Association between iron deficiency and prevalence of thyroid autoimmunity in pregnant and non-pregnant women of childbearing age: a cross-sectional study

Ferroptosis and Preeclampsia: Genetic Analysis of Potential Biomarkers and Therapeutic Targets

Ferroptosis is the oxidative death of cells attributed to an imbalance in intracellular lipid reactive oxygen species metabolism, a reduction in cell antioxidant capacity, and an accumulation of membrane lipid peroxides. Trophoblast cells are a group of cells susceptible to ferroptosis. The ferroptosis of trophoblast cells has a major effect on the development of preeclampsia (PE), although the impact of ferroptosis-related genes (FRGs) on PE has not been well characterized. This study obtained PE-related information from the Gene Expression Omnibus database and FRGs from the FerrDb ferroptosis database. Seventeen PE-related differentially expressed ferroptosis-related genes (DE-FRGs) that were closely associated with cellular regulation and immune response were obtained. According to the results of a subsequent functional enrichment analysis, it was found that the above marker genes may impact PE by regulating immune response, amino acid metabolism, the cell cycle, and multiple pathways correlated with PE pathogenesis. Subsequently, we used LASSO and support vector machine recursive feature elimination algorithms to help identify GOT1, CFL1, FZD7, VDR, PARP6, TMSB4X, VCP, and ENO3 as marker genes from the 17 obtained genes. According to the results of single-sample gene set enrichment analysis (ssGSEA), the immune microenvironment of PE changed, possibly due to the GOT1 and TMSB4X genes. Furthermore, 23 drugs targeting one marker gene were determined. A constructed ceRNA network revealed a complicated regulatory link based on the eight marker genes. In this study, diagnostic potency was developed, and insight into the mechanism of PE was provided. In-depth research should be conducted before clinical application to evaluate the diagnostic value of DE-FRGs in PE.

Emerging research themes in maternal hypothyroidism: a bibliometric exploration

Background

Hypothyroidism, a prevalent endocrine disorder, carries significant implications for maternal and infant health, especially in the context of maternal hypothyroidism. Despite a gradual surge in recent research, achieving a comprehensive understanding of the current state, focal points, and developmental trends in this field remains challenging. Clarifying these aspects and advancing research could notably enhance maternal-infant health outcomes. Therefore, this study employs bibliometric methods to systematically scrutinize maternal hypothyroidism research, serving as a reference for further investigations.

Objective

Through bibliometric analysis, this study seeks to unveil key research focus areas, developmental trends, and primary contributors in Maternal Hypothyroidism. The findings offer insights and recommendations to inform future research endeavors in this domain.

Methods

Literature metrics analysis was performed on data retrieved and extracted from the Web of Science Core Collection database. The analysis examined the evolution and thematic trends of literature related to Maternal Hypothyroidism. Data were collected on October 28, 2023, and bibliometric analysis was performed using VOSviewer, CiteSpace, and the Bibliometrix software package, considering specific characteristics such as publication year, country/region, institution, authorship, journals, references, and keywords.

Results

Retrieved from 1,078 journals, 4,184 articles were authored by 18,037 contributors in 4,580 institutions across 113 countries/regions on six continents. Maternal Hypothyroidism research publications surged from 44 to 310 annually, a 604.54% growth from 1991 to 2022. The USA (940 articles, 45,233 citations), China Medical University (82 articles, 2,176 citations), and Teng, Weiping (52 articles, 1,347 citations) emerged as the most productive country, institution, and author, respectively. "Thyroid" topped with 233 publications, followed by "Journal of Clinical Endocrinology & Metabolism" (202) with the most citations (18,513). "Pregnancy" was the most cited keyword, with recent high-frequency keywords such as "outcome," "gestational diabetes," "iodine intake," "preterm birth," "guideline," and "diagnosis" signaling emerging themes in Maternal Hypothyroidism.

Conclusions

This study unveils developmental trends, global collaboration patterns, foundational knowledge, and emerging frontiers in Maternal Hypothyroidism. Over 30 years, research has predominantly focused on aspects like diagnosis, treatment guidelines, thyroid function during pregnancy, and postpartum outcomes, with a central emphasis on the correlation between maternal and fetal health.

