseases

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

Introduction

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

Materials and methods

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

Results

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

Conclusion

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

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.

Nutrition as Prevention of Diet-Related Diseases-A Cross-Sectional Study among Children and Young Adults with Down Syndrome

BACKGROUND

The aim of this study was to assess the diet of children with Down syndrome (DS) and to identify potential dietary mistakes made by their parents.

MATERIALS AND METHODS

The study was conducted among 195 parents of people with DS between November 2020 and March 2021. Data for the study were collected anonymously using the CAWI method.

RESULTS

122 (62.6%) people with DS did not eliminate any nutrient from their diet. By contrast, in the study group, the following numbers of people reported the following dietary restrictions: 51 (26.2%) gluten, 56 (28.7%) lactose, 17 (8.7%) casein, 26 (13.3%) sucrose, 2 (1.0%) histamine, 2 (1.0%) lectins, and 1 (0.5%) dairy. The most frequent response for vegetable and fruit consumption was once a day, with 83 (42.6%) and 87 (44.6%) parents indicating this. The most frequent response for dairy product consumption was every day, with 72 (36.9%) parents indicating this, while 36 (20%) parents stated that their children do not eat dairy products at all. In the study group, the most frequent response for meat consumption was several times a week, this was indicated by 107 (54.9%) parents, while 1 (0.5%) of them said that their children do not eat meat products at all. The most frequent response for fish consumption was 1-2 times a week, this answer was indicated by 101 (51.8%) parents, while 13 (6.7%) said that their children do not eat these products at all.

CONCLUSIONS

A majority of the subjects with DS are usually fed in a normal way, but nutritional mistakes are made by the parents. Special attention should be paid to prolonging the period of natural feeding.

IMPACT OF GRAVES' DISEASE AND ANTITHYROID DRUG THERAPY ON BONE MINERAL DENSITY - PATHOPHYSIOLOGICAL MECHANISMS AND CLINICAL RELEVANCE

Graves' disease is an autoimmune disease characterized by excessive thyroid hormone production. One of the consequences of that state can be a decrease in bone mineral density (BMD). Graves' disease is often treated with antithyroid drugs (ATD) as first line therapy, which can lead to disease remission. Moreover, recent data show that improvement in BMD can be expected. However, vitamin D deficiency can coexist along with Graves' disease, which is also involved in the process of bone remodeling. It is still not known whether lower values of vitamin D can contribute to onset of Graves' disease and if its supplementation might be helpful in therapy for hyperthyroidism. In the past couple of decades, osteopenia and osteoporosis have become a major health burden not only in post-menopausal women but also as a result of other diseases, leading to extensive research into various pathophysiological mechanisms responsible for bone remodeling. The Wnt (wingless integrated) signaling pathway is a very important factor in bone homeostasis, especially the canonical pathway. Present data indicate that stimulation of the Wnt pathway leads to bone mass increase and, in contrast, its inhibition leads to bone mass decrease. Hence, inhibitors of the canonical Wnt pathway became the focus of interest, in particular sclerostin and dickkopf 1 (DKK1). Hyperthyroidism and osteopenia/osteoporosis are quite common today and can coexist together or as separate entities. In this article, we aimed to give an overview of possible associations and potential mutual pathophysiological mechanisms.

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.

Correlative studies on vitamin D and total, free bioavailable testosterone levels in young, healthy men

The relationship between vitamin D levels and testicular hormonal function in men has not been clearly established. Therefore, we aimed to investigate the relationship between deficiency/insufficiency levels of 25(OH)D and luteinizing hormone (LH), follicle-stimulating hormone (FSH), total (TT), free (FT), and bioavailable testosterone (BT), and sex hormone binding globulin (SHBG) in young, healthy men. We enrolled 176 healthy, active young men aged 18–35 years from a genetically homogenous population of Lower Silesia, Poland. Serum levels of 25(OH)D, LH, FSH, and TT were measured by electrochemiluminescence (ECLIA). FT levels were measured by enzyme-linked immunosorbent assay (ELISA). BT levels were calculated from TT, SHBG, and albumin. SHBG was measured by chemiluminescent immunoassay CLIA. We did not find any significant differences between the mean hormonal values (LH, FSH, TT, FT, BT, and SHBG) and the status of 25(OH)D level (deficient and insufficient). Based on our results, we concluded that there is no relationship between deficient and insufficient 25(OH)D concentration and androgen levels in young, healthy men.

