Publications by authors named "Ivana Gunjaca"

Calcitonin (CT), a hormone secreted by thyroid parafollicular C cells, plays a role in calcium homeostasis and bone health. Understanding the relationship between CT levels and dietary, sociodemographic, and lifestyle factors is essential for public health and hormonal balance studies. This study encompassed 3323 healthy participants from the Croatian biobank.

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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.

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The main goal of this research was to determine whether there is a correlation between adherence to the Mediterranean diet (assessed by the Mediterranean Diet Serving Score (MDSS)) and parameters indicating thyroid gland activity, such as concentration of thyroid-stimulating hormone (TSH), thyroid hormones (free triiodothyronine (fT3), free thyroxine (fT4)), thyroglobulin (Tg), antibodies to thyroid proteins (thyroglobulin antibodies (TgAb) and thyroid peroxidase antibodies (TPOAb)), and calcitonin (CT) in plasma and serum samples. An additional objective was to investigate whether there are differences in the values of the MDSS among clinical groups (euthyroid individuals, euthyroid individuals with positive TgAb and/or TPOAb, and hypothyroid and hyperthyroid participants). This cross-sectional study included 4620 participants over 18 years of age from the islands of Korčula and Vis, and the mainland city of Split.

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Article Synopsis
  • A genome-wide association study was conducted on thyroid function, analyzing data from up to 271,040 European individuals, focusing on hormones like TSH, FT4, and T3.
  • The study identified 259 significant genetic associations for TSH (61% were novel), and notable findings for FT4 and T3, indicating that specific genes influence thyroid hormone levels and metabolism.
  • The research findings enhance the understanding of thyroid hormone roles and suggest that variations in thyroid function may impact various health conditions including cardiovascular issues, autoimmune diseases, and cancer.
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Thyroid cancer is the predominant endocrine-related malignancy. ST6 β-galactoside α2,6-sialyltransferase 1 (ST6GAL1) has been studied in various types of cancers; however, the expression and function of ST6GAL1 in thyroid cancer has not been investigated so far. Previously, we conducted two genome-wide association studies and have identified the association of the gene with plasma thyroglobulin (Tg) levels.

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Laryngeal dystonia (LD), known or termed as spasmodic dysphonia, is a rare movement disorder with an unknown cause affecting the intrinsic laryngeal muscles. Neurophysiological studies point to perturbed inhibitory processes, while conventional genetic studies reveal fragments of genetic architecture in LD. The study's aims are to (1) describe transcranial magnetic stimulation (TMS) methodology for studying the functional integrity of the corticospinal tract by stimulating the primary motor cortex (M1) for laryngeal muscle representation and recording motor evoked potentials (MEPs) from laryngeal muscles; (2) evaluate the results of TMS studies investigating the cortical silent period (cSP) in LD; and (3) present the standard treatments of LD, as well as the results of new theoretical views and treatment approaches like repetitive TMS and laryngeal vibration over the laryngeal muscles as the recent research attempts in treatment of LD.

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Context: Thyroid function has been associated with metabolic syndrome (MetS) in a number of observational studies but the direction of effects and the exact causal mechanism of this relationship is still unknown.

Objective: To examine genetically predicted effects of thyroid function on MetS risk and its components, and vice versa, using large-scale summary genetic association data.

Methods: We performed a two-sample bidirectional Mendelian randomization (MR) study using summary statistics from the most comprehensive genome-wide association studies (GWAS) of thyroid-stimulating hormone (TSH, n = 119 715), free thyroxine (fT4, n = 49 269), MetS (n = 291 107), and components of MetS: waist circumference (n = 462 166), fasting blood glucose (n = 281 416), hypertension (n = 463 010), triglycerides (TG, n = 441 016) and high-density lipoprotein cholesterol (HDL-C, n = 403 943).

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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.

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During development, thyroid hormones play an important role in eye development, while in adults, some pathological thyroid conditions can affect the normal functioning of the eyes. Thyroid eye disease is the most well-known eye pathology caused by a pathological thyroid condition. Few studies have investigated the association between ocular parameters and thyroid function.