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

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

Relationship between Iron Deficiency and Thyroid Function: A Systematic Review and Meta-Analysis

Objective: Iron deficiency (ID) is the most prevalent nutritional deficiency worldwide. Low levels of serum ferritin (SF) could affect the thyroid gland and its functioning. The purpose of this systematic review and meta-analysis is to summarize the main currently available evidence and analyze data on the relationship between ID and thyroid function. Methods: This study included all articles evaluating the relationship between ID and thyroid function. Quality assessment was performed using Cambridge Quality Checklists. The search strategy included the following combination of Medical Subjects Headings terms and keywords: "iron deficiency", "thyroid function", "thyroid disease", "thyroid dysfunction", and "hypothyroidism". A meta-analysis was performed to evaluate whether thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels differed between patients with ID and healthy controls without ID. For statistical comparison between cases and controls, the mean difference (MD) was calculated, and a subgroup analysis of pregnant and non-pregnant women was performed. Cochran's Q testing and heterogeneity indices (I2) were used to assess statistical heterogeneity. Sensitivity analysis and publication bias analyses were also performed, both qualitatively and quantitatively. Finally, a meta-regression analysis was performed to evaluate the correlation between serum TSH or FT4 levels and SF in the study population. Results: Ten cross-sectional studies were identified and reviewed. Patients with ID showed TSH (MD: -0.24 mIU/L; 95% CI -0.41, -0.07; I2 = 100%, p = 0.005), FT4 (MD: -1.18 pmol/L; 95% CI -1.43, -0.94; I2 = 99%, p < 0.000001), and FT3 (MD: -0.22 pmol/L; 95% CI -0.32, -0.12; I2 = 99%, p < 0.00001) levels that were significantly lower. Subgroup analysis confirmed significantly lower TSH, FT4, and FT3 levels in pregnant women. Non-pregnant women showed significantly lower serum FT4 and FT3 levels but no difference in TSH values. Meta-regression analysis showed that serum TSH and FT4 levels were positively correlated with SF levels. Our systematic review of the literature found that ID significantly increases the prevalence of thyroid autoantibody (anti-thyroglobulin antibodies and anti-thyroid peroxidase antibodies) positivity both individually and collectively. Conclusion: Studies currently published in the literature indicate a possible relationship between ID, thyroid function, and autoimmunity, especially in some patient groups. Data analysis shows that thyroid hormone levels are lower in patients with ID and, in particular, in pregnant women. Further studies are needed to understand the role played by iron in thyroid metabolism.

Thyroid hormones and minerals in immunocorrection of disorders in autoimmune thyroid diseases

Thyroid hormones and essential elements iodine (I), selenium (Se), iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), etc. play an important role in the work of many organs and systems of the body, including the immune system and the thyroid gland, and a violation of their supply can be the cause of pathological changes in them. In pathology, the interaction between thyroid hormones (TG), minerals and the immune system is disturbed. The review of the literature examines the immunomodulatory role of TG, minerals, their properties, and their participation in the pathogenesis of autoimmune thyroid diseases (AITD). The study of the relationship between the excess or deficiency of minerals and AITD is described. The basis of the development of AITD - Hashimoto's thyroiditis (HT), Graves' disease (GD), Graves' ophthalmopathy (GO) is the loss of immune tolerance to thyroid antigens - thyroid peroxidase (TPO), thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R). Immune-mediated mechanisms - production of autoantibodies to thyroid antigens and lymphocytic thyroid infiltration - are involved in the pathogenesis of AITD. Insufficiency of regulatory T cells (Treg) and regulatory B cells (Breg), imbalance between Th17-lymphocytes and Treg-lymphocytes, abnormal production of pro-inflammatory cytokines has a significant influence on the progression of AITD. With AITD, the balance between oxidants and antioxidants is disturbed and oxidative stress (OS) occurs. The lack of modern effective pharmacological therapy of AITD prompted us to consider the mechanisms of influence, possibilities of immunocorrection of pathogenetic factors using TG, micro/macronutrients. In order to develop a more effective treatment strategy, as well as approaches to prevention, a critical analysis of the ways of immunotherapeutic use of dietary supplements of I, Se, Zn, Mg and other minerals in AITD was carried out.

Molecular Mechanisms in Autoimmune Thyroid Disease

The most common cause of acquired thyroid dysfunction is autoimmune thyroid disease, which is an organ-specific autoimmune disease with two presentation phenotypes: hyperthyroidism (Graves-Basedow disease) and hypothyroidism (Hashimoto’s thyroiditis). Hashimoto’s thyroiditis is distinguished by the presence of autoantibodies against thyroid peroxidase and thyroglobulin. Meanwhile, autoantibodies against the TSH receptor have been found in Graves-Basedow disease. Numerous susceptibility genes, as well as epigenetic and environmental factors, contribute to the pathogenesis of both diseases. This review summarizes the most common genetic, epigenetic, and environmental mechanisms involved in autoimmune thyroid disease.