Vitamin D Deficiency, Osteoporosis and Effect on Autoimmune Diseases and Hematopoiesis: A Review

Vitamin D (VD) is essential for bone homeostasis, but it is also involved in pleiotropic effects on various organs and tissues. In adults, VD deficiency can cause or exacerbate osteoporosis and induce osteomalacia. However, every tissue and cell in the body has a VD receptor, including the brain, heart, stomach, pancreas, skin, gonads, and immune cells, and a deficiency may modify the function of these organs. Thus, the wide-ranging actions of VD help to explain why a reduction in VD amount has been correlated with numerous chronic diseases. In fact, VD deficiency increases the risk of osteoporosis and several other diseases and complications characterized by impaired bone metabolisms, such as autoimmune diseases, inflammatory bowel diseases, allergy, endocrinological diseases, hematological malignancies, and bone marrow transplantation. This review aims to investigate the link between VD deficiency, osteoporosis, and its concomitant diseases. Further epidemiological and mechanistic studies are necessary in order to ascertain the real role of hypovitaminosis in causing the reported diseases; however, adequate vitamin supplementation and restoration of metabolic normality could be useful for better management of these pathologies.

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.

"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.

Familial hypocalciuric hypercalcemia in an index male: grey zones of the differential diagnosis from primary hyperparathyroidism in a 13-year clinical follow up

Familial hypocalciuric hypercalcemia (FHH) type 1, caused by a heterozygous inactivating mutation of the gene encoding the calcium-sensing receptor (CaSR), is characterized by mild to moderate hypercalcemia, hypocalciuria and inappropriately normal or elevated parathyroid hormone (PTH). FHH must be differentiated from primary hyperparathyroidism (PHPT) because parathyroidectomy is ineffective in the former. Herein, we report a 39-year-old male patient with a 13-year history of asymptomatic PTH-dependent hypercalcemia (mean calcium of 2.88 mmol/l; reference range 2.15-2.55 mmol/l) and calcium-to-creatinine clearance ratio (Ca/Cr) ranging from 0.007 to 0.0198, which is consistent with either FHH or PHPT. Although a family history of hypercalcemia was negative, and PET-CT with fluorocholine was suggestive of a parathyroid adenoma, genetic analysis of the CaSR gene identified a heterozygous inactivating mutation NM_000388.4:c.1670G>A p. (Gly557Glu) in exon 6 and a polymorphism NM_000388.4:c.1192G>A p. (Asp398Asn) in exon 4. The G557E mutation has been previously reported in a Japanese family in which all family members with the mutation had Ca/Cr below 0.01 consistent with FHH. The biochemical profile of FHH and PHPT may overlap. Our FHH patient with a G557E CaSR mutation illustrates that the differential diagnosis can be difficult in an index case with no family history, (false) positive parathyroid imaging and higher calciuria than expected for FHH. Calcium intake, vitamin D status and bone resorption might have contributed to the Ca/Cr variations over a 13-year clinical follow up. This case thus emphasizes the irreplaceable role of genetic testing of the CaSR gene when clinical evaluation is inconclusive.

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.

Thyroid Function and 25 (OH) Vitamin D Level among Sudanese Women in Early Pregnancy

AIM:

A cross-sectional study was conducted at Saad Abualila Hospital (Khartoum, Sudan) to evaluate the vitamin D levels and thyroid function among pregnant Sudanese women (132) in early pregnancy.

METHODS:

A cross-sectional study was conducted at Saad Abualila hospital (Khartoum, Sudan) during the period from March to July 2015. Women who were in early pregnancy with a singleton pregnancy were approached to participate in the study after signing informed consent. A sample size of 132 participants was calculated guided by the normal interval of thyroid function in Sudanese women in the first trimester and not the level of 25(OH) vitamin D. The 25 - hydroxyvitamin D (25 (OH) vitamins levels were measured using an electrochemiluminescence immunoassay on an Elecsys 2010 Analyzer (Roche Diagnostics, Mannheim, Germany).

