Introduction
disorder, bone metabolic disorders, hypothyroidism, T2DM, endocrine disorders, Hypothyroidism
THYROID DISEASE, THYROID DISORDERS, DISORDER, IODINE DEFICIENCY, CARDIOVASCULAR DISEASES, AUTOIMMUNE DISEASES, CHRONIC DISEASES, SUBCLINICAL HYPOTHYROIDISM, AUTOIMMUNE THYROIDITIS, VITAMIN D DEFICIENCY, HYPOTHYROIDISM, TYPE 2 DIABETES MELLITUS, SUBCLINICAL HYPOTHYROIDISM, ENDOCRINE DISORDERS, HYPOTHYROIDISM
Thyroid diseases are one of the most common endocrine disorders in the world (There are numerous thyroid disorders. Hypothyroidism is a pathophysiological phase with insufficient hormone production, resulting in an imbalance in basal metabolic rate and inefficient physiological roles of the body systems (The prevalence of subclinical hypothyroidism in adults is 4–20%, depending on such factors as race, age, and ethnicity. Subclinical hypothyroidism has various causes, including chronic autoimmune thyroiditis, iodine deficiency, etc. The disorder is related to antithyroid peroxidase antibodies in about 60–80% of cases. Subclinical hypothyroidism patients have few signs and symptoms. The presence of antithyroid peroxidase antibodies and female gender are linked with an enhanced risk of progression to overt hypothyroidism. Those with TSH levels higher than 10 mIU/L should be treated, and L-thyroxine is the common treatment in overt hypothyroidism (Vitamin D is a fat-soluble vitamin effective in reducing the risk of chronic diseases, such as bone metabolic disorders, type 2 diabetes mellitus (T2DM), cardiovascular diseases, autoimmune diseases, and hypothyroidism (According to the results of some studies, subjects with subclinical hypothyroidism have a lower serum 25-hydroxyvitamin D3 (25-OH D3) than normal limits, and vitamin D supplementation improves thyroid function by reducing TSH in these patients (Irisin is a hormone mainly synthesized by skeletal muscle and fat tissue. The mRNA of the fibronectin type III domain-containing protein 5 (FNDC5) gene precursor of irisin is found in various tissues, including the thyroid gland and fat tissue. Many researchers have reported its significant effect on metabolism and thermogenesis. Therefore, thyroid function can be directly or indirectly related to the regulation of irisin or, conversely, irisin can affect the thyroid. It was also reported that vitamin D supplementation may affect serum irisin concentrations in subjects with vitamin D deficiency and in T2DM patients (Although vitamin D deficiency has been reported mainly in patients with subclinical hypothyroidism (