Metabolic Characteristics of Hashimoto's Thyroiditis Patients and the Role of Microelements and Diet in the Disease Management-An Overview

Hashimoto’s thyroiditis (HT) is the most common autoimmune disease and the leading cause of hypothyroidism, in which damage to the thyroid gland occurs due to the infiltration of lymphocytes. It is characterized by increased levels of antibodies against thyroid peroxidase and thyroglobulin. In this review, we present the metabolic profile, the effectiveness of micronutrient supplementation and the impact of dietary management in patients with HT. For this current literature review, the databases PubMed, Cochrane, Medline and Embase were reviewed from the last ten years until March 2022. This article provides a comprehensive overview of recent randomized controlled trials, meta-analyses, and clinical trials. Many patients with HT, even in the euthyroid state, have excess body weight, metabolic disorders, and reduced quality of life. Due to frequent concomitant nutritional deficiencies, the role of vitamin D, iodine, selenium, magnesium, iron and vitamin B12 is currently debated. Several studies have underlined the benefits of vitamin D and selenium supplementation. There is still no specific diet recommended for patients with HT, but a protective effect of an anti-inflammatory diet rich in vitamins and minerals and low in animal foods has been suggested. There is insufficient evidence to support a gluten-free diet for all HT patients. Pharmacotherapy, along with appropriate nutrition and supplementation, are important elements of medical care for patients with HT. The abovementioned factors may decrease autoantibody levels, improve thyroid function, slow down the inflammatory process, maintain proper body weight, relieve symptoms, and prevent nutritional deficiencies and the development of metabolic disorders in patients with HT.

Association between thyroid autoimmunity and gestational diabetes mellitus in euthyroid women

OBJECTIVE

Pregnant women with autoimmune (subclinical) hypothyroidism have an increased risk of developing gestational diabetes mellitus (GDM). However, this association remains controversial in euthyroid women with thyroid autoimmunity (TAI). Therefore, the aim of the study was to determine the association between TAI and GDM in euthyroid women in a logistic regression analysis with adjustments for baseline/demographic parameters.

METHODS

Cross-sectional study in 1447 euthyroid women who performed their entire clinical/biological workup and oral glucose tolerance test (OGTT) in our center. At median 13 (11-17) weeks of gestation, thyroid-stimulating hormone, free T4, and thyroid peroxidase antibodies (TPOAb) were measured, baseline characteristics were recorded, and an OGTT was performed between 24 and 28 weeks of pregnancy. Exclusion criteria were pre-pregnancy diabetes, assisted pregnancies, and women with (treated) thyroid dysfunction before or after screening. The diagnosis of GDM was based on 2013 World Health Organization criteria, and TAI was defined as TPOAb levels ≥60 kIU/L.

RESULTS

Two hundred eighty women were diagnosed with GDM (19.4%), 26.1% in women with TAI, and 18.9% in women without TAI (P = 0.096). In the logistic regression analysis, TAI was associated with GDM in women older than 30 years (adjusted odds ratio 1.68 (95% CI, 1.01-2.78); P = 0.048). Maternal age >30 years, pre-pregnancy BMI ≥30 kg/m2, and other than Caucasian background were also associated with GDM; aOR 1.93 (95% CI, 1.46-2.56); P < 0.001, 2.03 (95% CI, 1.46-2.81); P < 0.001 and 1.46 (95% CI, 1.03-2.06); P = 0.034, respectively.

CONCLUSIONS

In older pregnant women, the presence of TAI in euthyroid women was associated with GDM. In line with the literature data, (higher) age and BMI were strongly associated with GDM. Future investigations should focus on treatments that might prevent the development of GDM in euthyroid women with TAI.

Trace elements and the thyroid

Trace elements, such as iodine and selenium (Se), are vital to human health and play an essential role in metabolism. They are also important to thyroid metabolism and function, and correlate with thyroid autoimmunity and tumors. Other minerals such as iron (Ir), lithium (Li), copper (Co), zinc (Zn), manganese (Mn), magnesium (Mg), cadmium (Cd), and molybdenum (Mo), may related to thyroid function and disease. Normal thyroid function depends on a variety of trace elements for thyroid hormone synthesis and metabolism. These trace elements interact with each other and are in a dynamic balance. However, this balance may be disturbed by the excess or deficiency of one or more elements, leading to abnormal thyroid function and the promotion of autoimmune thyroid diseases and thyroid tumors.The relationship between trace elements and thyroid disorders is still unclear, and further research is needed to clarify this issue and improve our understanding of how trace elements mediate thyroid function and metabolism. This paper systematically reviewed recently published literature on the relationship between various trace elements and thyroid function to provide a preliminary theoretical basis for future research.