RESULTS:

The mean (SD) of age, gravidity and gestational age was 27.6 (5.5) years, 2.2 (1.6) and 10.4 (2.2) weeks, respectively. The mean (SD) of the body mass index (BMI) and haemoglobin was 27.1 (5.2) kg/m² and 10.8 (1.1) g/dl, respectively. Median (interquartile) values of TSH, FT3, and FT4 were 1.164 IU/ml (0.079 -2.177 IU/ml), 4.639 nmol/l (3.843 - 6.562 nmol/l), and 16.86 pmol/l (13.02 - 31.48 pmol/l), respectively. There was no significant correlation between vitamin D levels and TSH, FT3 and FT4

CONCLUSION:

There is no correlation between 25 (OH) vitamin D levels and thyroid function during early pregnancy among Sudanese pregnant women, despite prevalent vitamin D deficiency among these women.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Hypothyrodism as a risk factor of periodontitis and its relation with vitamin D deficiency: mini-review of literature and a case report

Objective

The purpose of this report is to investigate the role and efficiency of the intra-ligamentary injection of vitamin D and calcium in the treatment of chronic periodontitis associated with hypothyroidism.

Design

A 43-year-old female with suspected hypothyroidism who revealed severe chronic periodontitis with grade III mobility. Pre-operative periodontal and systemic control preceded the used intervention. After 3 months, intra-ligamentary injectable vitamin D with calcium was introduced.

Results

Clinical evaluation revealed great improvement of the injected sites. Marked reduction of mobility, pocket depth and bleeding were detected.

Conclusions

Injectabe vitamin D is an adjunctive treatment modality that needs to be discovered in another way. It may provide further solutions for the periodontal regeneration problem. Clinical studies with large sample sizes and long term follow up are needed.

Vitamin D Supplementation Changed Relationships, Not Levels of Metabolic-Hormonal Parameters in Autoimmune Thyroiditis

In women with chronic autoimmune thyroiditis and vitamin D deficiency we have found reference levels of relevant metabolic-hormonal parameters except for parathormone and total calcium. Three months supplementation with vitamin D (4300 IU/day, cholekalciferol) did not lead to significant changes of investigated hormonal parameters, while the levels of parathormone and calcium reached normal levels. However, a correlation analysis revealed marked changes in mutual relations. First, an inverse correlation of vitamin D with parathormone, insulin secretion (C peptide, insulin) and its efficiency (HOMA IR) disappeared. Relationships of vitamin D to hepatic insulin resistance (insulin/C peptide), to DHEA (both negative), and to DHEAS/DHEA ratio (positive) were newly found. Second, a positive correlation of CRP with insulin secretion remained, while its relation to insulin efficiency (HOMA IR, insulin/ C peptide) was newly observed. Analogical positive correlations appeared also among anti TPO and insulinemia, insulin/C peptide, HOMA IR, and anti Tg to C peptide. A relationship of the CRP with anti TPO became significant (+). Third, out of glucose metabolism parameters only insulin/C peptide and glycemia did not correlate with vitamin D during its deficiency, while after supplementation insulin/ C peptide alone correlated positively with both DHEAS and DHEA, and negatively with vitamin D.

Biochemical assessments of thyroid profile, serum 25-hydroxycholecalciferol and cluster of differentiation 5 expression levels among children with autism

BACKGROUND

The exact pathogenesis of autism is still unknown. Both thyroid hormones and 25(OH)D are important for brain development, in addition to CD5; all have immunomodulatory actions by which their dysregulation may have a potential role in autism pathogenesis.

OBJECTIVES

The objectives of this study were to assess the thyroid profile, serum 25(OH)D levels and CD5 expression levels among autistic patients and to find out the correlations between the measured biomarkers with each other on one side and with the disease severity on the other side.

PATIENTS AND METHODS

This cross-sectional case-control study has been conducted on 60 children with autism and 40 controls, recruited from Qena Governorate, Upper Egypt. Childhood Autism Rating Scale (CARS) score was used to assess the included patients. Biochemical assays of thyroid function in the form of free triiodothyronine (FT3), free tetraiodothyronine (FT4), thyroid-stimulating hormone (TSH) and 25(OH)D were done using commercially available enzyme-linked immunosorbent assay (ELISA) kits, while CD5 expression levels were measured using flow cytometry (FCM) analysis for all the included patients and controls.