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Article Synopsis
  • A decrease in serotonergic transmission is an early sign of Alzheimer's disease (AD) and affects serotonin receptors, impacting behavioral and psychological symptoms in patients.
  • The study analyzed 115 AD patients, 53 with mild cognitive impairment, and 2701 healthy controls to see if specific gene polymorphisms were linked to faster disease progression and AD-related pathology.
  • Findings showed significant associations between certain genetic markers and changes in cerebrospinal fluid biomarkers, as well as poorer cognitive performance, suggesting these polymorphisms may play a role in AD's development and progression.
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Thyroid hormones (THs) play an indispensable role in skeletal development and bone remodeling. Some studies have reported associations of THs with serum osteocalcin (OC) levels, but the results are quite inconsistent and the molecular mechanism of their simultaneous or interdependent activity on bone is almost unknown. Therefore, the aim of this study was to determine the possible associations of plasma THs with plasma OC levels and the possible mediating effect of OC on the relationship between THs and bone mineral density (BMD).

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Focal laryngeal dystonia (LD) is a rare, idiopathic disease affecting the laryngeal musculature with an unknown cause and clinically presented as adductor LD or rarely as abductor LD. The most effective treatment options include the injection of botulinum toxin (BoNT) into the affected laryngeal muscle. The aim of this narrative review is to summarize the patho-neuro-physiological and genetic background of LD, as well as the standard recommended therapy (BoNT) and pharmacological treatment options, and to discuss possible treatment perspectives using neuro-modulation techniques such as repetitive transcranial magnetic stimulation (rTMS) and vibrotactile stimulation.

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Thyroid dysfunction appears to be the leading endocrine disorder. We conducted a cross-sectional study on 4402 individuals from three Croatian cohorts. The aim of this study was to analyse the prevalence of diagnosed and undiagnosed hypothyroidism, hyperthyroidism (subclinical and clinical) and positive thyroid antibodies in the Croatian population.

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Thyroglobulin (Tg) is an iodoglycoprotein produced by thyroid follicular cells which acts as an essential substrate for thyroid hormone synthesis. To date, only one genome-wide association study (GWAS) of plasma Tg levels has been performed by our research group. Utilizing recent advancements in computation and modeling, we apply a Bayesian approach to the probabilistic inference of the genetic architecture of Tg.

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Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied.

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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.

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Objectives: The aim of the study was to analyze the association of dietary groups (groups of food items) with thyroid hormone levels in healthy individuals.

Methods: This cross-sectional study enrolled 4585 healthy individuals from the Dalmatian region of south Croatia with measurements of plasma free triiodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) levels. Dietary intake was assessed according to data of the completed food frequency questionnaire, containing 58 food items.

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Thyroid hormones are necessary for the normal functioning of physiological systems. Therefore, knowledge of any factor (whether genetic, environmental or intrinsic) that alters the levels of thyroid-stimulating hormone (TSH) and thyroid hormones is crucial. Genetic factors contribute up to 65% of interindividual variations in TSH and thyroid hormone levels, but many environmental factors can also affect thyroid function.

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Aim: To analyze the association of thyroid function and hormone levels with metabolic syndrome (MetS) and its components.

Methods: This cross-sectional population-based study involved 2183 Croatian individuals with no history of thyroid disease, hypertension, diabetes, and hyperlipidemia. MetS was diagnosed according to the National Cholesterol Education Program's Adult Treatment Panel III criteria.

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Introduction: Thyroid peroxidase (TPO) and thyroglobulin (Tg) are main components of the thyroid gland and play an essential role in thyroid hormone synthesis. The development of antibodies to thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) is the major diagnostic hallmark and early indicator of autoimmune thyroid disease. TPOAb and TgAb are under strong genetic influence; however, genetic factors that determine thyroid antibody positivity are largely unknown.

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Thyroglobulin (Tg) is a 660 kDa iodoglycoprotein that serves as a scaffold for thyroid hormone synthesis. Although a twin study showed that variability of serum Tg levels has a substantial genetic basis, no genome-wide association study (GWAS) of serum/plasma Tg levels has been performed to date. The aim of this study was to identify genetic variants associated with plasma Tg levels among healthy individuals.

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Thyroid hormones (THs) are key regulators of cellular growth, development, and metabolism. The thyroid gland secretes two THs, thyroxine (T4) and triiodothyronine (T3), into the plasma where they are almost all bound reversibly to plasma proteins. Free forms of THs are metabolically active, however, they represent a very small fraction of total TH levels.

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Although the effect of isolated nutrients on plasma parathyroid hormone (PTH) is somewhat familiar, the effect of multiple nutrients on plasma PTH level has not yet been studied. The aim of this study was to identify groups of food items that are associated with the plasma PTH level in healthy individuals. This cross-sectional study enrolled 1180 healthy individuals from Croatia with plasma PTH levels inside the referent values.

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