Effects of animal protein intake during pregnancy on autoimmune thyroiditis in pregnant women with mild iodine deficiency

BACKGROUND

Iodine and animal protein may affect thyroid function. In the present study, we explored the association between animal protein intake and thyroid antibody status in pregnant women following universal salt iodisation.

METHODS

Pregnant women were enrolled using a multistage, stratified random sampling method in Shanghai. In total, 4646 eligible women were interviewed in person. We used a validated food frequency questionnaire and food composition tables to calculate the daily intakes of protein and iodine. We collected urine samples and performed thyroid antibody tests.

RESULTS

Positive thyrotropin receptor antibody (TR-Ab) rates were different among animal protein intake groups (p < 0.05). Median urinary iodine concentration (UIC) was higher in the thyroid peroxidase antibody (TPO-Ab) positive group than in the negative group (p < 0.05). The median of total protein intake, animal protein intake and UIC was higher in the TR-Ab positive group than in the negative group (p < 0.05). The median of total protein intake and UIC was higher in the TPO-Ab/TG-Ab/TR-Ab positive group than in the negative group (p < 0.05). Multivariable logistic regression results showed that insufficient iodine had a negative correlation with positive TPO-Ab and positive TR-Ab (p < 0.05). The middle third and top third animal protein intakes served as protective factors for TR-Ab (coefficient = 0.559, 95% confidence interval [CI] = 0.415-0.752, p < 0.001; coefficient = 0.0.406, 95% CI = 0.266-0.621, p < 0.001) and positive TPO-Ab/TR-Ab/TG-Ab (coefficient = 0.817, 95% CI = 0.687-0.971, p = 0.022; coefficient = 0.805, 95% CI = 0.672-0.964, p = 0.018).

CONCLUSIONS

Adequate animal protein intake protects against elevated anti-thyroid antibody levels in pregnant women with mild iodine deficiency.

Iron Deficiency, a Risk Factor of Thyroid Disorders in Reproductive-Age and Pregnant Women: A Systematic Review and Meta-Analysis

BACKGROUND

Iron deficiency (ID) is concerned as the most common nutritional deficiency worldwide. The effects of ID on thyroid function and autoimmunity in pregnant women and reproductive-age women are controversial. The aim of the current study was to summarize the evidences and evaluate the relationship between ID and thyroid disorders.

METHODS

In this systematic review and meta-analysis, studies published on the Cochrane, Embase, Medline, and PubMed databases by October 2020 were searched. A total of 636 studies which discussed the correlation between ID and thyroid disorders were eligible in the initial search. Pooled mean differences (MD) and 95% confidence intervals (CI) were calculated for the assessment of thyrotropin (TSH) and free thyroxine (FT4) levels. Combined odd ratios (OR) and 95% CI were calculated for the assessment of the prevalence of overt and subclinical hypothyroidism, positive thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb).

RESULTS

For women of reproductive age, ID could significantly increase the risk of positive TPOAb (OR: 1.89; 95% CI: 1.17, 3.06: P = 0.01) and both positive TPOAb and TgAb (OR: 1.48; 95% CI: 1.03, 2.11: P = 0.03). The meta-analysis of pregnant women showed that pregnant women with ID had increased serum TSH levels (MD: 0.12; 95% CI: 0.07, 0.17; P < 0.00001) and decreased FT4 levels (MD: -0.73; 95% CI: -1.04, -0.41; P < 0.00001). Meanwhile, the prevalence of overt (OR: 1.60; 95% CI: 1.17, 2.19; P = 0.004) and subclinical (OR: 1.37; 95% CI: 1.13, 1.66; P = 0.001) hypothyroidism in pregnant women with ID was significantly increased.

CONCLUSIONS

ID may adversely affect thyroid function and autoimmunity of pregnant and reproductive-age women and it is very necessary for monitoring iron nutritional status and early treatment of ID for them.

Thyroid-Gut-Axis: How Does the Microbiota Influence Thyroid Function?