RESULTS

The overall measurement results show significant higher mean serum TSH levels, mean CD5 expression levels with significant lower mean serum 25(OH)D levels among autistic children when compared with the control group (p<0.05 for all). Significant negative correlations between CD5 with FT3, FT4 and 25(OH)D were observed. CARS score showed significant negative correlations with both FT3 and 25(OH)D, while it was positively correlated with CD5 in a significant manner (p<0.05 for all).

CONCLUSION

Elevated CD5 expression and decreased 25(OH)D stores could play a potential role in the pathogenesis of autism via their immune-modulator actions. High TSH serum levels among autistic children, although within the physiological range, reflect the presence of thyroid dysfunction among such children, which needs further assessment.

The Role of Vitamin D in Thyroid Diseases

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

Sunshine vitamin and thyroid

Vitamin D exerts its canonical roles on the musculoskeletal system and in the calcium/phosphorus homeostasis. In the last years, increasing evidences suggested several extra-skeletal actions of this hormone, indicating that vitamin D may produce effects in almost all the body tissues. These are mediated by the presence of vitamin D receptor (VDR) and thanks to the presence of the 1-α-hydroxylase, the protein that converts the 25-hydroxyvitamin (calcidiol) to the active form 1,25-dihydroxyvitamin (calcitriol). Several studies evaluated the possible role of vitamin D in the pathogenesis of thyroid diseases, and this review will focus on the available data of the literature evaluating the association between vitamin D and thyroid function, vitamin D and autoimmune thyroid diseases, including Hashimoto's thyroiditis, Graves' disease and post-partum thyroiditis, and vitamin D and thyroid cancer.

A Higher Ratio of Estradiol to Testosterone Is Associated with Autoimmune Thyroid Disease in Males

BACKGROUND

Autoimmune thyroid disease (AITD) is highly prevalent. Although AITD is less common in males, it is unclear whether estradiol (E₂) combined with total testosterone (T) contributes to the prevalence of AITD. This study evaluated the association between the E₂/T ratio and the prevalence of AITD in males.

METHODS

The data were obtained from a cross-sectional population-based study, the SPECT-China study, 2014-2015. A total of 4109 males ≥18 years of age were enrolled in this study. Participants underwent several checkups, which included assays of serum E₂, T, thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) levels, as well as thyroid ultrasonography (US). AITD was defined based on the presence of TPOAb and TgAb levels, and the presence of thyroid US findings.

RESULTS

Overall, the prevalence of positivity for TPOAb and/or TgAb (TPO/TgAb[+]) was 11.02%, and the positivity for TPOAb and/or TgAb together with US (TPO/TgAb[+] and US[+]) was 4.58%. The E₂/T ratio levels were significantly higher in the TPO/TgAb(+) group and the TPO/TgAb(+) and US(+) group (7.91 ± 8.03 vs. 7.19 ± 10.30, p = 0.003; 8.78 ± 11.26 vs. 7.19 ± 10.30, p = 0.001) compared to the TPO and TgAb(-) group. The prevalence of TPO/TgAb(+) and US(+) significantly increased with an increasing E₂/T ratio (p = 0.013). Binary logistic analysis showed that increased E₂/T ratio levels were associated with an increased risk of AITD (TPO/TgAb[+]: odds ratio = 1.35, p = 0.002; TPO/TgAb[+] and US[+]: odds ratio = 1.48, p = 0.006).

CONCLUSIONS

AITD is highly prevalent in males in China. Higher E₂/T ratios were significantly associated with AITD among males. Further studies will be needed to assess whether there is a causal relationship between E₂/T ratios and AITD.

Multiple Nutritional Factors and the Risk of Hashimoto's Thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is considered to be the most common autoimmune disease. It is currently accepted that genetic susceptibility, environmental factors, and immune disorders contribute to its development. With regard to nutritional factors, evidence implicates high iodine intake and deficiencies of selenium and iron with a potential relevance of vitamin D status. To elucidate the role of nutritional factors in the risk, pathogenesis, and treatment of HT, PubMed and the Cochrane Library were searched for publications on iodine, iron, selenium, and vitamin D and risk/treatment of HT.

