The Intricate Relationship Between Thyroid Disorders and Type 2 Diabetes—A Narrative Review

Thyroid disorders (TDs) and diabetes mellitus (DM) represent significant metabolic pathologies with an important global burden. Diabetes, characterized by chronic hyperglycemia, induces widespread dysregulation of lipid, protein, and carbohydrate metabolism. The thyroid gland, a central regulator of endocrine homeostasis, modulates metabolic processes through the secretion of thyroid hormones (THs). A complex bidirectional relationship exists between type 2 diabetes mellitus (T2DM) and thyroid dysfunction, wherein each condition may exacerbate the pathophysiological consequences of the other. At the core of this interplay lies insulin resistance (IR), a fundamental mechanism underlying their coexistence and mutual aggravation. A thorough investigation into the underlying mechanisms of thyroid function could reveal new insights into the development and progression of T2DM. Grasping the clinical correlation between these widespread endocrine disorders is crucial for customizing treatments for individuals confronting both conditions. This narrative review seeks to offer an understanding of the epidemiological, pathophysiological, and clinical dimensions of the relationship between TD and T2DM. Considering the substantial clinical ramifications of concurrent T2DM and TD, it is imperative to institute suitable screening and management approaches for both endocrine disorders to guarantee optimal care for patients.