A healthy gut microbiota not only has beneficial effects on the activity of the immune system, but also on thyroid function. Thyroid and intestinal diseases prevalently coexist-Hashimoto's thyroiditis (HT) and Graves' disease (GD) are the most common autoimmune thyroid diseases (AITD) and often co-occur with Celiac Disease (CD) and Non-celiac wheat sensitivity (NCWS). This can be explained by the damaged intestinal barrier and the following increase of intestinal permeability, allowing antigens to pass more easily and activate the immune system or cross-react with extraintestinal tissues, respectively. Dysbiosis has not only been found in AITDs, but has also been reported in thyroid carcinoma, in which an increased number of carcinogenic and inflammatory bacterial strains were observed. Additionally, the composition of the gut microbiota has an influence on the availability of essential micronutrients for the thyroid gland. Iodine, iron, and copper are crucial for thyroid hormone synthesis, selenium and zinc are needed for converting T4 to T3, and vitamin D assists in regulating the immune response. Those micronutrients are often found to be deficient in AITDs, resulting in malfunctioning of the thyroid. Bariatric surgery can lead to an inadequate absorption of these nutrients and further implicates changes in thyroid stimulating hormone (TSH) and T3 levels. Supplementation of probiotics showed beneficial effects on thyroid hormones and thyroid function in general. A literature research was performed to examine the interplay between gut microbiota and thyroid disorders that should be considered when treating patients suffering from thyroid diseases. Multifactorial therapeutic and preventive management strategies could be established and more specifically adjusted to patients, depending on their gut bacteria composition. Future well-powered human studies are warranted to evaluate the impact of alterations in gut microbiota on thyroid function and diseases.

Maternal Thyroid Dysfunction and Gestational Anemia Risk: Meta-Analysis and New Data

Background: Previous studies indicate the effects of thyroid dysfunction on adverse obstetric outcomes and fetal neurodevelopment, of which the results on gestational anemia are controversial. Here, we evaluated the influence of thyroid dysfunction on gestational anemia via published epidemiological articles and a new prospective study conducted by our team, respectively. Methods: We searched studies on the PubMed, Embase, MEDLINE, and Cochrane databases as of November 2019, and conducted a prospective study in which participants underwent thyroid function and blood routine testing throughout pregnancy. Results: The meta-analysis showed that pregnancies with overt hypothyroidism [OH; odds ratio (OR) = 3.74, 95% confidence interval (CI): 1.95-7.15] or that were thyroid peroxidase antibody (TPOAb)-positive (OR = 1.97, 95%CI: 1.19-3.26) had increased anemia risk, but similar results were not found in pregnancies with subclinical hypothyroidism (SCH) and hyperthyroidism. In the prospective study from our new data, the hypothyroid group had significant reductions in hemoglobin (Hb) (P = 0.048) and increased anemia risk (OR = 6.384, 95%CI: 2.498-16.311) during the second half of pregnancy. From the first to second half of pregnancy, the longitudinal reductions in Hb, erythrocyte (RBC), and hematocrit (Hct) levels were significantly increased in hypothyroid group. Conclusions: Our meta-analysis indicates that untreated OH or TPOAb-positive pregnant women have increased risk of anemia. In addition, our new data showed that treated hypothyroidism is also a risk factor for anemia in the second half of pregnancy rather than in the first half. The results may guide strengthening of Hb monitoring in pregnancies with thyroid dysfunction.

IS IRON DEFICIENCY A RISK FACTOR FOR THE DEVELOPMENT OF THYROID AUTOANTIBODIES IN EUTHYROID WOMEN WITH REPRODUCTIVE AGES?

Contex

The first trimester of pregnancy is the most sensitive period in terms of thyroid hypofunction. Iron deficiency has been associated with both thyroid function and thyroid autoimmunity.

Objective

We aimed to investigate whether iron deficiency is a risk factor for thyroid autoimmunity in non-pregnant women at childbearing age.

Design

This cross- sectional study was conducted in non-pregnant women who presented to the Internal Medicine Policlinic between January 2018 and December 2018 in the University of Health Sciences "Fatih Sultan Mehmet" Training and Research Hospital.

Methods

Three hundred fifty-eight non-pregnant women of reproductive ages (203 iron deficient-ID, 155 control) participated in this study. Women with known thyroid disease, currently undergoing treatment for thyroid disease or whose thyroid function tests were outside the reference range were excluded from the study. Blood sample was taken after at least 8-10 hours of fasting for measurement of serum iron (Fe), total iron binding capacity (TIBC), serum ferritin (SF), whole blood count, thyroid function tests (fT4, TSH), anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibody (TgAb). The patients with SF levels ≤ 15 ng/dL were accepted as iron deficiency.

Results

The group with ID had higher TSH and lower T4 values that did not reach statistical significance compared to the control group (p=0.101 and p=0.098, respectively). Antibody positivity was more frequent in the ID group than in the control group (35.96% vs. 20.65%, p = 0.002).

Conclusions

Iron deficiency is associated with thyroid autoimmunity and it should be considered as a risk factor for screening thyroid antibody, particularly in pregnancy planning women.