SUMMARY

Chronic exposure to excess iodine intake induces autoimmune thyroiditis, partly because highly iodinated thyroglobulin (Tg) is more immunogenic. Recent introduction of universal salt iodization can have a similar, though transient, effect. Selenoproteins are essential to thyroid action. In particular, the glutathione peroxidases protect the thyroid by removing excessive hydrogen peroxide produced for Tg iodination. Genetic data implicate the anti-inflammatory selenoprotein S in HT risk. There is evidence from observational studies and randomized controlled trials that selenium/selenoproteins can reduce thyroid peroxidase (TPO)-antibody titers, hypothyroidism, and postpartum thyroiditis. Iron deficiency impairs thyroid metabolism. TPO, the enzyme responsible for the production of thyroid hormones, is a heme (iron-containing) enzyme which becomes active at the apical surface of thyrocytes only after binding heme. HT patients are frequently iron deficient, since autoimmune gastritis, which impairs iron absorption, is a common co-morbidity. Treatment of anemic women with impaired thyroid function with iron improves thyroid-hormone concentrations, while thyroxine and iron together are more effective in improving iron status. Lower vitamin D status has been found in HT patients than in controls, and inverse relationships of serum vitamin D with TPO/Tg antibodies have been reported. However, other data and the lack of trial evidence suggest that low vitamin D status is more likely the result of autoimmune disease processes that include vitamin D receptor dysfunction.

CONCLUSIONS

Clinicians should check patients' iron (particularly in menstruating women) and vitamin D status to correct any deficiency. Adequate selenium intake is vital in areas of iodine deficiency/excess, and in regions of low selenium intake a supplement of 50-100 μg/day of selenium may be appropriate.

No Association between 25 (OH) Vitamin D Level And Hypothyroidism among Females

AIM:

The aim was to investigate serum vitamin D (25-OH) level among females with hypothyroidism.

MATERIALS AND METHODS:

A case-control study (58 in each arm) was conducted in Arar Central Hospital, Kingdom Saudi Arabia. The cases were females with hypothyroidism, and healthy females were controls. TSH, thyroid hormones: Free T3 (FT3) and Free T4 (FT4) and haemoglobin levels were measured in all participants. Serum vitamin D (25-OH) level was measured using the spectrophotometry.

RESULTS:

While there was no significant difference in the age and haemoglobin level, body mass index (BMI) was significantly higher in the cases. Compared with the controls, cases had significantly higher TSH, had significantly lower T4, and there was no significant difference in FT3 and 25 (OH) vitamin D, [16.1 (8.8-26.7) vs. 14.0 (9.5-20.3 ng/ml; P = 0.577]. Linear regression showed no association between, age, BMI, haemoglobin, TSH, FT3, FT4 and the log of 25 (OH) vitamin D levels.

CONCLUSION:

There was no significant difference in vitamin D level among females with hypothyroidism and healthy controls.

Vitamin D: not just the bone. Evidence for beneficial pleiotropic extraskeletal effects

Vitamin D is a fat-soluble vitamin and a steroid hormone that plays a central role in maintaining calcium-phosphorus and bone homeostasis in close interaction with parathyroid hormone, acting on its classical target tissues, namely, bone, kidney, intestine, and parathyroid glands. However, vitamin D endocrine system regulates several genes (about 3 % of the human genome) involved in cell differentiation, cell-cycle control, and cell function and exerts noncalcemic/pleiotropic effects on extraskeletal target tissues, such as immune and cardiovascular system, pancreatic endocrine cells, muscle, and adipose tissue. Several studies have demonstrated the role of vitamin D supplementation in the prevention/treatment of various autoimmune diseases and improvement of glucose metabolism, muscle, and adipose tissue function. Hence, this review aims to elucidate the effects of vitamin D on extraskeletal target tissues and to investigate the potential therapeutic benefit of vitamin D supplementation among a broad group of pathological conditions, especially with regard to metabolic and autoimmune diseases. In addition, we focused on the best daily intakes and serum levels of vitamin D required for extraskeletal benefits which, even if still controversial, appear to be higher than those widely accepted for skeletal effects.